中锰钢常用的IA和QP工艺会产生奥氏体+铁素体和奥氏体+马氏体的组织，前者屈服强度难以提升， 后者塑性难以提高，导致出现力学性能瓶颈。 为开发新一代中锰钢，亟需引入新的相结构，其中贝氏体相变由于其强度 和塑性的较好配合逐渐引起关注。而中锰钢中锰含量较高，贝氏体相变的速率较慢，因此采用在等温前对过冷奥氏体进 行冷轧处理以引入位错的方法加速贝氏体相变的发生。研究结果表明，经过预变形处理后，贝氏体组织在变形样品中比 未变形样品提前24h出现，且相变基本完成的时间为60h，相较于未变形样品提前了12h。 实验中位错不会阻碍贝氏 体生长，最终含量减少的原因是位错极大地促进了珠光体组织的形核和长大，大量珠光体消耗了晶界处的形核点，使得 贝氏体最终的转变量由40%下降至18%(体积分数)。

The commonly used IA (intercritical annealing) and QP (quenching and partitioning) processes for medium manganese steel result in microstructures of austenite + martensite and austenite + ferrite. The former presents challenges in enhancing plasticity, whereas the latter struggles to improve yield strength, leading to a bottleneck in mechanical properties. To develop a new generation of medium manganese steel, it is essential to introduce new phase structures, among which bainitic transformation has garnered attention because of its favourable combination of strength and plasticity. However, the relatively high manganese content in medium manganese steel results in a relatively slow rate of bainitic transformation. Therefore, a method involving cold rolling of undercooled austenite prior to isothermal treatment was employed to introduce dislocations and accelerate the occurrence of bainitic transformation. Research findings indicate that after predeformation treatment, the bainitic microstructure appears 24 h earlier in deformed samples than in undeformed samples, with the transformation being nearly complete at 60 h, which is 12 h earlier than that in undeformed samples. In this experiment, dislocations do not hinder bainite growth; rather, the reduction in final bainite content is attributed to the significant promotion of pearlite nucleation and growth by dislocations. The extensive formation of pearlite consumes the nucleation sites at the grain boundaries, resulting in a decrease in the final transformation fraction of bainite from 40 vol.% to 18 vol.%.