Mechanical properties of stainless-clad bimetallic steel at elevated temperatures

Abstract

Stainless-clad (SC) bimetallic steel is an advanced high-performance (HP) laminated steel, which combines benefits of both the substrate steel and the cladding metal. Therefore it has great potential in structural engineering application, particularly in corrosive environment and high temperature conditions due to good corrosion and heat resistance of the stainless steel cladding layer, respectively. To investigate mechanical properties of the SC bimetallic steel at elevated temperatures, tension coupon tests are undertaken with temperatures ranging from 100 °C to 950 °C. Based on the test results, stress-strain curves and associated mechanical properties such as elastic modulus, proof strength, ultimate tensile stress and elongation percentage after fracture are obtained. In addition, reduction factors of the material properties compared with those at ambient temperature are also determined. It is found that with an increase of the temperature, both the elastic modulus and the strengths are reduced markedly. By comparing the test results with independent ones of conventional mild steel and stainless steel as well as that suggested by national standards, it is found that the high temperature performance of the SC bimetallic steel is in between. Specific equations for predicting the elastic modulus, proof strength and ultimate strength of the SC bimetallic steel at elevated temperatures are proposed in this paper, with effect of clad ratios being involved, which can be used to evaluate the bearing capacity of the SC bimetallic steel structures in fire.