感应淬火对42CrMo钢曲轴连杆轴颈组织性能的影响

Effect of induction hardening on microstructure and properties of 42CrMo steel crankshaft connecting rod journal

采用OM、SEM、X射线应力分析、力学性能测试等手段,分析了感应淬火处理对42CrMo钢曲轴连杆轴颈截面组织和残余应力的影响,探讨了不同淬火功率对淬硬层形貌、显微组织和力学性能的影响。结果表明,42CrMo钢曲轴连杆轴颈截面由淬硬层、过渡层和基体3部分组成,淬硬层组织为均匀细小的马氏体,过渡层组织为马氏体和回火索氏体的混合组织,基体组织为回火索氏体。经感应淬火处理,42CrMo钢曲轴连杆轴颈表面残余应力由拉应力变为压应力,随着感应淬火功率的增加,淬硬层深度增加,组织不断细化,当感应淬火功率为2500 W,组织最为均匀细小,表面硬度达到了751.3 HV0.1,耐磨性大幅提升;但是淬火功率过高会导致组织粗化,当感应淬火功率为2600 W时,组织有所粗化,硬度也有所降低。

Effect of induction hardening treatment on sectional microstructure and residual stress of the 42 CrMo steel crankshaft connecting rod journal was analyzed by means of OM, SEM, X-ray stress analysis and mechanical property test. The effect of quenching power on morphology, microstructure and mechanical properties of the hardened layer was discussed. The results show that the 42 CrMo steel crankshaft connecting rod journal is composed of three parts: the hardened layer, the transition layer and the matrix. The microstructure of the hardened layer is uniform and fine martensite, the transition layer is a mixture of martensite and tempered sorbite, and the matrix is tempered sorbite. After induction hardening, the surface residual stress of the 42 CrMo steel crankshaft connecting rod journal changes from tensile stress to compressive stress. With the increase of induction hardening power, the depth of hardened layer increases and the microstructure is refined continuously. When the quenching power is 2500 W, the microstructure is the most uniform and fine, the surface hardness reaches 751.3 HV0.1, and the wear resistance is greatly improved. However, too high induction hardening power will lead to microstructure coarsening. When the induction hardening power is 2600 W, the microstructure is coarsened and the hardness is reduced.