Abstract: During the sheet metal forming process, the ploughing effect had an important influence on the magnitude of surface deformation due to the similar roughness of tool-workpiece. To have an in-depth understanding of the ploughing process, single cone scratching tests of different grain sized materials were conducted in this study. It was found that the location of cracks and the flow directions of materials in scratching process varied significantly with the change of cone angle. The increase of grain size can restrain the initiation of cracks and lower the entire strain caused by the moving of the rigid cone, which in a row decrease the scratching hardness and pileup height in scratching process. The results of this study can improve the understanding of the ploughing process and further help the optimization of the surface quality of the metal-deformed products.

Key words: ploughing effect, surface scratching, grain size, metal forming