U.S. patent application number 10/615767 was filed with the patent office on 2004-01-15 for nickel based filler metal for brazing.
This patent application is currently assigned to NATIONAL SPACE DEVELOPMENT AGENCY OF JAPAN. Invention is credited to Sasabe, Ken, Shirai, Makoto, Watanabe, Takehiko.
Application Number | 20040009090 10/615767 |
Document ID | / |
Family ID | 29728512 |
Filed Date | 2004-01-15 |
United States Patent
Application |
20040009090 |
Kind Code |
A1 |
Shirai, Makoto ; et
al. |
January 15, 2004 |
Nickel based filler metal for brazing
Abstract
To provide a nickel based brazing filler metal which does not
contain at all boron (B) or phosphorus (P) that is likely to form a
hard and brittle compound in the brazed layer, in which the
liquidus is lowered below 1,100.degree. C. by adding a small amount
of silicon (Si) and is abundant in ductility, heat-resistance and
corrosion resistance. This is attained by a nickel based brazing
filler metal characterized by containing manganese (Mn) of 13 to
20% by wt. and silicon (Si) of 5 to 7% by wt. added as melting
point depression elements and chrome (Cr) of 16 to 21% by wt. and
the balance consisting of nickel (Ni) and the impurities.
Inventors: |
Shirai, Makoto; (Tokyo,
JP) ; Sasabe, Ken; (Tokyo, JP) ; Watanabe,
Takehiko; (Tokyo, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037
US
|
Assignee: |
NATIONAL SPACE DEVELOPMENT AGENCY
OF JAPAN
THE JAPAN WELDING ENGINEERING SOCIETY
|
Family ID: |
29728512 |
Appl. No.: |
10/615767 |
Filed: |
July 10, 2003 |
Current U.S.
Class: |
420/452 |
Current CPC
Class: |
B23K 35/0233 20130101;
B23K 35/304 20130101; B23K 35/0227 20130101 |
Class at
Publication: |
420/452 |
International
Class: |
C22C 019/05 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2002 |
JP |
2002-203135 (PATE |
Claims
What is claimed is:
1. A nickel based brazing filler metal characterized by containing
chrome (Cr) of 16 to 21% by wt., manganese (Mn) of 13 to 20% by wt.
and silicon (Si) of 5 to 7% by wt. and the balance consisting of
nickel (Ni) and the impurities.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to nickel based filler metal
to braze various kinds of heat-resistant alloys and corrosion
resistant alloys.
[0002] Conventionally, nickel brazing filler metals, silver brazing
filler metals, copper brazing filler metals or the like has been
used for brazing heat resistant alloys or corrosion resistant
alloys. Of these brazing filler metals, the brazed region of the
silver filler metal or the copper filler metal is inferior in the
joint strength, the heat-resistance and the corrosion resistance
and is not suitable for the application that requires the
performance which is substantially the same as that of the base
material. On the other hand, the brazing portion of the nickel
brazing filler metal is superior in the heat-resistance, the
corrosion resistance and the joint strength. The nickel brazing
filler metals generally used are Ni-B-Si system alloy, Ni-Si system
alloy, Ni-P system alloy or the like. Table 1 shows compositions,
melting points and brazing temperatures of typical nickel filler
metals standardized by JIS (Japanese Industrial Standards).
1 TABLE 1 Brazing Chemical composition (% by weight) Solidus
Liquidus temp Ni Cr B Si Fe P (C..degree. ) (C..degree. )
(C..degree. ) BNi-1 Balance 13-15 2.75-3.5 4-5 4-5 -- 975 1040
1065- (Ni-B-Si 1205 system) BNi-5 Balance 18-19.5 -- 9.75-10.5 --
-- 1080 1135 1150- (Ni-Si 1205 system) BNi-7 Balance 13-15 -- -- --
9.7-10.5 890 890 925- (Ni-P 1040 system)
[0003] As is apparent from the above-listed table, boron (B),
phosphorus (P) or a large amount of silicon (Si) (about 10% by wt.
in BNi-5) is added to the nickel filler metal as a melting point
depression element. It is known that the melting point depression
element such as B or P forms in a brazed layer a hard and brittle
compound such as boride or phosphide and also the brazing filler
metals containing a large amount of Si forms a hard and brittle
silicate in the brazed layer. When such a compound is formed in the
brazed layer, the bonding portion is brittle, resulting in
remarkable deterioration in mechanical strength or toughness of the
brazed joint. In particular, as a result, when the gap of the
brazing is large in physical size, such the compound is likely to
be formed so that the mechanical characteristics of the brazed
joint are largely deteriorated.
SUMMARY OF THE INVENTION
[0004] An object of the present invention is to provide nickel
based filler metal which does not contain at all B or P that is
likely to form a hard and brittle compound in the brazed layer and
in which the liquidus is lowered below 1,100.degree. C. by adding a
small amount of Si.
[0005] This object is attained by a brazing filler metal to which a
small amount of silicon and manganese are added as a melting point
depression elements, i.e., to provide a filler metal containing
silicon (Si) of 5 to 7% by wt., chrome (Cr) of 16 to 21% by wt. and
manganese (Mn) of 13 to 20% by wt. and the balance consisting of
nickel (Ni) and the inevitable impurities.
[0006] It should be also noted that the addition of Mn leads not
only to a depression of the melting point but also to the
additional effects to increase the wettability and to improve the
brazing characteristics. Also, the addition of Cr is to improve in
the heat-resistance and the corrosion resistance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1a is a scanning electron microscope image of a brazed
layer of a SUS304 stainless steel brazed at the brazing gap of
100.mu.m with the filler metal of 60% Ni-20% Cr- 14%Mn-6%Si.
[0008] FIG. 1b is a distribution image of Si by EDS.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The conventional filler metal such as those shown in Table 1
has been used only in the form of powder because the conventional
material is very brittle. However, the nickel based filler metal
according to the present invention has the ductility so that it may
be machined into a sheet or a wire. Accordingly, the subject filler
metal having high heat-resistance and corrosion resistance may be
used for the purpose of brazing of heat resisting alloys and
corrosion resisting alloys in the form of a sheet or a wire.
EXAMPLES
[0010] Butt joint of stainless steel (SUS304) round bars were
brazing with the filler metal according to the present invention.
The sheet of filler metal was put between the bonding surfaces and
brazed under the vacuum condition of 1.times.10.sup.2 Pa. The
brazing temperature was 1130.degree. C. and the brazing time was
ten minutes. The brazing gap was 50.mu.m. The tensile strength of
the joint was measured by the tensil test.
[0011] Table 2 shows the tensile strength of the brazed joint and
the solidus and the liquidus of the filler metal 1 according to the
present invention. For reference, the tensile strength of the
brazed joint using the conventional nickel filletr metal BNi-5 is
shown together.
2 TABLE 2 Tensile Chemical composition (% by weight) Solidus
Liquidus strength of Ni Cr Mn Si (C..degree. ) (C..degree. ) joint
(MPa) 1 Balance 20 14 6 1070 1080 580 BNi-5 Balance 19 -- 10 1080
1135 300
[0012] As has been apparent from Table 2, the liquidus of the
filler metal 1 according to the present invention was 1080.degree.
C., and the tensile strength of the brazed joint with this filler
metal was substantially the same as that of the base material and
was about twice higher than that of the joint with BNi-5.
[0013] Also, the brittle phase was locally present continuously in
the middle portion of the brazed layer of the conventional nickel
filler metal as shown in Table 1 but the presence of the brittle
phase was scarcely found in the brazed layer of the filler metal 1
according to the present invention and was dispersed.
[0014] Furthermore, even if the brazing gap was so wide as 100.mu.m
in the case of filler metal 1 according to the present invention,
the segregation of the brittle phase was not shown. FIG. 1a shows a
scanning electron micrograph image of the brazed layer in this
case, FIG. 1b shows distribution image of silicon (Si). It is
understood that there is no segregation of Si in the brazed layer
and the local presence of the brittle phase such as the
silicate.
[0015] As described above, with the nickel based filler metal
containing Si of 5 to 7% by wt., Mn of 13 to 20% by wt., Cr of 16
to 21% by wt. and the balance consisting of Ni and inevitable
impurities, it is possible to produce the brazing filler metal
having the ductility in the form of a sheet or a wire. The tensile
strength of the brazed joint using this filler metal is
substantially the same tensile strength as that of the base
metal.
* * * * *