Effect of Carbon, Phosphorus and Nitrogen Contents in Steel on Machined Surface and Cutting Force

Abstract

The effect of carbon, phosphorus and nitrogen content on the surface roughness and cutting force was studied with regard to the microstructure of specimen and the behavior of void formation and built-up edge during cutting. Specimens to plunge-cutting were prepared by adding each element into pure iron.
Two-phase microstructure such as ferrite-pearlite and ferrite-grain boundary where phosphides precipitate, increase the surface roughness and reduce the cutting force. On the contrary, the single-phase microstructure, that is to say, ferrite containing soluble nitrogen, slightly improves the surface roughness but raises the cutting force.
Since the ductility of each phase in the two-phase microstructure is different from each other, the formation of voids takes place along the interface due to cutting force. The void formation behavior in the primary shear zone is closely related to the projection length of the built-up edge and the surface roughness.