Investigation on plastic deformation behaviors in hard milling of H13 steel

Plastic deformation layer, as the topmost layer of machined surface, has a significant impact on the surface integrity. This research focuses on the plastic deformation behaviors in milling surface. First, the thermal model of machined surface and the classical infinitesimal milling force in hard milling process are developed, which were verified by a series of experiments. Secondly, the microstructure of plastic deformation layer is observed by a hard milling experiment and the scanning electronic microscopy analysis. Thirdly, based on the force model and thermal model, the reason that resulted in the nonuniformity of plastic deformation is analyzed by considering the mechanism of plastic deformation. Finally, the effect of cutting parameters on the thickness of plastic deformation is investigated; the results indicate that the more uniform plastic deformation can be obtained by employing the higher cutting speed and smaller feed rate in milling process. This research reveals the variation of plastic deformation layer, it is also helpful to optimize the cutting parameters so as to obtain the desired surface integrity.