Effect of Annealing Process on Microstructure and Mechanical Property of 1100 MPa Grade TRIP Steel

作     者：Hong-xiang YIN Zheng-zhi ZHAO Ai-min ZHAO Xiao LI Han-jiang HU Jiang-tao LIANG 

作者机构：Metallurgical Engineering Research InstituteUniversity of Science and Technology Beijing Beijing Laboratory of Metallic Materials and Processing for Modern Transportation 

出 版 物：《Journal of Iron and Steel Research International》 (国际钢铁研究杂志)

年 卷 期：2015年第22卷第7期

页      面：622-629页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：Item Sponsored by National Natural Science Foundation of China(51271035) 

主　　题：TRIP steel retained austenite intercritical annealing bainitic isothermal temperature automobile steel 

摘      要：To develop super-high strength TRIP steel for automobile application with good combination of strength and plasticity, an ultra high-strength TRIP steel 0.2 %C-2.0% Si-1.8% Mn was investigated at different intercritical annealing temperatures and bainitic isothermal temperatures. Microstructures were observed by scanning electron mi- croscopy, transmission electron microscopy, electron backscatter diffraction, and X-ray diffraction, and mechanical properties were tested under a uniaxial tensile testing machine. It shows that the best comprehensive mechanical properties were obtained for the experimental steel particularly annealed at 820 ℃ and austempered at 410 ℃. Yield strength of the tested steel mainly depends on ferrite, while the high strength of the tested steel is related to mar- tensite which forms through blocky austenite transformation during cooling and subsequent tensile test attributed to the TRIP effect. Hence, it could be concluded that the grain size of the retained austenite and carbon content in re- tained austenite are the main reasons for high elongation of the tested steel.