The stretch flangeability of a medium Mn steel prepared by quenching and partitioning was examined using a hole-expansion test. Samples were heat-treated at quenching temperatures 90 °C ≤ T_Q ≤ 170 °C, at which no secondary martensite is formed upon final quenching. The hole-expansion test used a 60° conical punch. The hole at the center of the specimens was prepared by punching or wire cutting. In both sample preparation conditions, hole expansion ratio (HER) increased as T_Q decreased. The dependence of HER on T_Q was more pronounced in the samples prepared by punching than in samples prepared by wire cutting. While there is no clear correlation between HER and tensile properties, the HER decreased as retained austenite increased. By punching, the retained austenite transformed to strain-induced martensite in the shear-affected zone near the hole edge. This martensite has a negative impact on the HER.

使用扩孔试验检查了通过淬火和分配而制备的中锰钢的拉伸凸缘性。在淬火温度下样品进行热处理90℃≤  Ť _Q ≤170℃，在该无二次马氏体在最后的骤冷而形成。扩孔测试使用60°锥形冲头。样品中心的孔是通过冲孔或线切割制备的。在两种样品制备条件下，孔扩展率（HER）随T _Q的降低而增加。HER对T _Q的依赖性在通过冲孔制备的样品中比在通过线切割制备的样品中更明显。尽管HER与拉伸性能之间没有明显的相关性，但HER随着残余奥氏体的增加而降低。通过冲压，残余奥氏体在孔边缘附近的受剪切影响的区域内转变为应变诱发的马氏体。该马氏体对HER具有负面影响。