Effect of time-step on simulating precision of temperature and phase-transformation field during quenching process

Quenching process is a high non-linear process with the interaction of temperature, phase-transformation and stress/strain. When the temperature field of quenching is evaluated using finite element method, the numerical oscillation is easily caused. In order to improve the precision of the temperature and phase-transformation field in quenching process, the methods of lumped and consistent mass matrices, mesh refinement and self-adaptive time step are used and a finite-element simulating program for evaluating the temperature and phase-transformation is developed in this paper. A new method of self-control and adaptive time-step is presented according to the maximum and minimum difference values of temperature field between the previous simulating step and the current simulating step. The quenching process of axisymmetric problem is evaluated using the programmed software. The comparison of the simulation results shows that the self-adaptive time step method presented in this paper can effectively avoid the numerical oscillation. The evaluating precision is improved, and the computation time is much less than those of other methods.