Numerical simulation of martensitic transformation plasticity of 42CrMo steel based on spot continual induction hardening model

Spot continual induction hardening (SCIH), as a new selective surface hardening technology proposed in recent years, has unique advantages in strengthening metallic component with complex geometric shapes. However, the prediction of residual stress distribution after SCIH is very complicated due to the existence of different kinds of strains during the process, especially the influence of transformation-induced plasticity (TRIP) strain on residual stress field. In this paper, a SCIH model considering the influence of transformation plasticity was proposed via the secondary development of commercial finite element software ABAQUS. The results show that the existence of transformation plasticity can coordinate the internal stress between parent phase and product phase effectively in martensitic transformation. The main contribution of this paper is to clarify the influence of the transformation plasticity coefficient (K) on the accuracy of residual stress prediction. The amplification effect of the equivalent stress on the value of K needs to be considered in martensitic transformation of SCIH process. However, the increment of K will reduce the equivalent stress during martensitic transformation and residual stress after SCIH treatment. Due to the feedback mechanism of transformation plasticity coefficient on the equivalent stress, the value of the TRIP strain doesn't increase linearly with the value of K increasing during SCIH process.