Mechanical properties of stainless-clad bimetallic steel bars exposed to elevated temperatures

Abstract

Fire is a frequent disaster, which performs the irreversible effects on mechanical properties of structural steels. When the structure experiences a fire and does not collapse, it is important to clarify the remaining resistance accurately. The stainless-clad bimetallic steel bar (SCBSB) consisting of the S30408 stainless-steel cladding layer and the HRB400 carbon steel substrate has the wide application in reinforced concrete structures serving in corrosive conditions. To evaluate residual resistance of SCBSB-concrete structures exposed to fire, post-fire mechanical properties of SCBSB are investigated experimentally. After the heating and cooling procedures, no cracking is observed in the cladding layer. Microstructures of SCBSB specimens are discussed. The stress–strain properties of SCBSB specimens exposed to elevated temperature and cooled with various methods are studied through the tensile coupon test. The dimensionless coefficients are selected to clarify effects of exposure temperature and cooling method on mechanical performances. These effects (at exposure temperatures lower than 600 °C) are relatively small. Predictive equations are suggested to determine mechanical performances of SCBSB specimens exposed to elevated temperature. The stress–strain models are proposed based on experimental results. Various energy indexes are selected to comprehensively investigate the ductile properties of the SCBSB specimens.