Effect of annealing temperature on the microstructure and mechanical properties of cold rolled medium manganese steel
The effects of annealing temperature on the microstructure and mechanical properties of cold rolled medium-Mn steels were investigated. Scanning electron microscopy was applied to characterize the microstructure evolution during annealing process; X-ray diffraction analysis was used to determine the residual austenite content in the steel. Tensile tests were carried out to measure the mechanical properties of the annealed steel. It was demonstrated that austenite reverted transformation took place during the annealing process, which results in an ultrafine austenite and ferrite dual-phase structure. As the annealing temperature rising up, the precipitates gradually got dissolved and the microstructures of the dual-phase phase got coarsened and tended to be equiaxial. The tensile results showed that the tensile strength (Rm) increased linearly with temperature but the yield strength (Rp0.2) first decreased and then increased at 675 ℃. Total elongation (A) and the product of tensile strength to total elongation (Rm x A) first increased and then decreased in the studied temperature range. Maximum values of A (-44.5％) and Rm×A (~40.5GPa ％) were obtained annealing at 625 ℃ for 4hours. At last the ultrahigh strength, ultrahigh elongation and the high product of tensile strength to elongation (Rm×A) were attributed to the enhanced TRIP effects of the large fractioned metastable austenite and the superfine grain size.
Medium Mn steel Cold rolling Austenite reverted transformation Metastable austenite TRIP effects
HU Jun ZHAN Wei SHI Jie LI Nan DONG Han LI Jian CAO Wen-quan
College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Institute for Structural Materials, Central Iron and Steel Research Institute, Beijing 100081, China College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan,
国际会议
北京
英文
123-127
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）