Microstructural predictions including arbitrary thermal histories, reaustenization and carbon segregation effects

Abstract

A microstructural prediction algorithm for hypoeutectoid steels is presented that accounts for carbon segregation effects and permits arbitrary thermal histories and austenite decomposition during reheating. Two austenization models are included: an instantaneous austenite formation and homo-genization model; and a transient, heterogeneous austenite formation algorithm. The transient heterogeneous model predicts slightly slower formation rates than measured but compares favourably with experimental results. The two models provide upper and lower bounds for the austenization time. Predicted grain size, martensite fraction and hardness distributions are compared with measurements taken from a weld heat-affected zone (HAZ). Predictions are in good agreement with experimental results.