Machinery's Handbook, 31st Edition
Plain Bearing Materials 2437 5) High thermal conductivity is required to absorb and carry away the heat generated in the bearing. This conductivity is most important, not in removing frictional heat generated in the oil film, but in preventing seizures due to hot spots caused by local asperity break throughs or foreign particles. 6) Corrosion resistance is required to resist attack by organic acids that are sometimes formed in oils at operating conditions. 7) Load capacity or strength is the ability of the material to withstand the hydrodynamic pressures exerted upon it during operation. Babbitt or White Metal Alloys.— Many different bearing metal compositions are re- ferred to as babbitt metals. The exact composition of the original babbitt metal is not known; however, the ingredients were probably tin, copper, and antimony in approxi mately the following percentages: 89.3, 3.6, and 7.1. Tin- and lead-base babbitts are probably the best known of all bearing materials. With their excellent embeddability and compatibility characteristics under boundary lubrication, babbitt bearings are used in a wide range of applications including household appliances, automobile and diesel en- gines, railroad cars, electric motors, generators, steam and gas turbines, and industrial and marine gear units. Table 2. White Metal Bearing Alloys—Composition and Properties ASTM B23-00 (R2014)
Melt ing Point ° F
Proper Pouring Temperature, ° F
Nominal Composition, Percent
Compressive Yield Point, b psi
Ultimate Compressive Strength, c psi
Brinell Hardness Number d
ASTM Alloy a Number
Sn Sb Pb Cu 68 ° F 212 ° F 68 ° F 212 ° F 68 ° F 212 ° F 1 91.0 4.5 … 4.5 4400 2650 12,850 6950 17.0 8.0 433
825 795 915 710 690 655 640 645 630 630 625 662 620
2 89.0 7.5 … 3.5 6100 3000 14,900 3 83.33 8.33 … 8.33 6600 3150 17,600 4 75.0 12.0 10.0 3.0 5550 2150 16,150 5 65.0 15.0 18.0 2.0 5050 2150 15,050 6 20.0 15.0 63.5 1.5 3800 2050 14,550
8700 24.5 12.0 9900 27.0 14.5 6900 24.5 12.0 6750 22.5 10.0 8050 21.0 10.5 6150 22.5 10.5
466 464 363 358 358 464 459 468 471 473 479 471 462
7 e 8 e
10.0 15.0 bal. 5.0 15.0 bal.
… 3550 1600 15,650 … 3400 1750 15,600
6150 20.0 5750 17.5 5100 15.0 5100 14.5
9.5 9.0 7.0 6.5
10 11 12
2.0 15.0 83.0 … 3350 1850 15,450 … 15.0 85.0 … 3050 1400 12,800 … 10.0 90.0 … 2800 1250 12,900
15 f
1.0 16.0 bal.
0.5 … … … … 21.0 13.0
16 10.0 12.5 77.0 0.5 … … … … 27.5 13.6
19 620 a Data for ASTM alloys 1, 2, 3, 7, 8, and 15 appear in the Appendix of ASTM B23-00 (R2014); the data for alloys 4, 5, 6, 10, 11, 12, 16, and 19 are given in ASTM B23-49. All values are for refer- ence purposes only. b The values for yield point were taken from stress-strain curves at the deformation of 0.125 per- cent reduction of gage. c The ultimate strength values were taken as the unit load necessary to produce a deformation of 25 percent of the length of the specimen. d These values are the average Brinell Hardness Number of three impressions on each alloy using a 10-mm ball and a 500-kg load applied for 30 seconds. e Also nominal arsenic, 0.45 percent. f Also nominal arsenic, 1 percent. 5.0 9.0 86.0 … … … 15,600 6100 17.7 8.0 The compression test specimens were cylinders 1.5 inches in length and 0.5 inch in diameter, ma- chined from chill castings 2 inches in length and 0.75 inch in diameter. The Brinell Hardness tests were made on the bottom face of parallel machined specimens cast in a 2-inch diameter by 0.625- inch deep steel mold at room temperature. Both the Society of Automotive Engineers and American Society for Testing and Mate rials have classified white metal bearing alloys. Table 1 and Table 2 give compositions and properties or characteristics for the two classifications.
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