Generation Mechanism of Work Hardened Surface Layer in Metal Cutting. 2nd Report. Study of Mechanical Factors Acting on Depth of Work Hardened Surface Layer Using Calculation Model.

Abstract

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effect of the cutting conditions and the complicated factors on the machined surface integrity is a serious problem. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force action point, coefficient of thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.