Effect of controlled rolling and controlled cooling processing on microstructures and mechanical properties of a fire-resistant steel for construction

Controlled rolling and controlled cooling was carried out in an experimental rolling mill for a steel microalloyed with Nb and Ti. Effect of processing parameters including finish rolling temperature and cooling rate on microstructures and mechanical properties of the steel was studied. The results showed that the strength of the steel mainly consisting of bainite was higher than that of steel in which ferrite was dominant and the strength of the former steel at high temperature was also higher, but its ductility deteriorated. High mechanical properties can be obtained by reasonably optimizing the processing parameters of the steel and the requirements for the fireresistant steel can be reached.