The numerical model prediction of phase components and stresses distributions in hardened tool steel for cold work

This study describes modelling of the processes of steel hardening. The first priority was given to a thermal phenomena, phase transformations in solid state and a mechanical phenomena. The issue of heat conductivity was based on the equation of transient heat conductivity with unit source. Numerical algorithms for kinetics of phase transformations and evaluation of fractions of phases were built on the diagrams of continuous heating and cooling of tool steel (CHT and CCT). The theoretical model of phase transformations was then verified by experiments. In modelling of mechanical phenomena, the equilibrium equations and constitutive relations were adopted in the rate form. Plastic strains are determined by the theory of non-isothermal plastic flow associated with the Huber-Mises condition. The model assumed isotropic and kinematics hardening and besides elastic, thermal, structural, plastic strains and transformations plasticity were included. Thermophysical properties including Young׳s modulus, tangent modulus and yield strength were directly dependent on temperature and material phase composition. The issues of thermo-elastic-plastic were solved using the finite element method. Implemented algorithms were applied in computer stimulation of hardening of non-alloy tool steel. Numerical analysis of thermal effects and phase transformations, i.e. stresses and strains in mechanical phenomena in a tool steel material undergoing hardening were made.