基于成形极限图不同应变路径对冷轧TRIP钢残余奥氏体转变量的影响

Effect of Different Strain Paths Based on Forming Limit Diagram on Retained Austenite Transformation of Cold-rolled TRIP Steel

以冷轧TRIP600为研究对象,通过试验建立成形极限图(FLD),同时采用金相显微镜、扫描电镜对未变形和变形后显微组织进行观察,并利用x射线衍射方法测定了经历不同应变路径下的残余奥氏体含量。试验结果表明:在平面应变状态下极限应变值(FLD0)为0.397。随着应变路径由拉伸至平面应变、再到胀形,残余奥氏体转变量逐渐增加。与DP600相比,TRIP600较高的FLD0值是由于TRIP效应的存在,变形过程中,缩颈区域较宽。

With cold-rolled TRIP600 steel as the object of research,forming limit diagram（FLD）was established by experiments.The undeformed and deformed sample microstructures were examined by metalloscopy and scanning electron microscopy,at the same time the content of retained austenite which experienced different strain paths were measured by X-ray diffraction.The results showed that the ultimate strain under plane strain state（FLD0）is 0.397.With the strain path from tensile to plane strain and the bulging,the transformation contents of residual austenite gradually increase.Compared with DP600,the higher FLD0 values of TRIP600 were ascribed to the TRIP effect,the necking area becoming wider during deformation.