曲轴感应淬火及残余应力的仿真与试验研究

Simulation and Experimental Study on Induction Hardening and Residual Stress of Crankshaft

曲轴在感应淬火时产生应力集中或应力分布不均会导致曲轴变形过大而失效。本文采用有限元方法对曲轴加热和冷却过程及残余应力进行了仿真,并对轴颈显微组织、轴颈淬硬层深度及曲轴残余应力进行了测试分析。结果表明,轴颈淬硬层为细针状马氏体,基体为回火索氏体,表面平均硬度为52.8 HRC,心部硬度为26.0-30.0 HRC,淬火后轴颈表面残余压应力为-154.3--254.9 MPa;连杆颈淬硬层深度为4.0 mm,过渡圆角处淬硬层深度为2.1 mm。曲轴感应淬火后淬硬层深度预测和残余应力的仿真结果与试验结果基本一致,仿真可预测淬硬层深度。

The stress concentration or the uneven distribution of the stress in the crankshaft induction quenching will cause too large deformation of the crankshaft, which is the failure. The heating and cooling process and residual stress of the crankshaft were simulated by using the finite element method. The microstructure, the depth of hardened layer of the journal and the residual stress of the crankshaft were measured and analyzed. The results show that the hardened layer of the journal is a fine acicular martensite, the matrix is tempered sorbite, the average surface hardness is 52.8 HRC, the core hardness is 26.0-30.0 HRC, and the residual compressive stress of the shaft neck surface after quenching is-154.3--254.9 MPa; the depth of hardened layer of connecting rod neck is 4.0 mm, the hardened layer depth of transition fillet is 2.1 mm. The simulation results of the depth of the hardened layer and the residual stress after induction hardening are consistent with the experimental results,and simulation can predict the depth of hardened layer.