Mechanical properties of double-sided stainless-clad bimetallic steel at elevated temperatures

This paper presents a comprehensive test program on the elevated-temperature mechanical properties of doublesided stainless-clad bimetallic steel (DSSCBS), which is a new type of high-efficiency material that has potential to be used for cold-formed thin-walled structural members. A total of 49 coupon specimens were extracted from two DSSCBS sheets as well as their corresponding substrate and cladding materials. Fire tests were carried out on tensile coupons by applying steady-state test method at 13 different temperatures up to 900 degrees C. Full range of stress-strain curves were obtained and key mechanical properties including elastic modulus, yield strength, strength at 2 % strain, ultimate strength, ultimate strain, and fracture strain were reported. The measured reduction factors of the DSSCBS specimens were compared with their corresponding values of the substrate and cladding materials, with the influence of clad ratios evaluated. In addition, the applicability of prediction curves for single-sided stainless-clad bimetallic steel, along with current design regulations as stipulated in American and European standards for carbon steel and stainless steel, were assessed. New design methods were proposed for reduction factor estimation of key mechanical properties and a constitutive model was formulated for stressstrain relationships of the bimetallic steel materials at various temperatures. Furthermore, the impact of peak temperature history on mechanical properties of DSSCBS at elevated temperatures was explored.