对含偏析带的热轧中锰钢进行临界退火处理，通过合理控制非偏析带区的逆奥氏体转变程度，获得了超高强塑积(PSE > 70 GPa·%)。结果表明，经不同温度热处理后，包(由原奥氏体晶粒边界定义)内晶粒的尺寸、取向显著影响中锰钢的力学性能和变形组织。在拉伸过程中，沿着拉伸方向，非偏析带内有利取向的包倾向形成拉长的条状细晶区，而不利取向的包倾向形成碎块状晶区。通过协调变形，相邻包将最终倾向形成上述2种微区亚结构的交替分布。非偏析带内的逆转变奥氏体因晶粒尺寸广泛分布而可承受较大的变形，从而使得偏析带内奥氏体发生足够的应变诱发马氏体相变(SIMT)，最终获得优异的强度和韧性匹配。

Recently, medium-Mn steel, used in the automotive industry, has attracted increasing attention as the one of the most promising candidates for the third generation of advanced high strength steels owing to its reasonable cost and excellent mechanical properties. In this study, the effect of intercritical annealing temperature on the microstructure and mechanical properties of a new composition steel was investigated, and its strengthening mechanism and related reasons were analyzed. In addition, a ultra-high product of strength and plasticity (> 70 GPa·%) of hot rolled medium manganese steel with a segregation band was eventually obtained. The results show that the grain size and orientation in the packet (defined by the original austenite grain boundary) significantly affect the mechanical properties and deformation microstructure of the material obtained under different temperatures. The obvious precipitation and dissolution processes of carbides occur at higher temperatures, and thus influence the mechanical stability of reversed austenite. During the tensile process, because it is easier to deform, the favorable packets in the non-segregation zone form an elongated-strip fine-grain zone along the loading direction, while the unfavorable packets form fragmentary grain regions. Moreover, martensite transformation preferentially occurs at the obvious orientation inside the austenite grain and the boundaries where large strain is accumulated. Through coordinated deformation, the adjacent packets eventually tend to form alternate distribution of the two kinds of micro-zone substructures, which is accompanied by the significant evolution of low-angle grain boundaries related to the dislocation activity. Due to the wide distribution of grain size in one packet, the reversed austenite in the non-segregation zone can withstand large deformation, which makes the austenite in the segregation zone undergo sufficient strain-induced martensitic transformation (SIMT), to obtain excellent combination of strength and toughness.