Finite element analysis of three-dimensional hot bending and direct quench process considering phase transformation and temperature distribution by induction heating

Abstract

In this study, a coupled thermo-mechanical-metallurgical finite element analysis (FEA) method was developed to investigate the deformation behavior in the three-dimensional hot bending and direct quench processes. In the developed FEA procedure, the temperature distribution was calculated by two methods. First was a three dimensional electromagnetic and heat conduction analysis that considered a non-linearity of permeability and magnetic transformation. Second was a simplified method that used an original heat source model for induction heating. In the deformation analysis, temperature, micro structure and strain rate dependencies of flow stress were taken into consideration. As for the microstructure evolution, an experimental formula was used to track the ferrite-austenite transformation, and Koistinen-Marburger relationship was employed to describe the austenite-martensite change. To confirm the effectiveness of the developed FEA method, the thickness change upon bending and the camber by inhomogeneous cooling were simulated. The results were in good agreement with the experimental measurements.