Effect of cold-form and tensile strain rate on mechanical properties of Q345 steel at elevated temperatures

In recent years, cold-formed steel has been extensively used, and the mechanical properties of cold-formed steel at elevated temperatures have been received considerable attention. However, little research on mechanical properties of the corner parts at elevated temperatures has been published. Meanwhile, the tensile strain rates adapted in the previous research on cold-formed steel are different, and the effect of this factor on mechanical properties was rarely investigated. In order to get a deeper understanding of the mechanical properties of cold-formed Q345 steel at elevated temperatures, an experimental investigation on flat and corner parts in cold-formed Q345 sections with two nominal thickness of 1.5 mm and 2.5 mm under three different tensile rates, 0.06/min, 0.6/min and 1.2/min, was carried out at elevated temperatures ranging from 20 °C to 800 °C. The effects of tension strain rate, cold-forming and thickness on mechanical properties of Q345 steel were systematically studied. Then the test results were compared with the prediction results provided by the current design standards and the other researchers. Furthermore, prediction equations were proposed to determine the mechanical properties of cold-formed Q345 steel. In order to get a deeper understanding of the mechanical properties of cold-formed Q345 steel at elevated temperatures, an experimental investigation on flat and corner parts in cold-formed Q345 sections with two nominal thickness of 1.5 mm and 2.5 mm under three different tensile rates, namely 0.06/min, 0.6/min and 1.2/min was carried out at elevated temperatures ranging from 20 °C to 800 °C. The effects of tension strain rate, cold-forming and thickness on mechanical properties of Q345 steel were systematically studied. Then the test results were compared with the prediction results provided by the current design standards and the other researchers. Furthermore, prediction equations were proposed to determine the mechanical properties of cold-formed Q345 steel. • Coupon tests on mechanical properties of cold-formed Q345 steel at elevated temperature were carried out. • Effect of cold-formed and tension strain rate on mechanical properties were investigated. • Comparison and discussion were conducted on test data and design codes. • Prediction equations were proposed to determine the mechanical properties of Q345 steel at elevated temperatures.