Material Properties of Cold-Rolled Thin-Walled Steel Plates at Elevated Temperatures

It is highly important to clarify the high temperature mechanical properties in the design of cold-formed steel structures under fire condition due to the unique deterioration feature in material properties under fire environment and associated reduction to the mechanical performance of members. This paper presents the material properties of coupons cut from raw cold-rolled thin-walled steel plates at elevated temperatures. A set of high temperature extensometer with a range of 12.5mm relative to 50mm gauge was employed in the experiments, which could collect more displacement data between the gauge scope before the coupon fail. The coupons were extracted from original cold-rolled plates of GR340, GR410 and G550 steels with thickness of 1.0mm and 1.2mm, and a total of 50 tensile tests were carried out by steady state test method for temperatures ranged from 20 to 700°C. Based on the tests, material properties including the yield strengths, ultimate strengths, the elasticity modulus and the stress-strain curve were obtained. Meanwhile, the ductility of cold-formed steel plates were discussed. Finally, the temperature-dependent retention factors of all the material properties were compared to those provided by design codes and former researchers