Mechanical properties of high-strength Q960 steel at elevated temperature

Abstract

This study experimentally investigates the temperature-induced deterioration in the mechanical properties of high-strength Q960 steel. High-strength steel has numerous advantages compared with conventional mild-strength steel and has gained wide applications in engineering structures, particularly in high-rise and long-span buildings. The fundamental issue in the fire-resistance design of high-rise or long-span steel buildings is the evaluation of mechanical properties under elevated temperature. There is little information on the temperature-induced mechanical-property deterioration of Q960 steel because of the limited research on this subject. To bridge this knowledge gap, a series of tensile coupon tests on Q960 steel was carried out under various temperatures from 20 to 900 °C to obtain the corresponding stress–strain relationships, yield strength, ultimate strength, and elastic modulus at elevated temperatures. The test results were compared with the results of other high-strength steel types such as Q460, Q690, and S960 steels reported in previous studies as well as the mechanical properties recommended in applicable design codes or standards. The comparison showed that the effects of temperature on the mechanical properties among different types of high-strength steels are different. New predictive equations for evaluating the material properties of Q960 steel at elevated temperatures were presented.