Predictions of material properties in cold-rolled austenitic stainless steel tubular sections

Abstract

Material properties in cold-rolled stainless steel members are significantly different from those in annealed sheets (e.g. considerable enhancement in 0.2% proof stress), which provides a potential to reduce the initial cost of stainless steel structures in the design stage. This study is aimed at proposing reasonable predictive formulas for the enhanced material properties in cold-rolled stainless steel tubular sections. A total of 130 tensile coupons were extracted from three types of material statuses (i.e. the coil, the circular hollow section and the square/rectangular hollow section) occurred in four cold-rolling production routes. Tensile coupon tests were then conducted to illustrate the change of material properties from coils to square/rectangular hollow sections (SHS/RHSs) as well as the detailed distributions of material properties in cross-sections. Based on test data, predictive formulas were developed for all material parameters in cold-rolled stainless steel hollow sections according to the “through thickness averaged plastic strain” method originally proposed by Gardner's group in Imperial College London. The predictions of the proposed formulas were evaluated using the test results in this study and in existing literature. Comparisons indicate that proposed models provide not only accurate predictions for the key material properties (e.g. the 0.2% proof stress, the 1% proof stress and the ultimate tensile strength), but also reasonable predictions for full-range stress-strain curves in cold-rolled stainless steel hollow sections. The predictions of the proposed models can be used in finite element analysis and advanced design methods for cold-rolled stainless steel hollow sections.