Effect of Laminar Cooling on Phase Transformation Evolution in Hot Rolling Process

The effect of temperature variation owing to the cooling pattern (CP) on the microstructural evolution was investigated by establishing a thermomechanical coupled FE (finite element) model. A set of constitutive equations of phase transformation was implanted into the commercial FE solver MARC through the user defined subroutine CR-PLAW, and the temperature field was calculated by another user defined subroutine FILM. The results show that the final microstructure is completely bainite phase for CP one, 98% of bainite phase and 2% of ferrite phase for CP two, and 55% of bainite phase, 35% of pearlite phase and 10% of ferrite phase for CP three.