High Ductility and Toughness of a Micro-duplex Medium-Mn Steel in a Large Temperature Range from—196 ℃ to 200 ℃

作     者：Si-lian CHEN Jun HU Xiao-dan ZHANG Han DONG Wen-quan CAO 

作者机构：Central Iron and Steel Research Institute School of Materials Science and EngineeringHuazhong University of Science and Technology Danish-Chinese Centre for NanometalsSection for Materials Science and Advanced CharacterizationDepartment of Wind EnergyTechnical University of Denmark 

出 版 物：《Journal of Iron and Steel Research International》 (Journal of Iron and Steel Research, International)

年 卷 期：2015年第22卷第12期

页      面：1126-1130页

核心收录：

学科分类：080503[工学-材料加工工程] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 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(51371057,51261130091) National Basic Research Program of China(2010CB630803) Danish National Research Foundation(DNRF86-5) 

主　　题：high strength high ductility intercritical annealing medium-Mn steel ultrafine grain size 

摘      要：A medium-Mn steel （0.2C5Mn） was processed by intercritical annealing at different temperatures （625 ℃ and 650 ℃ ）. An ultrafine-grained micro-duplex structure consisting of alternating austenite and ferrite laths was de- veloped by austenite reverse transformation （ART） during intercritical annealing after forging and hot rolling. Ultra- high ductility with a total elongation higher than 30% was achieved in the temperature range from -196 ℃ to 200 ℃, and high impact toughness no less than 200 J at -40 ℃ was obtained. Based on the analysis of microstructure and mechanical properties, it was found that the enhanced ductility was determined by the phase transformation effect of austenite （TRIP effect）, while the delayed ductile to brittle transition was controlled by austenite stability.