中锰钢两相区温轧淬火处理后的组织性能

Microstructure and properties of medium manganese steel after intercritical warm-rolling and quenching

采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、电子探针(EPMA)、室温拉伸等研究了0.1C-7.2Mn钢两相区温轧淬火处理后合金元素配分对碳化物、残留奥氏体、力学性能及加工硬化行为的影响。结果表明:随着退火时间的延长,经两相区保温后淬火(I&Q)处理的试验钢初始组织中多边形马氏体转变为板条状铁素体和奥氏体,铁素体沿长度方向长大变细;经两相区轧制保温后淬火(DI&Q)处理后,富C、富Mn碳化物先析出后溶解,同时铁素体回复多边化加剧,残留奥氏体由板条状逐渐转变为等轴状。相比I&Q处理,经DI&Q处理后,试验钢组织中富C区面积比由3.9%增加到8.7%,富Mn区面积比由0.9%增加到5.1%,残留奥氏体的含量由11.5%提高到17%,抗拉强度由1032.7 MPa提高到1171.5 MPa,断后伸长率由8.3%提高到15.8%,强塑积为18.5 GPa·%。

Effects of alloying element distribution on carbide,retained austenite,mechanical properties and work hardening behavior of 0.1C-7.2Mn steel after intercritical warm-rolling and quenching were investigated by means of scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD)analysis,electron probe microanalysis(EPMA)and room temperature tensile test.The results show that with the increase of annealing time,the polygonal martensite in the primary microstructure of the steel after intercritical and quenching(I&Q)treatment transforms into lath ferrite and austenite,and the ferrite grows and refines along the length direction.After intercritical warm-rolling and quenching(DI&Q)treatment,the C-rich and Mn-rich carbides precipitate first and then dissolve.Meanwhile,the ferrite returned to poly lateralization,and the retained austenite gradually transforms from lath to equiaxed.Compared with I&Q treatment,after DI&Q treatment,the area ratio of C-rich zone of the experimental steel increases from 3.9%to 8.7%,the area ratio of Mn-rich zone increases from 0.9%to 5.1%,the content of retained austenite increases from 11.5%to 17%,the tensile strength increases from 1032.7 MPa to 1171.5 MPa,the elongation increases from 8.3%to 15.8%,and the product of strength and plastic is 18.5 GPa·%.