Variations in the Microstructure and Properties of Mn-Ti Multiple-phase Steel with High Strength under Different Tempering Temperatures

作     者：LI Dazhao LI Xiaonan CUI Tianxie LI Jianmin WANG Yutian FU Peimao 

作者机构：School of Materials Scinece and Engineering North University of China Technology CenterTaiyuan Iron & Steel (Group) Co. School of Materials Scinece and Engineering Tianjin University 

出 版 物：《Chinese Journal of Mechanical Engineering》 (中国机械工程学报（英文版）)

年 卷 期：2015年第28卷第2期

页      面：430-436页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 080502[工学-材料学] 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：Supported by National Natural Science Foundation of China(Grant No.51201154) 

主　　题：multiple phase microstructure lath shaped ferrite polygonal ferrite precipitate retained austenite film 

摘      要：There are few relevant researches on coils by tempering,and the variations of microstructure and properties of steel coil during the tempering process also remain *** using thermo-mechanical control process（TMCP）technology,Mn-Ti typical HSLA steel coils with yield strength of 920 MPa are produced on the 2250 hot rolling production ***,the samples are taken from the coils and tempered at the temperatures of 220℃,350℃,and 620℃*** tempering the strength,ductility and toughness of samples are tested,and meanwhile microstructures are *** initially emerge inside the ferrite laths and the density of the dislocation ***,the lath-shaped ferrites begin to gather,and the retained austenite films start to ***,the retained austenite films are completely decomposed into coarse and short rod-shape precipitates composed of C and Ti *** yield strength increases with increasing tempering temperature due to the pinning effect of the precipitates,and the dislocation density *** yield strength is highest when the steel is tempered at 220℃because of pinning of the precipitates to *** total elongation increases in all samples because of the development of ferrites during *** tensile strength and impact absorbed energy decline because the effect of impeding crack propagation weakens as the retained austenite films completely decompose and the precipitates *** paper clarifies the influence of different tempering temperatures on phase transformation characteristics and process of Mn-Ti typical multiphase steels,as well as its resulting performance variation rules.