退火温度对0.14C-7Mn热轧中锰钢微观组织和力学性能的影响

Effect of annealing temperature on microstructure and mechanical properties of 0.14C-7Mn hot-rolled medium manganese steel

针对0.14C-7Mn热轧中锰钢分别在600、620、640℃进行了10 h的退火试验。结果表明,退火后组织均为板条状铁素体+奥氏体,随着退火温度的升高,奥氏体体积分数增加,奥氏体中的C、Mn含量逐渐降低,导致其力学稳定性降低。试验钢退火后拉伸曲线均表现为连续屈服。随着退火温度的升高,奥氏体体积分数升高且稳定性降低,变形时产生的马氏体增多,因此抗拉强度随着退火温度升高而升高。适量的、稳定性适中的逆相变奥氏体在变形过程中持续相变产生加工硬化,延迟了颈缩的产生,增加了均匀延伸率。

Annealing experiments of the hot-rolled 0.14C-7Mn medium manganese steel were carried out at 600℃,620℃and 640℃for 10 h,respectively.The results show that after annealing,lath ferrite and austenite are obtained.The volume fraction of austenite increases with the increase of annealing temperature,the content of C and Mn in austenite gradually decreases,which leads to the decrease of mechanical stability.The tensile curves of annealed steels show continuous yield.With the increase of annealing temperature,the volume fraction of austenite increases,while the stability decreases,and the martensite produced during deformation increases,so the tensile strength increases.During the deformation process,the continuous transformation of an appropriate amount of reversed austenite with moderate stability leads to work hardening,which delays the generation of neck shrinkage and increases the uniform elongation.