A set of steel grades aimed for processing through hot rolling resulting in bainitic microstructures have been designed based on phase transformation theory and acquired knowledge on bainitic microstructures [1–6]. During the design process a high fraction of fine bainitic ferrite and stable retained austenite with minimised amounts of hard brittle cementite and fresh martensite were pursued for a good combination of strength and ductility. The design also considered all possible industrial heat treatment constraints, and alloy cost.

In this work, the design procedures are validated at both, lab scale and pilot scale, where actual hot rolling and coiling schedules were applied. The resulting steels are characterised for both microstructures and mechanical properties, establishing the most relevant property-microstructure relationships.

This research is funded by Research Fund for Coal and Steel, grant number RFCS-2019-899482.