The behaviour of structural steels at elevated temperatures and the designof fire resistant steels

This paper reviews the current understanding of the characteristics of stru ctural steels at elevated temperatures typical of those experienced in a fi re and the design of fire-resistant steels for building construction. Follo wing a commercial view of the requirements and market for steels with enhan ced properties at elevated temperatures, the microstructure/property relati onships and the influence of these upon high temperature strength are discu ssed in detail. Steel composition and processing variables can be controlle d to modify grain size, the presence of second phases and precipitation, fe rrite/austenite transformation temperature, dislocation density and weldabi lity. These are reviewed as well as the important issues concerning structu ral aspects that determine the fire resistance of steels. The microstructur e and property requirements of fire resistant steels are outlined and the w ays in which these may be achieved are discussed including those that have already been developed.