US1988504A - Cadmium base bearing metal - Google Patents

Description

Patented Jan. 2 2, 1935' V UNITED STATE CADMIUM BASE BEARING METAL William E. McCullough, Detroit, Mich assignor to Bohn Aluminum & Brass Corporation, Detroit, Mich., a corporation of Michigan No Drawing. Application May 16, 1934,

Serial No. 725,997

3 Claims.

The invention relates to bearing metal alloys and has for its object the obtaining of a material having novel and valuable characteristics. Due to changes in recent motor design, such as reduced 5 bearing areas, increased speed in operation and the higher temperatures, bearings heretofore used are proving unsatisfactory. Among the alloys in use are, first, tin base babbitts. These are unsuitable, principally on account of their low melting point. Lead base bearing metals have also been used and have substantially higher melting points but have too low wear resistance. Leaded bronze bearing linings resist wear and have as good heat resistance as lead base alloys, .but have a tendency to wear the crank shafts which ordinarily have a Brinell hardness of 212-275 in motor car engines. Alloys of cadmium base metal combined with certain other metals such as nickel, zinc, antimony, magnesium, copper and lead, have been known, but as heretofore used, have been unsatisfactory. I have discov-' ered that a bearing material having improved characteristics can be obtained by'the use of a cadmium base with a relatively small'amount of copper and magnesium, in definite proportion and held within close limits. My invention therefore consists in the alloy as hereinafter set forth.

My improved cadmium base alloy is of the following composition:

Copper from 0.2% to 1.5%; magnesium from 0.1% to 0.75%; balance cadmium.

For steel back connecting rod bearings and bearings for similar uses, I have found that an alloy of copper 0.5%; magnesium 0.25% and'the balance of cadmium, has a much longer life than an alloy of the same elements with materially larger or smaller amountsof the copper and.

magnesium. This is doubtless for the reason that the copper and magnesium have a hardening effeet and if too much is used the result is excessive brittleness which decreases the length of life.

On the other hand, if smaller amounts of the copper and magnesium are used, the-alloy will be softer and not as well adapted for these specific bearings. However, for bearings designed for other uses, such as for high speeds and light loads, a cadmium base alloy having smaller amounts of copper and magnesium may be satisfactory. Also, for bearings designed for heavy duty, such as railway car journals, a larger amount of the hardening elements in the alloy may be used to advantage.

My improved bearing alloy has the following valuable characteristics:

1.. High compression strength compared to babbitt at varying temperatures up to 500 F.;

2. Greater hardness than babbitt up to 500 F.;

3. Higher melting point than babbitt not lower than 575 F.; 1

4. Ability to be bonded firmly to steel;

5. Ability to run at higher speed and temperature without undue wear of bearing or crank shaft, and

6. Ability to give satisfactory bearing performance under conditions that cause tin babbitt to fail.

What I claim as my invention is:

1. A hearing alloy comprising copper 0.2% to 1.5%; magnesium 0.1% to 0.75%, balance cadmm.

2. A bearing alloy comprising the following elements in substantially the proportions given:

Copper 0.5

3. In a steel back bearing, a bearing alloy comprising copper 0.2% to 1.5%, magnesium 0.1% to 0.25% and balance of cadmium, said alloy being firmly bonded to the steel backing.

7 WILLIAM E. McCULLOUGH.