US1731021A - Bearing-metal alloy - Google Patents

Description

Patented Oct. 8, 1929 KARL MI I LLER AND WILHELM SANDER, F ESSEN, GERMANY BEARING-METAL ALLOY No Drawing. Original application filed September 30, 1921, Serial No. 504,374,

1, 1920. Divided and this application As substitutes for the alloys with a high tin content formerly in common use for bearing metals, latterly alloys with a high lead content have been proposed and practically tried 5 such as, for instance, the so-called standardmetal containing approximately 80 per cent of lead, per cent of antimony and 5 per cent of tin. For the purpose-of avoiding segregation as well as increasing the degree of 10 hardness, small percentages of copper have been added to these lead alloys. ,However the alloys of this type did not show such properties as to render themcapable of being employed as full substitutes for the former bearing metals containing 15 per cent and more of tin. Thereafter it was attempted to develop the desired properties in the alloys mentioned by adding other metals, but owing to the fact that most of the metals will not alloy with lead, these experiments failed because in some cases it was impossible to get a perfect mixing or, in other'cases, on cooling, the additional metals separated out from the alloy. Moreover, if one succeeds in introducing small amounts of other metals without risk of separation on-cooling, the further disadvantage arisesthat these additions will solidify at temperatures above the eutectic of lead, antimony and tin, in such away that the alloys must pass through a rather large range of solidification and consequently become pasty on cooling. This fact involves a very igh casting temperature whereby oxidation will be advanced, the easily oxidizable constituents will be burned off, and the tendency to segregation will be increased. Besides, when casting such bearing metals, frequently piping and blisters are formed owing to the large melting range.

lVe have found that all the objections pointed out above can be avoided, and that it is possible to obtain in such alloys with a high lead content, though containing only a small (say 4 to 5 per cent) amount of tin, all those properties to make them fully equivalent substitutes for the high-grade tin alloys formerly used for bearing metals.

This surprising effect is essentially realized by relatively small (say 1 to 3 per cent) additions of nickel together with a somewhat and in Germany October Serial No. 294,578.

smaller quantity of copper. Preferably the copper is introduced in the shape of copper phosphide, the phosphorus in this combination increasing the hardness of the alloy to a certain extent. The phosphorus may in this case be wholly or partially replaced by arsenic which is known to be equivalent to phosphorus with respect to the metallurgical action under consideration.

Based on numerous elaborate experiments, the following limits can be stated for the constituents of alloys which will show the advantages mentioned above: 1 7

About 7 0 to 75 per cent of lead, about 15 to 25 per cent of antimony, about 3 to 6 per cent of tin, about 1 to 3 per cent of nickel, about 0.6 .to 1.5 per cent of copper (introduced in form of 0.8 to 2.2 per cent of copper phosphide) The many advantages of such alloys as described above are by no means lessened, but

filed July 21, 1928.

even in some respects are increased by wholly or partially substituting cobalt for nickel. Nickel and cobalt are metals of the same type, closely resembling each other, but for the present purposescobalt has some specific advantages. Such an alloy containing cobalt specifically differs from the corresponding nickel alloy, inasmuch as it possesses a higher degree of plasticity, and, consequently, a greater hardening capacity without risk of becoming too brittle.

Finally we have found that such alloys as described above, i. c. with a very high lead content and a lower content of antimony and tin, which are improved by small additions of nickel, or cobalt, together with copper will be improved further by introducing relatively very small quantities of metals belonging to the iron or chromium group, preferably conjointly with elements of the phosphorus group.

By way of example for such an alloy the following composition may be stated:

70 percent of lead, 20 percent of antimony, 5 percent of tin, 2 percent of nickel, 1 percent of copper, 0.7 percent of iron, 0.3 percent of manganese, 0.5 percent of phosphorus, 0.5 percent of arsenic. v

This bearing metal alloy by reason of its hardness, durability, smooth texture and low frictional factor will meet all requirements made of a bearing metal with high tin content, even in case of great strain and insufficient lubrication of the bearing.

This application is a division of Serial No.

504,37 1, filed September 30, 1921 now Patent Number 1,691,931 of Nov. 20, 1928.

lVhat We claim is:

1. A bearing metal alloy comprising about 70 to 75 percent of lead, about to 25 percent of antimony, about 3 to 6 percent of tin,

' about 1 to 3 percent of a metal of the cobalt type, about 0.6 to 2 percent of copper, and an appreciable amount not exceeding 1 percent of metals of the iron group.

2. A bearing metal alloy comprising about to 7 5 percent of lead, about 15 to 25 percent of antimony, about 3 to 6 percent of tin, about 1 to 3 percent of cobalt, about 0.6 to 2 percent of copper and an appreciable amount not exceeding 1 percent of metals of the iron group.

3. A hearing metal alloy comprising about 70 to percent of lead, about 15 to 25 percent of antimony, about 3 to 6 percent of tin, about 1 to 3 percent of nickel and cobalt aggregated, about 0.6 to 2 percent of copper, and an appreciable amount not exceeding 1 percent of metals of the iron group.

13' In testimony whereof We afl'ix our signaures.

KARL MULLER. WILHELM SANDER.