US2473028A

US2473028A - Copper base alloy

Info

Publication number: US2473028A
Application number: US715335A
Authority: US
Inventors: Kenneth H Koopman
Original assignee: Union Carbide and Carbon Corp
Current assignee: Union Carbide Corp
Priority date: 1946-12-10
Filing date: 1946-12-10
Publication date: 1949-06-14
Anticipated expiration: 1966-06-14

Description

Patented June 14, 1949 NITED STATES COPPER BASE ALLOY No Drawing. Application December 10, 1946,

Serial No. 715,335

7 Claims. (01. 75-159) This invention relates to copper base alloys referring more particularly to copper base alloys especially useful for deposition by welding methods and having when so deposited unusually high hardness and resistance to wear.

The use of copper base alloys for joining steel, cast iron or cuprous members by welding or brazing is widespread because or the ease with which sound strong joints may be attained. Some copper base materials are used for the purpose of rebuilding worn surfaces such as valve seats, and quite often new articles are protected by a surface layer of copper base material deposited by welding or brazing. The success with which these methods have met has led to a demand for their use in more extensive and more difilcult applications, and there is consequently a, demand for copper base materials having higher hardness and greater resistance to Wear than is possessed by the materials now commercially available.

It is the principal object of this invention to provide a copper base alloy which satisfies this demand. More specifically, the invention has for its primary object the provision of a copper base alloy adapted to deposition by welding or brazing methods which, when so deposited, has a high hardness, and improved resistance to wear and retains its high hardness at moderately elevated temperatures.

The invention by means of which this object is attained comprises a copper base alloy, and welding rods fabricated therefrom, containing critical proportions of nickel, zinc, tin and silicon. The alloy of the invention contains 23% to 30% nickel; 25% to 35% zinc; 5% to tin; 0.01% to 0.5% silicon; the remainder substantially all copper, and the sum of the zinc and tin contents being 35% to 4 of the alloy. A preferred range of constituents is to 27% nickel; 8% to 10% tin; 29% to 33% zinc; 0.2% to 0.4% silicon; the remainder copper and the sum of the tin and zinc contents being 37% to less than 41% of the alloy. A specific composition contains 25% to 27% nickel; 8.5% to 9.5% tin; to 32% zinc; 0.2% to 0.4% silicon and the remainder copper. The invention also includes metal articles exposed to wear, at least those portions of such articles subjected to wear being composed of the alloy described.

The alloys within the composition ranges just disclosed are readily deposited by orthodox welding procedures; have good flowing properties; show little evidence of the fuming which is a disadvantage of some copper base materials when deposited by welding; and form strong, nonporous deposits exhibiting excellent adherence to steel, cast iron or cuprous members. The melting point of alloys within the composition ranges disclosed is below 950 (1., generally being about 930 C. The Brinell hardness of deposits of alloys of this composition is of the order of 275 (3000 kg. load) at room temperature, and the Brinell hardness of the alloys as deposited is about to at a temperature of 430 C.

As will be seen from the above statements the alloy of the invention has properties which recommend it for use in hard surfacing operations, for example in the building up of wearresisting pads on machine tools; non-galling pads on door dogs; non-scoring pressure edges in deep-drawing dies; and many Wear-resisting surfaces on railroad rolling stock. Because of its retention of hardness at moderately elevated temperatures the alloy is also well suited to use in the provision of Wear-resisting surfaces exposed to elevated temperatures such as wrist pin bearings, seats for steam valves and lands on steam engine pistons. Since the alloy also exhibits eX- cellent resistance to corrosion it is useful for the production of corrosion-resisting non-scoring valve seats. Because of the silvery color of the alloy it is particularly suitable for the welding or brazing or hard surfacing of nickel or ferrous alloys where it is desired that the color of the deposited material be similar to that of the base.

As is indicated above, the composition limits of the invention and the proportioning of the constituents with respect to one another are critical. If the sum of the zinc and tin contents is less than 35% of the alloy, the requisite hardness is not attained. On the other hand, if the sum of the Zinc and tin contents is more than 41% of the alloy, the deposit produced by welding exhibits undesirable brittleness. The proportion of nickel in the alloy is important; if less than about 23% is present the deposited material does not have the desired hardness and the adherence of the deposit to steel or cast iron is not as good as is desired. Too high a nickel content, however, tends to raise the melding point undesirably. A high tin content on the other hand, tends to overcome the melting point raising effect of nickel. The presence of silicon in the alloy is important, silicon minimizing fuming of the molten alloy during deposition. Iron, a common impurity in copper base alloys, may be present in the alloy of the invention as an impurity, but if more than about 0.3% is present, the alloy tends to become sluggish when molten for deposition, and to develop porosity when deposited. The iron content therefore should be well below 1% and preferably less than 0.3%.

Specific examples of alloys within the composition limits of the invention are set forth in the following table, which also indicates the Brinell hardness measured at the temperatures indicated in the table with a 3000 kg. load.

Composition: Remainder Copper figf g Percent Percent Percent Percent Room Nickel Tin Zinc Silicon Temp.

23. s. 3 32. 3 0. 48 292 143 121 24. 5 30 0. 5 295 ms 121 7 31 0.2 240 25 9. 5 s1 0. 2 280 (0 25 1o 0. 2 274 22 5 33 0.2 230 26 1o. 5 25. 5 0.2 228 (0 26 10. 5 2s. 5 0.2 269 g 25 5. 5 34. 5 0. 2 290 1 Not tested.

Weld deposits having the compositions set forth in the abov table were all sound, being free from cracks, and adhered strongly to the steel base on which they were formed. The melting point of th weld metal averaged about 930 C.

While specific examples of the composition of the alloy of the invention and of specific applications for its use have been given, the invention is not limited to these particular examples or particular uses, but in general should find wide application for joining steel, cast iron or cuprous members one to another, and for protecting such members from undue wear by the provision thereon of deposits of the alloy of the invention.

I claim:

1. A copper base alloy containing 23% to 30% nickel; 25% to 30% zinc; 5% to 11% tin; 0.01% to 0.5% silicon; the remainder substantially all copper, the sum of the zinc and tin contents being to 41% of the alloy.

2. A copper base alloy containing 25% to 27% nickel; 29% to 33% zinc; 3% to 10% tin; 0.2% to 0.4% silicon; the remainder substantially all 4 copper, the sum of the zinc and tin contents being 37% to 41% of the alloy.

3. A copper base alloy containing 25% to 27% nickel; 30% to 32% zinc; 8.5% to 9.5% tin; 0.2% to 0.4% silicon; the remainder copper; the sum of the zinc and tin contents being less than 41% of the alloy.

4. A welding rod composed of a copper base alloy containing 23% to 30% nickel; 25% to 30% zinc; 5% to 11% tin; 0.01% to 0.5% silicon; the remainder substantially all copper, the sum of the zinc and tin contents being 35% to 41% of the alloy.

5. A welding rod composed of a copper base alloy containing 25% to 27% nickel; 29% to 33% Zinc; 8% to 10% tin; 0.2 to 0.4% silicon; the remainder substantially all copper, the sum of the zinc and tin contents being 37% to 41% of the alloy.

6. A welding rod composed of a copper base alloy containing 25% to 27% nickel; 30% to 32% zinc; 8.5% to 9.5% tin; 0.2% to 0.4% silicon; the remainder copper; the sum of the zinc and tin contents being less than 41% of the alloy.

7. A metal article required during its normal use to resist wear, at least the surface portions of said article exposed to wear, being composed of a copper base alloy containing 23 to 30 nickel; 25% to 30% zinc; 5% to 11% tin; 0.01% to 0.5% silicon; the remainder substantially all copper, the sum of the zinc and tin contents being 35% to 41% of the alloy.

KENNETH H. KOOPMAN.

REFERENCES CITED FOREIGN PATENTS Country Date Great Britain Apr. 22, 1926 OTHER. REFERENCES Journal of American Welding Society, Dec. 1928, page 9.

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