Experimental research on parameter optimization for high efficiency hard turning of ultrahigh strength steel 42CrMo

Ultrahigh strength steel was a structural material with extremely high tensile, shear and yield strength. While, it was difficult to machining due to the excellent mechanical properties. There was serious problem in high quality and high efficiency machining of ultrahigh strength steel in actual production. In this paper, the effect of different turning parameters on cutting force, surface roughness, chip form and tool wear during dry turning of a typical ultrahigh strength steel were experimentally investigated, and the cutting parameters were optimized, then the empirical formulas of the cutting force and surface roughness Ra were also obtained. Both the cutting forces and surface roughness Ra were decreased as the increase of cutting speed, and increased as the feed rate and cutting depth. Within the selected range of machining parameters in the experiments, all the chips were serrated. The normal wear stage of the tool was not obviously, and the tool life was about 2000 s, which fulfilled the needs of actual production. This study gave experimental support for the parameter optimization during dry machining of ultrahigh strength steel, comprehensive considering processing efficiency, tool wear and machined surface quality.