Effect of Mechanical Surface Treatment and Post-Treatment Polishing on Tensile Strength and Fatigue Life of High-Speed Tool Steel
N. Karunathilaka, N. Tada, T. Uemori, J. Sakamoto, R. Hanamitsu, M. Fujii, Y. Omiya and M. Kawano
The effect of mechanical surface treatment and post-treatment polishing on tensile strength and fatigue life of Wonder Process Craft (WPC) and Micro-abrasive blasting (MB) treated tool steel SKH 51was studied. Surface polishing was performed on the ground, WPC, and MB treated specimens. MB treatment brought a higher surface roughness increase compared to WPC treatment, while polishing decreased the surface roughness. WPC and MB treatments increased the surface compressive residual stress. Fatigue life showed a negative relationship with surface roughness, and this relationship varies with residual stress condition. Fatigue life at similar residual stress conditions showed a variation based on the surface roughness condition. There were 1.68 times and 4.72 times average fatigue life increase due to the MB treatment and the WPC treatment compared to the ground specimen. Dimension controlled post-treatment polishing on the MB treated showed 6.73 times, and the WPC treated specimens showed more than 7.74 times improvement in average fatigue life compared to the ground specimens.
Keywords: Fatigue life, wonder process craft (WPC) treatment, micro-abrasive blasting treatment, polishing, residual stress, surface roughness