PSI - Issue 71

Ninad Vasant Pawar et al. / Procedia Structural Integrity 71 (2025) 134–141

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Fig. 9 Comparison of surface treated 52100 and carburized 8620 for (a)Impact energy, (b) flange breaking load

Fig. 10 Setup layout of flange breaking load test on UTM with help of fixture

4. Conclusion

a) Application layout analysis indicates unsupported sections of cone flange where groove is also in unspported condition over pinion gear face, will create tensile stress condition and consequentially microstrains on groove surface, putting it into alternating tensile stress condition. As the material is surface treated for more wear resistance, it has limited toughness, which makes it prone to cracking on the groove area. b) The failure of the cone flange initiated on the groove area and propagated in fatigue mode, causing a complete fracture resulting in flange separation in the bearing cone. The fractured zone's periphery displays beach marks, initiation zone shows stable crack growth and further becoming unstable. c) Cone flange breaking load comparison indicates the case-carburized 8620 cone has a higher flange breaking load as compared with existing SAE52100 cones, indicating the proposal can be taken further in bearing life testing as an improvement. d) The tensile loads and micro-deformations on the groove can be reduced by introducing a strengthening collar made up of high-strength and sufficient toughness materials, such as SAE4340, which will increase the overall thickness and support of the cantilever loaded flange section, reducing the surface tensile stresses and cyclical microstrains generating onto the groove area. References Beswick, J.M., 1989. Fracture and fatigue crack propagation properties of hardened 52100 steel. Metallurgical Transactions A, 20, 1961-1973. Brett A. Miller, Roch J. Shipley, Ronald J. Parrington, and Daniel P. Dennies, 2002. ASM Handbook Volume 11: Failure Analysis and Prevention. Materials Park, OH: ASM International, p.645. Diesburg, D.E. and Eldis, G.T., 1978. Fracture resistance of various carburized steels. Metallurgical Transactions A, 9, 1561-1570. González-Velázquez, J.L., 2018. Fractography and failure analysis (Vol. 24). Switzerland: Springer International Publishing, p. 32. Gupta, S., Bhargava, A., Pareek, A. (2018). A method of carbonitriding a work piece. Indian patent no. 476905. Harris, T.A. and Kotzalas, M.N., 2006. Essential Concepts of Bearing Technology. CRC Press, p. 25. Lee, S.C. and Ho, W.Y., 1989. The effects of surface hardening on fracture toughness of carburized steel. Metallurgical Transactions A, 20, 519 525. Nakazawa, K. and Krauss, G., 1978. Microstructure and fracture of 52100 steel. Metallurgical Transactions A, 9, 681-689.