Microstructure engineering of hot-rolled steel strip

摘要

Microstructure engineering is increasingly gaining attention with the goal being to develop predictive tools which connect the operational parameters of a process with the properites of the product it makes. The concept of microstructure engineering has been applied to hot strip rolling of advanced low carbon steels microalloyed with Nb, Ti and/or V. A comprehensive, fundamentally based microstructure model has been proposed based on experimental investigations of recrystallization, grain growth, precipitation and austenite decomposition. A process model has been developed by combining the microstructure-property model with the temperature and deformation models. The critical processing step to develop the properites of hot rolled steels is cooling after rolling when the austenite-to-ferrite transformation as well as precipitation takes place thereby determining the final microstructure. The hot strip mill process model has been validated with industrial data for high strength low alloy (HSLA) steels including a state-of-the-art HSLA-80 steel.