Surface integrity and fatigue lifeof GH4169 by combined process of milling, grinding, and polishing

The effect of six processes including M (milling), G (grinding), MMP (milling and manual polishing), GMP (grinding and manual polishing), MCP (milling and CNC polishing), GCP (grinding and CNC polishing) on surface integrity and fatigue life of GH4169 are studied in this paper. The results show that grinding produce a larger degree of hardening compared to milling, and residual stress of grinding surface and milling surface are respectively compressive and tensile. Polishing can significantly reduce the surface roughness formed by the previous process. Surface tensile residual stress of milling is converted into compressive stress after polishing, while the degree of hardening and residual stress of grinding surface has no significant change after polishing. The roughness, residual stress, and hardening degree of the manual polishing and CNC polishing are similar, but there are many micro surface defects in the manual polishing surface. The fatigue life of GCP, MCP, GMP, and MMP gradually decreases. Therefore, the integration process of GCP can produce better surface integrity including surface roughness, hardening degree, and residual stress distribution.