Mechanism and machinability in novel electroplastic-assisted grinding ductile iron

Abstract

Owing to the hard brittle phase organization in their matrixes, brittle materials are prone to the formation of pits and cracks on machined surfaces under extreme grinding conditions, which severely affect the overall performance and service behavior of machined parts. Based on the electroplastic effect of pulsed currents during material deformation, this study investigates electroplastic-assisted grinding with different electrical parameters (current, frequency, and duty cycle). The results demonstrate that compared to conventional grinding, the pulsed current can significantly decrease the surface roughness (S_a) of the workpiece and reduce surface pits and crack defects. The higher the pulsed current, the more pronounced the improvement in the surface quality of the workpiece. Compared to traditional grinding, when the pulsed current is 1 000 A, S_a decreases by 46.4%, and surface pit and crack defects are eliminated. Under the same pulse-current amplitude and frequency conditions, the surface quality continues to improve as the duty cycle increases. When the duty cycle is 75%, S_a reaches a minimum of 0.749 μm. However, the surface quality is insensitive to the pulsed-current frequency. By investigating the influence of pulsed electrical parameters on the surface quality of brittle material under grinding conditions, this study provides a theoretical basis and technical support for improving the machining quality of hard, brittle materials.