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Fatigue Considerations of High Strength Rolling Bearing Steels 31


3. CONCLUSIONS


A brief introduction of the main causes and features of classic material fatigue of rolling bearings was presented along with some of the ramifications of using bearing grade steel in structural fatigue type applications, such as shafts.


Bearing steels will typically realize high scatter in fatigue results, relative to ductile steels, whether used as a bearing or as a structural machine member. Fatigue scatter with bearing steel is due largely to the inconsistent existence of sub-surface non-metallic inclusions randomly located within the volume stressed of the otherwise very strong microstructure. The effect of inclusions follows the fact that these very high hardness steels are highly notch sensitive, thus it is expected that the fatigue durability of these materials will be greatly diminished by surface imperfections as well as sub-surface inhomogeneities.


Recent INA USA VPD activities support these conclusions from real testing with bearing grade SAE52100 under finite life fatigue test conditions. It was shown that for these initial finite life VPD validation studies, good fatigue assessment correlations using fe-safeTM were made when considering L50 median life. More testing should be made with SAE52100 to increase confidence in the VPD methods used.


4. REFERENCES 1.


2. 3. 4. 5. 6.


7. 8.


9. 10.


Harris, T. A., Rolling Bearing Analysis, 3rd ed., John Wiley & Sons, 1991.


Eschmann, Hasbargen, and Weigand, Ball and Roller Bearings, Theory, Design, and Application, 2nd ed., John Wiley and Sons, 1985.


Tallian, T. E., Failure Atlas for Hertz Contact Machine Elements, 2nd ed., ASME Press, New York, 1999.


Hertz, H., “On the Contact of Rigid Elastic Solids and on Hardness,” Miscellaneous Papers, Macmillan, London, pp. 163-183 (1896).


Jones, A. B., Analysis of Stresses and Deflections, New Departure Engineering Data, Bristol, CT, pp. 12-22, 1946.


Shigley, J. E., and Mischke, C. R., Mechanical Engineering Design, 5th ed., Mc-Graw- Hill, 1989.


Dieter, G., Mechanical Metallurgy, 3rd ed., Mc-Graw-Hill, 1986.


International Standard ISO 281, 1st ed., 1990-12-01, Rolling Bearings – Dynamic Load Ratings and Rating Life, 1990.


Lundberg, G., and Palmgren, A., “Dynamic Capacity of Rolling Bearings,” Acta Polytech. Mechanical Engineering Series, Royal Swedish Academy of Engineering Sciences, Vol. 1 Nos. 3, 7, 1947.


Weibull, W., “A Statistical Theory of the Strength of Materials,” Proc. R. Swedish Inst. Eng. Res., No,. 151, Stockholm, 1939.


11. Murthy, D. N., Xie, M., and Jiang, R., Weibull Models, Wiley-I.E.E.E., 2003.


September 20, 2006, Gabriel F. Dambaugh, P.E.


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