Research on the plastic flow characteristics of metal material in mechanical scratching

Abstract

The plastic flow characteristics of the metal material in mechanical scratching is determined on the important parameters of the negative rake angle, the material deformation amount, the scratching force, the groove quality, and the tool wear. However, the chip flow angle and the plastic flow direction of the metal material in the cutting or mechanical scratching are often derived from the approximate solution according to the metal cutting theory and assumptions. Meanwhile, there is no theoretical model of the plastic flow characteristics suitable for the mechanical scratching the metal material with diamond wedge scratching tool (irregular triangular pyramid tool). Therefore, the unit plastic flow vector (PFV), the working negative rake angle, and the chip flow angle (CFA) theoretical model are established in this paper. And the evolution law of plastic flow angle of the unit PFV and CFA under the influence of the multi-scratching factors was also studied. It can be known that the PFA is related to the elevation angle of the scratching tool, but independent on the speed and material, while the CFA is related to the above multi-scratching factors. Meanwhile, the evolution law of theoretical PFA is consistent with the experimental value, and the maximum deviation is 6.687°, which verifies the theoretical model. In addition, compared with the CFA, the PFV can directly reflect the material plastic flow direction on the contact surface.