Post-fire constitutive model on explosively welded stainless-clad bimetallic steel after cold-forming process

Abstract

This study conducted an experiment on corner stainless-clad bimetallic steel (SBS) specimens to clarify the coupling effects of the cold-forming process and fire exposure on the monotonic mechanical properties of SBS, where different exposure temperatures and cooling methods were considered. The SBS produced through the explosive welding method was used to obtain cold-formed specimens. After the cold-forming process and fire exposure, no obvious cracking was observed in the stainless-steel cladding and metallurgical bonding layer. Based on the tensile coupon test results, the yield plateau in the stress–strain curve of the virgin SBS specimen disappeared because of the cold-forming process. The effects of the exposure temperature and cooling method on the stress–strain curves of the corner SBS specimen were clarified. The variation trends of the key mechanical parameters were discussed. Predictive equations were proposed for the key mechanical parameters of corner SBS specimen after fire exposure. Two constitutive models were suggested for the corner SBS stress–strain curves with and without the yield plateau, which could be used in the numerical and theoretical investigations on the post-fire-resistant performance of cold-formed SBS components. Comparing the experimental and predicted results indicated that the residual monotonic stress–strain curves of the corner SBS could be accurately described using the proposed constitutive models.