Abstract
Factors generating microscopic residual shear stress τZXW in uni-directionally machined layers produced by cutting and grinding were studied experimentally. In the affected layers, residual strain distributions depend on machining direction and the strains are generated by τZXW. In affected layers, generally, macroscopic residual stresses are thought to consist of three elements resulting from thermal, burnishing or rubbing and mechanical cutting action of a cutting tooth and abrasive grains during machining process. Relations between the three elements and τZXW were also investigated experimentally and the following can be summarized.τZXWis extinguished in process ofrecovery dueto heating at low temperature in furnace. τZXW produced by cutting and grinding increases as carbon content of steel increases, but has a tendency to be saturated in carbon segregated regions. These results show that τZXW is a phase stress generated by elastic recovery force of cementite acting upon slip plane of ferrite grains. On the other hand, the travelling heat source at high temperature decreasesτZXW and generates microscopic residualstress.τZXW generated in pearlite structure is greaterthan one in spheroidal cementite structure. The factors of generating τZXW are mechanical cutting and burnishing action, microstructures of steel and machining conditions.
