A MODEL FOR DESCRIPTION OF STRUCTURE FORMING PROCESSES DURING REHEATING STEELS FOR THERMAL-TREATMENT

Modern production technologies, applied for parts or billets of steels for heat treatment, demand a possibility to predict the resulting and important structure parameters. The description of the austenite stru cture before transformation is also interesting for technologies with austenite transformation. A concept is presented to model austenitizin g, including austenite nucleation, austenite nuclei growth and austeni te grain growth. Monte-Carlo-Simulation is the mathematical method for modelling. The influence of secondary phases, especially the dissolut ion, is taken into account by using an additional part of the model. T he mathematical method therefore is finite-differences. Based on this concept, a model is developed for description of austenization during reheating, The variables for input are estimated at metallo-grafical p lane. Tests were carried out with case hardening steels and tempering steels. Austenite nuclide density and grain growth behaviour were esti mated, both according to the initial state.