Rolling-Element Fatigue Life of AMS 5749 Corrosion Resistant, High Temperature Bearing Steel

Abstract

The rolling-element fatigue lives of AMS 5749 and AISI M-50 were compared in tests run in the five-ball fatigue tester and the rolling-contact (RC) fatigue tester. The effects of double vacuum melting and retained austenite on the life of AMS 5749 were determined in five-ball fatigue tests. The double vacuum melting process consisted of induction vacuum melting followed by vacuum arc remelting (VIM-VAR). In the five-ball tests, VIM-VAR AMS 5749 gave lives at least six times that of VIM-VAR AISI M-50. Similar tests in the rolling-contact (RC) fatigue tester showed no significant difference in the lives of the two materials. The rolling-element fatigue life of VIM-VAR AMS 5749 was at least 14 times that of vacuum induction melted AMS 5749. A trend toward increased rolling-element fatigue life with decreased retained austenite is apparent, but the confidence that the all experimental differences are significant is not great. The highest level of retained austenite, 14.6 percent, is, however, significantly detrimental to rolling-element fatigue life, relative to the intermediate level of 11.1 percent.