PSI - Issue 42

Mushfiq Hasan et al. / Procedia Structural Integrity 42 (2022) 1169–1176 Mushfiq Hasan et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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4. Conclusions • Under severe contact conditions/boundary lubrication, micropitting has an inverse relation with wear. When wear becomes dominant, micropits will wipe off because of the removal of the top layer of the fatigued surface. Therefore, high slide-to-roll ratios (SRR) led to a smaller micropitted area due to the effect of wear on the damage mechanism. • With a longer test period, the wear volume amount is similar regardless of the SRR values. Moreover, it is not easy to identify the micropits due to wear at a very high number of contact cycles. • There is a proportional relationship between roughness and wear. On the other hand, an opposite relation with micropitting is found. Film thickness can be enhanced by minimizing roughness due to milder asperity contact which reduces the wear volume amount. At combined RMS roughness = 0.55 µm and Lambda = 0.19, a balance between wear and micropitting has found during our experiments. • Surface treatments are found to be useful in delaying micropitting initiation. It has a significant influence on the tribological parameters which significantly improved the overall wear and pitting performance as compared to the untreated samples. However, an investigation should be carried out to see if similar performance can be obtained by polished smooth surface or not. References 1. Mohammed, O. D., Rantatalo, M., 2020. Gear fault models and dynamics-based modelling for gear fault detection – A review. Engineering Failure Analysis, 117, 104798. 2. Tallian, T. E., 1992. The Failure atlas for hertz contact machine elements. ASME Press, second ed., Newyork. 3. Oila, A., Bull, S. J., 2005. Assessment of the factors influencing micropitting in rolling/sliding contacts. Wear, 258,1510 – 24. 4. Errichello, R.L., 2012. Morphology of Micropitting.(December):74 – 81. 5. Rycerz, P., Kadiric, A., 2019. The Influence of Slide – Roll Ratio on the Extent of Micropitting Damage in Rolling – Sliding Contacts Pertinent to Gear Applications. Tribology Letters [Internet], 67(2):1 – 20. Available from: https://doi.org/10.1007/s11249-019-1174-7 6. Cen, H., Morina, A., Neville A., 2018. Effect of slide to roll ratio on the micropitting behaviour in rolling-sliding contacts lubricated with ZDDP-containing lubricants. Tribology International. Jun 1,122:210 – 7. 7. Liu, H., Liu, H., Zhu, C., Sun, Z., Bai, H., 2020. Study on contact fatigue of a wind turbine gear pair considering surface roughness. Friction. Jun 1;8(3):553 – 67. 8. Winkelmann, El-Saeed, O., Bell, M., 2009. The effect of superfinishing on gear micropitting. Gear Technology. 2, 60 – 65. 9. Singh, H., Ramirez, G., Eryilmaz, O., Greco, A., Doll, G., Erdemir, A., 2016. Fatigue resistant carbon coatings for rolling/sliding contacts. Tribology International. Jun 1, 98,172 – 8. 10. Mahmoudi, B., Tury, B., Hager, CH., Doll, GL. 2015. Effects of Black Oxide and a WC/a-C:H Coating on the Micropitting of SAE 52100 Bearing Steel. Tribology Letters. 58, 2. 11. Hamrock, B. J., Dowson, D., 1987. Minimum film thickness in elliptical contacts for different regimes of fluid-film lubrication. NASA Technical Paper 1342,1-26. 12. Vrček, A., Hultqvist, T., Johannesson, T., Marklund, P., Larsson, R., 2020. Micro-pitting and wear characterization for different rolling bearing steels: Effect of hardness and heat treatments. Wear, 458 – 459, 203404. 13. Kaneta, M., Murakamit, Y., 1987. Effects of oil hydraulic pressure on surface crack growth in rolling/sliding contact. Tribology International, 20, 210-217. 14. Cheng, W., Cheng, HS., Keer, LM., 1994. Experimental investigation on rolliing/sliding contact fatigue crack initiation with artificial defects. Tribology Transactions. 37, 1 – 12. 15. Webster, M., Norbart, CJ., 1995. An experimental investigation of micropitting using a roller disk machine. Tribology Transactions, 38, 883 – 93. 16 . Vrček , A., Hultqvist, T., Baubet, Y., Marklund, P., Larsson, R., 2019. Micro-pitting Damage of Bearing Steel Surfaces under Mixed Lubrication Conditions: Effects of Roughness, Hardness and ZDDP Additive. Tribology International, 138(May):239 – 49. 17 . Vrĉek , A., Hultqvist, T., Baubet, Y., Björling, M., Marklund, P., Larsson, R., 2019. Micro-pitting and wear assessment of PAO vs mineral-based engine oil operating under mixed lubrication conditions: Effects of lambda, roughness lay and sliding Direction. Lubricants, 7, 5. 18. Morales-espejel, GE., Brizmer, V., 2011. Micropitting Modelling in Rolling – Sliding Contacts : Application to R olling Micropitting Modelling in Rolling – Sliding Contacts : Application to Rolling Bearings. 54, 625-643 . 19. Zhmud, B., Åkerlund, EB., Jacobson, S., Hardell, J., Hammerström, L., Ohlsson, R., 2012. ANS Triboconditioning: In-Manufacture Running-in Process for Improving Tribological Properties of Mechanical Parts Made of Steel or Cast Iron. Proceeding of the 18th International Colloquium Tribology – Industrial and Automotive Lubrication, 10 – 12 January 2012, TAE, Ostfildern, Germany.