The influence of ultra-fast annealing prior to quenching and partitioning on the microstructure and mechanical properties

The microstructural evolution of a Quenching and Partitioning (Q&P) steel after ultra-fast annealing (UFA) was studied and correlated with the obtained mechanical properties. The shift of the transformation temperatures with increasing heating rates was shown by dilatometric experiments. The influence of the heating rate on the carbide precipitation and texture was evaluated. A remarkable refinement of the prior austenite grain size is observed resulting in a better combination of strength, ductility and fracture behavior compared to conventionally used heating rates.