U.S. patent application number 11/635681 was filed with the patent office on 2007-04-12 for production of the metallic parts with the alloyed layer containing dispersed compound particles, and the wear-proof parts.
Invention is credited to Mitsuo Chigasaki, Satoshi Furusawa, Yoshihisa Kiyotoki, Jiro Kuniya, Akira Sakamoto.
Application Number | 20070081916 11/635681 |
Document ID | / |
Family ID | 33487447 |
Filed Date | 2007-04-12 |
United States Patent
Application |
20070081916 |
Kind Code |
A1 |
Chigasaki; Mitsuo ; et
al. |
April 12, 2007 |
Production of the metallic parts with the alloyed layer containing
dispersed compound particles, and the wear-proof parts
Abstract
A powder of an alloy containing a compound is enclosed in a
cylindrical container, hot isostatic press and/or hot extrusion are
applied in that state, and compound is isolated by these workings
in order to metallically bond the powders with each other. When the
metallic part is inserted into the container or the metallic part
has a cylindrical shape, the container is formed of a material
which can be the metallic part. Then, machining is applied in order
to produce a metallic part having on a surface thereof an alloyed
layer containing the dispersed compound particles. The metallic
parts having on a surface thereof an alloyed layer containing
dispersed compound particles can be produced without using a
joining method such as welding.
Inventors: |
Chigasaki; Mitsuo; (Hitachi,
JP) ; Kuniya; Jiro; (Hitachi, JP) ; Kiyotoki;
Yoshihisa; (Hitachinaka, JP) ; Sakamoto; Akira;
(Mito, JP) ; Furusawa; Satoshi; (Hitachi,
JP) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Family ID: |
33487447 |
Appl. No.: |
11/635681 |
Filed: |
December 8, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10857952 |
Jun 2, 2004 |
|
|
|
11635681 |
Dec 8, 2006 |
|
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Current U.S.
Class: |
419/68 |
Current CPC
Class: |
B22F 2998/10 20130101;
B22F 7/08 20130101; Y10T 428/12063 20150115; B22F 2998/10 20130101;
B22F 3/1208 20130101; B22F 3/20 20130101; B22F 2998/10 20130101;
B22F 3/1208 20130101; B22F 3/15 20130101 |
Class at
Publication: |
419/068 |
International
Class: |
B22F 3/04 20060101
B22F003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 2003 |
JP |
2003-158787 |
Claims
1. A method for producing a metallic part having on a surface
thereof an alloyed layer containing dispersed compound particles,
comprising: enclosing a powder of an alloy containing the compound
in a cylindrical metallic container; applying at least one hot
plastic working selected from hot isostatic press and hot extrusion
in that state; segmenting the compound by the hot plastic working
and metallically bonding the powders with each other and the powder
with the metallic container; and then applying machining to
manufacture a cylindrical metallic part having on an inner surface
thereof an alloyed layer containing the dispersed compound
particles.
2. The method for producing the metallic part according to claim 1,
wherein the alloy containing the compound is formed of a
nickel-base alloy, a cobalt-base alloy or an iron-base alloy
containing the compound which is formed of at least one selected
from a silicide, a boride and a carbide.
3. The method for producing the metallic part according to claim 2,
wherein the nickel-base alloy consists of not more than 8 weight %
Si 0 to 4 weight % B 7 to 30 weight % Cr not more than 1.2 weight %
C 0 to 5 weight % of W not more than 42 weight % of Fe which does
not exceed an amount of Ni with a balance of Ni.
4. The method for producing the metallic part according to claim 1,
wherein the powder consists of an alloy powder manufactured by
atomization from a molten metal of the alloy.
5. The method for producing the metallic part according to claim 4,
wherein the alloy powder consists of a gas atomized powder
manufactured by an inert gas atomization.
6. The method for producing the metallic part according to claim 4,
wherein the alloy powder consists of an alloy powder containing a
compound dendritically precipitated in a powder production
process.
7. The method for producing the metallic part according to claim 1,
wherein a gas in the container is evacuated when enclosing the
alloy powder in the metallic container.
8. A method for producing a metallic part having on a surface
thereof an alloyed layer containing dispersed compound particles,
comprising: enclosing a powder of an alloy containing the compound
and the metallic part in a container; applying at least one hot
plastic working selected from hot isostatic press and hot extrusion
in that state; segmenting the compound by the hot plastic working
and metallically bonding the powder with each other and the powder
with the metallic part; and then applying machining to manufacture
a metallic part having on a surface thereof an alloyed layer
containing the dispersed compound particles.
9. The method for producing the metallic part according to claim 8,
wherein the alloy containing the compound is formed of a
nickel-base alloy, a cobalt-base alloy or an iron-base alloy
containing the compound formed of at least one selected from a
silicide, a boride and a carbide.
10. The method for producing the metallic part according to claim
9, wherein the nickel-base alloy consists of not more than 8 weight
% Si 0 to 4 weight % B 7 to 30 weight % Cr not more than 1.2 weight
% C 0 to 5 weight % of W not more than 42 weight % of Fe which does
not exceed an amount of Ni with a balance of Ni.
11. The method for producing the metallic part according to claim
8, wherein the powder consists of an alloy powder manufactured by
atomization from a molten metal of the alloy.
12. The method for producing the metallic part according to claim
11, wherein the alloy powder consists of a gas atomized powder
manufactured by an inert gas atomization.
13. The method for producing the metallic part according to claim
11, wherein the alloy powder consists of an alloy powder containing
a compound dendritically precipitated in a powder production
process.
14-18. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method for producing a
metallic part having on a surface thereof an alloyed layer
containing dispersed compound particles, and a wear-proof part.
BACKGROUND OF THE INVENTION
[0002] Metallic parts having on a surface thereof an alloyed layer
containing dispersed compound particles are used in wear-proof
parts such as valves (see, e.g., claims of JP-A-11-63251 and
JP-A-2001-288521).
[0003] JP-A-11-63251 discloses that a wearing surface of a valve is
formed of a nickel-base alloy of a Ni--Cr--B--Si system in which
chromium boride particles are dispersed. Further, JP-A-2001-288521
discloses that a wearing surface of a valve is formed of a
cobalt-base, nickel-base or iron-base alloy in which granular or
lumpy eutectic carbides are dispersed.
[0004] Both prior arts relate to increase a wear resistance and an
antiseizure property by dispersing hard compound particles into an
alloy. The alloy in which the hard compound particles are dispersed
generally has the poor ductility and is hard to be processed. Thus,
an alloyed layer containing dispersed compound particles is formed
on only a wearing surface, while a main body of a valve is formed
of another metal having the excellent processability. As a method
for forming the alloyed layer containing dispersed compound
particles, welding is the most common method, but performing
welding results in forming a solidification structure containing
coarse and large compounds due to melting, and an initial fine
particle state cannot be maintained.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to form an alloyed
layer containing dispersed compound particles on a surface of a
metallic part without adopting joining means such as welding.
[0006] According to the present invention, a metallic part having
on a surface thereof an alloyed layer containing dispersed compound
particles is manufactured by at least one hot plastic working which
is selected from hot isostatic press and hot extrusion.
[0007] When applying the hot plastic working, an alloy powder
containing compounds is prepared and it is enclosed in a container.
When enclosing, it is desirable to evacuate a gas, mainly air,
remained in the container, thereby preventing the powder from being
oxidized. In a state that the powder is enclosed in the container,
one or both of the hot isostatic press and the hot extrusion are
applied. With these plastic workings, the compounds are segmented
and converted into a granular or lumpy state. Furthermore, the
powders are metallically bonded with each other. If the container
is formed of a metal, the metallic container and the powder are
also metallically bonded to each other. There also occurs a
phenomenon that the powder partially makes inroads into an inner
surface of the metallic container. After the hot plastic workings,
machining, e.g., cutting work by wire cutting is performed. If the
container is a cylindrical metallic container, it is possible to
produce a cylindrical metallic part having on an inner surface
thereof an alloyed layer containing dispersed compound
particles.
[0008] Moreover, when enclosing the powder in the container,
inserting the metallic part at the same time can manufacture a
metallic part having on a surface of the metallic part an alloyed
layer containing dispersed compound particles. In case of forming
an alloyed layer containing dispersed compound particles, on an
inner surface of a tubular metallic part, the tubular metallic part
can also function as the container.
[0009] The present invention is preferable as a method for forming
an alloyed layer containing dispersed compound particles, on a
wearing surface of a valve, a shaft of a valve, a ball sleeve, a
bush or the like.
[0010] Other objects, features and advantages of the invention will
become apparent from the following description of the embodiments
of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] As an example of a preferable alloy containing dispersed
compound particles when embodying the production method according
to the present invention, a nickel-base, cobalt-base or iron-base
alloy containing at least one selected from a silicide, a boride
and a carbide, can be used.
[0012] As the nickel-base alloy, it is desirable to use a material
which consists of not more than 8 weight % Si, 0 to 4 weight % B, 7
to 30 weight % Cr, not more than 1.2 weight % C, 0 to 5 weight % W,
not more than 42 weight % Fe which does not exceed an amount of Ni,
with a balance of Ni.
[0013] Additionally, it is desirable to use an atomized powder
manufactured by atomization from a molten metal of an alloy. Since
the atomized powder becomes excellently rounded particles, it is
suitable to be packed in a container. As an atomization method,
either a method for a liquid atomizing or a method for a gas
atomizing can be applied, but a method for an inert gas atomizing
is desirable. In case of a water atomized powder, a surface of the
powder is apt to be oxidized, and it is hard to obtain particles
with a rounded shape since this oxidization is involved. In case of
an inert gas atomized powder, no oxidization occurs, and particles
with a rounded shape can be readily obtained.
[0014] On enclosing the powder in a container, a compound in the
powder does not have to be formed into a granular state. In case of
the atomized powder, although a compound is dendritically
precipitated in a process that the molten metal is powdered and
then solidified, such a powder can be used. For example, an
atomized powder of a nickel-base alloy with the above composition
range can be used, while a silicide and, in some cases, a boride
are dendritically precipitated. The dendritically precipitated
compound is segmented to a granular or lumpy form in a process of
hot isostatic press or hot extrusion.
[0015] According to the method of the present invention, an alloyed
layer containing dispersed compound particles can be formed on a
surface of a metallic part. Further, since the alloyed layer is not
molten in a process in which it is formed on the surface of the
metallic part, compound particles having a fine granular form or
lumpy form can be dispersed.
[0016] The hot isostatic press or the hot extrusion can be
performed by a generally known method. For example, as the hot
isostatic press, a known method by which an inert gas such as argon
gas is used as a pressure medium and a container in which the
powder is enclosed is subjected to pressurizing processing at a
predetermined temperature under a predetermined pressure, can be
applied. Furthermore, as the hot extrusion, a method by which a raw
material is extruded by using a die has been known. The container
in which the powder is enclosed can be extruded by applying this
method.
[0017] According to the present invention, an alloyed layer
containing dispersed compound particles is formed by the hot
plastic working which is at least one selected from the hot
isostatic press and the hot extrusion, and a wear-proof part
integrated with a main body of the wear-proof part is provided at
the time of that plastic working.
[0018] The wear-proof part according to the present invention can
be used for various kinds of valves. Moreover, it can be used for a
shaft of a swing check valve or a butterfly valve, a ball sleeve, a
bush or others.
[0019] When the present invention is used in a wear-proof part, it
is desirable to form on a surface of a part consisting of a carbon
steel, a low-alloy steel or a stainless steel a layer of a
nickel-base alloy, a cobalt-base alloy or an iron-base alloy in
which at least one kind of silicide particles, boride particles and
carbide particles is dispersed. The nickel-base alloy, the
cobalt-base alloy or the iron-base alloy containing dispersed
granular or lumpy compound particles has the excellent wear
resistance and antiseizure property, and it is suitable for a
wear-proof part. Additionally, when the present invention is used
in a wear-proof part, a surface of the alloyed layer containing
dispersed compound particles may be coated with a ceramic film,
thereby increasing the wear resistance. As a ceramic material, it
is possible to use chromium nitride (CrN), titanium nitride (TiN),
titanium carbide (TiC), hafnium nitride (HfC) or the like.
EXAMPLE 1
[0020] An inert gas atomizing method was used to manufacture a
powder of nickel-base alloy which consists of 6.1% Si, 1.1% B,
19.7% Cr, 0.32% C, 2.0% W, 7.6% Fe by weight % with a balance of Ni
and incidental impurities. The Ni-base alloy powder having a
particle size distribution of 70 to 250 mesh was filled in a
container made of a carbon steel S12C which has a hollow
cylindrical form whose outside diameter is 145 mm.phi., and inside
diameter is 123 mm.phi.. Compression molding was carried out at a
room temperature and then the container was sealed. Thereafter, the
hot isostatic press was carried out at a temperature of
approximately 950.degree. C., and the hot extrusion was further
performed at a temperature of 950.degree. C. The hot extrusion was
effected under conditions that an extrusion pressure was
approximately 5,000 kg/cm.sup.2 and a stem speed was 20 mm/second.
The container was processed until the outside diameter became 60
mm.phi.. Then, machining was applied, and various kinds of test
pieces were cut out to carry out various kinds of tests.
[0021] The powders of the nickel-base alloy were metallically
bonded with each other. Additionally, the nickel-base alloy powder
was metallically bonded with the container made of a carbon steel.
Further, a part of the powder bit into the inside of the
cylindrical container made of a carbon steel and was firmly bonded
with the container. Furthermore, in the nickel-base alloy layer
formed on the inner surface of the cylindrical container made of a
carbon steel, the compound which was dendritically precipitated in
the atomized powder state was segmented to a granular or lumpy
compound having a diameter of not more than 10 .mu.m. The compound
was mainly formed of a silicide, and a boride was also partially
contained.
[0022] For various kinds of tests, the part according to the
embodiment was compared with a welded overlay part which is buildup
welded with a welding rod cut out from the nickel-base alloy layer
manufactured by this embodiment.
[0023] First, the nickel-base alloy layer according to the
embodiment of the present invention was superior in the ductility
which is threefold or more of that of the welded overlay part.
Moreover, the nickel-base alloy layer according to the present
invention demonstrated a high impact value which was approximately
2.5-fold in an impact test without a notch and approximately
1.4-fold in a U-notch impact test, as compared with the welded
overlay part. The hardness of both the part according to the
present invention and the welded overlay part falls within a range
of 550 to 600 Hv.
[0024] There was conducted a Strauss test (JIS G0575) in which test
pieces were soaked in a boiling water solution containing sulfuric
acid and copper sulfate for 72 hours, and cross sections were
observed after the test. The layer according to the present
invention has a maximum corrosion depth of not more than 10 .mu.m
and was superior in the corrosion resistance as compared with the
welded overlay part having a maximum corrosion depth of
approximately 200 .mu.m.
[0025] A friction coefficient was measured in high-temperature
water under conditions that a bearing stress is 2000 kg/cm.sup.2
and a sliding speed is 300 mm/minute, in which a precipitation
hardened stainless steel SUS630 whose surface is coated with a
chromium nitride film was used as a wear-proof opposite material.
The part according to the present invention demonstrated a friction
coefficient of 0.34, whereas the welded overlay part demonstrated
0.43. As a result, it was confirmed that the part according to the
present invention is suitable for a use in a shaft of a swing check
valve or a butterfly valve, a ball sleeve or the like having a
rotary wear-proof portion or a reciprocating wear-proof
portion.
Example 2
[0026] An inert gas atomized powder formed of a nickel-base alloy
which consist of 6.0% Si, 1.6% B, 20.0% Cr, 0.7% C, 1.6% W and 5.0%
of Fe by weight % with a balance of Ni and incidental impurities
was filled and sealed in a container formed of a low-alloy steel
F11A (1.5 Cr-0.5 Mo steel) which has a hollow cylindrical shape
whose outside diameter is 145 mm.phi., and inside diameter is 123
mm.phi.. The hot isostatic press and the hot extrusion were carried
out at a temperature of approximately 900.degree. C., and the
container was processed to have an outside diameter of 70 mm.phi..
When the cylindrical container was cut by machining, the inside
diameter was 56 mm.phi., and a nickel-base alloy containing
dispersed granular or lumpy silicide particles and boride particles
or the like having a diameter of not more than 10 .mu.m in a matrix
of metallographic structure was stuck. When a shear strength
between the cylindrical container formed of the low-alloy steel and
the nickel-base alloy stuck therein was measured, it was not less
than 15 kg/mm.sup.2. When the shear strength is low, peeling or the
like is apt to occur, and the part is hard to be applied to a ball
sleeve of a swing check valve. It was confirmed that the part
according to this embodiment is not fractured even if a shear force
of 15 kg/mm.sup.2 is applied on an interface between the alloyed
layer and the low-alloy steel and it can withstand a bearing stress
of approximately 3,000 atomospheric pressure (3000 kg/cm.sup.2)
assuming that a friction coefficient with respect to a shaft of a
check valve which is a wear-proof opposite part of, e.g., a ball
sleeve is 0.5.
[0027] A ball sleeve of a swing check valve having an outside
diameter of 68 mm.phi., an inside diameter of 50 mm.phi. and a
length of 160 mm was manufactured from the part according to this
embodiment by machining. A nickel-base alloy layer having a
thickness of 3 mm is formed on the inner side of a cylinder made of
a low-alloy steel.
[0028] On the other hand, as a shaft of the swing check valve,
there was produced a shaft with an outside diameter of 50 mm.phi.
which was obtained by coating a surface of a precipitation hardened
stainless steel SUS630 (17-4PH) with a chromium nitride film having
a thickness of approximately 10 .mu.m by evaporation.
[0029] Additionally, a part having a length of 150 mm was cut out
from the part with an outside diameter of 70 mm.phi. according to
this embodiment, hot press was performed vertically with respect to
an axial direction at a temperature of 950 to 1000.degree. C. in
order to extend the outside diameter to be not less than 100
mm.phi., and a valve disc bush was manufactured from this member by
machining.
[0030] The part according to this embodiment is resistant against
mechanical impacts, hard to be fractured and has the excellent
corrosion resistance as compared with a welded overlay part.
[0031] According to the present invention, a metal part having on a
surface thereof an alloyed layer containing dispersed granular or
lumpy compound particles can be manufactured without using a
joining method such as welding.
[0032] It should be further understood by those skilled in the art
that although the foregoing description has been made on
embodiments of the invention, the invention is not limited thereto
and various changes and modifications may be made without departing
from the spirit of the invention and the scope of the appended
claims.
* * * * *