某QSTE500TM钢零件在冲压过程中发生折弯开裂。采用宏观观察、化学成分分析、金相检验、扫描电镜和能谱分析等方法对零件的开裂原因进行分析。结果表明：零件中的硫元素和锰元素含量较高，以及锰元素的偏析是钢中产生带状组织的主要原因；带状组织中分布着非金属夹杂物，夹杂物与基体界面的结合力弱，使零件在变形时产生裂纹；试样中的硫化锰使零件形成了多个小裂纹源，在冲压变形时造成零件折弯开裂。

A QSTE500TM steel part was bent and cracked during stamping.Macroscopic observation, chemical composition analysis, metallographic examination, scanning electron microscopy and energy spectrum analysis were used to analyze the cracking causes of the part. The results show that the high content of sulfur and manganese in the part and the segregation of manganese were the main reasons for the banded structure in the steel. Non-metallic inclusions were distributed in the banded structure, and the interface adhesion between inclusions and matrix was weak, which made the part crack during deformation. The manganese sulfide in the sample caused multiple small crack sources to form in the part, and caused bending cracking of the part during stamping deformation.