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Патент USA US3068106

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Dec. 11’, 1962
J. K. ELBAUM ETAL
3,068,096
WEAR-RESISTANT ALLOY
Filed March 10. 1960
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HElHW?N SSBNOHVH TIHNIBQ I
INVENTORS
JEROME K. ELBAUM
EDWIN L. WAGONER
19%;.“ J. MM
ATTORNEY
v
3,068,096
United States Patent. ()?Fice
Patented Dec. 11, 1962
1
2
3068 096
,
It is the primary object of this invention, therefore,
,
to provide a nickel-base wear-resistant alloy which ‘ex
WEAR'RESIQTANT ALLOY
hibits high strength and hardness at both room tempera~
Jemnie K’ Elbaunt and Edvym L‘ wagon?" Kokomo’ hid"
assignors to Umon Carbide Corporatlon, a corporation
of New York
Filed Mar. 10, 1§60,Ser.No. 15,027
1 Claim (CL 75_171)
.
_
_
_
ture and elevated temperature which alloy contains a
.
_
base wear-resistant
This invention relates toia nickel-base alloy suitable
for use in applications requirlng wear resistance.
’
.
.
5 lower amount of expensive and strategic materials than
Present commerclal alloys; ,
,
_
_
It 18 another object of this invention to provide a nickel
alloy possessing
good impact re
sistance, corrosion and oxidation resistance, and thermal
10 stability, which alloy may be used in castings and in hard
The special property of resistance to wear and abrasion
surfaced deposits produced by welding.
is required in machine components subjected to the continual rubbing action of other movmg parts such as the
valve seats in internal combustion engines. Because of
t is a further object of this invention to provide a
nickel-base wear-resistance alloy suitable for use in valve
seats in internal combustion engines,
the need for wear resistance in many such applications, 15
In accordance with these objects, a wear-resistant alloy
alloys have been developed Whlch eSPeC1a1lY_eXh1b1t lihls
property- such_ ‘alloys ‘3f? noted for then‘ hardness,
is provided consisting essentially of from 25 to 30 percent
by weight chromium, from 5 to 12 percent by weight
strength, and ability to retain hardness at elevated tern-‘tungsten, from 10 to 17.5 percent by weight iron, from
peratures. These wear-resistant alloys, most of which
0,8 to 1,6 percent by Weight carbon, up to 12 percent by
have a cobalt-base, are used mainly in the form_of cast- 20 Weight cobalt, from 5 to 12 percent by weight molybde_
lngs 01‘ hard-suffac?d dEPQSItS Product?d by Weldlng-
‘
5 num, and the balance nickel in a minimum amount of
However, alloys. of thls type ‘have heretofore been
20 percent by weight and incidental impurities.
Characteflzed by hlgh cost, low Impact resistance, allfl
The alloy may also contain up to 1.5 percent by weight
high strategic element content. In Table l thecomposrSilicon and up to 2.0 percent by weight manganese.
tlOHS Of typical commercial cobalt-base and nickel-base 2-5
Preferred eomposi?gns of the alloy are set forth in,
wear-resistant alloys are shown.
Table 2.
TABLE 1
TABLE 2
'
c‘mstltuents
AHOYA
All
"YB
30
__________________________________ __
2_5
0.4
0, 7
Marltvqnpqp
Bornn
Cobalt ______________________________________ __
mm
.
A116y1 Alloy2 Alloy3 Alloyé Alloyli Alloytl'
Chromiun1_
Carbm,
Silicon ______________________________________ _-
Nickel ______________________________________ __
Constituents
(1)
2,4
0.6
0,2
Tungsten“
Iron....-
Carbon-..
__..
_.-_
2s
26
26.27
26. 27
25.89
25.29
10
12.5
10
12.5
1.4
9. 64
12.6
1. 36
11.77
12.6
1. 36
9.32
16.6
1. 3
9.32
17.3
1. 3
1.6
0.1 __________ __ 35 Manganese _______ ._
10
Molybdenum ..... ..
0.4
5.3
0.2
10
0.16
9.8
0.16
10.72
0.18
9.6
0.18
0.6
2
0.6
0.7
0. 64
0.64
0.77
0.77
13.0
(1)
Silicon.-.
27,0
ille?ifme'
Cobalt
Nickel-
40
(0
10
(1)
10
0. 49
0.49
(l)
10.36
0)
10.36
(1)
(1)
1 Balance.
Nickel-base alloys have not been used as widely as cohalt-base alloys (despite the less-expensive nature of
_'Ihe mechanical properties _of these alloys and of the
prior commercial alloys previously designated Alloys A
nickel-base alloys) because nickel-base alloys heretofore
and B are shown 1n Table 3.
TABLE 3
Alloy N0.
Mechanical Property
A
Ultimate Tensile Strength, p.s.l ............... -.
Hardness:
70° F., Rockwell "0” Test Reading ....... --
1
2
3
90,000
52
4
5
6
90,000 ________________ __
51
51
51
51
800° F., Brinell Hardness Number..
425 ________________________ __
1,000° F. Brinell Hardness Number
1,200° F., Brinell Hardness Number
420
385
385
364
408
371
1,400° F., Brinell Hardness Number
315
265
272
3-5
3-4
Impact Strength, Ft.-lbs _____________________ --
produced have not shown the hardness of the cobalt-base
alloys. The cobalt-base alloy of Table 1, Alloy A, has
a hardness corresponding to a Rockwell “C” test reading
of 51-53, while the nickel-base alloy, Alloy B, has a
hardness of only 42-44.
B
It is to be noted that the hard
ness of a material is generally related to its wear-resistance
characteristics. In the drawing, the hardness-versus-tem
perature characteristics of several alloys, including Alloys
370
354
374
373
276 .... __
__________ _.
Some of the data presented in Table 3 is shown graph
ically in the drawing wherein the hardness-versus-tem
perature characteristics of new Alloy 2, and prior com
mercial alloys, Alloy A and Alloy B, are shown. It is.
seen that the nickel-base alloy of this invention has nearly
the same room temperature hardness as the prior cobalt
base alloy, Alloy A, and has equivalent hot hardness
characteristics compared to those of the cobalt-base alloy.
In fact between the temperatures of 500° F. and 1100“
A and B, are shown. The graphs show the superior
F., the nickel-base alloy of this invention exhibits slightly
hot-hardness characteristics of the cobalt-base alloy.
superior hardness. It is to be noted that the superior
Since nickel-base alloys are generally less expensive and
hardness characteristics of the alloy of this invention
contain a lower strategic element content than cobalt 70 compared to those of prior commercial nickel-base wear
resistant alloys, such as Alloy B in FIGURE 1, are due
base ‘alloys, the development of new nickel-base wear
to the novel composition of this alloy.
resistant alloys is avidly sought.
‘3,068,096
4
The special properties of this alloy are attributable to
Manganese and silicon may be present in minor
amounts in the preferred composition, but should not
exceed 2 percent and 1.5 percent, respectively.
Of the two preferred compositions listed, it is seen
that Alloy 2 has a higher hardness than Alloy 1. This is
so because of the higher molybdenum content of Alloy
2, molybdenum being a particularly effective hardner.
the critical composition wherein a number of carbides of
the M23C6 and Mac types are present in a stable micro
structure. The chromium present in this alloy contributes
to oxidation resistance, strength, and hardness, both at
room temperature and elevated temperatures. Tungsten,
molybdenum, iron and cobalt enhance the strength and
hardness of the alloy, along with chromium, mainly
through the formation of carbides of both M23C6 and
metallurgical practices; and may be utilized in cast form
MGC types wherein “M” refers to atoms of metals from
or as a hard-surfacing material deposited by a welding
the group consisting of chromium, cobalt, molybdenum,
operation wherein the welding rod is made of the alloy.
This alloy is suitable for any application requiring re
sistance to wear and abrasion and is particularly suited
The alloy of this invention may be prepared by standard
tungsten and iron.
In reference to the hard carbide constituents, it is to be
noted that the carbon content should not vary greatly
from 0.8 percent to 1.6 percent. While carbon is es
for service in valve seats in internal combustion engines.
Having high corrosion and oxidation resistance, along with
sential in the alloy, many prior alloys contained higher
high hardness at elevated temperatures and good im
pact resistance, the alloy is suited for extended service
carbon contents which would not favor this alloy. In
the critical composition of this alloy at carbon content sub
stantially over about 1.6 percent would result in a change
in the hard carbide constituents in the microstructure
as valve seat inserts exposed to the hot, corroding atmos
phere found in internal combustion engines.
Another useful property possessed by this alloy is a
high degree of thermal stability whereby parts composed
from the M23C6 and MGC types to the M703 type carbide.
While the M7C3 type carbide is useful in resisting wear,
its presence causes embrittlement of the alloy and thereby
lowers the impact resistance. Furthermore, higher car
bon contents change the character of the solid solution
matrix of the alloy, causing a weakening and lowering
of the ductility of the alloy.
As can be seen in Table 3, at low temperatures the co
balt content of from 0 to 12 percent cobalt may be re
placed in whole or part by nickel. Thus Alloy 3, an
of the alloy are able to withstand extended exposure to
elevated temperatures without a change in dimensions or
loss of ‘surface soundness. To illustrate this property of
the ‘alloy, castings of a composition corresponding to
Alloy 2 were exposed to an environment having a tempera
ture of 1800° F. for 20 hours. Similar castings made
from a prior commercial nickel-base alloy corresponding
to Alloy B, were also tested. The results of these tests
30 are shown in Table 4. The thermal stability of this alloy
is believed to derive from the size and distribution of the
carbides in the microstructure.
This application is a continuation-in-part of our co
essentially cobalt-free alloy having only 0.49 percent co
balt, exhibits a hardness and strength at low tempera
tures almost comparable to Alloy 2 which contains 10
pending application Serial No. 811,906, ?led May 8, 1959.
TABLE 4
Change in Dimensions and Hardness Characteristics After 20 Hour Exposure to 1800‘I F.
Environment
Change in
Change in Hardness
Dimensions,
Characteristics, Rockwell
Inches
Alloy
Before
After
Hardness Hardness
Heating Heating
Part fabricated from Alloy 2____ 1. 6285
Part fabricated from Alloy B..._ 1. 628
1. 6290
1. 620
“0” Test
Change
Before
After
Heating Heating
+0. 0005
+0. 001
51-52
42-43
Change
51-52
45-40
0
+3
What is claimed is:
percent cobalt. However, at higher temperatures, on 50
A wear-resistant alloy consisting essentially of about
the order of 1000” F. and above, Alloy 2, with a cobalt
26 percent by weight chromium, about 10 percent by
content of 10 percent, exhibits substantially improved hot
weight tungsten, about 12.5 percent by Weight iron, about
hardness which permits up to 200° F. higher operational
1.4 percent by weight carbon, about 10 percent by weight
temperatures without loss of hardness.
The molybdenum and tungsten contents may be up to 55 cobalt, about 10 percent by weight molybdenum, about
12 percent of each. A high molybdenum and tungsten
0.7 percent by weight silicon, about 0.2 percent by weight
content is advisable when the cobalt content is very low.
The molybdenum and tungsten contents then serve to
manganese, and the balance nickel and incidental im
purities.
help recover the slight loss of hot hardness in the alloy
due to the reduction or absence of cobalt. Alloy 4 with 60
high molybdenum and tungsten contents and lower co
References Cited in the ?le of this patent
UNITED STATES PATENTS
balt contents, has hot hardness values substantially equiv
alent to those of Alloy 2 which contains 10 percent each
1,520,033
MacGregor __________ __ Dec. 23, 1924
of molybdenum, tungsten, and cobalt.
1,587,992
Spitzley et al. _____ ..;___._ June 8, 1928
The iron content may be up to 17.5 percent. Alloys 65
5 and 6, which contain 16.6 and 17.3 percent iron, re
spectively, exhibit hot-hardness values comparable to the
2,214,810
2,299,871
2,392,821
2,955,934
Chester?eld __________ .._ Sept. 17,
Baird _______________ __ Oct. 27,
Kreag ________________ __ Jan. 15,
Emery _______________ __ Oct. 11,
prior art high cobalt-low iron alloys.
1940
1942
1946
1960
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