Investigation of grindability and surface integrity in creep feed grinding of GH738 alloy using different grinding wheels

GH738 superalloy offers exceptional material properties at elevated temperature and is widely applied to the critical components of aero-engines and gas turbine. However, high strength and poor thermal conductivity bring significant challenges for the machining and surface qualities of GH738 superalloy. In this work, the creep feed grinding performance of GH738 was investigated. The variation laws and formation mechanism of surface integrity were explored with three common types of alumina grinding wheels under various grinding parameters. The experimental results showed that there is considerable impact of grinding parameters on the grinding force and grinding temperature. The stronger coupling of thermal and mechanical aggravates worse surface integrity. The propensity of grinding burn could be more sensitive when the maximum undeformed chip thickness is greater than 0.45–0.5 μm. With the material removal rate in the range of 0.83–1.67 mm³/mm·s, surface defects are visible, and the thickness of plastic deformation layer is about 4–6 μm. In addition, the surface quality ground by the white and pink fused alumina mixed abrasive grinding wheel (WA-PA) is slightly superior to that of the WA and BA grinding wheels. Finally, the grinding parameters for creep feed grinding GH738 are recommended as v_w ∈ [50, 150] mm/min, v_s ∈ [25, 35] m/s, and a_p ∈ [0.2, 0.6] mm.