深冷对逆相变处理中锰钢组织性能的影响

摘要：为了研究原始组织状态对逆相变退火中锰钢微观组织和力学性能的影响，对淬火处理的中锰钢再进行-74℃深冷处理，采用SEM、EBSD、XRD等手段评价了逆相变退火处理后的微观组织，用单轴拉伸和冲击试验评价力学性能。研究结果表明：淬火态中锰钢的组织由马氏体和体积分数约为33%的残余奥氏体组成，深冷处理后得到残余奥氏体体积分数小于15%的细小马氏体组织；相对于淬火+逆相变处理的样品，深冷+逆相变样品奥氏体体积分数从31%提高到49%，具有更高的奥氏体稳定性使屈服强度从650MPa提高到852MPa，断后伸长率从22%提高到37%。

Effect of cryogenic treatment on microstructure and properties of medium manganese steel treated by ART annealing

In order to study the effect of the original microstructure on the microstructure and mechanical properties of the manganese steel in ART annealing, the quenched medium manganese steel was further subjected to -74℃ cryogenic treatment, and the ART annealed microstructure was characterized by SEM, EBSD, and XRD, the mechanical properties were also evaluated by uniaxial tensile and Charpy impact tests. The results show that the microstructure of the as quenched steel is composed of martensite and residual austenite with a volume fraction of about 33%. After cryogenic treatment, a fine martensite structure with a residual austenite volume fraction of less than 15% is obtained; compared with the quenched + ART annealed sample, the austenite volume fraction of the cryogenic + ART annealed sample increases from 31% to 49%, and with higher stability of austenite, the yield strength increases from 650MPa to 852MPa, the corresponding elongation of fraction increases from 22% to 37%.