ART退火后冷却方式对0.1C-7.2Mn钢加工硬化行为的影响

Effect of cooling methods after ART annealing on work hardening behavior of 0.1C-7.2Mn steel

以0.1C-7.2Mn热轧和冷轧中锰钢为研究对象,采用扫描电镜(SEM)、X射线衍射仪(XRD)、室温拉伸试验等手段,研究了奥氏体逆相变(ART)退火后不同冷却方式对中锰钢加工硬化行为的影响。结果表明,热轧试验钢ART退火后得到板条状铁素体-奥氏体组织,退火后空冷试样中有大量碳化物析出,而水冷抑制了碳化物析出。冷轧试验钢ART退火后得到了等轴状铁素体-奥氏体组织,退火后空冷试样表现为连续屈服,而水冷促进了组织的等轴化;热轧试样获得更高体积分数的残留奥氏体,获得了优异的力学性能;残留奥氏体体积分数越大,拉伸变形过程中发生的TRIP效应越持久,提供更高、更持续的加工硬化。

Taking 0.1 C-7.2 Mn hot rolled and cold rolled medium manganese steel as the research object, the effect of different cooling methods after ART annealing on work hardening behavior of the medium manganese steel were studied by means of scanning electron microscope(SEM), X-ray diffraction(XRD) and room temperature tensile test. The results show that lath ferrite austenite structure is obtained in the hot rolled steel after ART annealing, and a large number of carbides precipitate in the air-cooled specimens, while water cooling inhibits carbides precipitation. The equiaxed ferrite and austenite micro structure is obtained in the cold rolled steel after ART annealing, and the air-cooled specimens shows continuous yield, and water cooling promots the equiaxed microstructure. Higher volume fraction of retained austenite is obtained in the hot rolled specimens, which show a excellent mechanical properties. The larger the volume fraction of retained austenite, the longer the TRIP effect during tensile deformation, providing higher and more sustained work hardening.