Next generation phase transformation models for advanced low-carbon steels

The austenite-ferrite transformations are a key metallurgical tool to tailor properties of advanced low-carbon steels. Even though significant progress has been made to develop knowledge-based process models for the steel industry it remains critical to improve the predictive capabilities of these models by developing next generation modelling approaches with a minimum of empirical parameters. Computational materials science now offers tremendous opportunities to formulate microstructure evolution models containing fundamental information on the underlying atomistic mechanisms that can be implemented across different length and time scales.

The phase transformation kinetics depends critically on interface migration rates which are significantly affected by the presence of alloying elements, e.g. Mn, Mo and Nb in steels. Here, an approach is illustrated that links atomistic scale models for the solute-interface interaction with phase field modelling and conventional diffusion models. The overall status of this multi-scale phase transformation model approach will be analyzed for intercritical annealing of dual-phase steels and the rapid heat treatment cycles in the heat affected zone of linepipe steels.