Post-fire behavior of double-sided stainless-clad bimetallic steels

Abstract

This paper presents an experimental investigation of the post-fire behavior of double-sided stainless-clad bimetallic steels (DSSCBS), which is a new type of high-efficiency material and is promising to be used in cold-formed structures. A total of 48 tensile coupon specimens were extracted from two types of DSSCBS plates, with 316L stainless steel as the cladding material and Q235 or Q345 carbon steel as the substrate material. The specimens were heated up to various temperatures up to 1000 °C and subsequently cooled down to ambient temperature via air-cooling or water-cooling methods, to evaluate the effect of different cooling approaches. Additionally, the influence of in-fire stresses, which reflects the load ratios of structural members in fire hazards, was also examined. Stress-strain curves as well as key mechanical properties including the elastic modulus, yield strength, ultimate strength, ultimate strain and fracture strain were obtained and fully reported. Moreover, the measured post-fire retention factors were compared with existing prediction equations for carbon steel and stainless steel, as well as the prediction curves for single-sided stainless-clad bimetallic steel to assess their applicability to this novel material. New predictive rules for retention factors of DSSCBS in post-fire conditions were proposed with stress-strain models advanced to offer a reference for future numerical simulation and assessment of the post-fire behavior of members and structures of DSSCBS.