A model for the estimation of hardness of laser bent strips

In this work, a model is developed for the estimation of hardness of the laser bent parts. The model incorporates the effects of phase fraction, cooling rate as well as strain hardening. This is accomplished by using microstructure integrated finite element method simulation of laser bending of steel strips. The methodology is illustrated with an example of laser bending of AH36 steel strips. The Johnson-Mehl-Avrami-Kolmogorov law and Scheil's additivity rule are employed to simulate the kinetics of diffusional phase transformation, while Koistinen-Marburger equation is employed for non-diffusional phase transformation. Effects of latent heat release during phase transformations, temperature and phase fractions on the variation of thermo-physical properties are considered. The proposed model is validated through experiments. The model is able to simulate the kinetics of phase transformation in laser bending that leads to reasonably accurate estimation of phase fractions and hardness of laser bent strips.