Evaluation and review of simultaneous transformation model in high strength low alloy steels

This work briefly describes and evaluates one of the most complete transformation models, which deals with the non-isothermal decomposition of austenite. The model, that does not consider the effect of precipitation on phase transformations, has been experimentally validated in high strength low alloy steels in order to evaluate how it works for microalloyed steels, where precipitation may play an important role. It has been found that the simultaneous transformation model is able to predict with an excellent agreement in microalloyed steels the formation of microstructures consisting of ferrite plus pearlite. However, the bainite formation is not successfully described by the model. The calculations incorrectly predict the formation of martensite instead of bainite in many situations. (C) 2002 IoM Communications Ltd.