Two different types of rolling element fatigue testers and a full-scale bearing tester were used in a program aimed at developing a highly fatigue-resistant powder-processed material (P/M) for use in turbine engine bearings. The testers were the single-ball machine evaluating 0.0238-m (15/16-in.)-diameter balls, a rolling contact fatigue machine evaluating 0.00953-m (⅜ in.) rods, and a full-scale bearing rig evaluating 140-mm-bore, 0.0238-m (15/16 in.)-diameter ball, angular contact thrust bearings.

The two-element testers, used to screen three different P/M alloys and the baseline vacuum induction melted-vacuum arc remelted (VIMVAR) M-50 alloy, each produced essentially the same ranking for these materials. The best results, about twice the life of the baseline VIMVAR M-50, were achieved with P/M CRB-7, a 14 percent chrome corrosion-resistant alloy. P/M M-50 produced lives equivalent to VIMVAR M-50. P/M T-15, a 4 percent chrome alloy, exhibited lives ranging from that realized with the baseline material down to one third of that level. Based on these tests, CRB-7 was selected as the material out of which the balls and races for 20 full-scale 140-mm bearings were subsequently fabricated and tested. The tests were conducted at a thrust load of 34 872 N (7 840 lb) and at a speed of 12 500 rpm. A wear problem encountered in these tests was circumvented by nickel plating the cage guiding surfaces of the inner ring lands. The B₁₀ rolling contact fatigue life realized with these bearings was equivalent to that expected for these same bearings had they been made of conventional VIMVAR M-50 material. These results were quite encouraging considering the fact that this was the first attempt at applying powder processing to the manufacture of aircraft-quality rolling element bearings.