Experimental Investigation on Mechanical Properties of Q235B Hot-Rolled Structure Steel at Elevated Temperatures

The deterioration of the mechanical properties of yield strength and modulus of elasticity is considered as the primary properties affecting the performance of steel structures under fire. Accurate mechanical properties data at elevated temperature is requisite in the safety design and analysis of hot-rolled steel structures under fire. However, the variation of these properties for steel structures at different temperatures is not systematically reported in China for the moment. Grade Q235B hot-rolled structure steels are widely used in China. Therefore, the steady state tensile tests were conducted for structure steels taken from the beam of Grade Q235B hot-rolled structure steel at different temperatures ranged from 20 to 1000 degrees C to derive accurate reduction factors for mechanical properties in fire safety calculation. The experimental results were presented in the paper, and the simplified models for the stress-strain curves of the steel studied at elevated temperatures were proposed also. Some test results are compared with material model for steel according to the EC3, AS4100 and BS5950-8, which are standards of Europe, Australian, and British respectively, since the effective yield strength of different strain levels are adopted in these standards.