Experimental study on creep-feed grinding burn of DD9 Nickel-based single crystal superalloy

Aiming at the problem of grinding burns on the third-generation single crystal superalloy DD9, a three-factor and five-level experiment is designed in this paper. From the perspectives of surface morphology, microhardness and microstructure, the effect of grinding process parameters on grinding burns are studied. The experimental results show that: when the workpiece feed speed is less than 250 mm/min, the grinding surface roughness R_a changes slightly around 0.8 μm, and the surface quality is good. When the feed speed is more than 250 mm/min and the grinding depth is more than 1.0 mm, the temperature in the grinding area rises sharply, the grinding lines are destroyed, grinding defects such as coating and pits appear, and the surface of the workpiece burns. The surface and surface of DD9 alloy are work hardened by slow feed grinding. The microhardness range is 400 to 600 HV, the depth of hardened layer is 50 to 110 μm, and the thickness range of plastic deformation layer is 1 to 10 μm. The recommended combination of DD9 grinding process parameters is: grinding wheel linear velocity v_s=20 m/s, feed speed v_w=250 mm/min, grinding depth a_p=0.6 mm.