Study of controlled rolling and controlled cooling on a fire-resistant steel for construction

Experiments of controlled rolling and controlled cooling processing have been carried out on a (Nb, Ti) microalloyed fire-resistant steel for construction. A series of test method and means such as optical microscope, transmission electron microscope, scanning electron microscope and mechanical property tests are utilized to analyse the effect of different cooling style (air cooling, furnace cooling and water cooling) on microstructure and mechanical properties. And the strain induced precipitation behavior is also investigated. By controlling the processing parameters that the yield strength about 524MPa , tensile strength about 749MPa, impact toughness about 60J, ratio of σ0.2/σb lower 0. 8 and the high temperature strength at 600℃ larger the 2/3 of the room temperature strength can be obtained, which can reach the mechanical property requirements of the fire-resistant steel for construction.