Rotating Beam Fatigue Testing and Hybrid Ceramic Bearings.
Final rept. 1 Mar 92-1 Mar 94,
TORRINGTON CO CT
Pagination or Media Count:
Silicon nitride is the material of choice for ceramic rolling bearings. The issue of low operational reliability in certain rolling contact applications in DoD systems may be related to its limited room temperature bending strength as compared with modern bearing steels. To explore the cyclic fatigue strength of silicon nitride, rotating beam fatigue tests have been performed for two types of high quality bearing-grade HPSN. A total of 122 rotating beam specimens have been tested, mostly in the maximum stress range 600 - 850 MPA. Statistical method has been applied to the test data to obtain the fatigue exponent, Weibull slope and crack growth parameter for the two baseline materials. Theory of ceramic reliability has been applied to predict the failure probability of ceramic rod in RCF test and ceramic balls in thrust loaded hybrid ball bearings in terms of fatigue cycles and friction coefficient. Forty-eight 48 hybrid ceramic 6206 size ball bearings have been endurance tested using sudden-death method and ceramic balls of the same materials used in the rotating beam tests.
- Machinery and Tools