淬硬超高强度钢 45CrNiMoVA 硬车削加工性研究

In order to avoid tensile residual stress and heavy use of highly-polluting cutting fluid, in the grinding process of hardened steel, a hard turning process is proposed. The turning process is carried out for the quenched-tempered 45CrNiMoVA steel. The cutting forces during the process are recorded, and the surface morphology, residual principal stress, and microhardness of the machined surfaces are analyzed. The results show that the cutting forces increase with the cutting depth and feed rate. However, the change in cutting speed has little effect on the cutting force. The surface roughness Ra of the workpiece after hard turning can reach 0.64 μm. The consistency of surface morphologies is also satisfying. The residual principal stress decreases with the increase of the feed rate and the cutting depth. By comparison, the residual principal stress first decreases and then increases with the increase of the cutting speed. The direction angle of the maximum residual principal stress changes steadily within the range of 37°~45° with the increase of cutting speed and cutting depth. It first increases and then maintains stable within the range of 22°~45° with the increase of feed. The surface microhardness decreases with the increase of cutting speed, and the depth of hardened layer is about 200 μm.