Abstract: Transient law of temperature field and phase transformation hardening law of 45 steel during quenching process were obtained by numerical simulation, and the influence of single factor change on phase transformation hardened zone was analyzed. The thermal coupling model of laser quenching process of the 45 steel was established based on software Comsol Multiphysics, the whole of which is then modified by JMatpro calculated phase transformation curves and CCT curves, and the change curves of some thermal physical parameters of the material with temperature. The phase transformation hardened zone was defined based on the phase transformation curve and CCT curve. The results show that the hardened layer has a Gaussian distribution, and the laser quenching hardened layer is obviously different under different process parameters. Under the same other conditions, the depth and width of phase transformation hardened layer are positively correlated with laser power, and negatively correlated with scanning speed and spot diameter. It is concluded that, by combining JMatpro with Comsol Multiphysics, a thermodynamic coupling model of laser quenching considering the change of thermal physical parameters can be established and calculated, by which the prediction of laser quenching temperature field and phase transformation hardened zone can be realized.

Key words: laser quenching, transformation hardening, temperature field, numerical simulation