U.S. patent application number 10/242768 was filed with the patent office on 2003-09-11 for free cutting alloy.
This patent application is currently assigned to Kiyohito ISHIDA. Invention is credited to Ebata, Takashi, Inoguchi, Takayuki, Ishida, Kiyohito, Oikawa, Katsunari, Okabe, Michio, Shimizu, Tetsuya.
Application Number | 20030170138 10/242768 |
Document ID | / |
Family ID | 27792354 |
Filed Date | 2003-09-11 |
United States Patent
Application |
20030170138 |
Kind Code |
A1 |
Ishida, Kiyohito ; et
al. |
September 11, 2003 |
Free cutting alloy
Abstract
Provided is free cutting alloy excellent in machinability,
preserving various characteristics as alloy. The free cutting alloy
contains: one or more of Ti and Zr as a metal element component;
and C being an indispensable element as a bonding component with
the metal element component, wherein a (Ti, Zr) based compound
including one or more of S, Se and Te is formed in a matrix metal
phase. The free cutting alloy is more excellent in machinability,
preserving various characteristics as alloy at similar levels to a
conventional case. The effect is especially conspicuous, for
example, when a compound expressed in a chemical form of (Ti,
Zr).sub.4C.sub.2(S, Se, Te).sub.2 as the (Ti, Zr) based compound is
formed at least in a dispersed state in the alloy structure.
Inventors: |
Ishida, Kiyohito;
(Sendai-shi, JP) ; Oikawa, Katsunari;
(Shibata-gun, JP) ; Ebata, Takashi; (Shibata-gun,
JP) ; Inoguchi, Takayuki; (Tokai-shi, JP) ;
Shimizu, Tetsuya; (Nagoya-shi, JP) ; Okabe,
Michio; (Chita-shi, JP) |
Correspondence
Address: |
Ronald R, Snider
Snider & Associates
P.O. Box 27613
Washington
DC
20038-7613
US
|
Assignee: |
Kiyohito ISHIDA
Sendai-shi
JP
|
Family ID: |
27792354 |
Appl. No.: |
10/242768 |
Filed: |
September 13, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10242768 |
Sep 13, 2002 |
|
|
|
09653344 |
Aug 31, 2000 |
|
|
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Current U.S.
Class: |
420/70 |
Current CPC
Class: |
C22C 38/105 20130101;
C22C 19/057 20130101; C22C 19/055 20130101; C22C 38/28 20130101;
C22C 38/40 20130101; C22C 38/52 20130101; C22C 19/058 20130101;
C22C 38/06 20130101; C22C 38/60 20130101 |
Class at
Publication: |
420/70 |
International
Class: |
C22C 038/28 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 1999 |
JP |
11-250902 |
Mar 14, 2000 |
JP |
2000-070257 |
Jul 21, 2000 |
JP |
2000-221433 |
Aug 22, 2000 |
JP |
2000-251602 |
Aug 22, 2000 |
JP |
2000-251626 |
Claims
What is claimed is:
1. Free cutting alloy constituted as ferrite containing stainless
steel containing: 2 mass % or lower, including zero, Ni; 12 to 35
mass % Cr; and 0.021 to 0.4 mass % C; one or more of Ti and Zr such
that W.sub.Ti+0.52 W.sub.Zr=0.14 to 3.5 mass %, wherein W.sub.Ti
and W.sub.Zr denote respective contents in mass % of Ti and Zr; and
one or more of S and Se in the respective ranges of 0.01 to 1 mass
% for S and 0.01 to 0.8 mass % for Se so that the total amount of S
content; wherein S content is determined such that a value of
W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less, wherein W.sub.S
demotes a S content; and wherein a (Ti, Zr) based compound
containing one or more of Ti and Zr as a metal element component, C
being an indispensable element as a bonding component with the
metal element component, and one or more of S, Se and Te is
dispersed in a matrix metal phase.
2. Free cutting alloy according to claim 1, the W.sub.so value of
which is less than 0.035 mass % when the following test is
performed: an alloy test piece is prepared so as to have the shape
of a rectangular prism in size of 15 mm in length, 25 mm in width
and 3 mm in thickness with the entire surface being polished with
No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm
in width and 0.1 mm in thickness with a purity of 99.9% or higher
as a S getter and 0.5 cc of pure water are sealed in a vessel of an
inner volume of 250 cc together with said test piece; a temperature
in said vessel is raised to 85.degree. C. and said temperature is
then kept there for 20 hr; and thereafter, a S content W.sub.SO in
mass % in said silver foil piece is analyzed.
3. Free cutting alloy according to claim 1, containing 2 mass % or
lower Si; 2 mass % or lower Mn; 2 mass % or lower Cu; and 2 mass %
or lower Co.
4. Free cutting alloy according to claim 1, containing one or more
of Mo and W in the respective ranges of 0.1 to 4 mass % for Mo and
0.1 to 3 mass % for W.
5. Free cutting alloy according to claim 1, containing: 0.05 mass %
or lower P; and 0.03 mass % 0; and 0.05 mass % or lower N.
6. Free cutting alloy according to claim 1, containing one or more
of Te, Bi and Pb in the respective ranges of 0.005 to 0.1 mass %
for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass % for
Pb.
7. Free cutting alloy according to claim 1, containing one or more
selected from the group consisting of Ca, Mg, B and metal elements
classified as Group 3A in the periodic table of elements in the
range of 0.0005 to 0.01 mass % for one element or as a total
content of more than one elements combined.
8. Free cutting alloy according to claim 1, containing one or more
selected from the group consisting of Nb, V, Ta and Hf each of
which is in a range of 0.01 to 0.5 mass %.
9. Free cutting alloy constituted as martensite containing
stainless steel containing: 2 mass % or lower, including zero, Ni;
9 to 17 mass % Cr; one or more of Ti and Zr such that W.sub.Ti+0.52
W.sub.Zr=0.03 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Zr; and one or more of S
and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01
to 0.8 mass % for Se; and 0.19 mass % or more of C so as to satisfy
the following formulae: 0.375 (W.sub.S+0.4 W.sub.Se
)<W.sub.C.ltoreq.1.5 (Formula A) 0.125 (W.sub.Ti+0.52
W.sub.Zr)<W.sub.C<1.5 (Formula B) , wherein W.sub.Ti,
W.sub.Zr W.sub.C, W.sub.S and W.sub.Se denote respective contents
of Ti, Zr, C, S and Se, all in mass %; and wherein a (Ti, Zr) based
compound containing one or more of Ti and Zr as a metal element
component, C being an indispensable element as a bonding component
with the metal element component, and one or more of S, Se and Te
is dispersed in a matrix metal phase.
10. Free cutting alloy according to claim 9 whose S content is
determined such that a value of W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is
0.45 or less, wherein W.sub.S demotes a S content.
11. Free cutting alloy according to claim 10, the W.sub.so value of
which is less than 0.035 mass % when the following test is
performed: an alloy test piece is prepared so as to have the shape
of a rectangular prism in size of 15 mm in length, 25 mm in width
and 3 mm in thickness with the entire surface being polished with
No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm
in width and 0.1 mm in thickness with a purity of 99.9% or higher
as a S getter and 0.5 cc of pure water are sealed in a vessel of an
inner volume of 250 cc together with said test piece; a temperature
in said vessel is raised to 85.degree. C. and said temperature is
then kept there for 20 hr; and thereafter, a S content W.sub.SO in
mass % in said silver foil piece is analyzed.
12. Free cutting alloy according to claim 9 further containing: 2
mass % or lower Si; 2 mass % or lower Mn; 2 mass % or lower Cu; and
2 mass % or lower Co.
13. Free cutting alloy according to claim 9 further containing one
or more of Mo and W in the respective ranges of 0.1 to 4 mass % for
Mo and 0.1 to 3 mass % for W.
14. Free cutting alloy according to claim 9 further containing:
0.05 mass % or lower P; and 0.03 mass % or lower O; and 0.05 mass %
or lower N.
15. Free cutting alloy according to claim 9 further containing one
or more of Te, Bi and Pb in the respective ranges of 0.005 to 0.1
mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass %
for Pb.
16. Free cutting alloy according to claim 9 further containing one
or more selected from the group consisting of Ca, Mg, Band metal
elements classified as Group 3A in the periodic table of elements
in the range of 0.0005 to 0.01 mass % for one element or as a total
content of more than one elements combined.
17. Free cutting alloy according to claim 9 further containing one
or more selected from the group consisting of Nb, V, Ta and Hf each
of which is in a range of 0.01 to 0.5 mass %.
18. Free cutting alloy constituted as austenite iron containing
alloy containing: 2 to 50 mass % Ni; 12 to 50 mass % Cr; 5 to
85.926 mass % Fe; 0.021 to 0.4 mass % C. one or more of Ti and Zr
such that W.sub.Ti+0.52 W.sub.Zr=0.03 to 3.5 mass %, wherein
W.sub.Ti and W.sub.Zr denote respective contents in mass % of Ti
and Zr; and one or more of S and Se in the respective ranges of
0.01 to 1 mass % for S and 0.01 to 0.8 mass % for Se so that the
total amount of S and Se is more than the C content; and wherein a
(Ti, Zr) based compound containing one or more of Ti and Zr as a
metal element component, C being an indispensable element as a
bonding component with the metal element component, and one or more
of S, Se and Te is dispersed in a matrix metal phase.
19. Free cutting alloy according to claim 18 whose S content is
determined such that a value of W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is
0.45 or less, wherein W.sub.S and W.sub.C demote a S content and a
C content, respectively.
20. Free cutting alloy according to claim 19, the W.sub.so value of
which is less than 0.035 mass % when the following test is
performed: an alloy test piece is prepared so as to have the shape
of a rectangular prism in size of 15 mm in length, 25 mm in width
and 3 mm in thickness with the entire surface being polished with
No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm
in width and 0.1 mm in thickness with a purity of 99.9% or higher
as a S getter and 0.5 cc of pure water are sealed in a vessel of an
inner volume of 250 cc together with said test piece; a temperature
in said vessel is raised to 85.degree. C. and said temperature is
then kept there for 20 hr; and thereafter, a S content W.sub.SO in
mass % in said silver foil piece is analyzed.
21. Free cutting alloy according to claim 18 further containing: 4
mass % or lower Si; 4 mass % or lower Mn; 4 mass % or lower Cu; and
4 mass % or lower Co.
22. Free cutting alloy according to claim 18 further containing one
or more of Mo and W in the respective ranges of 0.1 to 10 mass %
for Mo and 0.1 to 10 mass % for W.
23. Free cutting alloy according to claim 18 further containing:
0.05 mass % or lower P; and 0.03 mass % or lower O; and 0.05 mass %
or lower N.
24. Free cutting alloy according to claim 18 further containing one
or more of Te, Bi and Pb in the respective ranges of 0.005 to 0.1
mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass %
for Pb.
25. Free cutting alloy according to claim 18 further containing one
or more selected from the group consisting of Ca, Mg, B and metal
elements classified as Group 3A in the periodic table of elements
in the range of 0.0005 to 0.01 mass % for one element or as a total
content of more than one elements combined.
26. Free cutting alloy according to claim 18 further containing one
or more selected from the group consisting of Nb, V, Ta and Hf each
of which is in a range of 0.01 to 0.5 mass %.
27. Free cutting alloy constituted as electromagnetic stainless
steel containing: 0.01 to 3, the upper limit not included, mass %
Si; 2 mass % or lower Mn; to 25 mass % Cr; 0.01 to 5, the lower
limit not included, mass % Al; one or more of Ti and Zr so that X
defined by the following formula 1 is in the range of 0.05 to 0.5
mass %; C in the range of 0.02 X to 0.06 X mass %, wherein X is
expressed by the following formula 1; one or more of S, Se and Te
in the range of (Z-0.07)X to (Z+0.07)X mass %, wherein X, Z and Y
are values of the respective following formulae 1, 3 and 2; Ti
%+0.52 Zr %=X (Formula 1) S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3) Fe being the main component of
the alloy; inevitable impurities; wherein Pb content is less than
0.01 mass %; and wherein a (Ti, Zr) based compound containing one
or more of Ti and Zr as a metal element component, C being an
indispensable element as a bonding component with the metal element
component, and one or more of S, Se and Te is dispersed in a matrix
metal phase.
28. Free cutting alloy according to claim 27 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
29. Free cutting alloy according to claim 27 further containing one
or more selected from the group consisting of B and metal elements
classified as Group 3A in the periodic table of elements in the
respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or
lower for one or more of metal elements classified as Group 3A in
the periodic table of elements in total.
30. Free cutting alloy according to claim 29 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
31. Free cutting alloy constituted as electromagnetic stainless
steel containing: 0.01 to 3, the upper limit not included, mass %
Si; 2 mass % or lower Mn; to 25 mass % Cr; 0.01 to 5, the lower
limit not included, mass % Al; one or more of Ti and Zr so that X
defined by the following formula 1 is in the range of 0.05 to 0.5
mass %; C in the range of 0.19 X to 0.26 X mass %, wherein X is
expressed by the following formula 1; one or more of S, Se and Te
in the range of (Z-0.07)X to (Z+0.07)X mass %, wherein X, Z and Y
are values of the respective following formulae 1, 3 and 2; Ti
%+0.52 Zr %=X (Formula 1) %+0.41 Se %+0.25 Te %=Y (Formula 2) 32(C
%/X-0.125).sup.2=Z (Formula 3) Fe being the main component of the
alloy; inevitable impurities; and wherein a (Ti, Zr) based compound
containing one or more of Ti and Zr as a metal element component, C
being an indispensable element as a bonding component with the
metal element component, and one or more of S, Se and Te is
dispersed in a matrix metal phase.
32. Free cutting alloy according to claim 31 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
33. Free cutting alloy according to claim 31 further containing one
or more selected from the group consisting of Pb, B and metal
elements classified as Group 3A in the periodic table of elements
in the respective ranges of 0.15 mass % or lower for Pb, 0.01 mass
% or lower for B; and 0.1 mass % or lower for one or more of metal
elements classified as Group 3A in the periodic table of elements
in total.
34. Free cutting alloy according to claim 31 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
35. Free cutting alloy constituted as electromagnetic stainless
steel containing: 0.01 to 3, the upper limit not included, mass %
Si; 2 mass % or lower Mn; to 25 mass % Cr; 0.01 to 5, the lower
limit not included, mass % Al; one or more of Ti and Zr so that X
defined by the following formula 1 is in the range of 0.05 to 0.5
mass %; C in the range of 0.02 X to 0.26 X mass %, wherein X is
expressed by the following formula 1; one or more of S, Se and Te
in the range of (Z+0.07)X to (Z+0.45)X mass %, wherein X, Z and Y
are values of the respective following formulae 1, 3 and 2; Ti
%+0.52 Zr %=X (Formula 1) S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3) Fe being the main component of
the alloy; inevitable impurities; wherein Pb content is less than
0.01 mass %; and wherein a (Ti, Zr) based compound containing one
or more of Ti and Zr as a metal element component, C being an
indispensable element as a bonding component with the metal element
component, and one or more of S, Se and Te is dispersed in a matrix
metal phase.
36. Free cutting alloy according to claim 35 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
37. Free cutting alloy according to claim 35 further containing one
or more selected from the group consisting of B and metal elements
classified as Group 3A in the periodic table of elements in the
respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or
lower for one or more of metal elements classified as Group 3A in
the periodic table of elements in total.
38. Free cutting alloy according to claim 35 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
39. Free cutting alloy constituted as electromagnetic stainless
steel containing: 0.01 to 3, the upper limit not included, mass %
Si; 2 mass % or lower Mn; to 25 mass % Cr; 0.01 to 5, the lower
limit not included, mass % Al; one or more of Ti and Zr so that X
defined by the following formula 1 is in the range of 0.05 to 0.5
mass %; C in the range of 0.02 X to 0.26 X mass %, wherein X is
expressed by the following formula 1; one or more of S, Se and Te
in the range of (Z+0.45)X to (Z+0.70)X mass %, wherein X, Z and Y
are values of the respective following formulae 1, 3 and 2; Ti
%+0.52 Zr %=X (Formula 1) S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3) Fe being the main component of
the alloy; inevitable impurities; and wherein a (Ti, Zr) based
compound containing one or more of Ti and Zr as a metal element
component, C being an indispensable element as a bonding component
with the metal element component, and one or more of S, Se and Te
is dispersed in a matrix metal phase.
40. Free cutting alloy according to claim 39 further containing one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
41. Free cutting alloy containing 20 to 82 mass % Ni and the part
except for Ni of which is mainly constituted by one or more of Fe
and Cr further containing: one or more of Ti and Zr so that X
defined by the following formula 1 in the range satisfying a
relation of 0.05.ltoreq.X.ltoreq.3; one or more of S, Se and Te so
that Y defined by the following formula 2 in the range satisfying a
relation of 0.014.ltoreq.Y.ltoreq.0.5 X; C in the range satisfying
a relation of 0.2 Y.ltoreq.W.sub.C.ltoreq.0.3, wherein when a Ti
content is indicated by W.sub.Ti in mass %, a Zr content by
W.sub.Zr in mass %, a C content by W.sub.C in mass %, a S content
by W.sub.S in mass %, a Se content by W.sub.Se in mass % and a Te
content by W.sub.Te in mass %, the following formulae 1 and 2 are
given in order to define X and Y: X (mass %)=W.sub.Ti+0.52 W.sub.Zr
(formula 1) Y (mass %)=W.sub.S+0.41 W.sub.Se+0.25 W.sub.Te (formula
2); one or more of Si, Mn and Al in the respective ranges of 1 mass
% for Si, 1 mass % for Mn and 1 mass % for Al; wherein a (Ti, Zr)
based compound containing one or more of Ti and Zr as a metal
element component, C being an indispensable element as a bonding
component with the metal element component, and one or more of S,
Se and Te is dispersed in a matrix metal phase.
42. Free cutting alloy according to claim 41 further containing one
or more of Mo and Cu in the respective ranges of 7 mass % or lower
for Mo and 7 mass % or lower for Cu.
43. Free cutting alloy according to claim 41 further containing 12
mass % or lower Cr.
44. Free cutting alloy according to claim 41 further containing 18
mass % or lower Co.
Description
BACKGROUND ART
[0001] The present invention relates to free cutting alloy
excellent in machinability.
[0002] Alloy has widespread applications because of a variety of
characteristics thereof. A free cutting alloy excellent in
machinability is, in a case, selected for improvement of
productivity. In order to improve machinability, for example, free
cutting alloy containing an element improving machinability such as
S, Pb, Se or Bi (hereinafter referred to as machinability-improving
element) is widely used. Especially in a case where machinability
is particularly required because of precise finishing in machining
or for other reasons, not only is a content of such a
machinability-improving element increased in an alloy, but the
elements are also added to an alloy in combination.
[0003] While S, which has widely been used for improvement of
machinability, is in many cases added in the form of MnS, addition
thereof in an alloy in a large content is causes for degrading
corrosion resistivity, hot workability and cold workability of the
alloy. Moreover, when the alloy is exposed to the air, a sulfur
component included in the alloy is released into the air in the
form of a sulfur containing gas, which causes sulfur contamination
in peripheral areas of parts with ease. Therefore, there arises a
necessity of suppressing release of sulfur containing gas
(hereinafter referred to as improvement on out-gas resistivity).
Elements such as S. Se and Te, however, deteriorate magnetic
properties to a great extent in an electromagnetic stainless steel
and the like.
[0004] Therefore, various proposals have been made: a Mn content is
limited, a Cr content in sulfide is increased or in a case where S
is contained, Ti is added in combination with S in order to
disperse sulfide in the shape of a sphere (for example, see
JP-A-98-46292 or JP-A-81-16653). To increase a Cr content in
sulfide, however, tends to greatly decrease in machinability and
hot workability and therefore, such an alloy has been restricted on
its application in many cases.
[0005] Although such prior arts as JP11-140597 ('597), JP10-130794
('794), JP2-170948 ('948), JP63-93843 ('843), JP60-155653 ('653)
and U.S. Pat. No. 4,969,963 (Hoinkura et al.) disclose various free
cutting alloys, these alloys are not satisfactory in machinability,
sulfur out-gassing characteristics and elimination of Pb
content.
[0006] It is accordingly an object of the present invention is to
provide free cutting alloy excellent in machinability, showing
outstanding characteristics as an alloy such as corrosion
resistivity, hot workability and cold workability or specific
magnetic characteristics, which are comparable to those of
conventional alloys.
SUMMARY OF THE INVENTION
[0007] In order to achieve the above described object, a free
cutting alloy of the present invention is characterized by that the
free cutting alloy contains: one or more of Ti and Zr as a metal
element component; and C being an indispensable element as a
bonding component with the metal element component, wherein a (Ti,
Zr) based compound including one or more of S, Se and Te is formed
in a matrix metal phase.
[0008] Machinability of an alloy can be improved by forming the
above described (Ti, Zr) based compound in a matrix metal phase of
the alloy. Furthermore, by forming this compound in the alloy,
formation of compounds such as MnS and (Mn, Cr)S, easy to reduce
corrosion resistivity and hot workability of the alloy, can be
prevented or suppressed, thereby enabling corrosion resistivity,
hot workability and cold workability to be retained at good levels.
That is, according to the present invention, a free cutting alloy
excellent in machinability can be realized without any degradation
in useful characteristics as an alloy such as hardness, corrosion
resistivity, hot workability, cold workability and specific
magnetic characteristics.
[0009] Further, a (Ti, Zr) based compound formed in a free cutting
alloy of the present invention can be dispersed in the alloy
structure. Especially dispersing the compound in an alloy structure
can further increase machinability of an alloy. In order to
increase the effect, a particle size of the (Ti, Zr) based compound
as observed in the structure of a polished section of the alloy is
preferably, for example, approximately in the range of 0.1 to 30
.mu.m on the average and further, an area ratio of the compound in
the structure is preferably in the range of 1 to 20%, wherein the
particle size is defined by the maximum distance between two
parallel lines circumscribing a particle in observation when
parallel lines are drawn intersecting on a region including the
particle in observation while changing a direction of the parallel
lines.
[0010] The above described (Ti, Zr) based alloy can include at
least a compound expressed in a composition formula (Ti, Zr) 4 (S,
Se, Te).sub.2C.sub.2 (hereinafter also referred to as
carbo-sulfide/selenide)- , wherein one or more of Ti and Zr may be
included in the compound and one or more of S, Se and Te may be
included in the compound. By forming a compound in the form of the
above described composition formula, not only can machinability of
an alloy be improved, but corrosion resistivity is also
improved.
[0011] It should be appreciated that identification of a (Ti, Zr)
based compound in an alloy can be performed by X-ray diffraction
(for example, a diffractometer method), an electron probe
microanalysis method (EPMA) and the like technique. For example,
the presence or absence of the compound of (Ti, Zr).sub.4 (S, Se,
Te).sub.2C.sub.2 can be confirmed according to whether or not a
peak corresponding to the compound appear in a diffraction chart
measured by an X-ray diffractometer. Further, a region in the alloy
structure in which the compound is formed can also be specified by
comparison between two-dimensional mapping results on
characteristic X-ray intensities of Ti, Zr, S, Se or C obtained
from a surface analysis by EPMA conducted on a section structure of
the alloy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a graph showing compositional regions in
combination of a content of one or more of Ti and Zr, a content of
C and a content of one or more of S, Se and Te in a free cutting
alloy of the present invention constituted as electromagnetic
stainless alloy;
[0013] FIG. 2 is a graph showing an X-ray diffraction chart of an
inventive steel specimen No. 5 in experiment of Example 1;
[0014] FIG. 3 is an optical microphotograph of the inventive steel
specimen No. 5 in Example 1;
[0015] FIG. 4 is a graph showing EDX analytical results of a second
selection inventive specimen No. 2 in Example 2;
[0016] FIGS. 5A and 5B are optical microphotograph of second
selection inventive steels specimen Nos. 2 and 13 in Example 2;
[0017] FIG. 6 is a representation describing measuring points for a
hardness test in Example 2;
[0018] FIG. 7 is a graph showing an example of Schaeffler
diagram;
[0019] FIGS. 8A and 8B are graphs showing EDX analytical results of
a third selection inventive steel specimen No. 2 in experiment of
Example 3;
[0020] FIG. 9 is an optical microphotograph of the third selection
inventive steel No. 2 in Example 3;
[0021] FIG. 10 is a graph showing a relation between B1 or Hc and
.alpha. in Example 4;
[0022] FIG. 11 is a graph showing a relation between a boring time
or a cracking threshold working ratio and .alpha. in Example 4;
[0023] FIG. 12 is a graph showing a relation between a pitting
potential and .alpha. in Example 4;
[0024] FIG. 13 is a graph showing dependencies of solubility
products on temperature of components of TiO, TiN,
Ti.sub.4C.sub.2S.sub.2, TiC, TiS and CrS in .gamma.-Fe;
[0025] FIG. 14 is an optical microphotograph of a fifth selection
inventive steel specimen No. 30 in Example 5;
[0026] FIG. 15 is a graph showing a relation between a range of
parameters of X and Y and evaluation results on hot workability in
Example 5;
[0027] FIG. 16 is a graph showing a relation between a drill boring
time and Y in mass % of an alloy in Example 5;
[0028] FIG. 17 is a graph showing compositional regions of the
present invention constituted as electromagnetic stainless alloy
with alloy compositions in prior arts.
PREFERRED EMBODIMENTS OF THE INVENTION
[0029] A free cutting alloy constituted as stainless steel of the
present invention can be, to be more detailed, ferrite containing
stainless steel (hereinafter referred to as a first selection
invention (claim 1)). In this case, a composition of the free
cutting alloy of the present invention is as follows:
[0030] The free cutting alloy contains:
[0031] 2 mass % or lower, including zero, Ni; 12 to 35 mass % Cr;
and 0.021 to 0.4 mass % C;
[0032] one or more of Ti and Zr such that W.sub.Ti+0.52
W.sub.Zr=0.14 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Zr; and one or more of S
and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01
to 0.8 mass % for Se so that the total amount of S content;
[0033] wherein S content is determined such that a value of
W.sub.S/(W.sub.Ti+0. 52W.sub.Zr) is 0.45 or less, wherein W.sub.S
demotes a S content;
[0034] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0035] The reason why the constituting elements and contents
thereof in the first selection invention constituted as ferrite
containing stainless steel are determined is as follows:
[0036] (1) The Ti content being defined such that W.sub.Ti+0.52
W.sub.Zr=0.14 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Z
[0037] Ti and Zr are indispensable elements for forming a (Ti, Zr)
based compound playing a central role in exerting the effect of
improving machinability of a free cutting alloy of the present
invention. In the ferrite containing stainless steel as the first
selection of this invention, when a value of W.sub.Ti+0.52 W.sub.Zr
is lower than 0.14 mass %, the (Ti, Zr) based compound is
insufficiently formed in amount, thereby disabling the effect of
improving machinability to be satisfactorily exerted. On the other
hand, when in excess of the value, machinability is reduced on the
contrary. For this reason, the value of W.sub.Ti+0.52 W.sub.Zr is
required to be suppressed to 3.5 mass % or lower. The above effect
exerted when Ti and Zr are added into an alloy is determined by the
sum of the numbers of atoms (or the sum of the numbers of values in
mol), regardless of kinds of metals, Ti or Zr. Since a ratio
between atomic weights is almost 1:0.52, Ti of a smaller atomic
weight exerts a larger effect with a smaller mass. Thus, a value of
W.sub.Ti+0.52 W.sub.Zr is said to be compositional parameter
reflects the sum of the numbers of atoms of Zr and Ti included in
an alloy.
[0038] (2) One or more of S and Se in the respective ranges of 0.01
to 1.0 mass % for S and 0.01 to 0.8 mass % for Se
[0039] S and Se are elements for useful in improving machinability.
By adding S and Se into an alloy, in an alloy structure, formed is
a compound useful for improving machinability (for example, a (Ti,
Zr) based compound expressed in the form of a composition formula
(Ti, Zr).sub.4 (S, Se).sub.2C.sub.2). Therefore, contents of S and
Se are specified 0.01 mass % as the lower limit. When the contents
are excessively large, there arises a chance to cause a problem of
deteriorating hot workability and therefore, there have to be the
upper limits: It is preferable that a S content is set to 1 mass %
and a Se content is set to 0.8 mass % as the respective upper
limits. Further, S and Se are both desirably added into an alloy in
a necessary and sufficient amount in order to form a compound
improving machinability of the alloy, such as the above described
(Ti, Zr) based compound, and from this viewpoint, a total content
in mass % of S and Se is preferably set to a value higher than two
times a C content in mass %. An excessive addition of S results in
deterioration of the out-gas resistivity.
[0040] (3) 0.021 to 0.4 mass % C
[0041] C is an important element forming a compound improving
machinability. When a content thereof is lower than 0.021 mass %,
however, an effect exerting sufficient machinability can not be
imparted to the alloy, while when in excess of 0.4 mass %, much of
a single carbide not effective for improving machinability is
formed. Addition of C is preferably set in the range of 0.021 to
0.1 mass %, wherein it is preferable that addition of C is adjusted
so properly that the effect of imparting machinability on the alloy
is optimized depending on an amount of a constituting element of a
compound improving machinability such as a (Ti, Zr) based
compound.
[0042] (4) 2 mass % or lower Ni
[0043] Ni can be added according to a necessity since the element
is effective for improving corrosion resistivity, particularly in
an environment of a reducing acid. Excessive addition, however, not
only reduce stability of a ferrite phase, but also causes cost-up
and therefore, a content thereof has the upper limit of 2 mass %,
wherein a case of no addition of Ni may be included.
[0044] (5) 12 to 35 mass % Cr
[0045] Cr is an indispensable element for ensure corrosion
resistivity and is added in the range of 12 mass % or higher. On
the other hand, excessive addition is not only harmful to hot
workability but also causes reduction in toughness and therefore
the upper limit is set to 35 mass %.
[0046] While a factor determining out-gas resistivity of a material
mainly is a composition of the material, since a S component
dissolved in an Fe based matrix constituting stainless steel tends
to gather at grain boundaries, it is desirable to fix S as
carbo-sulfides of Ti and Zr for improvement on out-gas resistivity
of the material. For the purpose, an S content should be determined
such that a value of W.sub.S/(W.sub.Ti+0. 52W.sub.Zr) is 0.45 or
less, or alternatively a value of W.sub.S/W.sub.C is 0.4 or less
and W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less, wherein
W.sub.S and W.sub.C demote an S content and a C content,
respectively. With such a range of components adopted, an S content
dispersed in the matrix metal phase (Fe-based matrix phase) can be
limited and thereby, the out-gas resistivity of the matrix metal
phase of stainless steel is improved.
[0047] A free cutting alloy of the present invention constituted as
stainless steel can be martensite containing stainless steel
(hereinafter referred to a second selection invention (claim 9)).
In this case a composition of the free cutting alloy of the present
invention is as follows:
[0048] 2 mass % or lower, including zero, Ni; 9 to 17 mass %
Cr;
[0049] one or more of Ti and Zr such that W.sub.Ti+0.52
W.sub.Zr=0.03 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Zr; and one or more of S
and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01
to 0.8 mass % for Se;
[0050] and 0.19 mass % or more of C so as to satisfy the following
formulae:
0.375 (W.sub.S+0.4 W.sub.Se)<W.sub.C.ltoreq.1.5 (Formula A)
0.125 (W.sub.Ti+0.52 W.sub.Zr)<W.sub.C.ltoreq.1.5 (Formula
B)
[0051] , wherein W.sub.Ti, W.sub.Zr W.sub.C, W.sub.S and W.sub.Se
denote respective contents of Ti, Zr, C, S and Se, all in mass
%;
[0052] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0053] Martensitic stainless steel is in more of cases used in
equipment and parts requiring hardness and corrosion resistivity as
performances. Since martensitic stainless steel increases hardness
thereof by a quenching heat treatment, there was a case where
machining was performed in an annealed state and thereafter,
quenching and tempering were performed, such that workability was
improved. However, in the case, strain was produced in stainless
steel by a quenching heat treatment and thereby, machining had to
be, in a case, performed after a quenching heat treatment when
precision processing was intended. Furthermore, when in order to
increase machinability, machinability improving elements such as S,
Se, Pb and Bi were added into a stainless steel, there arose a
problem specific to martensite containing stainless steel since not
only corrosion resistivity, hot workability and the like but
quenchability were also deteriorated, thereby disabling sufficient
hardness to be acquired. It should be appreciated that martensite
containing stainless steel is a generic name for stainless steel
forming a martensitic phase in the matrix by a quenching heat
treatment.
[0054] As examples of compositions of the martensite containing
stainless steel: there can be named: corresponding kinds of
stainless steel, such as SUS 403, SUS 410, SUS 410S, SUS 420J1, SUS
420J2, SUS 429J1, SUS 440A and the like, all shown within JISG4304.
Moreover, it should be appreciated that in the present invention,
martensitic heat resisting steel is handled as conceptually
included in martensite containing stainless steel. As examples of
composition of martensitic heat resisting steel, there can be named
corresponding kinds of steel whose compositions are defined in JIS
G 4311 and G 4312, such as SUS 1, SUS 3, SUS 4, SUS 11, SUS 600 and
SUS 616. However, neither of elements Ti, Zr, S and Se as essential
features of the present invention is naturally expressed in
compositions described in the standard. In this case, it should be
understood that part of Fe content of each of the above described
kinds of stainless steel is replaced with the above described
elements in the respective above described compositions and thereby
martensite containing stainless steel of the present invention is
obtained. Therefore, while in description of the present
specification, the same JIS Nos. are used, those actually means
alloys specific to the present invention, which alloys have
compositions defined in JIS standards as a base only.
[0055] Since martensite containing stainless steel changes a
martensitic transformation temperature (Ms point) and quenchability
depending on components included therein, attention has to be paid
to ranges of the components in content. For this reason, the ranges
of components in content of a (Ti, Zr) based compound described
above are required to be set considering the following conditions:
First, contents of components are desirably determined such that a
(Ti, Zr) based compound is not formed so excessively that a
martensitic formation temperature (Ms point) and quenchability are
affected. Since atoms included in the (Ti, Zr) based compound
exerts almost no influence on characteristics of the stainless
steel, such as a hardness of the martensitic phase and
quenchability thereof, it is considered that the elements left
behind by excluding the amount of the elements included in the (Ti,
Zr) based compound from the elements added originally in the
martensite containing stainless steel (hereinafter referred to as
residual elements) are dissolved as solid solution in the matrix
phase and the residual elements exert an influence on martensitic
transformation. Accordingly, ranges in content of the respective
elements are preferably set, considering an influence on
martensitic transformation using a continuous cooling
transformation diagram of stainless steel having a composition
analogous to a composition of the residual elements. Especially,
since C has a great influence on martensitic transformation, a C
content is adjusted such that the above described formulae A and B
are satisfied so as to be 0.19 mass % or more. As a result, not
only is machinability is improved, but hardness after quenching,
quenchability and the like become compatible with conventional
martensite containing stainless steel.
[0056] Below, description will be given of the reason why the
components and contents thereof in the second selection invention
of the present invention constituted as martensite containing
stainless steel are selected and limited as follows:
[0057] (1)' The Ti content being defined such that W.sub.Ti+0.52
W.sub.Zr=0.03 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Z
[0058] In the martensite containing stainless steel as the second
selection of this invention, when a value of W.sub.Ti+0.52 W.sub.Zr
is lower than 0.03 mass %, the (Ti, Zr) based compound is
insufficiently formed in amount, thereby disabling the effect of
improving machinability to be satisfactorily exerted. On the other
hand, when in excess of the value, machinability is reduced on the
contrary. For this reason, the value of W.sub.Ti+0.52 W.sub.Zr is
required to be suppressed to 3.5 mass % or lower.
[0059] (6) 2 mass % or lower Ni
[0060] Ni can be added according to a necessity since the element
is effective for improving corrosion resistivity, particularly in
an environment of a reducing acid. Excessive addition, however, not
only reduces a martensitic transformation temperature (Ms
temperature), but also increases stability of an austenitic phase
of the matrix phase excessively, whereby a case arises in which an
amount of martensite necessary to ensure hardness is hard to be
obtained. Moreover, hardness after annealing becomes high producing
a solid solution hardening effect caused by Ni in excess, which
sometimes makes performances such as machinability decrease. For
the above described reason, a Ni content has the upper limit of 2
mass %.
[0061] (7) 9 to 17 mass % Cr
[0062] Cr is an indispensable element for ensuring corrosion
resistivity and added 9 mass % or higher in content. However, when
a content is in excess of 17 mass %. Phase stability is
deteriorated and thereby high temperature brittleness occurs with
ease, leading to poor hot workability. Moreover, it is considered
that as the content increases, toughness decreases. Especially,
when a stainless steel including Cr in excess receives a long heat
treatment at a temperature in the intermediate range of 400 to
450.degree. C., toughness at room temperature is lost with ease. A
Cr content is desirably set in the range of 11 to 15 mass % and
more desirably in the range of 12 to 14 mass %.
[0063] Also in the second selection of this invention, the S
content is desirably determined such that a value of
W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less, or alternatively a
value of W.sub.S/W.sub.C is 0.4 or less and
W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less. With such a range
of components adopted, the out-gas resistivity of the matrix metal
phase of stainless steel can be improved.
[0064] Further, free cutting alloys of the first and second
selection inventions of the present invention constituted as
ferrite containing stainless steel and martensite containing
stainless steel, respectively, can contain: 2 mass % or lower Si; 2
mass % or lower Mn; 2 mass % or lower Cu; and 2 mass % or lower Co.
In addition, the free cutting alloys can further contain one or
more of Mo and W in the respective ranges of 0.1 to 4 mass % for Mo
and 0.1 to 3 mass % for W.
[0065] Description will be given of the reason why the elements and
contents thereof are defined as follows:
[0066] (8) 2 mass % or lower Si
[0067] Si is added as a deoxidizing agent for steel. That Si is
added in excess, however, is unfavorable because not only cold
workability is deteriorated, but formation of a ferrite increases
in amount, thereby degrading hot workability of steel. Moreover, an
Ms point decreases in excess in a case of martensite containing
stainless steel. Consequently, a Si content has the upper limit of
2 mass %. In a case where cold workability is particularly regarded
as important, the Si content is preferably set 0.5 mass % or
lower.
[0068] (9) 2 mass % or lower Mn
[0069] Mn acts a deoxidizing agent for steel. In addition, since a
compound useful for increase in machinability in co-existence with
S or Se, there arises a necessity of addition when machinability is
highly thought of. On the other hand, since MnS especially
deteriorates corrosion resistivity, affects cold workability
adversely and moreover, reduces a Ms point excessively in
martensite containing stainless steel, therefore a Mn content has
the upper limit of 2 mass %. Especially when cold workability is
regarded as important, an Mn content is desirably limited to 0.4
mass % or lower.
[0070] (10) 2 mass % or lower Cu
[0071] Cu can be added according to a necessity since the element
is effective for improving corrosion resistivity, particularly in
an environment of a reducing acid. It is preferable to contain 0.3
mass % or higher in order to obtain a more conspicuous effect of
the kind. When in excess, however, not only does hot workability
decrease, but in martensite containing stainless steel, a Ms point
decreases and quenchability is also deteriorated, whereby it is
preferable for a Cu content to be set 2 mass % or lower. Especially
when hot workability is regarded as important, it is more desirably
to suppress the Cu content to 0.5 mass % or lower.
[0072] (11) 2 mass % or lower Co
[0073] Co is an element effective for improving corrosion
resistivity, particularly in an environment of a reducing acid and
in addition, can also be added to martensite containing stainless
steel depending on a necessity since Co increases an Ms point and
improves quenchability. To contain Co in content equal to 0.3 mass
% or higher is preferable in order to obtain more of
conspicuousness in the effects. When added in excess, however, not
only does hot workability decrease, but a raw material cost
increases, and therefore, it is preferable to set a content of Co
in the range of 2 mass % or lower. Especially when hot workability
and decrease in raw material cost are regarded as important, a
content of Co is more desirably suppressed to 0.5 mass % or
lower.
[0074] (12) One or more of Mo and W in the respective ranges of 0.1
to 4 mass % for Mo and 0.1 to 3 mass % for W
[0075] Since Mo and W can further increase corrosion resistivity
and strength, the elements may be added according to a necessity.
The lower limits are both 0.1%, where the effects thereof become
clearly recognized. On the other hand, when added in excess, not
only is hot workability deteriorated, but in martensite containing
stainless steel, a Ms point decrease excessively and further cost
increases and therefore, the upper limits of Mo and W are set 4
mass % and 3 mass %, respectively.
[0076] Free cutting alloy of the present invention constituted as
stainless steel can be austenite containing stainless steel
(hereinafter referred to a third selection invention). In this
case, the free cutting alloy contains:
[0077] 2 to 50 mass % Ni; 12 to 50 mass % Cr; 5 to 85.926 mass %
Fe; 0.021 to 0.4 mass % C.
[0078] one or more of Ti and Zr such that W.sub.Ti+0.52
W.sub.Zr=0.03 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Zr; and one or more of S
and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01
to 0.8 mass % for Se so that the total amount of S and Se is more
than the C content;
[0079] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0080] Herein, austenite containing stainless steel means stainless
steel containing not only Fe as a main component, but an austenitic
phase in the structure. While there are below exemplified
corresponding kinds of steel exhibited in JIS G 4304, neither of
elements Ti, Zr, S and Se as essential features of the present
invention is naturally expressed in compositions described in the
standard. In this case, part of Fe content of each of the above
described kinds of stainless steel is replaced with the above
described elements in the respective above described compositional
ranges and thereby martensite containing stainless steel of the
present invention is obtained. Therefore, while in description of
the present specification, the same JIS Nos. are used, those
actually means alloys specific to the present invention, which
alloys have compositions defined in JIS standards as a base
only.
[0081] (1) Austenitic stainless steel is stainless steel showing an
austenitic structure even in room temperature and can be
exemplified as follows: SUS 201, SUS 202, SUS 301,SUS 301J, SUS
302, SUS 302B, SUS 304, SUS 304N1, SUS 304N2, SUS 305, SUS 309S,
SUS 310S, SUS 316, SUS 316N, SUD 316J1, SUS 317, SUS 317J1, SUS
321, SUS 347, SUS XM15JI, SUS 836L, SUS 890L and so on.
[0082] (2) Austenitic-ferritic stainless steel is stainless steel
showing a dual phase structure of austenite and ferrite and can be
exemplified SUS 329J4L and so on.
[0083] (3) Precipitation hardening stainless steel is a stainless
steel obtained by adding elements such as aluminum and copper, and
precipitating a compound with the elements as main components by a
heat treatment to harden and can be exemplified SUS 630, SUS 631
and so on. It should be appreciated that a concept of "stainless
steel" includes heat resisting steel exemplified below as well:
[0084] (4) Austenitic heat resisting steel
[0085] Compositions are stipulated in JIS G 4311 and G 4312, for
example, and can be exemplified as follows: SUH 31, SUH 35, SUH 36,
SUH 37, SUH 38, SUH 309, SUH 310, SUH 330, SUH 660, SUH 661 and so
on.
[0086] Description will be given of the reason why the constituting
elements and preferable ranges in content thereof are defined in
the third selection invention of the present invention constituted
as austenite containing stainless:
[0087] (1)' The Ti content being defined such that W.sub.Ti+0.52
W.sub.Zr=0.03 to 3.5 mass %, wherein W.sub.Ti and W.sub.Zr denote
respective contents in mass % of Ti and Z
[0088] In the austenite containing stainless steel as the third
selection of this invention, when a value of W.sub.Ti+0.52 W.sub.Zr
is lower than 0.03 mass %, the (Ti, Zr) based compound is
insufficiently formed in amount, thereby disabling the effect of
improving machinability to be satisfactorily exerted. On the other
hand, when in excess of the value, machinability is reduced on the
contrary. For this reason, the value of W.sub.Ti+0.52 W.sub.Zr is
required to be suppressed to 3.5 mass % or lower.
[0089] (2)' One or more of S and Se in the respective ranges of
0.01 to 1.0 mass % for S and 0.01 to 0.8 mass % for Se
[0090] (3)' 0.021 to 0.4 mass % C
[0091] The same as the first selection of this invention.
[0092] (13) 2 to 50 mass % Ni
[0093] Ni is necessary to be added to stainless steel in a content
of at least 2 mass % in order to stabilize an austenitic phase in
the stainless steel. Moreover, while Ni has many chances to be
added into the matrix since Ni is useful for improving corrosion
resistivity in an environment of a reducing acid, it is preferable
to add at 2 mass % or higher in content from the viewpoint of
improvement on corrosion resistivity. Moreover, when non-magnetism
is desired, a necessary amount of Ni is required to be added so as
to stabilize an austenitic phase more and thereby obtain an alloy
as austenite containing stainless steel, considering connection
with contents of other elements such as Cr and Mo. In this case, a
Schoeffler diagram shown in FIG. 7 can be utilized for
determination of the Ni content. An austenite forming element and a
ferrite forming element are converted to equivalents of Ni and Cr
amounts and a relationship between the equivalents and the
structure is shown in FIG. 7 (see Revised 5.sup.th version Kinzoku
Binran (Metal Hand Book) published by Maruzen in 1990, p. 578).
However, it is required to obtain a necessary amount of Ni in
consideration of exclusion of an amount in Ti and/or Zr compound
from constituting elements of the matrix. Since not only does
excessive addition of Ni result in cost-up, but specific
characteristics as stainless steel are also degraded, a Ni content
is limited to 50 mass % or lower.
[0094] (14) 12 to 50 mass % Cr
[0095] Cr is an indispensable element for ensuring corrosion
resistivity of stainless steel. Hence, Cr is added in a content
equal to 12 mass % or higher. When a Cr content is lower than 12
mass %, corrosion resistivity as stainless steel cannot be ensured
due to intergranular corrosion caused by increased sensitivity at
grain boundaries. On the other hand, when added in excess, there
arises a risk that not only is hot workability degraded, but
toughness is also reduced due to formation of a compound such as
CrS. Furthermore, a problem occurs since high temperature
embrittlement becomes conspicuous. For this reason, a Cr content is
preferably set in the range of 12 to 50 mass % and performances
specific to stainless steel are, in a case, degraded outside the
range in content of Cr. Desirably, a Cr content is set in the range
of 15 to 30 mass % and more desirably in the range of 17 to 25 mass
%.
[0096] (15) 5 to 85.926 mass % Fe
[0097] Fe is an indispensable component for constituting stainless
steel. Therefore, a Fe content is at 5 mass % or higher. When an Fe
content is lower than 5 mass %, the Fe content is not preferable
since no strength specific to stainless steel can be obtained. That
an Fe content exceeds 85.95 mass % is impossible in connection with
required contents of other components. Consequently, an Fe content
is in the range of 5 to 85.926 mass %. An Fe content is desirably
set in the range of 15 to 75 mass % and more desirably in the range
of 40 to 65 mass %.
[0098] (16) 0.021 to 0.4 mass % C
[0099] C is an indispensable component for improvement on
machinability and added in a content of 0.021 mass % or higher.
With C being included in the matrix, a (Ti, Zr) based compound is
formed, and formation of the compound is considered to improves
machinability of stainless steel. When a C content is lower than
0.021 mass %, formation of the (Ti, Zr) based compound is
insufficient and the effect of improving machinability is not
sufficiently attainable. On the other hand, when the content
exceeds 0.4 mass %, a carbide not useful for improvement on
machinability is excessively formed and therefore, machinability is
deteriorated on the contrary. It is considered that residual C not
included, as a constituting element, in the (Ti, Zr) based compound
contributing to improvement on machinability is dissolved in the
matrix phase of stainless steel in a solid state and the residual C
in solid solution gives birth to an effect of increasing a hardness
of the stainless steel as well. Therefore, a C content is
preferably set in a proper manner taking into consideration not
only that C is added such that a machinability improvement effect
is exerted in best conditions according to an amount of
constituting elements of a compound improving machinability, such
as the (Ti, Zr) based compound, but also the effect of improving
hardness exerted by the residual C dissolved in a solid solution
state in the matrix phase. In consideration of the above described
circumferences, a C content is desirably in the range of 0.03 to
0.3 mass % and more desirably in the range of 0.05 to 0.25 mass
%.
[0100] Also in the third selection of this invention, the S content
is desirably determined such that a value of
W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less, or alternatively a
value of W.sub.S/W.sub.C is 0.4 or less and
W.sub.S/(W.sub.Ti+0.52W.sub.Zr) is 0.45 or less. With such a range
of components adopted, the out-gas resistivity of the matrix metal
phase of stainless steel can be improved.
[0101] In a free cutting alloy of the present invention constituted
as austenite containing stainless steel, a composition may have the
following components and contents thereof in order to achieve
better characteristics. That is, the composition can be 4 mass % or
lower Si; 4 mass % or lower Mn; 4 mass % or lower Cu; and 4 mass %
or lower Co. Description will be given of the reason why the
composition has the elements and contents thereof as follows:
[0102] (17) 4 mass % or lower Si
[0103] Si can be added as a deoxidizing agent for steel. However,
when a content of Si is excessive high, not only is a hardness
after solid solution heat treatment disadvantageously high, which
in turn leads to poor cold workability, but an increased amount of
a .delta.-ferrite phase is formed, thereby deteriorating hot
workability of the steel. Hence, the upper limit of Si in content
is set to 4 mass %. Especially, when cold workability and hot
workability are both regarded as important characteristics, a Si
content is desirably set to 1 mass % or lower and more desirably to
0.5 mass % or lower.
[0104] (18) 4 mass % or lower Mn
[0105] Mn not only acts as a deoxidizing agent of the steel, but
also exerts an effect to suppress formation of a .delta.-ferrite
phase. Furthermore, Mn has an effect to stabilize an austenitic
phase. Since Mn forms a compound useful for increase in
machinability in co-existence with S and Se, Mn may added to the
matrix when machinability is regarded as an important
characteristic. When an effect of improving machinability is
expected to be conspicuous, a Mn content is preferably set to 0.6
mass % or higher. When Mn is added, MnS is formed with ease.
However, since MnS not only degrades corrosion resistivity to a
great extent, but also reduces cold workability, formation of MnS
is unwelcome. Therefore, the Mn content is set to 4 mass % or
lower. Especially, when corrosion resistivity and cold workability
are both regarded as important characteristics, the Mn content is
desirably set to 1 mass % or lower and more desirably to 0.5 mass %
or lower.
[0106] (19) 4 mass % or lower Cu
[0107] Cu is not only useful for increase in corrosion resistivity,
particularly for improving corrosion resistivity in an environment
of a reducing acid, but also reduces work hardnability and improves
moldability. Moreover, since a heat treatment or the like
processing can improve an antibacterial property, Cu may added if
necessary. However, when Cu is excessively added, hot workability
is degraded and therefore, a Cu content is preferably set to 4 mass
% or lower. Especially, when hot workability is regarded as an
important characteristic, the Cu content is more desirably set to 1
mass % or lower.
[0108] (20) Co equal to 4 mass % or lower Co
[0109] Co is an element not only useful for improving corrosion
resistivity, particularly in an environment of a reducing acid, but
to exert an effect of ensuring non-magnetism and therefore, may
added to the matrix if necessary. It is preferable to add in
content of 1 mass % or higher in order to obtain more of
conspicuousness of the effect. However, when Co is added in excess,
not only is hot workability reduced but cost-up occurs on raw
material. Hence, a Co content is preferably set to 4 mass % or
lower. Especially, when hot workability or cost is taken seriously,
the Co content is more desirably suppressed to 3 mass % or
lower.
[0110] In the third selection invention constituted as austenite
containing stainless steel, the stainless steel can contain one or
more of Mo and W in the respective ranges of 0.1 to 10 mass % for
Mo and 0.1 to 10 mass % for W. Addition of Mo and W can improve
corrosion resistivity due to strengthened passivation and
furthermore attain improved hardness due to second hardening. It is
preferable to add Mo and W in each content of 0.1 mass % or higher
in order to make the effect exerted clearly. On the other hand,
when in excess, hot workability is reduced and therefore, the
content of Mo and W combined is preferably set to 10 mass % as the
upper limit.
[0111] In the ferrite containing stainless steel, the martensite
containing stainless steel and the austenite containing stainless
steel, all described above, contents of other elements are as
follows: the stainless steels can contain: 0.05 mass % or lower P;
and 0.03 mass % 0; and 0.05 mass % or lower N. Moreover, the
stainless steels can further contain one or more of Te, Bi and Pb
in the respective ranges of 0.005 to 0.1 mass % for Te; 0.01 to 0.2
mass % for Bi; and 0.01 to 0.3 mass % for Pb. Description will be
given of the reason why the elements and contents thereof are
defined as follows:
[0112] (21) 0.05 mass % or lower P
[0113] P is segregated at grain boundaries and not only increases
intergranular corrosion sensibility but also sometimes reduces
toughness. Therefore, a P content is preferably set as low as
possible and to 0.05 mass % or lower. Although the P content is
more desirably set to 0.03 mass % or lower, reduction in content
more than necessary has a chance to be reflected on increased
production cost.
[0114] (22) 0.03 mass % or lower O
[0115] O combines with Ti or Zr both of which are constituting
elements of a compound useful for improving machinability and forms
oxides not useful for improving machinability. Therefore, an O
content should be suppressed as low as possible and is set to 0.03
mass % as the upper limit. The O content is desirably set to 0.01
mass % or lower if allowable in consideration of increase in
production cost.
[0116] (23) 0.05 mass % or lower N
[0117] N combines with Ti or Zr both of which are constituting
elements of a compound useful for improving machinability and forms
nitrides not useful for improving machinability. Therefore, a N
content should be suppressed as low as possible and is set to 0.05
mass % as the upper limit. The N content is desirably set to 0.03
mass % or lower and more desirably to 0.01 mass %, if allowable in
consideration of increase in production cost.
[0118] (24) One or more of Te, Bi and Pb in the respective ranges
of 0.005 to 0.1 mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01
to 0.3 mass % for Pb
[0119] Since Te, Bi and Pb can further improve machinability, the
elements may add if necessary. The lower limits thereof at which
the respective effects are exerted to clearness are as follows:
0.005 mass % Te; 0.01 mass % Bi and 0.01 mass % Pb, respectively.
On the other hand, since excessive addition reduces hot
workability, the upper limits are set as follows: 0.1 mass % Te;
0.2 mass % Bi; and 0.3 mass % Pb.
[0120] Furthermore, when a free cutting alloy of the present
invention is constituted as stainless steel, the alloy can contain
one or more selected from the group consisting of Ca, Mg, B and REM
(one or more of metal elements classified as Group 3A in the
periodic table of elements) in the range of 0.0005 to 0.01 mass %
for one element or as a total content in a case of two or more
elements. The elements are useful for improving hot workability of
steel. The effect of improving hot workability obtainable by
addition of the elements is more conspicuously exerted in the range
of 0.0005 mass % or higher for one element or as a total content of
more than one elements combined. On the other hand, when the
elements are added in excess, the effect is saturated and hot
workability is then reduced on the contrary. Therefore, the content
of a single element or total content of the elements combined is
set to 0.01 mass % as the upper limit. As for REM, since low
radioactivity elements are easy to be handled when being mainly
used, from this viewpoint, it is useful to use one or more selected
from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb,
Dy, Ho, Er, Tm, Yb and Lu. It is desirable to use light rare earth
elements, especially La or Ce from the viewpoint of conspicuous
exertion of the effect and price. However, there arises no trouble
with mixing-in of a trace of radioactive rare earth elements such
as Th and U inevitably remaining, without being excluded, in a
process to separate rare earth elements. Further, from the
viewpoint of reduction in raw material cost, there can be used
not-separated rare earth elements such as mish metal and
didymium.
[0121] A free cutting alloy of the present invention constituted as
stainless steel can contain one or more selected from the group
consisting of Nb, V, Ta and Hf in each range of 0.01 to 0.5 mass %.
Since Nb, V, Ta and Hf has an effect of forming carbo-nitrides to
miniaturize crystalline particles of steel and increase toughness.
Hence, the elements can add in each content up to 0.5 mass % and
desirably contain 0.01 mass % or higher in the range.
[0122] A free cutting alloy of the present invention constituted as
the above described stainless steel can contain 0.035 mass % or
lower S in W.sub.SO value, wherein W.sub.SO is defined as a value
obtained in a procedure as follows: An alloy test piece is prepared
so as to have the shape of a rectangular prism in size of 15 mm in
length, 25 mm in width and 3 mm in thickness with the entire
surface being polished with No. 400 emery paper. A silver foil in
size of 10 mm in length, 5 mm in width and 0.1 mm in thickness with
a purity of 99.9% or higher as a S getter and 0.5 cc of pure water
are sealed in a vessel of an inner volume of 250 cc together with
the test piece and a temperature in the vessel is raised to
85.degree. C. and said temperature is then kept there for 20 hr;
and thereafter, a S content W.sub.SO in mass % in the silver foil
piece is analyzed.
[0123] A (Ti, Zr) based compound being a feature of the present
invention is formed and in the course of the formation, added S is
included in the stainless steel as a constituting element of the
(Ti, Zr) based compound. As a result, a S amount present in the
matrix metal phase (Fe based matrix phase) in a dispersed state
decreases and therefore, a S amount released into the air from the
stainless steel also decreases. Consequently, an out-gas
resistivity of the stainless steel can also be improved by
formation of the (Ti, Zr) based compound.
[0124] In this case, when the out-gas resistivity test is
performed, a S component released from the test piece as a sulfur
containing gas is forced to be absorbed in the silver foil as a
getter and a sulfur content W.sub.SO in the silver foil is measured
to quantitatively determine the out-gas resistivity of a material.
A S content in the stainless steel is defined using the W.sub.SO
value and set to 0.035 mass % or lower in W.sub.SO. Stainless steel
of the present invention controlled so as to be 0.035 mass % or
lower in W.sub.SO is hard to cause sulfur contamination in the
peripheral parts when exposed to the air since a S component
released form the stainless steel into the air is very small and
thereby the stainless steel can be preferably used as parts of
industrial equipment requiring the out-gas resistivity.
[0125] While the composition as stainless steel of the present
invention is described above, machinability as an alloy is required
not only in the above described stainless steel, but also in an
electromagnetic alloy used as a functional material. Although
electromagnetic alloys are in many cases poor machinability, not
only corrosion resistivity and cold workability but also
electromagnetic characteristics were in cases deteriorated when
machinability-improving elements such as S and Pb were added for
improvement on machinability. Moreover, since characteristics of
the alloy are largely changed by subtle shifts in balances between
constituting elements, it has been difficult that machinability is
improved while retaining excellent electromagnetic characteristics.
According to the present invention, an effect of improving
machinability can be achieved while the characteristics in the
electromagnetic alloy is maintained.
[0126] To be concrete, the present invention can be preferably used
as an electromagnetic alloy (hereinafter referred to as a fourth
selection invention). The present inventors have acquired the
following findings and completed the fourth selection invention
based thereon: When in ferritic electromagnetic alloy, one or more
of Ti and Zr, C, and one or more of S, Se and Te are added in
combination, the components are in combinations of the specific
contents: a content of one or more of Ti and Zr is in the range of
0.005 to 0.5 mass % in terms of Ti %+0.52 Zr % (which is indicated
by X); a content of C is in the ranges of 0.02 X to 0.06 X mass %,
0.19 X to 0.26 X mass % or 0.02 X to 0.26 X; and a content of one
or more of S, Se and Te is in the ranges of (Z-0.07)X to (Z+0.07)X
mass %, (Z+0.07)X to (Z+0.45)X mass %, the lower limit not
included, or (Z+0.45) X to (Z+0.70)X mass %, the lower limit not
included, wherein S%+0.41 Se %+0.25 Te % is indicated by Y, and
thereby machinability can be improved while soft magnetic
characteristics, cold workability and corrosion resistivity are
controlled in good states. Furthermore, the fourth selection
invention includes four composition combinations, and particularly
the first and the third combination exhibit excellent machinability
without the aid of a significant addition of Pb.
[0127] In description of the fourth selection invention, expression
of a element symbol with % following such as Ti %, Zr %, S %, Se %,
Te % or C % means a content in mass % of a corresponding component
indicated by the element symbol. C/X and C %/X in the following
description are the same in meaning.
[0128] That is, the fourth selection invention of the present
invention is constituted as the electromagnetic stainless steel and
the first combination containing:
[0129] 0.01 to 3, the upper limit not included, mass % Si;
[0130] 2 mass % or lower Mn;
[0131] 5 to 25 mass % Cr;
[0132] 0.01 to 5, the lower limit not included, mass % Al;
[0133] one or more of Ti and Zr so that X defined by the following
formula 1 is in the range of 0.05 to 0.5 mass %;
[0134] C in the range of 0.02 X to 0.06 X mass %, wherein X is
expressed by the following formula 1;
[0135] one or more of S, Se and Te in the range of (Z-0.07)X to
(Z+0.07)X mass %, wherein X, Z and Y are values of the respective
following formulae 1, 3 and 2;
Ti %+0.52 Zr %=X (Formula 1)
S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3)
[0136] Fe being the main component of the alloy;
[0137] inevitable impurities;
[0138] wherein Pb content is less than 0.01 mass %;
[0139] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0140] In the first combination, the alloy can further contain one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V. The alloy can further contain one or
more selected from the group consisting of B and metal elements
classified as Group 3A in the periodic table of elements in the
respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or
lower for one or more of metal elements classified as Group 3A in
the periodic table of elements in total.
[0141] The second combination contains:
[0142] 0.01 to 3, the upper limit not included, mass % Si;
[0143] 2 mass % or lower Mn;
[0144] 5 to 25 mass % Cr;
[0145] 0.01 to 5, the lower limit not included, mass % Al;
[0146] one or more of Ti and Zr so that X defined by the following
formula 1 is in the range of 0.05 to 0.5 mass %;
[0147] C in the range of 0.19 X to 0.26 X mass %, wherein X is
expressed by the following formula 1;
[0148] one or more of S, Se and Te in the range of (Z-0.07)X to
(Z+0.07)X mass %, wherein X, Z and Y are values of the respective
following formulae 1, 3 and 2;
Ti %+0.52 Zr %=X (Formula 1)
S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3)
[0149] Fe being the main component of the alloy;
[0150] inevitable impurities;
[0151] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0152] In the second combination, the alloy can further contain one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V. The alloy can further contain one or
more selected from the group consisting of Pb, B and metal elements
classified as Group 3A in the periodic table of elements in the
respective ranges of 0.15 mass % or lower for Pb, 0.01 mass % or
lower for B; and 0.1 mass % or lower for one or more of metal
elements classified as Group 3A in the periodic table of elements
in total.
[0153] The third combination contains:
[0154] 0.01 to 3, the upper limit not included, mass % Si;
[0155] 2 mass % or lower Mn;
[0156] 5 to 25 mass % Cr;
[0157] 0.01 to 5, the lower limit not included, mass % Al;
[0158] one or more of Ti and Zr so that X defined by the following
formula 1 is in the range of 0.05 to 0.5 mass %;
[0159] C in the range of 0.02 X to 0.26 X mass %, wherein X is
expressed by the following formula 1;
[0160] one or more of S, Se and Te in the range of (Z+0.07)X to
(Z+0.45)X mass %, wherein X, Z and Y are values of the respective
following formulae 1, 3 and 2;
Ti %+0.52 Zr %=X (Formula 1)
S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3)
[0161] Fe being the main component of the alloy;
[0162] inevitable impurities;
[0163] wherein Pb content is less than 0.01 mass %;
[0164] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0165] In the third combination, the alloy can further contain one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V. The alloy can further contain one or
more selected from the group consisting of B and metal elements
classified as Group 3A in the periodic table of elements in the
respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or
lower for one or more of metal elements classified as Group 3A in
the periodic table of elements in total.
[0166] The fourth combination contains:
[0167] 0.01 to 3, the upper limit not included, mass % Si;
[0168] 2 mass % or lower Mn;
[0169] 5 to 25 mass % Cr;
[0170] 0.01 to 5, the lower limit not included, mass % Al;
[0171] one or more of Ti and Zr so that X defined by the following
formula 1 is in the range of 0.05 to 0.5 mass %;
[0172] C in the range of 0.02 X to 0.26 X mass %, wherein X is
expressed by the following formula 1;
[0173] one or more of S, Se and Te in the range of (Z+0.45)X to
(Z+0.70)X mass %, wherein X, Z and Y are values of the respective
following formulae 1, 3 and 2;
Ti %+0.52 Zr %=X (Formula 1)
S %+0.41 Se %+0.25 Te %=Y (Formula 2)
32(C %/X-0.125).sup.2=Z (Formula 3)
[0174] Fe being the main component of the alloy;
[0175] inevitable impurities;
[0176] and wherein a (Ti, Zr) based compound containing one or more
of Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0177] In the fourth combination, the alloy can further contain one
or more selected from the group consisting of Ni, Cu, Mo, Nb and V
in the respective ranges of 2 mass % or lower for Ni; 2 mass % or
lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb
and 1 mass % or lower for V.
[0178] Next, the combinations of the ranges in content are
described with reference to a graph shown in FIG. 1, where the
abscissa is used for plotting C/X and the ordinate is used for
plotting Y/X. A first combination of a content of one or more of Ti
and Zr; a content of C and a content of one or more of S, Se and Te
is a region enclosed by a straight line perpendicular to the
abscissa passing through a position of C/X=0.02, a straight line
perpendicular to the abscissa passing through a position of
C/X=0.06, and curves of Y/X=32 (C/X-0.125).sup.2-0.07 and Y/X=32
(C/X-0.125).sup.2+0.07, wherein the formulae of Y/X=32
(C/X-0.125).sup.2-0.07 and Y/X=32 (C/X-0.125).sup.2+0.07 are
obtained by substituting Z=32(C/X-0.125).sup.2 into the above
described (Z-0.07)X.ltoreq.Y/X.ltoreq.(Z+0.07), that is
Y/X=(Z-0.07) to (Z+0.07). Further, a broken line in FIG. 1,
Y/X=0.32(C/X-0.125).sup.2 is a curve circumscribed by the C/X axis
(a value on the Y/X axis =0) and .alpha. in FIG. 1 is defined by a
formula Y/X-32(C/X-0.125).sup.2=.alpha.. Further, a mark
.largecircle. with a number in FIG. 1 indicates a specimen No. of
fourth selection inventive steel of the present invention of
Example 4 and a mark .tangle-solidup. indicates a specimen No. of
an inventive steel of Example 4.
[0179] A second combination of a content of one or more of Ti and
Zr; a content of C and one or more of S, Se and Te is a region
enclosed by a straight line perpendicular to the abscissa passing
through a position of C/X=0.19, a straight line perpendicular to
the abscissa passing through a position of C/X=0.26, and curves of
Y/X=32 (C/X-0.125).sup.2-0.07 and Y/X=32 (C/X-0.125).sup.2+0.07 in
FIG. 1. A third combination of a content of one or more of Ti and
Zr; a content of C and one or more of S, Se and Te is a region
enclosed by a straight line perpendicular to the abscissa passing
through a position of C/X=0.2, a straight line perpendicular to the
abscissa passing through a position of C/X=0.26, and curves of
Y/X=32 (C/X-0.125).sup.2+0.07 and Y/X=32 (C/X-0.125).sup.2+0.45 in
FIG. 1.
[0180] A fourth combination of a content of one or more of Ti and
Zr; a content of C and one or more of S, Se and Te is a region
enclosed by a straight line perpendicular to the abscissa passing
through a position of C/X=0.02, a straight line perpendicular to
the abscissa passing through a position of C/X 0.26, and curves of
Y/X=32 (C/X-0.125).sup.2+0.45 and Y/X=32 (C/X-0.125).sup.2+0.07 in
FIG. 1.
[0181] Next, description will be given of the reason why the
elements and contents thereof are selected of a free cutting alloy
relating to the fourth selection invention as follows:
[0182] (25) 0.01 to 3, the upper limit not included, mass % Si
[0183] Si is useful not only as a deoxidizing agent, but also for
contributing to increase in the maximum magnetic permeability and
reduction in coercive force among soft magnetic characteristics as
an electromagnetic stainless steel and furthermore, useful for
increase in electric resistivity and improvement on responsibility
in a high-frequency band, and therefore, Si is added for the
purposes. While a Si content is necessary to be 0.01% or higher in
order to attain the effect, since when the content is excessive
high, hardness increases and cold workability is degraded, the
content is reduced when cold workability is regarded as a more
important characteristic and intended increases in the soft
magnetic characteristics and a high-frequency responsibility are
compensated mainly by addition of Al, described later,
corresponding to decrease in Si content. However, when
machinability is regarded as an important characteristics, the
upper limit of the Si content is set to 3 mass %.
[0184] (26) 2 mass % or lower Mn
[0185] Mn is an element useful as a deoxidizing agent, but since
when a Mn content exceeds 2 mass %, soft magnetic characteristics
are degraded, the Mn content is set to 2 mass % or lower.
[0186] (27) 5 to 25 mass % Cr
[0187] Cr is useful for improvement on corrosion resistivity and
electric resistivity of steel, but for improvement on machinability
by forming Cr (S, Se, Te) with S, Se and Te, which will be
described later. Therefore, Cr is added for the improvements.
Although it is necessary for Cr to be included in the range of 5
mass % or higher, the Cr content in excess of 25 mass % reduces
cold workability and accordingly, the Cr content is set to 5 to 25
mass %.
[0188] (28) 0.01 to 5, the lower limit not included, mass % Al
[0189] Al is useful not only as a deoxidizing agent, but for
contributing increase in the maximum magnetic permeability and
reduction in coercive force and furthermore, useful for increase in
electric resistivity and improvement on responsibility in a
high-frequency band, similar to Si. Therefore, Al is included for
the improvements. Although it is necessary for Al to be included
exceeding 0.01 mass % in order to exert the effects, not only a
specific refining method is required but cold workability is also
degraded when an Al content exceeds 5 mass % and accordingly, the
Al content is set to from 0.01 to 5 mass &.
[0190] (29) One or more of Ti and Zr in the range of 0.05 to 0.5
mass % in terms of Ti %+0.52 Zr %=X
[0191] Ti and Zr forms (Ti, Zr).sub.4C.sub.2(S, Se, Te).sub.2
and/or (Ti, Zr) (S, Se, Te) in co-existence with C, S, Se and Te to
contribute to increase in machinability and since among the two,
(Ti, Zr).sub.4C.sub.2(S, Se, Te).sub.2 especially deteriorates
neither soft magnetic characteristics nor corrosion resistivity and
contributes to improvement on machinability without any loss of
cold workability, due to fine dispersion thereof, the elements are
therefore added for the improvements. Although the content of the
elements singly or in combination is required to be 0.05 mass % of
higher in terms of X in order to exert the effects, the soft
magnetic characteristics are degraded when the content in terms of
X exceeds 0.5 mass % and accordingly, the content is set to the
range of 0.05 to 0.5 mass % in terms of X.
[0192] (30) C in the range of 0.02 X to 0.06 X mass %, 0.19 X to
0.26 X mass % or 0.02 X to 0.26 X mass %
[0193] The reason why a C content is set to 0.02 X to 0.06 X mass %
(0.02.ltoreq.C/X.ltoreq.0.06) or 0.19 X to 0.26 X mass %
(0.19.ltoreq.C/X.ltoreq.0.26), wherein
.vertline..alpha..vertline.<0.0- 7, .vertline..alpha..vertline.
being the absolute value of a and this applying hereinafter, and
.alpha.=Y/X-32 (C/X-1.25).sup.2 (see FIG. 1), is that with such
compositions adopted, in an electromagnetic stainless steel, soft
magnetic characteristics and cold workability are especially
excellent, machinability is also good due to dispersion in a fine
particle state of (Ti, Zr).sub.4C.sub.2(S, Se, Te).sub.2 and (Ti,
Zr) (S, Se, Te), the latter of which is formed in a small amount,
and further, corrosion resistivity is also good, wherein (Ti,
Zr).sub.4C.sub.2(S, Se, Te).sub.2 has a little effect to degrade
the soft magnetic characteristics. Excellence in the soft magnetic
characteristics in the region of this a is because of extremely low
level of the presence of (Ti, Zr)C, (Ti, Zr) (S, Se, Te) and Mn (S,
Se, Te).
[0194] In the content range of C of C/X<0.02 (C<0.02 mass %)
and 0.06<C/X<0.19 (a C content exceeds 0.06 X mass % and less
than 0.19 X mass %), formation of (Ti, Zr).sub.4C.sub.2(S, Se,
Te).sub.2 is excessively small in amount, which exerts the effect
at a poor level but in the content range of C of C/X>0.26
(C>0.26 mass %), (Ti, Zr) C increases and thereby, the soft
magnetic characteristics, cold workability and corrosion
resistivity are degraded on the contrary, and accordingly, the C
content is limited to the ranges of 0.02.ltoreq.C/X.ltoreq.0.06
(0.02 X to 0.06 X mass %) or 0.19.ltoreq.C/X.ltoreq.0.26 (0.19 X to
0.26 X mass %).
[0195] Moreover, the reason why the C content is set to the
compositional range of 0.2 X to 0.26 X mass %
(0.02.ltoreq.C/X.ltoreq.0.26), wherein 0.07.alpha..ltoreq.0.45, is
that electromagnetic stainless steel with good machinability, good
soft magnetic characteristics and good cold workability can be
attained by formation of (Ti, Zr).sub.4C.sub.2(S, Se, Te).sub.2 and
(Ti, Zr) (S, Se, Te) excellent in corrosion resistivity, in a
slightly increased amount. However, in the range of C<0.02 X
mass % (C/X<0.02), the soft magnetic characteristics are
degraded due to decrease in formation of (Ti, Zr).sub.4C.sub.2 (S,
Se, Te).sub.2 and increase in (Ti, Zr) (S, Se, Te) and in the range
of C>0.026 X (C/X>0.26), the soft magnetic characteristics,
cold workability and corrosion resistivity are deteriorated due to
increase in (Ti, Zr) C. Accordingly, the C content range is limited
to C=0.02 X to 0.26 X mass % (0.02.ltoreq.C/X.ltoreq.0.26).
[0196] Further, the reason why the ranges of a C content are set to
compositional range of 0.02 X to 0.26 X mass %
(0.02.ltoreq.C/X.ltoreq.0.- 26), wherein
0.45.ltoreq..alpha..ltoreq.0.70, is that because of increase in
(Ti, Zr) S, Cr (S, Se, Te) and Mn (S, Se, Te), electromagnetic
stainless steel can be obtained with machinability especially
excellent, corrosion resistivity and soft magnetic characteristics
are at practical levels, though cold workability with a high
working ratio is hard to be attained. However, in the compositional
range of .alpha.>0.70 and C<0.02 X mass % (C/X<0.02), the
soft magnetic characteristics and corrosion resistivity are largely
degraded due to increase in (Ti, Zr) S, Cr (S, Se, Te) and Mn (S,
Se, Te), further in the compositional range of C>0.26 mass %
(C/X>0.26), decreases in the soft magnetic characteristics and
in corrosion resistivity are large due to increase in (Ti, Zr) C
and accordingly, the C content is limited to C=0.02 X to 0.26 C
mass % (0.02.ltoreq.C/X>0.26), wherein
0.45.ltoreq..alpha..ltoreq.0.- 70.
[0197] One or more of S, Se and Te is in the ranges of (Z-0.07)X to
(Z+0.07)X mass %, (Z+0.07)X to (Z+0.45)X, the lower limit not
included, mass %, or (Z+0.45) X to (Z+0.70)X, the lower limit not
included, mass %, wherein Y=S %+0.41 Se %+0.25 Te % is indicated by
Y and Z=32(C/X-0.125).sup.2.
[0198] In a case where Y is in the range of (Z-0.07)X to (Z+0.07)X
mass %:
[0199] The reason why Y is set to (Z-0.07)x to (Z+0.07)X mass %
(-0.07.ltoreq..alpha..ltoreq.0.07) and C is set to 0.02 X to 0.06 X
mass % (0.02.ltoreq.C/X.ltoreq.0.06) or 0.19X to 0.26X mass %
(0.19>C/X>0.26) is that in electromagnetic stainless steel of
the composition, the soft magnetic characteristics and cold
workability are especially excellent, machinability is good due to
dispersion in a fine state of (Ti, Zr).sub.4C.sub.2(S, Se,
Te).sub.2 and (Ti, Zr) (S, Se, Te), the latter of which is formed
at a small amount, and moreover, corrosion resistivity is good as
well. However, when Y is lower than (Z-0.07)X %, that is when Y/X
is lower than 32(C/X-0.125).sup.2-0.07, formation of (Ti,
Zr).sub.4C.sub.2(S, Se, Te).sub.2 is excessively small in amount
and thereby the effect thereof is poor, while Y is higher than
(Z+0.07)X mass %, that is when Y/X is higher than
32(C/X-0.125).sup.2+0.07, the soft magnetic characteristics, cold
workability and corrosion resistance are degraded on the contrary
and therefore, Y is set in the range (Z-0.07)X to (Z+0.07)X mass
%.
[0200] In a case where Y is in the range of (Z+0.07)X to (Z+0.45)X,
the lower limit not included, mass %:
[0201] The reason why Y is set in the range of (Z+0.07)X to
(Z+0.45)X, the lower limit not included, mass %
(0.07.ltoreq..alpha..ltoreq.0.45) and C is set in the range of
0.02X to 0.26X mass % (0.02.ltoreq.C/X.ltoreq.0.26- ) is that in
electromagnetic stainless steel with the composition, there are
realized excellent corrosion resistivity and machinability better
than when Y is in the range of (Z-0.07)X to (Z+0.07)X mass % and in
addition, good soft magnetic characteristics and good workability
due to formation of (Ti, Zr).sub.4C.sub.2(S, Se, Te).sub.2 and (Ti,
Zr) (S, Se, Te), slightly increased in amount. However, when Y is
higher than (Z+0.45)X mass %, that is when Y/X is higher than
32(C/X-0.125).sup.2+0.4- 5, machinability is more excellent due to
increase in (Ti, Zr) S, Cr (S, Se, Te) and Mn (S, Se, Te) while
cold workability, corrosion resistivity and soft magnetic
characteristics are degraded and therefore, Y is set in the range
of (Z+0.07)X to (Z+0.45)X mass %.
[0202] In a case where Y is in the range of (Z+0.45)X to (Z+0.70)X
mass %:
[0203] The reason why Y is set in the compositional range of
(Z+0.45)X to (Z+0.70)X mass % (0.45.ltoreq..alpha..ltoreq.0.70) and
C is set in the range of 0.02X to 0.26X mass %
(0.02.ltoreq.C/X.ltoreq.0.26) is that in electromagnetic stainless
steel with the composition, electromagnetic stainless steel can be
obtained with especially excellent machinability, corrosion
resistivity and soft magnetic characteristics thereof are at
practical levels due to increase in (Ti, Zr) S, Cr (S, Se, Te) and
Mn (S, Se, Te), though cold workability with a high working ratio
is hard to be attained. However, when Y is set higher than
(Z+0.70)X mass %, that is when Y/X is set higher than
32(C/X-0.125).sup.2+0.70, machinability is further excellent due to
increase in (Ti, Zr) S, Cr (S, Se, Te) and Mn (S, Se, Te), while
since cold workability, corrosion resistivity and soft magnetic
characteristics decrease lower than a level of practicability, Y is
set in the range of (Z+0.45)X to (Z+0.70)X mass %.
[0204] 2 mass % or lower Ni, 2 mass % or lower Cu, 2 mass % or
lower Mo, 1 mass % or lower Nb and 1 mass % or lower V:
[0205] Ni. Cu, Mo, Nb and V are all useful for more of improvement
on corrosion resistivity in a free cutting alloy relating to the
fourth selection invention and therefore, the elements are included
in the electromagnetic stainless steel. However, when the elements
are added in excess of the respective upper limits, soft magnetic
characteristics and cold workability are deteriorated. Accordingly,
the contents are set as described above.
[0206] 0.15 mass % or lower Pb; 0.01 mass % or lower B; and 0.1
mass % or lower REM:
[0207] Pb is an element included for more of improvement on
machinability and since the effect of improving machinability more
than in a conventional case can be exerted with a Pb content a half
that in the conventional case, the Pb content is set to 0.15 mass %
or lower. Particularly, the first and the third combination exhibit
excellent machinability despite of the low Pb content less than
0.01 mass %.
[0208] Since B and REM are elements useful for improving cold
workability more in a steel of a free cutting alloy relating to the
fourth selection invention, the elements are added in the steel.
However, when the contents exceed the respective above described
upper limits, hot and cold workabilities decrease and accordingly,
the contents are set as described above. As for REM, since low
radioactivity elements are easy to be handled when being mainly
used and from this viewpoint, it is useful to use one or more
selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. It is desirable to use light
rare earth elements, especially La or Ce from the viewpoint of
conspicuous exertion of the effect and price. However, there arises
no trouble in mixing-in of a trace of radioactive rare earth
elements such as Th and U inevitably remaining in a process to
separate rare earth elements. Further, from the viewpoint of
reduction in raw material cost, there can be used not-separated
rare earth elements such as mish metal and didymium.
[0209] Description will be given of a production method for free
cutting alloy relating to the fourth selection invention
constituted as electromagnetic stainless steel as follows:
[0210] Free cutting alloy relating to the fourth selection
invention has a composition with a content of one or more of Ti and
Zr, a content of C and a content of one or more of S, Se and Te,
the elements being included in conventional electromagnetic
stainless steel, wherein the contents are individually specified
and the elements in combinations of the contents are included in
the alloy and therefore, electromagnetic stainless steel of the
fourth selection invention can be produced by a production method
similar to a conventional production method for electromagnetic
stainless steel.
[0211] Further, the present invention can be preferably applied for
(Fe, Ni) based electromagnetic alloy, (Fe, Ni) based heat resisting
alloy and (Fe, Ni) based alloy such as Invar alloy, Elinvar alloy
and the like with a small thermal expansion coefficient, a small
thermal coefficient of an elastic modulus, for use in precision
machine parts (hereinafter referred to as a fifth selection
invention). In Ni based electromagnetic alloy, the alloy including
20 to 80 mass % Ni is generally used, and there can be exemplified
as the alloy; for example, alloys called Permalloy or Perminver. Ni
heat resisting alloy including 40 to 80 mass % Ni is widely
used.
[0212] The fifth selection invention of the present invention
containing 20 to 82 mass % Ni and the part except for Ni of which
is mainly constituted by one or more of Fe and Cr, (Fe, Ni) based
heat resisting alloy or the like. It further contains:
[0213] one or more of Ti and Zr so that X defined by the following
formula 1 in the range satisfying a relation of
0.05.ltoreq.X.ltoreq.3;
[0214] one or more of S, Se and Te so that Y defined by the
following formula 2 in the range satisfying a relation of
0.014.ltoreq.Y.ltoreq.0.5 X;
[0215] C in the range satisfying a relation of 0.2
Y.ltoreq.W.sub.C.ltoreq- .0.3, wherein when a Ti content is
indicated by W.sub.Ti in mass %, a Zr content by W.sub.Zr in mass
%, a C content by W in mass %, a S content by W.sub.S in mass %, a
Se content by W.sub.Se in mass % and a Te content by W.sub.Te in
mass %, the following formulae 1 and 2 are given in order to define
X and Y:
X (mass %)=W.sub.Ti+0.52 W.sub.Zr (formula 1)
Y (mass %)=W.sub.S+0.41 W.sub.Se+0.25 W.sub.Te (formula 2);
[0216] one or more of Si, Mn and Al in the respective ranges of 1
mass % for Si, 1 mass % for Mn and 1 mass % for Al;
[0217] wherein a (Ti, Zr) based compound containing one or more of
Ti and Zr as a metal element component, C being an indispensable
element as a bonding component with the metal element component,
and one or more of S, Se and Te is dispersed in a matrix metal
phase.
[0218] The present inventors had findings that in (Fe, Ni) based
alloy for use in electromagnetic material and/or heat resistant
material (for example Ni or Fe based heat resistant alloy of a
solid solution strengthening type), (Ti, Zr) based compound (for
example, a compound in the form of (Ti, Zr) 4 (S, Se,
Te).sub.2C.sub.2)) is formed and thereby, machinability of the
alloy is improved. Further findings were added thereto that while
some of indispensable elements constituting the (Ti, Zr) based
compound acts a harmful influence, such as degradation in
performances of electromagnetic material and/or heat resistant
material, on the alloy, such a harmful influence can be deleted if
a prescribed condition is imposed on contents of the indispensable
elements of the (Ti, Zr) based compound, thereby enabling
machinability to improve while maintaining excellent performances
as the electromagnetic material and/or the heat resistant
material.
[0219] That is, a free cutting alloy of the present invention with
the following composition is excellent in machinability and hot
workability without deterioration in excellent performances as
electromagnetic material and/or heat resistant material, the
composition being:
[0220] one or more of Ti-and Zr in the range satisfying a relation
of 0.05.ltoreq.X.ltoreq.3 (hereinafter referred to as a condition
formula (1)),
[0221] one or more of S, Se and Te in the range satisfying a
relation of 0.014.ltoreq.Y.ltoreq.0.5 X (hereinafter referred to as
a condition formula (2)),
[0222] C in the range satisfying a relation of 0.2
Y.ltoreq.W.sub.C.ltoreq- .0.3 (hereinafter referred to as a
condition formula (3)), wherein when a Ti content is indicated by
W.sub.Ti in mass %, a Zr content by W.sub.Zr in mass %, a C content
by W.sub.C in mass %, a S content by Ws mass %, a Se content by
W.sub.Se and a Te content by W.sub.Te, the following formulae (1)
and (2) are given in order to define X and Y:
X (mass %)=W.sub.Ti+0.52 W.sub.Zr (hereinafter referred to as
Formula (1)) and
Y (mass %)=W.sub.S+0.41 W.sub.Se+0.25 W.sub.Te (hereinafter
referred to as Formula (2)).
[0223] Description will be given of the reason why the elements,
contents thereof and condition formulae are selected or determined
as follows:
[0224] (31) 20 to 82 mass % Ni
[0225] A free cutting alloy of the fifth selection invention of the
present invention includes (Fe, Ni) based electromagnetic alloy and
(Fe, Ni) based heat resisting alloy. Accordingly, Ni is an
indispensable element for the free cutting alloy of the present
invention. Further, (Fe, Ni) based electromagnetic alloy and (Fe,
Ni) based heat resisting alloy are widely employed with content of
the range of 20 to 82 mass % for Ni and since the alloys including
Ni in content of this range are particularly required improvement
on machinability, the Ni content is limited to the range.
[0226] (32) one or more of Ti and Zr in content satisfying a
relation of 0.05.ltoreq.X.ltoreq.3 (hereinafter referred to as a
condition formula (1))
[0227] When Ti and Zr are added in the above described range
together with C, S, Se and Te, (Ti, Zr) based compounds, for
example, mainly (Ti, Zr) 4 (S, Se, Te).sub.2C.sub.2and/or a small
amount of (Ti, Zr) (S, Se, Te), are formed and therefore, Ti and Zr
are useful for improvement on machinability. Moreover, since
formation of (Mn, Cr, Ni)S, especially NiS, is suppressed, Ti and
Zr are also useful for prevention of cracking in hot working and
the free cutting alloy of the fifth selection invention can
maintain excellent characteristics as (Fe, Ni) based
electromagnetic alloy or (Fe, Ni) based heat resisting alloy such
as a thermal expansion coefficient, an elastic constant, magnetic
characteristics or a high temperature strength. While Ti and Zr is
required to be included in the range of 0.05 mass % or higher in X
of a compositional parameter in order to attain an effect of
improving machinability, X in excess of 3 mass % is not preferable
since when X is in excess of 3 mass %, a specific refining method
is required, being accompanied with poor productivity. Accordingly,
the range of the parameter X is preferably set in the range of 0.5
to 3 mass % and more preferably in the range of 0.1 to 0.5.
Further, when Ti and Zr are included in the range satisfying the
condition formula (1), either one of Ti and Zr or both Ti and Zr
may be included.
[0228] (33) One or more of S, Se and Te in contents satisfying a
relation of 0.014.ltoreq.Y.ltoreq.0.5 X (hereinafter referred to as
a condition formula (2))
[0229] S, Se and Te are indispensable elements for formation of the
above described (Ti, Zr) based compound. Therefore, the elements
are indispensable components for improvement on machinability and
are required to be included in the range of 0.014 mass % or higher
in terms of the parameter Y. When the elements are added in excess,
a compound not useful for improving machinability is formed and in
a case, performances of the alloy are deteriorated. Therefore, when
the parameters X and Y are related so as to satisfy the above
described condition formula (2), that is when the parameter Y
corresponding to a total number of S, Se and Te atoms is half the
parameter X corresponding to a total number of Ti and Zr atoms, an
additive amount of one or more of S, Se and Te is not excessive but
falls within the proper range in amount and therefore, formation of
a compound not useful for improvement on machinability can be
suppressed and deterioration in performances of the alloy can be
prevented or suppressed. As far as S, Se and Te are included in the
ranges to satisfy the condition formula (2), either only one of
them or two or more of them may be included in the alloy.
[0230] (34) C in content satisfying a relation of 0.2
Y.ltoreq.W.sub.C.ltoreq.0.3 (hereinafter referred to as a condition
formula (3))
[0231] C forms (Ti, Zr) based compound in co-existence with Ti and
Zr, and S, Se and Te and, it is an indispensable element for
improvement on machinability. Moreover, C acts usefully for
prevention of cracking occurrence in hot workability. Especially,
since C accelerates formation of (Ti, Zr).sub.4(S, Se,
Te).sub.2C.sub.2 more stable than (Ti, Zr) (S, Se, Te), improvement
by C on machinability is more effective. It is necessary to include
C so as to satisfy the condition formula (3) for achievement of the
effects. That is, C is required to be included in the range of at
least more than 0.2 times the parameter Y (a parameter on which a
total number of S, Se and Te atoms is reflected). When a C content
W.sub.C is W.sub.C<Y/5, the C content is excessively small, the
effect of improving machinability cannot be acquired. On the other
hand, an excessive addition of C is not preferable since such a C
content causes deterioration in performances of Ni based
electromagnetic alloy and Ni based heat resisting alloy.
Accordingly, the C content W.sub.C is preferably limited to 0.3
mass % or lower. When the C content exceeds 0.3 mass %, loss of
performances of Ni based alloy becomes large. The C content is
desirably set in the range of Y/4 to 0.2 mass % and more desirably
in the range of Y/4 to Y/2 mass %.
[0232] The fifth selection invention of the present invention
constituted as (Fe, Ni) based alloy can contain one or more of Si,
Mn and Al in the respective ranges of 1 mass % or lower for Si; 1
mass % or lower for Mn; and 1 mass % or lower for Al. Description
will be given of the reason why the elements and contents thereof
are selected as follows:
[0233] (35) 1 mass % or lower Si
[0234] Si is an element useful as a deoxidizing agent and in
addition, for adjustment of hardness and electric resistivity and
accordingly, added depending on a necessity. However, when an
additive amount of Si is in excess, hardness after heat treatment
for solid solution is excessively high, which disadvantageously
brings poor workability. Characteristics such as thermal expansion,
an elastic constant, magnetic characteristics, heat resistance
(high temperature strength) and the like are degraded in some
cases. Accordingly, the Si content is limited to 1 mass % as the
upper limit and when cold workability is regarded as an important
requirement, the Si content is preferably set to 0.5 mass % or
lower.
[0235] (36) 1 mass % or lower Mn
[0236] Mn is an element useful as an deoxidizing agent and further,
since Mn forms a compound excellent in machinability in
co-existence with S and Se, Mn is added to alloy according to a
requirement especially when machinability is regarded as important.
The Mn content is desirably set to 0.1 mass % or higher in order to
attain more conspicuousness of the effect. On the other hand, when
added in excess, corrosion resistivity and cold workability are
degraded and deterioration sometimes occurs in characteristics such
as thermal expansion, an elastic constant, magnetic
characteristics, heat resistivity (high temperature strength) and
the like as well. Accordingly, the Mn content is preferably limited
to 1 mass % or lower and more desirably to 0.5 mass % or lower.
[0237] (37) 1 mass % or lower Al
[0238] Al is an element useful as a deoxidizing agent and added to
alloy in necessary since Al is effective for adjustment for
hardness and electric resistivity. However, when added in excess,
deterioration sometimes occurs in characteristics such as thermal
expansion, an elastic constant, magnetic characteristics, heat
resistivity (high temperature strength) and the like. Accordingly,
the Al content is limited to 1 mass % or lower.
[0239] Further, the above described free cutting alloy using (Fe,
Ni) based alloy as base can contain Mo or Cu in the ranges of 7
mass % or lower for Mo; and 7 mass % or lower for Cu. Description
will be given of the reason why the elements and contents thereof
are selected as follows:
[0240] (38) 7 mass % or lower Mo
[0241] Mo is an element useful for improvement on corrosion
resistivity and strength. When the effects are desired to be
conspicuous, Mo is preferably included in the range of 0.2 mass %
or higher. On the other hand, when added in excess, not only is hot
workability deteriorated, but cost-up also occurs and furthermore,
deterioration sometimes occurs in characteristics such as thermal
expansion, an elastic constant, magnetic characteristics, heat
resistivity (high temperature strength) and the like. Accordingly,
the Mo content is preferably limited to 1 mass % or lower and more
desirably to 0.7 mass % or lower.
[0242] (39) 7 mass % or lower Cu
[0243] C is not only useful for improvement on corrosion
resistivity, especially in an environment of a reducing acid, but
effective for improvement on moldability, decreasing work
hardnability. Moreover, since heat treatment or the like processing
can also improve an antibacterial property, Cu may be added to the
alloy according to a necessity. However, since when added in
excess, hot workability decreases, the Cu content is preferably set
to 7 mass % or lower and especially when hot workability is
regarded as important, the Cu content is desirably suppressed to 4
mass % or lower.
[0244] Further, a free cutting alloy of the present invention can
contain 12 mass % or lower Cr and moreover, 18 mass % or lower Co.
For example, in 30.about.40 Ni--Fe alloy, magnetostriction acts so
as reduce a volume in company with reduction in spontaneous
magnetization, which cancels thermal expansion in the ordinary
sense. Especially, 36 at % Ni--Fe alloy is generally called Invar
alloy and a thermal expansion coefficient in the vicinity of
environment temperature is very small, which makes the alloy find a
practically important application. The alloy is in many cases used
in precision machine material such as of a spring for a measuring
instrument. By adding Cr or Co to such an alloy, it is possible to
effectively control a thermal expansion coefficient and an elastic
constant and thereby, desired performances to match with an
intended application can be attained. While Cr is more effective
for control of an elastic constant and Co is more effective for
control of a thermal expansion coefficient, the elements are not
limited to the use in the controls. When Cr or Co are added in
excess of the respective above-described ranges, an unfavorably
large change occurs in compositional conditions on the elements of
Ti, Zr, S, Se, Te and C associated with formation of (Ti, Zr).sub.4
(S, Se, Te).sub.2C.sub.2. Accordingly, the Cr and Co contents are
set to 12 mass % or lower and 18 mass % or lower, respectively.
[0245] Materials to which the present invention can be applied are
in a concrete manner exemplified in trade names among Permalloy
generally used as high permeability material, Perminvar used as
iso-permeability magnetic material and functional material such as
alloy excellent in invar characteristics represented by Invar, and
in addition solid-solution strengthening type heat resisting
material. It should be appreciated that in the case of stainless
steel, an alloy composition means a composition in which part of Fe
and Ni as main components is replaced with the elements of Ti, Zr,
S, Se, C and the like effective for improvement on machinability in
the compositional ranges defined in the present invention.
Accordingly, while trade names are employed, alloys under the trade
names mean alloys specific to the present invention composed with
the alloys of compositions under product specifications as a base
only (it should be appreciated that the alloy compositions inherent
in products under respective trade names are described in a
literature (Revised 3rd Version Kinzoku (Metal) Data Book published
by Maruzen, p 223), therefore detailed description thereof is
omitted):
[0246] (1) High permeability materials including 78-Permalloy,
45-Permalloy, Hipernik, Monimax, Sinimax, Radiometal, 1040 Alloy,
Mumetal, Cr-Permalloy, Mo-Permalloy, Supermalloy, Hardperm,
36-Permalloy and Deltamax;
[0247] (2) Iso-permeability alloy including 25-45 Perminvar, 7-70
Perminvar, 7-25-45 Perminvar, Isoperm and Senperm;
[0248] (3) Invar alloy including Invar, Superinvar, Stainlessinvar,
Nobinite alloy and LEX alloy;
[0249] (4) Elinvar alloy including Elinvar, EL-1, EL-3,
Iso-elastic, Metelinvar, Elinvar Extra, Ni-Span C-902, Y Nic,
Vibralloy, Nivarox CT, Durinval I, Co-Elinvar and Elcoloy IV;
[0250] (5) Fe based super heat resisting alloy including Haynes
556, Incoloy 802, S-590, 16-25-6 and 20-CB3; and
[0251] (6) Ni based heat resisting alloy including Hastelloy-C22,
Hastelloy-C276, Hastelloy-G30, Hasteolloy X, Inconel 600 and
KSN.
EXAMPLES
[0252] The following experiments were performed in order to confirm
the effects of the present invention. It should be appreciated that
in the following description, test alloy relating to the present
invention is referred to as inventive steel or inventive alloy, and
test alloy relating to each of the selection inventions is referred
to as a selection inventive steel or a selection inventive
alloy.
Example 1
Ferrite Containing Stainless Steel (Corresponding to the First
Selection Invention (claim 1-8))
[0253] The effects of a free cutting alloy constituted as ferrite
containing stainless steel (a first selection inventive steel) were
confirmed by the following experiment. First, 50 kg steel blocks
with respective compositions in mass % shown in Table 1 were molten
in a high frequency induction furnace and ingots prepared from the
molten blocks were heated at a temperature in the range of from
1050 to 1100.degree. C. and the ingots were forged in a hot state
into rods with a circular section of 20 mm diameter and the rods
were further heated at 800.degree. C. for 1 hr, followed by air
cooling (annealing) as a source for test pieces.
[0254] While main inclusions of an inventive steel of the present
invention was (Ti, Zr).sub.4(S, Se).sub.2C.sub.2, other inclusions
such as (Ti, Zr) S and (Ti, Zr) S.sub.3 are locally recognized in
the matrix. Further, in a specimen No. 7 high in Mn content, (Mn,
Cr) S is recognized, though in a trace amount. An identification
method for inclusions was performed in the following way: A test
piece in a proper amount was sampled from each of the rods. A metal
matrix portion of the test piece was dissolved by electrolysis
using a methanol solution including tetramethylammonium chloride
and acetylaceton at 10% as a electrolytic solution. The
electrolytic solution after the electrolysis was subjected to
filtration and compounds not dissolved in steel were extracted from
the filtrate. The extract was dried and subjected to chemical
analysis by an X-ray diffraction method with a diffractometer. A
compound was identified based on peaks of a diffraction chart. A
composition of a compound particle in the steel structure was
separately analyzed by EMA and a compound with a composition
corresponding to a compound observed by X-ray diffraction was
confirmed based on formation from two-dimensional mapping results.
FIG. 2 shows an X-ray diffraction chart of an inventive steel No. 5
by a diffractometer and FIG. 3 is an optical microphotograph of an
inventive steel specimen No. 5 shot on a surface thereof in a
magnification 400.times.. Further, specimens Nos. 1 to 14 in Table
1 are kinds of steel corresponding to the first selection inventive
steel and specimens Nos. 15 to 28 are of kinds of steel as
comparative examples.
[0255] The following experiments were performed on the above
described test pieces:
[0256] 1) Hot Workability Test
[0257] Evaluation of hot workability was effected based on visual
observation of whether or not defects such as cracks occur in hot
forging. (.largecircle.) indicates that substantially no defect
occurred in hot forging, (X) indicates that large scale cracks were
recognized in hot forging and .DELTA. indicates that small cracks
occurred in hot forging.
[0258] 2) Evaluation of Machinability
[0259] Evaluation of machinability was collectively effected based
on cutting resistance in machining, finished surface roughness and
chip shapes. A cutting tool made of cermet was used to perform
machining under a dry condition at a circumferential speed of 150
m/min, a depth of cutting per revolution of 0.1 mm and a feed rate
per revolution of 0.05 mm. A cutting resistance in N as a unit was
determined by measuring a cutting force generating in the
machining. The finished surface roughness was measured by a method
stipulated in JIS B 0601 and a value thereof was an arithmetic
average roughness (in pm Ra) on a test piece surface after the
machining. Moreover, chip shapes were visually observed and when
friability was good, the result is indicated by (G) and when
friability is bad and all chips are not separated but partly
connected, the result is indicated by (B).
[0260] 3) Evaluation of Out-Gas Resistivity
[0261] Evaluation of out-gas resistivity was performed by
determining 4,5 an amount of released S. To be concrete, test
pieces in use each had the shape of a rectangular prism of 15 mm in
length, 25 mm in width and 3 mm in thickness and the entire surface
of each were polished with an emery paper. A test piece was placed
in a sealed vessel having an inner volume of 250 cc together with a
silver foil having a size of 10 mm in length, 5 mm in width and 0.1
mm in thickness and 0.5 cc of pure water, and a temperature in the
vessel was maintained at 85.degree. C. for 20 hr. A S content
W.sub.S0 in the silver foil after the process for the test was
measured by a combustion type infrared absorbing analysis
method.
[0262] 4) Cold Workability Test
[0263] Evaluation of cold workability was performed by measuring a
threshold compressive stain in a compression test on specimens Nos.
1 to 5 and 13. Test pieces for compression each had the shape of a
cylinder of 15 mm in diameter and 22.5 mm in height and each piece
was compressed by a 600 t oil hydraulic press to obtain a threshold
compressive strain, wherein the threshold compressive strain is
defined as ln (H0/H) or a natural logarithm of H0/H, H0 being an
initial height of the test piece and H being a threshold height
which is a maximum height at which no cracking has occurred. First
selection inventive alloys of the specimens Nos. 1 to 5 were
confirmed to have high threshold compressive ratios almost equal to
comparative steel specimen No. 15 and higher than comparative steel
specimen No. 16 by about 20%, and have a good cold workability as
well.
[0264] 5) Evaluation of Corrosion Resistivity
[0265] Evaluation of corrosion resistivity was performed by a salt
spray test. Test pieces each were prepared so to have the shape of
a cylinder of 10 mm in diameter and 50 mm in height. The entire
surface of each test piece was polished with #400 emery paper and
cleaned. A test piece was exposed to a fog atmosphere of 5 mass %
NaCl aqueous solution at 35.degree. C. for 96 hr. Final evaluation
was visually performed with the naked eye. As a result, the
inventive steel of the present invention was confirmed to maintain
good corrosion resistivity. The results are shown in Table 2.
[0266] It is found from Table 2 that first selection inventive
steel of the present invention is comparable with conventional
ferrite containing stainless steel in hot workability, cold
workability and corrosion resistivity and moreover, is better in
machinability than the conventional ferrite containing stainless
steel. Further, it is found from Table 2 when comparing with
comparative steel specimens Nos. 16 and 18 that the first selection
inventive steel of the present invention is smaller in W.sub.S0 and
better in out-gas resistivity. The reason why kinds of steel of
comparative alloy specimens Nos. 16 and 18 each have a high
W.sub.S0 is considered that since the steel of the kinds has
neither Ti nor Zr, carbo-sulfide is hard to be formed, whereby a S
amount in the matrix is excessively high. In comparative alloy
specimen No. 18, hot workability is poor and therefore, evaluation
of machinability was not performed.
[0267] The prior arts publications, i.e., JP11-140597 ('597) and
JP10-130794 ('794) seem to disclose alloy composition having
composition overlapping for several elements. Table 16 presents
claim 1 of this invention in contrast to these publications.
[0268] Although '597 coincides with claim 1 in some of the
components, the ratio WS/(WTi+0.52WZr) of the content of S (WS) to
the content of Ti/Zr (WTi+0.52WZr) is not specifically defined in
'597. As a specific alloy composition by adding S and Ti, No. 13 in
Table 1 of '597 is presented as only one example, but when
WS/(WTi+0.52WZr) is calculated, it is 2.33, which is out of the
range (0.45 or less) defined in claim 1. When WS/(WTi+0.52WZr)
exceeds 0.45, the out-gas resistivity cannot be assured
sufficiently. In these tables, results of reference alloys 19 and
20 tested are presented in Table 2. Alloy 20 has a same composition
as in '597, and WS/(WTi+0.52WZr) is 2.33. On the other hand, alloys
1 to 14 are compositions corresponding to claim 1, and
WS/(WTi+0.52WZr) is 0.45 or less in all of them. Reference alloy 20
has a considerably large value of W0S as the index of out-gas
resistivity, whereas alloys 1 to 14 in claim 1 are small in the
value of W0S, and are hence known to be excellent in out-gas
resistivity.
[0269] On the other hand, in '794, the content of C is defined at
0.03 mass % or less. This C content overlaps with that of claim 1
of this invention, i.e., 0.021-0.4 mass %. However, all specific
alloy examples in '794 are compositions with C content of 0.02 mass
% or less as shown in Table 1 of '794. The reason limiting is as
follows according to paragraph 0007 of the publication: "Although C
is a representative solid solution reinforcing element, its content
is preferred to be lower because it has adverse effects of lowering
the corrosion resistance and toughness at ordinary temperature.
However, if decreased extremely, the manufacturing cost is raised,
and hence considering the refining technology, its upper limit is
defined at 0.03%." This purpose is completely different from
enhancement of machinability relating to claim 1 of this invention.
Of course, nothing is mentioned in '794 about the effect of
enhancement of machinability by sufficient formation of (Ti, Zr)
based compound by selecting the C content of 0.021 mass % or more
in the wide C content range up to 0.03 mass % in '794.
[0270] In experimental data in Tables 1 and 2, in reference alloy
19 of which C content is lower than 0.021 mass %, the cutting
resistance is high, whereas the cutting resistance is lower than 25
N in alloys 1 to 14 in claim 47, and a favorable machinability is
realized.
[0271] Thus, claim 1 achieves, in a composition range more limited
than in '597 and '794, evident and unpredictable effects not
disclosed in these publications.
Example 2
Martensite Containing Stainless Steel (Corresponding to the Second
Selection Invention (claim 9-17))
[0272] The following experiment was performed on martensite
containing stainless steel and second selection inventive steel of
the present invention. First, 50 kg steel blocks of compositions in
mass % shown in Table 3 were molten in a high frequency induction
furnace to form respective ingots. The ingots were heated at
temperature in the range of from 1050 to 1100.degree. C. to be
forged in a hot state and be formed into rods each with a circular
section, of a diameter of 20 mm. The rods were further heated at
750.degree. C. for 1 hr, followed by air cooling to be applied to
the test.
[0273] In Table 3, specimens Nos. 1 to 19 are second selection
inventive steels of the present invention constituted as martensite
containing stainless steel. Further, in comparative examples,
specimens correspond to stainless steel: a specimen No. 20
corresponds to SUS 410, a specimen No. 21 to SUS 416, a specimen
No. 22 to SUS 420F and a specimen No. 23 to SUS 440F. Further,
specimens Nos. 24 to 26 are of stainless steel, wherein a C content
of each does not satisfy the formulae A and B, and although alloy
of the specimens is outside the scope of the second selection
invention, the alloy still falls within the scope of the present
invention.
[0274] While main inclusions of the inventive steel of the present
invention was of (Ti, Zr).sub.4 (S, Se).sub.2C.sub.2, other
inclusions such as (Ti, Zr) S and (Ti, Zr) S.sub.3 are locally
recognized in the matrix. Further, in a specimen No. 9 high in a Mn
content and the like, (Mn, Cr) S was recognized, though in a small
amount. An identification of inclusions was performed similar to in
Example 1. FIG. 4 shows EDX (Energy Dispersive X-ray spectrometer)
analytical results of inclusions in a second selection inventive
steel specimen No. 2 and from the results, formation of (Ti, Zr)
based compound can be recognized. Further, FIGS. 5A and 5B show
optical microphotograph of second selection inventive steel
specimens Nos. 2 and 13 shot under a magnification of
400.times..
[0275] The following experiment was performed on the above
described test pieces.
[0276] 1) Hot Workability Test
[0277] Evaluation of hot workability was effected based on visual
observation of whether or not defects such as cracks occur in hot
forging. While workability in hot forging was at levels at which
processing can be performed with no problem, as not only inclusions
but an amount of alloy elements increase, deterioration in the
workability was a tendency observed in the test. It was found that
kinds of steel of the present invention in which one or more of Ca,
B, Mg and REM was included had good hot workability when comparing
with a kind of steel in which none of the elements was
included.
[0278] 2) Evaluation of Machinability
[0279] Evaluation of machinability was collectively effected based
on tool ware loss in machining, finished surface roughness and ship
shapes. A cutting tool made of cermet was used to perform machining
under a wet condition by water-soluble cutting oil at a
circumferential speed of 120 m/min, a depth of cutting per
revolution of 0.1 mm and a feed rate per revolution of 0.05 mm. The
tool ware loss was measured at a flank of the cutting tool after 60
min machining with .mu.m as a unit of the tool wear loss. The
finished surface roughness was measured by a method similar to that
in Example 1.
[0280] The following evaluations were performed using material
subjected to treatments in which the material is kept at 980 to
1050.degree. C. for 30 min, thereafter subjected to a quenching
heat treatment and still further subjected to a tempering treatment
of holding at 180.degree. C. for 1 hr, followed by air cooling.
[0281] 3) Hardness Test
[0282] Measurement of hardness on a test piece was performed on a C
scale Rockwell hardness by the Rockwell hardness test stipulated in
JIS Z 2245. The Rockwell hardness was obtained as the average of
measurements at arbitrary 5 measuring points S on a circle drawn on
a cross section of a rod test piece having a circular section, the
circle drawn on the cross section being a circle satisfying a
relation of PS=0.25 PG, wherein G denotes a point almost coinciding
with a center of the circular section, P denotes an arbitrary point
on the outer periphery of the test piece and a point S is on a line
segment PG
[0283] 4) Evaluation of Out-Gas Resistivity
[0284] Evaluation of out-gas resistivity was performed similar to
in Example 1.
[0285] 5) Evaluation of Corrosion Resistivity
[0286] Evaluation of corrosion resistivity was performed by a
method similar to in Example 1. Test pieces each were prepared so
to have the shape of a cylinder of 15 mm in diameter and 50 mm in
height. The entire surface of each test piece was polished. Each
test piece was polished and thereafter, a test piece was held in a
thermohygrostat at a temperature of 60.degree. C. and a relative
humidity of 90% RH for 168 hr. An evaluation method was such that
when no rust was confirmed, the test piece was evaluated (A), when
dot-like stains were recognized at several points on a test piece,
the test piece was evaluated (B), when red rust was recognized in
an area of an area ratio of 5% or less, the test piece was
evaluated (C) and when red rust was recognized in an area wider
than an area ratio of 5%, the test piece was evaluated (D). The
results are shown in Table 4.
[0287] It is found from Table 4 that while in stainless steel of
comparative specimens Nos. 20 to 23, hardness is sufficiently
ensured, machinability is poor. It is further found that specimens
Nos. 21 to 23 are inferior in corrosion resistivity and out-gas
resistivity. When an inventive steel is compared with a second
selection inventive steel, it is found that the inventive steel has
improved machinability, while the second selection inventive steel
has improved hardness, improved corrosion resistivity and improved
out-gas resistivity. The reason why the second selection inventive
steel was improved in hardness as compared with the inventive steel
is considered that a C content satisfies the formulae A and B and
thereby, a C content constituting a (Ti, Zr) based compound and a C
content as additive establishes an adjusted balance and thereby, a
C component is sufficiently dispersed in a Fe based matrix phase.
Further, the reason why out-gas resistivity was improved is
considered that S is added excessively relative to an amount of a
(Ti, Zr) based compound that can be formed.
[0288] The prior arts publications, i.e., U.S. Pat. No. 4,969,963
(Honkura), JP2-170948 ('948) and JP63-93843 ('843) seem to disclose
alloy composition having composition overlapping for several
elements. Table 17 presents claim 9 in contrast to these
publications.
[0289] Specifically, in claim 9, the content of C is defined at
0.19 mass % or more, but as shown in Table 17, the content of C is
0.15 mass % or less in all publications. For example, in line 59 of
column 2 of Honkura, the content of C is indicated to be less than
0.15%.
[0290] The invention as set forth in claim 1 relates to a
martensitic stainless steel, and if the content of C is less than
0.19 mass %, quench-hardening is not sufficient, and the hardness
of steel tends to be insufficient. As specifically described in the
specification, aside from sufficient hardness by hardening, in
order to enhance the machinability by forming (Ti, Zr) based
compound, the composition ranges of Ti/Zr and S/Se/Te are
defined.
[0291] According to Table 3 and Table 4 attached to the
specification, numbers 25 and 26 show results when the content of C
is less than 0.19 mass %, and the hardness after hardening is as
low as 21 or 28 in HRC. On the other hand, in numbers 1 to 19
corresponding to claim 1, the content of C is 0.19 mass % or more,
and the hardness is 32 or higher.
[0292] Thus, claim 9 achieves, in a composition range more limited
than in Honkura, '948 and '843, evident and unpredictable effects
not disclosed in these publications.
Example 3
Austenite Containing Stainless Steel (Corresponding to the Third
Selection Invention (claim 18-26))
[0293] An experiment was performed on a free cutting alloy of the
present invention constituted as austenite containing stainless
steel (a third selection inventive steel). 50 kg blocks of
compositions in mass % shown in Table 5 were molten in a high
frequency induction furnace to form ingots. The ingots were heated
at a temperature in the range from 1050 to 1100.degree. C. and hot
forging was applied on the ingot at the same temperature to be
formed into rods each having a circular section, of a diameter of
20 mm. Specimens Nos. 1 to 18 and 22 to 26 are steel corresponding
to third selection inventive steels and specimens Nos. 19 to 21 and
27 to 29 are of comparative steels. The specimen No. 19 corresponds
to SUS 304, the specimen No. 20 to SUS 303, the specimen No. 27 to
SUS 329J4L. Among them, the specimens Nos. 1 to 21 are kinds of
steel for use in application of a non-magnetism and the specimens
Nos. 22 to 29 are kinds of steel for use in application other than
non-magnetism. Among them, the specimens Nos. 1 to 24 and 27 were
heated at 1050.degree. C. for 1 hr and thereafter water-cooled,
while the other kinds of steel were heated at 750.degree. C. for 1
hr and thereafter water-cooled. Thereafter, both group of kinds of
steel were further heated at 650.degree. C. for 2 hr and thereafter
water-cooled, followed by tests. All the test pieces of inventive
steels obtained each had a main phase in which at least an
austenitic phase was formed. Main phases of third selection
inventive steels are shown in Table 5, wherein A denotes an
austenitic phase, B a ferritic phase and C a martensitic phase.
[0294] While main inclusions of the inventive steel of the present
invention was of (Ti, Zr).sub.4(S, Se).sub.2C.sub.2, other
inclusions such as (Ti, Zr) S and (Ti, Zr) S.sub.3 are locally
recognized. Further, in specimens Nos. 9, 10 and 13 high in a Mn
content and the like, (Mn, Cr) S was recognized, though in a small
amount. Identification of inclusions was performed similar to in
Example 1. FIG. 8 shows EDX analytical results of inclusions in the
third selection inventive steel specimen No. 2 and from the
results, formation of (Ti, Zr) based compound can be recognized.
Further, FIG. 9 shows an optical microphotograph of the third
selection inventive steels specimen Nos. 2 and 13 shot under a
magnification of 400.times..
[0295] The following experiments were performed on the above
described test pieces for 1) hot workability test, 2) evaluation of
machinability, 3) evaluation of out-gas resistivity, 4) cold
workability test and 5) evaluation of corrosion resistivity by
methods similar to those in Example 1. The experiment on the
evaluation of machinability adopted a circumferential speed of a
cutting tool of cermet at 120 m/min. The results obtained are shown
in Table 6.
[0296] It is found from Table 6 that a free cutting alloy
constituted as austenite containing stainless steel of the present
invention is comparable with conventional stainless steel in hot
workability, cold workability and corrosion resistivity and
moreover, is improved in machinability compared with conventional
stainless steel. Further, it is found that when comparing with
comparative steel of the specimen No. 19, third selection inventive
steels of the specimens Nos. 1 to 18 are improved in machinability.
Further it is found that when comparing with comparative steel
specimen No. 20, the specimens Nos. 1 to 18 are smaller in W.sub.S0
and excellent in out-gas resistivity. Further, when comparing with
comparative steel specimens Nos. 27 to 29, it is found that third
selection inventive steel Nos. 22 to 26 are improved on
machinability. That is, the third selection inventive steel is
comparable with the comparative steel in corrosion resistivity and
hot workability and in addition, improved on machinability and
out-gas resistivity.
[0297] The prior art publication, i.e., JP60-155653 ('653) seems to
disclose alloy composition having composition overlapping for
several elements. Table 19 presents claim 18 in contrast to the
publication. However, in the alloy composition of '653, the total
content of S and Se is lower than C, but in claim 18, the total
content of S and Se is higher than the content of C. This is
intended to enhance the machinability by sufficiently forming (Ti,
Zr) based compound. Meanwhile, since the machinability also depends
on the matrix composition (the composition of the remaining
components excluding the components relating to the (Ti, Zr) based
compound such as Ti, Zr, C, S, Se, Te), it is important to compare
the effects of forming components of (Ti, Zr) based compound while
the matrix composition is kept almost the same, from the viewpoint
of checking the effects.
[0298] The results, alternately exhibiting the results of alloys
(corresponding to claim 18) having the total content of S and Se
higher than the content of C, in various matrix compositions (Table
5 attached to the specification: 1 to 18), and the results of
reference alloys having the total content of S and Se lower than
the content of C, in the nearly same matrix compositions are
presented in Tables 19 and 20. In all matrix compositions, the
alloys of claim 18 having the total content of S and Se higher than
the content of C are substantially lowered in the cutting
resistance as compared with the reference alloys, and are enhanced
in machinability.
[0299] Thus, claim 18 achieves, in a composition range more limited
than in '653, evident and unpredictable effects not disclosed in
the publication.
Example 4
Electromagnetic Stainless Steel (Corresponding to the Fourth
Selection Invention (claim 27-40))
[0300] Next, the following experiment was performed on a free
cutting alloy relating to the fourth selection inventive steel of
the present invention constituted as electromagnetic stainless
steel. First, 7 kg blocks of inventive steels of the present
invention and comparative steels provided for tests, whose
compositions in mass % shown in Tables 7 and 8, were molten in a
induction furnace in an Ar stream to obtain ingots of 80 mm in
diameter. Then, the ingots were processed in hot forging at a
temperature in the range of 1000 to 1050.degree. C. to be formed
into rods of a circular section of 22 mm in diameter and
thereafter, the rods were each machined into a diameter of 21 mm,
followed by cold rolling into a diameter of 18 mm. The rods thus
rolled were subjected to tests. In Tables 7 and 8, specimens Nos. 1
to 38 are test rods of fourth selection inventive steels and
specimens Nos. 39 to 47 are test rods of inventive steels. The test
rods were measured on magnetic characteristics, electric
resistivity, machinability, cold workability and corrosion
resistivity by measuring methods described below, which will be
described below:
[0301] Measuring Methods
[0302] 1) Magnetic Characteristics
[0303] A test piece in the shape of a ring, of 10 mm in outer
diameter, 5 mm in inner diameter and 5 mm in thickness was prepared
for measurement of magnetic characteristics. The test piece
received magnetic annealing at 950.degree. C. and thereafter,
direct current magnetic characteristics including a magnetic flux
density and a direct current coercive force were measured by a B-H
loop tracer: a magnetic flux density Bi (KG) under a magnetic field
of 1 Oe and a magnetic flux density B10 (KG) under a magnetic field
of 10 Oe and a direct current coercive force Hc (A/cm). Relations
between a magnetic flux density B1 or a coercive force Nc and a are
shown in FIG. 10.
[0304] 2) Electric Resistivity
[0305] Electric resistivity was measured on test pieces, which were
each prepared by subjecting a test rod to cold wire-drawing to
obtain a wire of 1 mm in diameter, and then performing vacuum
annealing at 950.degree. C. thereon.
[0306] 3) Machinability
[0307] Machinability was evaluated as follows: a SKH 51 drill of 5
mm in diameter was used on a test piece of steel for machining at a
number of revolution of 915 rpm under a load of 415 N on a cutting
edge thereof and a time in sec consumed for boring a hole of 10 mm
in depth was measured. Machinability was evaluated by a length of
the time in sec.
[0308] 4) Cold Workability
[0309] Cold workability was evaluated by a cracking threshold
working ratio and a procedure was as follows: a test piece was
prepared in the shape of a cylinder, 20 mm in diameter and 30 mm in
height. The test piece was annealed at 720.degree. C. and there
after a compression test was performed on the test piece under a
hydraulic pressure of 400 t to evaluate a cracking threshold
working ratio. Relations of a boring time or a cracking threshold
working ratio and a are shown in FIG. 11.
[0310] 5) Pitting Potential
[0311] A test piece was prepared in the shape of a disc whose size
is 18 mm in diameter and 2 mm in thickness. The test piece was
polished with sand papers up to No. 800 and subjected to magnetic
annealing at 950.degree. for 2 hr in a vacuum. Thereafter, a
pitting potential Vc in mV was measured on the test piece in a 3.5%
NaCl aqueous solution at 30.degree. C. FIG. 12 shows a relation
between a pitting potential and a. The measuring results are shown
in Tables 9 and 10.
[0312] As can be found from Tables 9 and 10, and FIG. 10, very
excellent magnetic characteristics are shown: at
.vertline..alpha..vertline..ltoreq- .0.07, Hc<1.0 A/cm and
B1>2.5 KG. The magnetic characteristics changes rapidly in the
vicinity of .alpha.=0.07 and gradually in the range of
0.07<.alpha..ltoreq.0.45. The magnetic characteristics in
relatively good ranges of 1.0<Hc<1.5 A/cm and
1.0<B1<2.0 KG are retained in the range of
0.07<.alpha..ltoreq.0.45. While the magnetic characteristics
again starts growing larger from a point in the vicinity of
.alpha.=0.45, the magnetic characteristics show 1.4<Hc<2.5
A/cm and 0.4<B1<1.0 KG in the range of
0.45<.alpha..ltoreq.0.70, which falls in the ranges usable
practically as electromagnetic stainless steel.
[0313] Moreover, as can be clear from Tables 9 and 10, and FIG. 11,
while machinability does not show a correlation with ax as clear as
magnetic characteristics have, a relatively good machinability was
obtained in the range of .vertline..alpha..vertline..ltoreq.0.70
showing a boring time in the range of 14 to 17 sec, and excellent
cold workability in the same range of
.vertline..alpha..vertline..ltoreq.0.70 was obtained showing a
cracking threshold working ratio in the range of 80 to 86%. The
machinability and cracking threshold working ratio each show a
large fluctuation between a values adjacent to each other, which
occurs probably due to a difference in content of Si, Mn and Cr as
one of causes. In the range of 0.07<.alpha..ltoreq.0.45,
relatively good machinability was obtained showing a boring time in
the range of 13 to 17 sec, and relative good cold workability was
obtained showing a cracking threshold working ratio in the range of
75 to 85%. On the other hand, in the range of
0.45<.alpha..ltoreq.0.70, while cold workability at a high
working ratio is hard showing a cracking threshold working ratio
being 76% or less, excellent machinability was obtained showing a
boring time in the range of 10 to 16 sec.
[0314] Specimens Nos. 8, 10, 19, 21, 30 and 32 including Pb as a
component each have a short boring time compared with specimens of
inventive steel of the present invention with respective .alpha.
values close to those of the specimens including Pb. Further,
specimens Nos. 8, 9 to 11, 19 to 22 and 30 to 33 including B and/or
REM as a component each have a large cracking threshold working
ratio compared with specimens of inventive steel of the present
invention with respective a values close to those of the specimens
including B and/or REM.
[0315] As can be clear from Tables 9 and 10, and FIG. 12 (where
high Cr stainless steel with an extremely high Vc and low Cr
stainless steel with a very low Vc are excluded), in the range of
.vertline..alpha..vertline..- ltoreq.0.07, Vc is in the range of
-80<Vc<0 in mV and good corrosion resistivity is shown. In
the range of 0.07<.alpha..ltoreq.0.45, Vc is in the range of
-50<Vc<70 in mV and better corrosion resistivity is shown.
While Vc decreases further in the range of 0.45<.alpha..ltoreq.-
0.70, Vc is considered to be practically useful as far as
Vc>-150 mV.
[0316] Specimens Nos. 6, 7, 10, 11, 17, 18, 21, 22, 28, 29, 32 and
33 including Ni, Cu, Mo, Nb and V, which improve corrosion
resistivity, have high Vc compared with specimens of inventive
steel of the present invention with respective a values close to
the specimens including Ni, Cu, Mo, Nb and V. Further, specimens
Nos. 27 and 38 including an element which improves corrosion
resistivity keep Vc of the same order as those of specimens of
inventive steel of the present invention with respective a values
smaller than the specimens including the corrosion resistivity
improving element.
[0317] Specimens Nos. 39 to 47 of inventive steel of the present
invention are outside the scope of the fourth selection inventive
steel, as shown in FIG. 1. When comparing the inventive steel of
the present invention with the fourth selection inventive steel, it
is found that all the specimens of the inventive steel each show a
cracking threshold working ratio of 72% or less and therefore, the
fourth selection inventive steel is superior in cold workability.
Further, when specimens of both kinds with respective a values
close to each other are compared with each other, it is found that
the fourth selection inventive steel is more excellent than the
inventive steel in magnetic characteristics and corrosion
resistivity. Further, when comparing specimens Nos. 39 to 42 of the
inventive steel with specimens of the fourth selection inventive
steel, it is found that the fourth selection inventive steel is
better than the inventive steel in machinability. When comparing
inventive steels of specimens Nos. 43 and 44 and fourth selection
inventive steels, it is found that while both kinds of steel show
almost the same level of machinability, the fourth selection
inventive steels are better than the inventive steels in the other
characteristics and when comparing inventive steels of specimens
Nos. 45 to 47 with fourth selection inventive steels, it is found
that the fourth selection inventive steels have better magnetic
characteristics and better corrosion resistivity.
[0318] FIG. 13 shows dependencies of solubility products on
temperature of compounds of TiO, TIN, Ti.sub.4C.sub.2S.sub.2, TIC,
TiS and CrS in .gamma.-Fe (an austenitic phase). Since Zr has a
chemical property analogous to Ti, and Se and Te have a chemical
property analogous to S, it is considered that compounds are formed
in the descending order of priority of (Ti, Zr)O>(Ti,
Zr)N>(Ti, Zr).sub.4C.sub.2 (S, Se, Te)>(Ti, Zr)C>(Ti, Zr)
(S, Se, Te)>Cr (S, Se, Te). Further, it was confirmed that the
above described compounds were present in steel by X-ray
analysis.
[0319] The prior arts publications, i.e., JP60-155653 ('653),
JP11-140597 ('597), JP10-130794 ('794), Honkura, JP2-170948 (1948),
and JP63-938743 ('843) seems to disclose alloy composition having
composition overlapping for several elements. Table 21 presents
claims 27 to 40 in contrast to these publications. FIG. 17 shows
the composition ranges specified in claims 27 to 40, in which the
axis of abscissas denotes C/X and the axis of ordinates represents
Y/X, by using X and Y defined in the claims. The alloy compositions
presented in the publications are plotted in the diagram.
[0320] The alloy composition presented in '794 (indicated by solid
wedge mark) seems to belong to the range of claims 27 (first
combination) and 35 (third combination). However, corresponding
alloy compositions in Table 1 of '794 (inventive steel 11, 13, 14,
15) all contains Pb of more than 0.17 mass %, which is much exceeds
the upper limit of Pb in claims 27 and 35, i.e., 0.01 mass %. As is
shown in Table 7-10, the alloy compositions defined in claims 27
and 35 exhibit excellent machinability despite of the limited Pb
content less than 0.01 mass %.
[0321] On the other hand, the alloy compositions in the
publications are all outside of the scope of claims 31 (second
combination) and 39 (third combination), presented in FIG. 17 by
the hatching area. Table 22 extracts the alloy compositions
belonging to the hatching area across the composition boundary and
alloy compositions outside of the region, from the data of Tables 7
to 10 attached to the specification, and arranges alternately so
that those similar in matrix composition can be compared with each
other. The compositions in claims 31 and 39 are notably excellent,
as compared with the compositions outside of the region, in the
value of B1 (magnetic flux density in magnetic field of 1 Oe) which
shows the initial magnetization start-up characteristic, an
important index for magnetic, especially, soft magnetic material.
Besides, the limit processing rate is also high, and an obvious
difference is noted in cold processability. Further, the pit
generation potential is also high, and the corrosion resistance is
excellent. Thus, in the limited composition ranges of claims 31 and
39, marked effects are achieved in magnetic property, cold
processability and corrosion resistance, and these effects are not
mentioned in any one of the publications.
[0322] Therefore, claims 27, 31, 35, 39 achieve, in a composition
range more limited than in the publications, evident and
unpredictable effects not disclosed in these publications.
Example 5
(Fe, Ni) Based Alloy (Corresponding to the Fifth Selection
Invention (claim 41-44))
[0323] A free cutting alloy of the present invention constituted
with Ni based alloy used as (Fe, Ni) based electromagnetic material
and (Fe, Ni) based heat resisting material (the fifth selection
invention) was prepared in the following way to be applied to
tests: First, Test alloy of various compositions in mass % shown in
Tables 11, 12 and 13, which is 7 kg blocks, were molten in a high
frequency furnace in an Ar stream to be formed into ingots of 80 mm
in diameter. Then, the ingots were processed in hot forging at a
temperature in the range of 950 to 1100.degree. C. into rods having
a circle section, 24 mm in diameter. Thereafter, the rods were
machined to a diameter of 23 mm, followed by cold rolling into a
diameter of 22 mm, to obtain test alloys.
[0324] Further, identification of inclusions in the structure was
performed by a method similar to Example 1. While main inclusion in
inventive steel of the present invention was (Ti, Zr) 4 (S,
Se)C.sub.2, inclusions such as (Ti, Zr)S and (Ti, Zr) S.sub.3 were
locally recognized. A trace of (Mn, Cr)S was recognized in each of
specimens Nos. 2, 14, 19, 29, 36, 39, 49 and 55, all having a high
Mn content. An optical microphotograph of a specimen No. 30 of a
third selection inventive alloy is shown in FIG. 14.
[0325] Thus obtained Ni based alloys of the compositions were
evaluated on not only hot workability and machinability, but also
characteristics required of Ni alloy among magnetic
characteristics, a thermal expansion coefficient and an elastic
constant. Evaluation methods for respective characteristics are as
follows:
[0326] 1) Hot Workability Test
[0327] Evaluation of hot workability was effected based on visual
observation of whether or not defects such as cracks occur in hot
forging. (.largecircle.) indicates that substantially no defect
occurred in hot forging, (X) indicates that large scale cracks were
recognized in hot forging and .DELTA. indicates that so small
cracks as to be removed by a grinder occurred in hot forging. A
relation between the ranges of the parameters of X and Y defined by
the formulae (1) and (2) and evaluation results of hot workability
is shown in FIG. 15.
[0328] 2) Machinability
[0329] Machinability was evaluated as follows: a SKH 51 drill of 5
mm in diameter was used on a test piece of steel for machining at a
number of revolution of 915 rpm under a load of 415 N on a cutting
edge thereof and a time in sec consumed for boring a hole of 10 mm
in depth on steel was measured. Machinability was evaluated by a
length of the time. A relation between a parameter Y in mass % and
a boring time is shown FIG. 16.
[0330] 3) Magnetic Characteristics
[0331] Test pieces each in the shape of a ring, of 10 mm in outer
diameter, 4.5 mm in inner diameter and 5 mm in thickness were
prepared for measurement of magnetic characteristics. A test piece
received magnetic annealing at 1000.degree. C. and thereafter,
direct current magnetic characteristics including a magnetic flux
density, a maximum magnetic permeability and a direct current
coercive force were measured by a B-H loop tracer: a magnetic flux
density B1 (T) under a magnetic field of 1 Oe, a magnetic flux
density B5 (T) under a magnetic field of 5 Oe, and a magnetic flux
density B10 (T) under a magnetic field of 10 Oe, a maximum magnetic
permeability (.mu.m) and a direct current coercive force Hc
(A/cm).
[0332] 4) Thermal Expansion Coefficient
[0333] Test alloy pieces each were prepared in a procedure in which
cold-worked rods were each shaped into a cylinder of 5 mm in
diameter and 50 mm in height and thereafter, processed in a
solution treatment at 1000.degree. C., followed by rapid cooling.
After the rapid cooling, an alloy cylinder as an intermediate was
subjected to an aging heat treatment at temperatures from 580 to
590.degree. C. into a final test alloy piece. Young's modulus was
measured on the test alloy pieces at temperatures ranging from 20
to 100.degree. C. using a free resonance elastic modulus tester.
The results are shown in Tables 14 and 15.
[0334] Data of evaluations of hot workability are indicated by
plotting of the marks .largecircle., .DELTA. and X. A straight line
1 is a boundary line (Y=0.5 X) of the condition formula (2) and a
straight line 2 is a boundary line (0.2Y=W.sub.C) of the condition
formula (3). In the prior art, it was considered that when Ni was
included in a large content, hot workability was extremely
deteriorated if S was added as a free cutting element. However,
when comparing specimens Nos. 1 to 20 of fifth selection inventive
alloys of compositions shown in Tables 11, 12 and 13 with specimens
Nos. 71 to 75 of inventive alloys of the present invention and
specimens Nos. 66to 70of comparative alloy, it is found that the
fifth selection inventive alloy has hot workability better than the
comparative alloys and the inventive alloys of the present
invention have, regardless of a magnitude of each of contents of
additive elements Si, Mn, Al and Mo, each in the range of 1% or
lower. This is considered because, in such conditions, since a
percent of inclusions of carbo-sulfide based (Ti,
Zr).sub.4C.sub.2(S, Se, Te).sub.2 especially stable among sulfide
based inclusions is large, formation of (Mn, Cr, Ni)S being a cause
for hot-work cracking is controlled. This mechanism was confirmed
by actual analysis on components of the inclusions. That is, it is
found that machinability is improved in the inventive alloy of the
present invention and moreover, not only machinability but also hot
workability are improved in the fifth selection inventive
alloy.
[0335] Judging from Tables 14 and 15, it is found that while
magnetic characteristics of specimens Nos. 9 to 12 of fifth
selection inventive alloys with Permalloy B as a base component are
almost not deteriorated, machinability is improved by a great
margin when compared with the characteristics of Permalloy B alloy
shown as a specimen No. 60 of a comparative alloy. While thermal
expansion coefficients of specimens Nos. 5 to 8 of fifth selection
inventive alloys with low expansion alloy of specimen No. 59 of a
comparative alloy similar to Invar alloy as a base composition are
also almost not deteriorated, machinability thereof is greatly
improved. That is, the fifth selection inventive alloy of the
present invention to which Ti and Zr, and S, Se and Te are added so
as to satisfy the condition formulae (1) to (3) has no reduction in
hot workability and furthermore, almost no deterioration in
functional performances inherited from the base alloy.
[0336] It is found that in specimens Nos. 17 to 26 of fifth
selection inventive alloys, an effect of improving machinability
can be attained even if Cr is added with 12 mass % as the upper
limit. For example, specimens Nos. 20 to 23 of fifth selection
inventive alloys with specimen No. 61 of a comparative alloy, as
abase composition, which is a constant-modulus alloy whose elastic
characteristics are constant in the vicinity of room temperature,
has not only good hot workability, but also greatly increased
machinability, and in addition, a temperature coefficient of a
Young's modulus is almost not affected either, thereby enabling use
as constant modulus alloy in a proper manner.
[0337] It is found that in specimens Nos. 27 to 36 of fifth
selection inventive alloys, even when Co is added with 18% as the
upper limit, good hot workability and the effect of improving
machinability can be obtained. Thermal coefficients of specimens
Nos. 30 to 33 of fifth selection inventive alloys with a glass
sealing agent of a comparative alloy as a base composition receive
almost no influence either but the specimens Nos. 30 to 33 improve
machinability by a great margin. Tn such a way, even when Co is
added in the range of 18% or less, none of the effects of the
present invention changes and the fifth selection inventive alloy
can be preferably used as Invar alloy excellent in machinability.
The effect to contain Cr or Co can be exerted when both elements
are co-existent as well.
[0338] FIG. 16 is a graph obtained by plotting a drill boring time
on alloy in Example 5 against Y in mass %. As can be seen in the
graph, when Y is less than 0.01 mass %, it is seen that a boring
time tends to accelerate its increase.
[0339] While some of Examples are shown above on a free cutting
alloy, the examples are shown for illustrative purposes only and
the present invention can be performed in other embodiments having
modifications based on knowledge of those skilled in the art
without departing from the spirit or scope of the following
claims.
[0340] The present invention can be applied to not only Fe based
alloy shown in Examples, but other alloy requiring machinability.
For example, The present invention can be applied to Ni based
alloy, Co based alloy, Ti based alloy, Cu based alloy, or the like
as well and when applied to these kinds of alloy, a (Ti, Zr) based
compound are preferably formed in the alloy structure by
substituting (Ti, Zr)C and (S, Se, Te) for part of the alloy
composition.
[0341] The prior arts publications, i.e., JP60-155653 ('653),
JP11-140597 ('597), JP10-130794 ('794), Honkura, JP2-170948 ('948),
and JP63-938743 ('843) seem to disclose alloy composition having
composition overlapping for several elements. Table 23 presents
claims 41 to 44 in contrast to these publications. In claim 41,
meanwhile, the content of S (Se, Te) is amended to 0.014 mass % or
more. Specifically, in claim 41, the content of S (Se, Te) is
defined at 0.014 mass % or more, but as shown in Table 23, it is
0.012 mass % or less in '653. In other publications, the content of
Ni in far smaller than in claim 41, and above all the alloy system
is different from that of the present invention.
[0342] Table 24 extracts the compositions of S (Se, Te) content of
0.014 mass % or more and those of less than 0.014 mass %, from the
data of Tables 11 to 15 attached to the specification, and arranges
alternately so that those similar in matrix composition can be
compared with each other. As clear from this table, when the (Se,
Te) content is 0.014 mass % or more, the boring time is notably
shortened, and the cutting performance is extremely excellent.
[0343] Thus, claim 41 achieves, in a composition range more limited
than in the publications, evident and unpredictable effects not
disclosed in these publications.
1 TABLE 1 Ws/ C Si Mn P Cu Ni Cr N O Ti Zr S Se note (W.sub.t1 +
0.52W.sub.Zr) first 1 0.029 0.22 0.05 0.01 0.05 0.05 16.7 0.006
0.004 0.58 -- 0.21 -- -- 0.36 selec- 2 0.149 0.18 0.28 0.01 0.19
0.13 19.3 0.016 0.006 1.15 -- 0.33 0.13 -- 0.29 tion 3 0.103 0.52
0.35 0.02 0.45 0.83 20.5 0.009 0.002 0.52 0.61 0.28 -- 0.8Mo 0.53
inven- 4 0.021 0.33 0.55 0.02 0.22 0.63 28.3 0.007 0.008 0.14 --
0.05 -- 0.16Pb 0.36 tive 5 0.159 0.22 0.29 0.01 1.17 0.04 20.2
0.007 0.009 1.01 0.52 0.42 -- 1.8Mo, 0.02Te 0.42 steel 6 0.111 0.87
0.52 0.02 0.13 0.65 18.5 0.004 0.001 1.05 -- 0.34 -- 2.2W, 0.001BMg
0.32 7 0.095 0.26 1.79 0.01 0.11 0.33 21.4 0.004 0.005 0.89 -- 0.25
0.11 0.11Bl, 0.0027Ca 0.28 8 0.072 0.32 0.43 0.02 0.25 1.21 24.3
0.008 0.005 0.77 -- 0.25 -- 0.0033B 0.32 9 0.216 0.28 0.18 0.02
0.25 0.25 19.2 0.013 0.009 1.65 -- 0.47 0.18 0.11Ta, 0.0025REM 0.28
10 0.100 0.14 0.33 0.02 0.22 0.23 19.0 0.007 0.009 0.85 -- 0.28 --
0.23Nb 0.33 11 0.094 0.36 0.85 0.01 0.54 0.13 15.2 0.003 0.011 0.94
-- 0.31 -- 2.8Mo, 0.25Hf, 0.33 0.0022B 12 0.133 0.29 0.33 0.02 0.42
0.32 22.2 0.002 0.004 1.16 -- 0.38 -- 1.5Co 0.33 13 0.075 0.49 0.41
0.03 0.31 0.11 17.9 0.012 0.007 0.68 -- 0.22 -- 0.17Pb, 0.03Te,
0.32 2.2Mo 14 0.096 0.24 0.67 0.02 0.08 0.54 20.2 0.008 0.006 0.82
-- 0.28 -- 0.26Pb 0.34 com- 15 0.002 0.29 0.05 0.02 0.15 0.24 16.5
0.008 0.003 --* -- --* -- -- -- par- 16 0.002 0.19 0.88 0.02 0.17
0.19 17.2 0.018 0.002 --* -- 0.21 -- -- .infin. ative 18 0.019 0.33
1.06 0.01 0.25 0.24 18.9 0.011 0.012 --* -- 0.42 -- 0.38Pb, 0.15Te
.infin. steel 19 0.014 0.31 1.12 0.01 0.3 0.25 17.6 0.018 0.011
0.51 -- 0.26 -- -- 0.51 20 0.070 1.10 1.40 -- 0.3 -- 24.3 -- --
0.09 -- 0.21 -- -- 2.33 *indicates "outside the scope of the
present invention."
[0344]
2 TABLE 2 finished cutting surface hot resistance roughness chip
Wos workability [N] [.mu.m] shape [mass %] first 1 .largecircle.
24.5 1.12 G 0.005 selec- 2 .largecircle. 21.9 0.95 G 0.014 tion 3
.largecircle. 23.8 1.09 G 0.017 in- 4 .largecircle. 25.8 1.35 G
0.009 ven- 5 .largecircle. 19.5 0.81 G 0.011 tive 6 .largecircle.
21.8 0.99 G 0.017 steel 7 .largecircle. 19.4 0.83 G 0.031 8
.largecircle. 25.9 1.32 G 0.019 9 .largecircle. 20.0 0.86 G 0.011
10 .largecircle. 23.4 1.15 G 0.018 11 .largecircle. 23.6 1.09 G
0.023 12 .largecircle. 21.6 1.00 G 0.014 13 .largecircle. 19.8 0.78
G 0.013 14 .largecircle. 20.5 0.90 G 0.015 com- 15 .largecircle.
35.4 1.87 B 0.002 par- 16 .largecircle. 26.3 1.41 G 0.062 ative 18
X -- -- -- 0.052 steel 19 .largecircle. 27.1 1.44 G 0.043 20
.largecircle. 26.4 1.53 G 0.056 * indicates "outside the scope of
the present invention."
[0345]
3 TABLE 3 C Si Mn P Cu Ni Cr N O Ti Zr S Se note formula A formula
B sec- 1 0.23 0.38 0.23 0.01 0.08 0.09 12.9 0.001 0.004 0.37 --
0.12 -- -- .largecircle. .largecircle. ond 2 0.25 0.49 0.33 0.02
0.05 0.22 14.1 0.003 0.005 0.88 -- 0.31 0.05 -- .largecircle.
.largecircle. selec- 3 0.53 0.53 0.29 0.02 0.06 0.17 13.4 0.005
0.002 1.00 -- 0.34 -- -- .largecircle. .largecircle. tion 4 0.81
0.42 0.24 0.01 0.02 0.08 13.3 0.003 0.002 0.91 -- 0.31 -- --
.largecircle. .largecircle. in- 5 1.16 0.12 0.22 0.01 0.02 0.02
14.1 0.002 0.003 0.89 -- 0.35 -- -- .largecircle. .largecircle.
ven- 6 0.38 0.11 0.10 0.02 0.23 0.12 11.4 0.002 0.003 1.77 -- 0.58
-- 0.4Mo .largecircle. .largecircle. tive 7 0.43 0.65 0.26 0.01
0.05 0.06 13.6 0.015 0.005 2.22 -- 0.72 -- 0.9W .largecircle.
.largecircle. steel 8 0.31 1.03 0.31 0.01 0.04 0.04 10.5 0.003
0.004 0.63 0.53 0.31 -- 0.5Mo .largecircle. .largecircle. 9 0.35
0.11 1.16 0.02 0.02 0.01 11.2 0.002 0.004 0.84 -- 0.23 0.11 0.8Mo
.largecircle. .largecircle. 10 0.45 0.35 0.32 0.01 0.82 0.22 13.1
0.009 0.006 0.91 -- 0.29 -- 0.0025Ca .largecircle. .largecircle. 11
0.66 0.24 0.34 0.02 0.18 0.23 15.2 0.004 0.007 0.88 -- 0.25 0.15
0.0019B .largecircle. .largecircle. 12 0.19 0.45 0.52 0.02 0.35
0.11 13.6 0.001 0.004 0.10 -- 0.03 -- 0.18Pb .largecircle.
.largecircle. 13 0.50 0.32 0.24 0.01 0.08 0.11 9.5 0.002 0.012 0.68
-- 0.23 -- 1.6Mo .largecircle. .largecircle. 14 0.42 0.25 0.25 0.03
0.16 0.32 13.8 0.007 0.004 0.75 0.42 0.33 -- 0.11Bi, 0.0015Mg
.largecircle. .largecircle. 15 0.48 0.15 0.31 0.02 0.24 1.23 13.4
0.004 0.005 0.88 -- 0.22 0.22 1.8Co, 0.0022REM .largecircle.
.largecircle. 16 0.32 0.26 0.39 0.02 0.42 0.19 12.8 0.009 0.006
0.65 0.12 0.18 0.15 0.03Te, 0.12Nb .largecircle. .largecircle. 17
0.42 0.43 0.32 0.02 0.15 0.32 12.9 0.003 0.006 0.91 -- 0.31 --
0.21V, 0.05Pb .largecircle. .largecircle. 18 0.52 0.52 0.51 0.02
0.13 0.22 12.8 0.004 0.002 0.75 -- 0.23 0.12 0.30Hf, 0.0034B
.largecircle. .largecircle. 19 0.38 0.39 0.25 0.01 0.03 0.29 12.6
0.004 0.005 0.72 -- 0.25 -- 0.15Ta, 0.02Bi .largecircle.
.largecircle. com- 20 0.14 0.45 0.72 0.02 0.15 0.19 12.5 0.009
0.006 -- -- -- -- -- -- -- par- 21 0.13 0.38 0.96 0.02 0.09 0.16
12.8 0.006 0.005 -- -- 0.27 -- -- -- -- ative 22 0.34 0.45 0.62
0.02 0.11 0.22 13.2 0.008 0.007 -- -- 0.24 -- -- -- -- steel 23
1.04 0.51 1.03 0.02 0.05 0.12 16.2 0.004 0.003 -- -- 0.22 -- -- --
-- in- 24 0.22 0.45 0.32 0.01 0.32 0.31 13.4 0.005 0.005 1.42 --
0.45 -- -- .largecircle. X ven- 25 0.14 0.38 0.44 0.02 0.21 0.19
13.5 0.005 0.006 1.05 -- 0.15 -- -- .largecircle. X tive 26 0.13
0.28 0.51 0.03 0.08 0.32 12.9 0.011 0.008 0.25 -- 0.25 -- -- X
.largecircle. steel
[0346]
4 tool finished ware surface hardness loss roughness chip corrosion
out-gas [HRC] [.mu.m] [.mu.m] shape resistivity resistivity sec- 1
35 390 1.21 G A 0.008 ond 2 32 305 0.93 G A 0.014 selec- 3 54 315
0.97 G A 0.013 tion 4 59 355 0.85 G A 0.017 in- 5 61 370 0.88 G A
0.015 ven- 6 32 275 0.81 G A 0.019 tive 7 33 255 0.75 G A 0.022
steel 8 38 300 0.90 G A 0.011 9 45 310 0.95 G A 0.022 10 50 325
1.02 G A 0.012 11 57 330.0 1.05 G A 0.014 12 34 325.0 1.20 G A
0.005 13 55 340.0 0.98 G A 0.018 14 44 305 1.06 G A 0.018 15 54 335
1.00 G A 0.015 16 37 305 1.05 G A 0.009 17 47 310 1.08 G A 0.020 18
55 330 0.92 G A 0.015 19 45 300 0.95 G A 0.013 com- 20 36 >500
2.07 B A 0.004 par- 21 35 320 1.65 G C 0.063 ative 22 54 340 1.72 G
C 0.048 steel 23 61 395 1.57 G C 0.071 in- 24 22 335 1.39 G A 0.019
ven- 25 21 430 1.32 I A 0.009 tive 26 28 330 1.11 G B 0.013
steel
[0347]
5 TABLE 5 Ti + main C Ni Cr Ti Zr S Se Si Mn P O N note 0.52Zr
phase third 1 0.075 9.8 18.8 0.61 0.21 0.19 0.28 0.025 0.003 0.007
0.61 A selection 2 0.118 12.2 20.5 0.96 0.32 0.28 0.39 0.013 0.007
0.004 0.8Cu 0.96 inventive 3 0.175 11.9 19.4 1.31 0.44 0.15 0.57
0.018 0.003 0.007 1.31 steel 4 0.262 8.5 18.1 2.13 0.68 0.31 0.32
0.008 0.003 0.009 2.13 5 0.118 7.9 17.8 0.98 0.30 0.31 0.42 0.019
0.003 0.008 1.3Mo 0.98 6 0.171 10.4 17.9 1.28 0.45 0.33 0.12 0.033
0.004 0.011 0.4Cu, 0.4Mo 1.28 7 0.121 8.7 17.8 1.02 0.31 0.21 0.30
0.028 0.004 0.014 2.8Cu 1.02 8 0.169 19.2 24.2 1.05 0.42 0.28 0.61
0.18 0.042 0.001 0.019 1.27 9 0.062 18.6 24.5 0.55 0.24 0.19 0.32
1.68 0.007 0.002 0.024 0.4Cu, 5.8Mo, 0.0029B 0.67 10 0.122 35.9
30.2 1.01 0.32 0.29 1.23 0.005 0.005 0.007 1.2Co, 0.0018Ca 1.01 11
0.265 12.4 17.8 2.09 0.57 0.22 0.49 0.38 0.029 0.004 0.012 2.2Mo,
0.13Pb, 0.0015Mg 2.09 12 0.048 41.9 15.6 0.52 0.24 0.18 0.07 0.32
0.37 0.015 0.013 0.039 5.2Mo, 4.7W, 0.0031REM 0.64 13 0.141 20.4
24.2 1.14 0.38 0.06 0.72 2.44 0.002 0.002 0.004 0.08Bi, 0.15Nb 1.14
14 0.071 15.2 22.9 0.51 0.33 0.08 0.88 0.019 0.005 0.009 1.9W,
0.03Te, 0.0031B 0.51 15 0.032 10.9 20.2 0.18 0.07 0.61 0.34 0.011
0.002 0.009 0.21Pb, 0.14V 0.18 16 0.092 15.3 19.1 0.88 0.34 2.17
0.21 0.028 0.004 0.012 0.0022Ca, 0.22Ta 0.88 17 0.155 7.9 17.2 1.11
0.41 0.04 0.19 0.011 0.002 0.021 1.8Cu, 0.17Hf 1.11 18 0.089 6.2
17.1 0.59 0.19 0.32 0.63 0.019 0.002 0.012 0.25Pb 0.59 com- 19 0.05
8.1 18.2 0.01 0.42 1.33 0.028 0.008 0.025 0.00 parative 20 0.03 8.6
18.5 0.33 0.29 1.93 0.018 0.012 0.033 0.00 steel 21 0.03 12.3 17.8
0.33 0.45 0.22 0.018 0.007 0.018 2.1Mo 0.00 22 0.021 8.2 25.8 0.15
0.05 0.41 0.50 0.025 0.004 0.004 3.2Mo, 1.1W, 0.0012Mg 0.15 F + A
inventive 23 0.024 4.2 22.8 0.17 0.06 0.32 0.41 0.016 0.003 0.009
2.2Mo, 0.0011Ca 0.17 steel 24 0.042 4.2 16.2 0.22 0.08 0.25 0.93
0.022 0.005 0.012 3.1Cu 0.22 M + A 25 0.111 2.11 16.4 0.51 0.18
0.33 0.54 0.016 0.006 0.009 0.51 26 0.055 5.33 15.8 0.52 0.15 0.27
0.64 0.025 0.005 0.006 0.52 com- 27 0.018 7.9 25.4 0.001 0.23 0.88
0.013 0.005 0.21 2.8Mo 0.00 parative 28 0.06 2.02 16.3 0.005 0.61
0.29 0.019 0.009 0.013 0.00 steel 29 0.03 5.03 16.2 0.004 0.31 0.78
0.023 0.007 0.007 0.00
[0348]
6 TABLE 6 finished threshold hot cutting surface chip corrosion
out-gas compressive workability resistance roughness shape
resistivity resistivity strain third 1 .largecircle. 33.6 2.05 G A
0.008 1.9 selec- 2 .largecircle. 31.2 1.92 G A 0.017 1.9 tion 3
.largecircle. 30.9 1.84 G A 0.025 1.8 inven- 4 .largecircle. 25.2
1.95 G A 0.024 1.7 tive 5 .largecircle. 31.9 1.91 G A 0.019 1.9
steel 6 .largecircle. 29.4 1.81 G A 0.004 1.8 7 .largecircle. 29.8
1.88 G A 0.015 2.0 8 .largecircle. 32.7 1.99 G A 0.009 9
.largecircle. 36.2 2.21 G A 0.030 10 .largecircle. 30.5 2.16 G A
0.027 11 .largecircle. 24.3 1.99 G A 0.021 12 .largecircle. 37.6
2.13 G A 0.018 13 .largecircle. 28.9 1.91 G A 0.034 14
.largecircle. 29.0 1.96 G A 0.029 15 .largecircle. 32.6 2.02 G A
0.003 16 .largecircle. 33.3 2.00 G A 0.007 17 .largecircle. 31.1
1.85 G A 0.011 18 .largecircle. 26.8 1.90 G A 0.022 com- 19
.largecircle. 42.5 2.46 B A 0.004 2.1 par- 20 .largecircle. 31.5
1.95 G C 0.062 1.3 ative 21 .largecircle. 35.2 2.02 G A 0.014 1.3
steel 22 .DELTA. 39.7 2.35 G A 0.003 inven- 23 .largecircle. 38.0
2.22 G A 0.004 tive 24 .largecircle. 38.0 2.11 G A 0.004 steel 25
.largecircle. 36.4 2.08 G A 0.014 26 .largecircle. 35.9 1.95 G A
0.010 com- 27 .largecircle. 47.2 2.88 B A <0.001 par- 28
.largecircle. 45.0 2.91 B A 0.003 ative 29 .largecircle. 45.5 2.77
B A 0.003 steel
[0349]
7 TABLE 7 No. C Si Mn P S Se Te Cr Al Ti Zr note 1 note 2 .alpha.
C/X X/Y fourth 1 0.016 0.02 1.92 0.011 0.144 -- -- 24.21 4.75 0.484
-- -- -- 0.033 0.034 0.298 selec- 2 0.006 0.41 0.38 0.009 0.060 --
-- 5.75 0.92 0.213 -- -- -- -0.032 0.026 0.282 tion 3 0.003 2.87
0.18 0.008 0.009 -- -- 15.25 0.02 0.058 -- -- -- -0.015 0.051 0.160
inven- 4 0.005 0.77 0.21 0.008 0.090 -- -- 13.21 0.28 0.235 -- --
-- 0.052 0.023 0.385 tive 5 0.014 0.79 0.19 0.010 0.049 -- -- 13.01
0.29 0.239 -- -- -- 0.057 0.057 0.205 steel 6 0.009 0.78 0.19 0.008
0.048 -- -- 13.05 0.30 0.225 -- Ni: 1.82 -- -0.009 0.042 0.211 Nb:
0.87 7 0.006 0.77 0.18 0.009 0.070 0.011 0.008 13.11 0.31 0.227
0.008 Cu: 1.92 -- 0.010 0.025 0.330 Mo: 1.80 V: 0.93 8 0.008 0.79
0.19 0.009 0.050 -- -- 13.15 0.29 0.235 -- -- Pb: 0.12 -0.041 0.036
0.212 B: 0.008 9 0.007 0.78 0.20 0.007 0.050 0.010 0.009 13.22 0.32
0.233 0.007 -- REM: 0.08 -0.047 0.031 0.236 10 0.010 0.79 0.20
0.007 0.057 -- -- 13.07 0.28 0.227 -- Ni: 1.85 Pb: 0.13 0.039 0.044
0.249 Nb: 0.86 B: 0.009 11 0.007 0.78 0.19 0.009 0.070 0.012 0.010
13.08 0.29 0.221 0.008 Cu: 1.91 Mo: REM: 0.07 0.060 0.031 0.343
1.79 V: 0.93 12 0.110 0.03 1.94 0.010 0.180 -- -- 24.36 4.81 0.484
-- -- -- 0.033 0.228 0.372 13 0.045 0.43 0.36 0.007 0.060 -- --
5.32 0.89 0.213 -- -- -- 0.043 0.211 0.282 14 0.012 2.90 0.19 0.009
0.009 -- -- 15.21 0.03 0.058 -- -- -- -0.057 0.205 0.148 15 0.047
0.79 0.20 0.009 0.045 -- -- 12.95 0.31 0.241 -- -- -- 0.031 0.195
0.188 16 0.061 0.78 0.21 0.008 0.113 0.015 0.009 12.98 0.28 0.234
0.012 -- -- -0.033 0.255 0.508 17 0.047 0.81 0.20 0.009 0.047 -- --
13.01 0.29 0.225 -- NI: 1.84 -- -0.011 0.208 0.209 Nb: 0.85 18
0.052 0.79 0.19 0.009 0.070 0.011 0.008 13.06 0.33 0.227 0.008 Cu:
1.93 -- 0.010 0.225 0.330 Mo: 1.86 V: 0.91 19 0.050 0.80 0.21 0.008
0.050 -- -- 13.09 0.30 0.235 -- -- Pb: 0.11 -0.041 0.214 0.212 B:
0.007 20 0.052 0.81 0.22 0.007 0.050 0.010 0.009 13.15 0.29 0.233
0.007 -- REM: 0.09 -0.047 0.219 0.236 21 0.054 0.77 0.21 0.009
0.094 -- -- 12.98 0.31 0.227 -- Ni: 1.87 Pb: 0.13 0.020 0.236 0.414
Nb: 0.88 B: 0.008 22 0.054 0.79 0.18 0.008 0.076 0.012 0.010 13.03
0.32 0.221 0.008 Cu: 1.94 REM: 0.08 -0.039 0.238 0.370 Mo: 1.83 V:
0.94 23 0.105 0.02 1.94 0.008 0.235 -- -- 23.92 4.50 0.455 -- -- --
0.158 0.231 0.518 24 0.008 0.38 0.41 0.012 0.125 -- -- 5.95 0.88
0.211 -- -- -- 0.357 0.039 0.594
[0350]
8 TABLE 8 No. C Si Mn P S Se Te Cr Al Ti Zr note 1 note 2 .alpha.
C/X X/Y fourth 25 0.003 2.91 0.19 0.009 0.017 -- -- 15.04 0.02
0.058 -- -- -- 0.126 0.052 0.297 selec- 26 0.006 0.76 0.20 0.008
0.147 -- -- 13.05 0.28 0.205 -- -- -- 0.415 0.028 0.716 tion 27
0.052 0.77 0.22 0.009 0.126 0.013 0.011 13.01 0.29 0.196 0.009 --
-- 0.111 0.257 0.669 inven- 28 0.026 0.79 0.20 0.009 0.052 -- --
13.07 0.31 0.210 -- NI: 1.86 -- 0.249 0.123 0.249 tive V: 0.85
steel 29 0.042 0.78 0.21 0.010 0.114 0.010 0.008 12.97 0.30 0.205
0.011 Cu: 1.89 -- 0.401 0.197 0.567 Mo: 1.91 V: 0.91 30 0.022 0.78
0.20 0.012 0.049 -- -- 12.96 0.31 0.209 -- -- Pb: 0.13 B: 0.007
0.221 0.105 0.234 31 0.040 0.77 0.20 0.009 0.069 0.009 0.009 13.03
0.29 0.200 0.009 -- REM: 0.07 0.205 0.196 0.366 32 0.020 0.78 0.21
0.009 0.047 -- -- 13.10 0.30 0.201 -- Ni: 1.85 Pb: 0.12 0.209 0.098
0.232 Nb: 0.87 B: 0.009 33 0.040 0.79 0.19 0.007 0.072 0.011 0.009
13.16 0.29 0.193 0.010 Cu: 1.89 REM: 0.08 0.211 0.201 0.396 Mo:
1.93 V: 0.93 34 0.119 0.02 1.91 0.008 0.465 -- -- 23.50 4.85 0.480
-- -- -- 0.493 0.247 0.969 35 0.005 0.42 0.37 0.009 0.181 -- --
5.87 0.93 0.185 -- -- -- 0.670 0.027 0.977 36 0.008 2.88 0.19 0.010
0.035 0.009 0.003 14.45 0.02 0.056 0.011 -- -- 0.655 0.135 0.658 37
0.014 0.77 0.20 0.009 0.107 -- -- 13.18 0.28 0.181 -- Ni: 1.83 --
0.516 0.076 0.593 Nb: 0.88 38 0.013 0.79 0.21 0.008 0.099 0.008
0.009 13.21 0.29 0.174 0.010 Cu: 1.88 -- 0.488 0.070 0.585 Mo: 1.93
V: 0.89 inven- 39 0.013 0.81 0.22 0.010 0.018 -- -- 13.45 0.33
0.180 -- -- -- 0.007 0.071 0.100 tive 40 0.039 0.79 0.21 0.009
0.021 -- -- 13.21 0.31 0.213 -- -- -- -0.015 0.185 0.100 steel 41
0.020 0.78 0.20 0.007 0.009 -- -- 13.11 0.29 0.065 -- NI: 1.83 --
-0.105 0.038 0.137 42 0.035 0.76 0.19 0.009 0.023 -- -- 13.09 0.28
0.155 -- Cu: 1.81 -- -0.175 0.226 0.151 43 0.003 0.80 0.20 0.011
0.151 -- -- 13.04 0.31 0.230 -- Mo: 1.89 -- 0.248 0.012 0.657 44
0.096 0.79 0.20 0.009 0.297 -- -- 13.01 0.30 0.345 -- V: 0.84 --
0.121 0.277 0.860 45 0.005 0.77 0.21 0.007 0.421 -- -- 13.08 0.29
0.457 0.020 Nb: 0.83 -- 0.485 0.011 0.901 46 0.022 0.78 0.18 0.009
0.149 -- -- 12.98 0.30 0.189 -- Ni: 1.86 B: 0.008 0.783 0.115 0.756
47 0.051 0.78 0.21 0.008 0.233 -- -- 13.17 0.31 0.187 -- -- Pb:
0.11 0.527 0.275 1.247
[0351]
9 TABLE 9 cold corrosion workability resistivity electric
machinability threshold pitting magnetic characteristics
resistivity boring time working ratio potential No. B.sub.1 (KG)
B.sub.10 (KG) Hc (A/cm) (.mu.-.OMEGA. cm) (sec) (%) (mV) fourth 1
3.55 12.38 0.97 133 16.3 75 338 selection 2 3.75 12.55 0.99 67 15.6
83 -315 inventive 3 3.87 12.58 0.75 85 16.3 71 -68 steel 4 3.53
12.48 0.85 68 16.8 83 -40 5 3.19 12.46 0.87 68 16.6 84 -34 6 3.75
12.60 0.84 81 16.5 81 -13 7 3.72 12.62 0.80 82 16.1 79 -15 8 3.67
12.47 0.86 68 14.8 85 -42 9 3.64 12.53 0.88 67 16.7 81 -58 10 3.65
12.47 0.91 81 14.6 85 -23 11 3.05 12.42 0.93 76 16.4 83 -17 12 3.51
11.30 0.81 130 15.8 73 363 13 3.58 12.41 0.94 83 15.3 80 -331 14
3.58 12.51 0.91 84 15.8 77 -54 15 3.77 12.59 0.81 69 15.6 83 -68 16
3.71 12.53 0.83 69 14.6 82 -78 17 3.73 12.56 0.78 72 15.2 80 -21 18
3.73 12.60 0.85 86 15.6 80 -18 19 3.62 12.52 0.89 81 14.2 81 -71 20
3.61 12.49 0.87 69 16.2 86 -57 21 3.75 12.53 0.95 73 14.1 82 -20 22
3.68 12.55 0.89 86 15.0 84 -31 23 1.18 12.28 1.24 129 14.8 77 381
24 1.05 11.94 1.47 67 15.7 76 -298
[0352]
10 TABLE 10 cold corrosion workability resistivity electric
machinability threshold pitting magnetic characteristics
resistivity boring time working ratio potential No. B.sub.1 (KG)
B.sub.10 (KG) Hc (A/cm) (.mu.-.OMEGA. cm) (sec) (%) (mV) fourth 25
1.23 12.35 1.33 84 16.5 80 68 selection 26 1.03 11.86 1.49 68 14.2
77 -39 inventive 27 1.27 12.37 1.27 69 13.9 80 -68 steel 28 1.13
12.12 1.34 83 15.8 76 2 29 1.02 11.88 1.41 87 14.1 77 -11 30 1.14
12.16 1.31 68 14.1 80 -15 31 1.16 12.20 1.30 68 15.4 79 38 32 1.14
12.18 1.32 82 14.3 82 16 33 1.15 12.18 1.32 86 15.5 79 -3 34 0.98
11.72 1.45 134 10.5 78 334 35 0.74 11.36 2.23 69 10.9 71 -335 36
0.81 11.35 2.08 84 13.8 72 -107 37 0.98 11.67 1.51 82 14.8 76 -42
38 1.00 11.72 1.49 86 15.3 77 -36 inventive 39 1.31 12.47 1.13 68
17.3 71 -69 steel 40 0.95 12.38 1.61 80 18.5 68 -78 41 1.84 12.43
1.58 81 17.4 72 -60 42 0.83 12.24 1.69 77 17.8 66 -98 43 0.62 12.10
1.78 78 15.6 62 -72 44 0.55 12.34 1.84 73 10.5 69 -93 45 0.39 11.71
2.62 72 12.4 63 -132 46 0.35 11.15 2.88 79 12.5 65 -155 47 0.37
11.64 2.83 71 9.6 68 -178
[0353]
11TABLE 11 C Si Mn P S Se Te Ni Cr Co Mo Cu Al Ti Zr X Y C/X Y/X
remark 1 0.015 0.08 0.23 0.003 0.026 0.000 0.000 20.68 0.05 0.03
0.00 0.02 0.932 0.053 0.000 0.053 0.026 0.276 0.488 fifth 2 0.031
0.08 0.92 0.004 0.099 0.008 0.000 20.81 0.03 0.03 0.00 0.02 0.004
0.206 0.011 0.212 0.102 0.147 0.483 sele- 3 0.018 0.10 0.39 0.006
0.085 0.000 0.006 20.34 0.04 0.04 0.00 0.03 0.003 0.221 0.031 0.237
0.086 0.077 0.363 ction 4 0.026 0.95 0.48 0.003 0.066 0.006 0.007
20.08 0.03 0.03 0.00 0.01 0.003 2.889 0.103 2.943 0.071 0.009 0.024
inven- 5 0.010 0.09 0.51 0.002 0.037 0.000 0.008 35.89 0.04 0.02
0.00 0.02 0.002 0.187 0.000 0.187 0.039 0.051 0.207 tive 6 0.016
0.14 0.48 0.001 0.034 0.009 0.000 36.13 0.02 0.02 0.00 0.03 0.003
0.187 0.013 0.194 0.038 0.082 0.196 alloy 7 0.292 0.12 0.45 0.003
0.195 0.010 0.008 36.21 0.03 0.03 0.00 0.02 0.003 0.935 0.034 0.953
0.201 0.306 0.211 8 0.015 0.11 0.52 0.002 0.011 0.000 0.000 36.44
0.03 0.02 0.00 0.02 0.002 0.124 0.112 0.182 0.011 0.083 0.062 9
0.006 0.13 0.39 0.005 0.021 0.012 0.000 45.64 0.01 0.03 0.00 0.03
0.013 0.155 0.011 0.161 0.026 0.039 0.164 10 0.015 0.16 0.38 0.004
0.021 0.000 0.013 45.78 0.02 0.03 0.00 0.02 0.016 0.147 0.012 0.153
0.024 0.097 0.158 11 0.043 0.15 0.43 0.004 0.020 0.010 0.009 46.26
0.01 0.04 0.00 0.01 0.013 0.152 0.011 0.158 0.027 0.274 0.168 12
0.012 0.11 0.42 0.003 0.007 0.011 0.000 46.31 0.03 0.02 0.00 0.02
0.017 0.156 0.013 0.163 0.012 0.074 0.072 13 0.015 0.10 0.37 0.005
0.025 0.000 0.013 81.78 0.03 0.03 0.00 0.03 0.912 0.058 0.000 0.058
0.028 0.256 0.491 14 0.038 0.08 0.93 0.002 0.146 0.008 0.000 81.36
0.04 0.03 0.00 0.02 0.012 0.306 0.011 0.312 0.149 0.122 0.477 15
0.028 0.96 0.59 0.005 0.123 0.000 0.012 81.41 0.05 0.04 0.00 0.01
0.014 0.278 0.036 0.297 0.126 0.093 0.423 16 0.026 0.07 0.68 0.004
0.045 0.011 0.000 81.33 0.02 0.02 0.00 0.02 0.011 2.867 0.084 2.911
0.049 0.009 0.017 17 0.011 0.09 0.47 0.003 0.027 0.000 0.009 20.46
11.32 0.03 0.00 0.02 0.920 0.061 0.000 0.061 0.030 0.176 0.484 18
0.021 0.92 0.41 0.004 0.086 0.012 0.008 20.17 11.67 0.03 0.00 0.01
0.013 0.290 0.023 0.302 0.093 0.069 0.307 19 0.032 0.08 0.93 0.003
0.031 0.014 0.005 20.58 11.46 0.02 0.00 0.02 0.016 2.839 0.096
2.889 0.038 0.011 0.013 20 0.007 0.53 0.46 0.004 0.027 0.000 0.000
42.08 5.21 0.03 0.00 0.03 0.512 2.719 0.007 0.223 0.027 0.032 0.121
21 0.014 0.56 0.48 0.002 0.025 0.000 0.007 41.63 5.56 0.02 0.00
0.02 0.503 2.715 0.005 0.218 0.027 0.066 0.124 22 0.298 0.51 0.44
0.003 0.152 0.011 0.006 42.13 5.14 0.04 0.00 0.01 0.523 3.885 0.005
1.388 0.158 0.215 0.114 23 0.029 0.59 0.47 0.003 0.010 0.005 0.003
41.88 5.33 0.03 0.00 0.02 0.516 2.726 0.006 0.229 0.013 0.128 0.058
24 0.010 0.21 0.39 0.005 0.022 0.005 0.005 76.51 11.21 0.03 0.00
0.01 0.965 0.052 0.000 0.052 0.025 0.193 0.477 25 0.021 0.93 0.41
0.004 0.088 0.009 0.008 73.63 11.74 0.02 0.00 0.03 0.017 0.344
0.015 0.352 0.094 0.061 0.267 26 0.038 0.28 0.96 0.005 0.015 0.010
0.008 81.08 4.36 0.03 0.00 0.02 0.015 2.872 0.138 2.944 0.021 0.013
0.007
[0354]
12TABLE 12 C Si Mn P S Se Te Ni Cr Co Mo Cu Al Ti Zr X Y C/X Y/X
remark 27 0.011 0.07 0.31 0.004 0.025 0.000 0.008 20.41 0.04 17.55
0.00 0.02 0.941 0.055 0.000 0.055 0.027 0.208 0.482 fifth 28 0.025
0.94 0.38 0.005 0.106 0.008 0.007 20.58 0.03 17.34 0.00 0.04 0.013
0.284 0.014 0.291 0.111 0.086 0.381 sele- 29 0.041 0.08 0.92 0.004
0.074 0.011 0.000 20.38 0.06 17.73 0.00 0.03 0.005 2.848 0.110
2.905 0.078 0.014 0.027 ction 30 0.012 0.12 0.23 0.005 0.032 0.000
0.000 32.42 0.02 5.41 0.00 0.03 0.004 0.214 0.000 0.214 0.032 0.058
0.151 inven- 31 0.031 0.14 0.19 0.004 0.052 0.005 0.005 32.04 0.02
5.24 0.00 0.02 0.003 0.233 0.009 0.238 0.055 0.132 0.233 tive 32
0.294 0.10 0.21 0.003 0.302 0.009 0.011 32.13 0.01 5.57 0.00 0.02
0.003 1.230 0.013 1.237 0.308 0.238 0.249 alloy 33 0.037 0.13 0.20
0.005 0.005 0.009 0.010 32.26 0.03 5.63 0.00 0.03 0.004 0.272 0.012
0.278 0.011 0.133 0.039 34 0.010 0.15 0.31 0.006 0.022 0.000 0.008
70.43 0.03 17.58 0.00 0.02 0.937 0.054 0.000 0.054 0.024 0.188
0.453 35 0.029 0.94 0.42 0.004 0.109 0.008 0.012 81.71 0.02 5.73
0.00 0.04 0.005 0.332 0.022 0.343 0.116 0.085 0.337 36 0.046 0.18
0.91 0.005 0.051 0.009 0.000 81.76 0.03 2.76 0.00 0.02 0.004 2.392
0.936 2.879 0.055 0.016 0.019 37 0.008 0.09 0.38 0.005 0.019 0.007
0.008 20.63 0.03 0.04 2.84 6.63 0.911 0.051 0.000 0.051 0.024 0.164
0.468 38 0.033 0.96 0.31 0.004 0.129 0.007 0.008 20.51 0.03 0.04
6.87 1.55 0.006 0.410 0.027 0.424 0.134 0.079 0.316 39 0.035 0.07
0.92 0.006 0.042 0.006 0.007 20.22 0.02 0.03 0.00 0.03 0.014 2.807
0.206 2.914 0.047 0.012 0.016 40 0.012 0.08 0.52 0.004 0.042 0.012
0.000 78.28 0.03 0.04 4.58 3.48 0.967 0.160 0.012 0.166 0.047 0.071
0.284 41 0.026 0.06 0.50 0.003 0.043 0.006 0.000 78.14 0.04 0.03
4.58 3.59 0.003 0.156 0.010 0.161 0.045 0.162 0.281 42 0.296 0.07
0.51 0.003 0.307 0.007 0.009 77.94 0.04 0.04 4.46 3.51 0.004 1.121
0.011 1.127 0.312 0.263 0.277 43 0.028 0.05 0.50 0.003 0.010 0.000
0.000 78.36 0.05 0.04 4.51 3.46 0.005 0.169 0.011 0.175 0.010 0.159
0.059 44 0.013 0.16 0.28 0.005 0.026 0.000 0.009 81.13 0.05 0.04
2.01 4.42 0.941 0.059 0.000 0.059 0.029 0.223 0.486 45 0.010 0.91
0.31 0.006 0.036 0.007 0.008 81.59 0.03 0.03 3.58 2.33 0.017 0.176
0.012 0.182 0.041 0.053 0.224 46 0.046 0.06 0.93 0.005 0.087 0.008
0.000 81.35 0.05 0.04 0.00 0.02 0.012 2.804 0.189 2.902 0.090 0.016
0.031 47 0.009 0.07 0.33 0.005 0.023 0.010 0.000 20.24 0.03 17.71
0.00 0.02 0.928 0.056 0.000 0.056 0.027 0.153 0.483 48 0.015 0.97
0.31 0.004 0.067 0.000 0.011 20.38 11.83 0.05 0.00 0.03 0.011 0.195
0.018 0.204 0.070 0.075 0.341 49 0.024 0.07 0.96 0.003 0.050 0.010
0.009 20.54 0.04 0.02 6.51 0.03 0.014 0.320 0.021 0.331 0.056 0.072
0.169 50 0.292 0.08 0.29 0.004 0.277 0.007 0.006 20.49 0.03 0.03
0.00 6.92 0.008 1.578 0.020 1.588 0.281 0.184 0.177 51 0.037 0.07
0.30 0.006 0.011 0.000 0.000 20.55 0.05 0.02 0.00 0.05 0.011 0.338
0.019 0.348 0.011 0.105 0.033 52 0.047 0.20 0.23 0.004 0.062 0.000
0.000 20.16 0.02 0.03 0.00 0.04 0.018 2.885 0.157 2.967 0.062 0.016
0.021
[0355]
13TABLE 13 C Si Mn P S Se Te Ni Cr Co Mo Cu Al Ti Zr X Y C/X Y/X
remark 53 0.008 0.21 0.23 0.004 0.028 0.000 0.000 81.01 0.03 7.43
0.00 0.04 0.905 0.058 0.000 0.058 0.028 0.136 0.479 fifth 54 0.011
0.91 0.37 0.005 0.035 0.008 0.000 81.43 0.04 6.89 0.00 0.04 0.013
0.205 0.011 0.211 0.038 0.053 0.182 selec- 55 0.040 0.15 0.97 0.004
0.049 0.000 0.009 81.27 0.03 0.03 6.72 0.03 0.010 0.317 0.011 0.323
0.051 0.123 0.158 tion 56 0.293 0.31 0.42 0.006 0.160 0.007 0.008
81.62 1.44 1.39 1.24 2.91 0.021 1.249 0.013 1.256 0.165 0.233 0.131
inven- 57 0.053 0.06 0.44 0.005 0.014 0.000 0.000 81.35 0.05 0.03
0.00 0.03 0.012 0.296 0.012 0.302 0.014 0.174 0.048 tive 58 0.052
0.07 0.31 0.004 0.063 0.000 0.000 81.53 0.02 0.05 0.00 0.03 0.011
2.848 0.056 2.877 0.063 0.018 0.022 alloy 59 0.005 0.16 0.48 0.005
0.009 0.000 0.000 36.27 0.03 0.02 0.00 0.02 0.009 0.198 0.011 0.204
0.009 0.103 0.044 compa- 60 0.006 0.06 0.39 0.006 0.003 0.000 0.000
46.58 0.03 0.03 0.00 0.03 0.012 0.005 0.000 0.005 0.003 1.602 0.603
rative 61 0.005 0.52 0.41 0.006 0.005 0.000 0.000 42.18 5.12 0.03
0.00 0.03 0.511 2.325 0.301 2.482 0.005 0.004 0.002 alloy 62 0.007
0.21 0.24 0.007 0.013 0.000 0.000 32.31 0.03 5.04 0.00 0.02 0.009
0.030 0.000 0.030 0.013 0.167 0.445 63 0.008 0.05 0.52 0.006 0.006
0.000 0.000 78.13 0.02 0.03 4.51 3.42 0.008 0.181 0.013 0.188 0.006
0.956 0.033 64 0.006 0.03 0.41 0.007 0.008 0.000 0.000 21.03 0.02
0.02 0.00 0.01 0.080 0.211 0.000 0.211 0.008 0.882 0.038 65 0.007
0.04 0.42 0.005 0.008 0.000 0.000 81.32 0.03 0.04 0.00 0.02 0.009
0.188 0.014 0.195 0.008 0.901 0.041 66 0.023 0.08 0.49 0.003 2.284
0.008 0.000 35.89 0.03 0.02 0.00 0.02 0.003 0.836 0.000 0.836 2.287
0.028 2.736 67 0.022 0.14 0.41 0.006 2.262 0.012 0.000 45.84 0.02
0.02 0.00 0.04 0.011 0.944 0.010 0.949 2.267 0.023 2.389 68 0.059
0.51 0.48 0.005 0.433 0.000 0.000 42.07 5.17 0.03 0.00 0.02 0.508
3.673 0.000 3.673 0.433 0.016 0.118 69 0.130 0.11 0.25 0.004 2.272
0.000 0.000 32.35 0.02 5.35 0.00 0.02 0.007 3.712 0.000 3.712 2.272
0.035 0.612 70 0.007 0.07 0.51 0.003 0.044 0.000 0.000 78.05 0.04
0.03 4.51 3.52 0.007 0.158 0.000 0.158 0.044 0.047 0.277 inven- 71
0.021 0.91 0.55 0.004 0.123 0.000 0.000 81.23 0.03 0.03 0.00 0.02
0.012 0.281 0.000 0.281 0.123 0.073 0.438 tive 72 0.012 0.06 0.35
0.003 0.030 0.000 0.000 20.15 0.03 17.21 0.00 0.02 0.884 0.058
0.000 0.058 0.030 0.211 0.523 alloy 73 0.011 0.07 0.49 0.004 0.034
0.000 0.000 20.29 11.58 0.03 0.00 0.02 0.957 0.064 0.000 0.064
0.034 0.176 0.531 74 0.016 0.09 0.25 0.003 0.030 0.000 0.000 20.77
0.04 0.02 0.00 0.03 0.912 0.057 0.000 0.057 0.030 0.288 0.524 75
0.009 0.08 0.91 0.004 0.109 0.000 0.000 81.15 0.04 0.03 0.00 0.03
0.014 2.953 0.000 2.953 0.109 0.003 0.037
[0356]
14TABLE 14 temperature thermal coefficient? (machinability)
expansion of Young's magnetic characteristics (hot boiling time
coefficient modulus B1 B5 B10 .mu.m Hc workability) (sec) (.times.
10.sup.-7/K) (10.sup.-5/K) (T) (T) (T) (T) (A/cm) remark 1
.largecircle. 16.7 -- -- -- -- -- -- -- fifth 2 .largecircle. 11.3
-- -- -- -- -- -- -- selection 3 .largecircle. 10.9 -- -- -- -- --
-- -- inventive 4 .largecircle. 10.7 -- -- -- -- -- -- -- alloy 5
.largecircle. 20.4 7.57 -- -- -- -- -- -- 6 .largecircle. 21.5 7.21
-- -- -- -- -- -- 7 .largecircle. 14.3 7.86 -- -- -- -- -- -- 8
.largecircle. 27.7 8.22 -- -- -- -- -- -- 9 .largecircle. 28.5 --
-- 1.05 1.30 1.39 26,100 0.14 10 .largecircle. 23.9 -- -- 0.99 1.25
1.36 25,900 0.16 11 .largecircle. 28.3 -- -- 0.92 1.19 1.31 23,500
0.17 12 .largecircle. 29.3 -- -- 0.95 1.21 1.33 24,500 0.15 13
.largecircle. 17.4 -- -- -- -- -- -- -- 14 .largecircle. 12.0 -- --
-- -- -- -- -- 15 .largecircle. 12.3 -- -- -- -- -- -- -- 16
.largecircle. 14.8 -- -- -- -- -- -- -- 17 .largecircle. 15.4 -- --
-- -- -- -- -- 18 .largecircle. 11.2 -- -- -- -- -- -- -- 19
.largecircle. 14.8 -- -- -- -- -- -- -- 20 .largecircle. 26.5 --
.+-.1 -- -- -- -- -- 21 .largecircle. 26.4 -- .+-.1 -- -- -- -- --
22 .largecircle. 17.5 -- .+-.1 -- -- -- -- -- 23 .largecircle. 26.8
-- .+-.1 -- -- -- -- -- 24 .largecircle. 13.8 -- -- -- -- -- -- --
25 .largecircle. 11.3 -- -- -- -- -- -- -- 26 .largecircle. 18.6 --
-- -- -- -- -- -- 27 .largecircle. 12.1 -- -- -- -- -- -- -- 28
.largecircle. 9.1 -- -- -- -- -- -- -- 29 .largecircle. 9.4 -- --
-- -- -- -- -- 30 .largecircle. 12.1 4.92 -- -- -- -- -- -- 31
.largecircle. 9.7 4.35 -- -- -- -- -- -- 32 .largecircle. 10.4 5.03
-- -- -- -- -- -- 33 .largecircle. 17.8 4.55 -- -- -- -- -- -- 34
.largecircle. 12.8 -- -- -- -- -- -- -- 35 .largecircle. 16.8 -- --
-- -- -- -- -- 36 .largecircle. 18.8 -- -- -- -- -- -- -- 37
.largecircle. 13.5 -- -- -- -- -- -- -- 38 .largecircle. 9.9 -- --
-- -- -- -- -- 39 .largecircle. 14.3 -- -- -- -- -- -- -- 40
.largecircle. 18.2 -- -- -- -- -- 124,000 0.015
[0357]
15TABLE 15 temperature thermal coefficient? (machinability)
expansion of Young's magnetic characteristics (hot boiling time
coefficient modulus B1 B5 B10 .mu.m Hc workability) (sec) (.times.
10.sup.-7/K) (10.sup.-5/K) (T) (T) (T) (T) (A/cm) remark 41
.largecircle. 24.4 -- -- -- -- -- 121,000 0.013 fifth 42
.largecircle. 13.2 -- -- -- -- -- 112,000 0.017 selection 43
.largecircle. 27.9 -- -- -- -- -- 120,000 0.014 inventive 44
.largecircle. 26.8 -- -- -- -- -- -- -- alloy 45 .largecircle. 12.6
-- -- -- -- -- -- -- 46 .largecircle. 13.3 -- -- -- -- -- -- -- 47
.largecircle. 13.2 -- -- -- -- -- -- -- 48 .largecircle. 10.2 -- --
-- -- -- -- -- 49 .largecircle. 12.5 -- -- -- -- -- -- -- 50
.largecircle. 10.8 -- -- -- -- -- -- -- 51 .largecircle. 15.9 -- --
-- -- -- -- -- 52 .largecircle. 11.3 -- -- -- -- -- -- -- 53
.largecircle. 22.3 -- -- -- -- -- -- -- 54 .largecircle. 23.1 -- --
-- -- -- -- -- 55 .largecircle. 18.3 -- -- -- -- -- -- -- 56
.largecircle. 17.6 -- -- -- -- -- -- -- 57 .largecircle. 20.6 -- --
-- -- -- -- -- 58 .largecircle. 15.1 -- -- -- -- -- -- -- 59
.largecircle. 27.4 7.76 -- -- -- -- -- -- 60 .largecircle. 25.8 --
-- 1.13 1.35 1.42 28,300 0.12 61 .largecircle. 27.6 -- .+-.1 -- --
-- -- -- comparative 62 .largecircle. 19.1 4.21 -- -- -- -- -- --
alloy 63 .largecircle. 33.8 -- -- -- -- -- 12,600 0.013 64
.largecircle. 20.8 -- -- -- -- -- -- -- 65 .largecircle. 25.4 -- --
-- -- -- -- -- 66 X -- -- -- -- -- -- -- -- 67 X -- -- -- -- -- --
-- -- 68 X -- -- -- -- -- -- -- -- 69 X -- -- -- -- -- -- -- -- 70
X -- -- -- -- -- -- -- -- 71 .DELTA. 11.8 -- -- -- -- -- -- --
inventive 72 .DELTA. 12.7 -- -- -- -- -- -- -- alloy 73 .DELTA.
15.3 -- -- -- -- -- -- -- 74 .DELTA. 16.8 -- -- -- -- -- -- -- 75
.DELTA. 12.9 -- -- -- -- -- -- --
[0358]
16 TABLE 16 JP10- JP11-140597 130794 claim 1-8 C .about.0.1 wt %
.about.0.03 0.021.about.0.4 wt % Si .about.2.0 wt % .about.2.0 --
Mn .about.2.0 wt % .about.2.0 -- Cr 19.about.25 wt % 16.about.25
12.about.35 wt % S(Se) 0.20.about.0.35 wt % .about.0.50
0.01.about.1 wt % Ti(Zr) 0.01.about.0.50 wt % .about.1.0
0.14.about.3.5 wt % S + Se more than C(No. 13 more than more than C
Table 1) C Ws 2.33(more than 0.45) not more than 0.45 {overscore
(W.sub.T1 + 0.52W.sub.Zr)} No. 13(Table 1)
[0359]
17TABLE 17 claim 9-17 JP60-155653 JP11-140597 Honkura JP2-170948
JP63-93843 Ti + Zr(X) 0.03.about.3.5 1.5.about.3 0.01.about.0.5
0.05.about.0.35 .about.3.0 0.02.about.2 C more than 0.19
.about.0.15.sup..DELTA. .about.0.1.sup..DELTA.
.about.0.015.sup..DELTA. .about.0.015.sup..DELTA.
.about.0.08.sup..DELTA. S, Se, Te(Y) 0.01.about.1.0S .about.0.015
0.2.about.0.35 .about.0.05 .about.0.015 .about.0.015
0.01.about.0.8Se C/X 0.125.about.1.5/X 0.about.0.037.sup..DELTA.
0.about.0.78 0.about.0.3 0.about.0.088.sup..DELTA. 0.about.0.25 C/Y
0.375.about.1.5/Y 0.about.1.15 0.about.0.5 0.about.0.3.sup..DELTA.
0.about.1.6 0.about.3.67 .sup..DELTA.the range does not overlap
with claim 55-63
[0360]
18 TABLE 18 claim 18-26 JP60-155653 Ni 2.about.50 20.about.30 Cr
12.about.50 10.about.20 Fe 5.about.86.95 bal. C 0.024.about.0.4
.about.0.15 Ti + 0.52Zr 0.03.about.3.5 1.5.about.3 S 0.01.about.1
.about.0.015 Se 0.01.about.0.8 -- S + Se more than C.sup..DELTA.
less than C(Table 1).sup..DELTA. .sup..DELTA.the range does not
overlap with JP60-155653
[0361]
19TABLE 19 C Ni Cr Ti Zr S Se Si Mn P O N note Ti + 0.52Zr third 1
0.075 9.8 18.8 0.61 0.21 0.19 0.28 0.025 0.003 0.007 0.61 selection
1' 0.083 9.6 18.9 0.63 0.06 0.22 0.31 0.026 0.005 0.006 0.63
inventive 2 0.118 12.2 20.5 0.96 0.32 0.28 0.39 0.013 0.007 0.004
0.8Cu 0.96 steel 2' 0.096 12.2 20.2 0.83 0.01 0.22 0.32 0.021 0.006
0.005 0.8Cu 0.83 4 0.262 8.5 18.1 2.13 0.68 0.31 0.32 0.008 0.003
0.009 2.13 4' 0.255 8.8 18.2 2.43 0.21 0.35 0.35 0.012 0.005 0.006
2.43 5 0.118 7.9 17.8 0.98 0.30 0.31 0.42 0.019 0.003 0.008 1.3Mo
0.98 5' 0.102 7.8 17.8 0.59 0.07 0.30 0.41 0.019 0.004 0.006 1.3Mo
0.59 7 0.121 8.7 17.8 1.02 0.31 0.21 0.30 0.028 0.004 0.014 2.8Cu
1.02 7' 0.133 9.0 18.3 0.99 0.13 0.25 0.30 0.027 0.005 0.009 2.6Cu
0.99 8 0.169 19.2 24.2 1.05 0.42 0.28 0.61 0.18 0.042 0.001 0.019
1.27 8' 0.175 19.8 23.7 0.95 0.58 0.14 0.55 0.21 0.033 0.003 0.012
1.25 9 0.062 18.6 24.5 0.55 0.24 0.19 0.32 1.68 0.007 0.002 0.024
0.4Cu, 5.8Mo, 0.0029B 0.67 9' 0.056 18.6 24.3 0.51 0.18 0.03 0.32
1.42 0.011 0.003 0.021 0.6Cu, 5.7Mo, 0.0012B 0.60 10 0.122 35.9
30.2 1.01 0.32 0.29 1.23 0.005 0.005 0.007 1.2Co, 0.0018Ca 1.01 10'
0.123 34.4 28.6 0.83 0.09 0.25 1.08 0.009 0.004 0.009 1.2Co,
0.0032Ca 0.83 15 0.032 10.9 20.2 0.18 0.07 0.61 0.34 0.011 0.002
0.009 0.21Pb, 0.14V 0.18 15' 0.075 10.6 20.9 0.23 0.05 0.58 0.28
0.021 0.005 0.006 0.24Pb, 0.12V 0.23 16 0.092 15.3 19.1 0.88 0.34
2.17 0.21 0.028 0.004 0.012 0.0022Ca, 0.22Ta 0.88 16' 0.103 14.2
19.5 0.82 0.06 1.83 0.35 0.023 0.006 0.008 0.0015Ca, 0.05Ta 0.82
The dashed sample numbers indicate comparative examples.
[0362]
20TABLE 20 finished threshold hot cutting surface chip corrosion
out-gas compressive workability resistance roughness shape
resistivity resistivity strain third 1 .largecircle. 33.6 2.05 E A
0.008 1.9 selection 1' .largecircle. 41.5 3.21 E A 0.004 1.5
inventive 2 .largecircle. 31.2 1.92 E A 0.017 1.9 steel 2'
.largecircle. -- -- -- A 0.003 1.5 4 .largecircle. 25.2 1.95 E A
0.024 1.7 4' .largecircle. -- -- -- A 0.007 1.3 5 .largecircle.
31.9 1.91 E A 0.019 1.9 5' .largecircle. 38.5 2.64 E A 0.008 1.5 7
.largecircle. 29.8 1.88 E A 0.015 2.0 7' .largecircle. 42.2 2.92 E
A 0.010 1.4 8 .largecircle. 32.7 1.99 E A 0.009 8' .largecircle.
40.4 3.00 E A 0.004 9 .largecircle. 36.2 2.21 E A 0.030 9'
.largecircle. 43.5 2.88 B A 0.006 10 .largecircle. 30.5 2.16 E A
0.027 10' .largecircle. 40.2 3.11 E A 0.009 15 .largecircle. 32.6
2.02 E A 0.003 15' .largecircle. 35.3 2.58 G A 0.004 16
.largecircle. 33.3 2.00 E A 0.007 16' .largecircle. 39.5 3.06 E A
0.004 The dashed sample numbers indicate comparative examples.
[0363]
21TABLE 21 Honkura claim 27-40 JP11-140597 JP10-130794 (USP4, 969,
963) JP2-170948 JP63-93843 JP60-155653 Si 0.01.about.3 .about.2.0
.about.2.0 .about.2.0 .about.0.10 0.1.about.3.0 .about.1.5 Mn
.about.2.0 .about.2.0 .about.2.0 .about.0.35 .about.0.30 .about.0.5
.about.2.0 Cr 5.about.25 19.about.25 16.about.25 8.about.13
4.about.20 8.about.18 10.about.20 Al 0.01.about.5 0.01.about.5 --
.about.0.02 0.03.about.0.2 .about.0.5 0.1.about.0.5 Ti + Zr(X)
0.05.about.0.5 0.01.about.0.5 .about.1.0 0.05.about.0.35 .about.3.0
0.02.about.2 1.5.about.3 (0.09 No. 13 Tab. 1) C 0.02X.about.0.06X
.about.0.1 .about.0.03 .about.0.015 .about.0.015 .about.0.08
.about.0.15 0.19X.about.0.26X (0.07 No. 13 Tab. 1) S, Se, Te(Y) see
FIG. 1 0.2.about.0.35 .about.0.50 .about.0.05 .about.0.015
.about.0.015 .about.0.015 (0.21 No. 13 Tab. 1) C/X see FIG. 1
0.about.10 0.025.about.0.041 0.about.0.3 0.about.0.28 0.about.0.29
0.about.0.1 (0.33 No. 13 Tab. 1) Y/X see FIG. 1 0.4.about.35
0.34.about.0.51 0.about.1 0.about.0.08 0.about.0.12 0.about.0.01
(2.33 No. 13 Tab. 1)
[0364]
22TABLE 22 No. B.sub.1 B.sub.10 Hc .mu. b. t (sec) t. w. r (%) p. p
(mV) 35 0.7 11.36 2.23 69 10.9 71 -33.5 45* 0.39.sup..DELTA. 11.71
2.62 72 12.4 63 -13.2 15 3.77 12.59 0.81 69 15.6 83 -68 40*
0.95.sup..DELTA. 12.38 1.61 80 18.5 68.sup..DELTA. -78.sup..DELTA.
20 3.61 12.49 0.87 69 16.2 86 -57 42* 0.83.sup..DELTA. 12.24 1.69
77 17.8 66.sup..DELTA. -98.sup..DELTA. 34 0.98 11.67 1.51 82 14.8
76 -42 47* 0.37.sup..DELTA. 11.64 2.83 71 9.6 68.sup..DELTA.
-178.sup..DELTA. 36 0.81 11.35 2.08 84 13.8 72 -107 46*
0.35.sup..DELTA. 11.15 2.88 79 12.5 65.sup..DELTA. -155.sup..DELTA.
*inventive steel (comparative reference for fourth selection
inventive steel)
[0365]
23TABLE 23 claim 41-44 JP60-155653 JP11-140597 Honkura JP2-170948
JP63-93843 Ni 20.about.82 20.about.30 0.1.about.4.0.sup..DELTA.
.about.0.5.sup..DELTA. .about.3.0.sup..DELTA. No
discloswe.sup..DELTA. Ti + Zr(x) 0.05.about.3 1.5.about.3
0.01.about.0.5 0.05.about.0.35 .about.3.0 0.02.about.2 S, Se, Te(Y)
0.014.about.0.5x 0.002.about.0.012.sup..- DELTA.
0.2.about.0.35.sup..DELTA. .about.0.05 .about.0.015 .about.0.015 C
0.2Y.about.0.3 0.about.0.15 .about.0.1 .about.0.015 .about.0.015
.about.0.08 Si .about.1.0 .about.1.5 .about.2.0 .about.0.2
.about.0.10 0.1.about.3.0 Mn .about.1.0 .about.2 .about.2.0
.about.0.35 .about.0.30 .about.0.5 Al .about.1.0 0.1.about.0.5
0.01.about.0.5 .about.0.02 0.03.about.0.2 .about.0.5
.sup..DELTA.the range does not overlap with claim 41-44
[0366]
24TABLE 24 No. Ni Ti C S hot workability boring time 30 32.42 0.214
0.012 0.032 .largecircle. 12.1 59.sup..DELTA. 36.27 0.198 0.005
0.009 .largecircle. 27.4.sup..DELTA. 31 32.04 0.233 0.031 0.052
.largecircle. 9.7 62.sup..DELTA. 32.31 0.030 0.007 0.013
.largecircle. 19.1.sup..DELTA. 40 78.28 0.160 0.012 0.042
.largecircle. 18.2 63.sup..DELTA. 78.13 0.181 0.008 0.006
.largecircle. 33.8.sup..DELTA. 48 20.38 0.195 0.015 0.067
.largecircle. 10.2 64.sup..DELTA. 21.03 0.211 0.006 0.008
.largecircle. 20.8.sup..DELTA. 45 81.59 0.176 0.010 0.036
.largecircle. 12.6 65.sup..DELTA. 81.32 0.180 0.007 0.008
.largecircle. 25.4.sup..DELTA. 32 32.13 1.230 0.294 0.302
.largecircle. 10.4 66.sup..DELTA. 35.89 0.836 0.023 2.284 X
--.sup..DELTA. .sup..DELTA.comparative reference for fifth
selection inventive steel.
* * * * *