The generation mechanism of the residual stress at press-blanked and laser-blanked edges of a 1.5 GPa ultra-high strength martensite steel sheet was investigated. The residual stress at the press-blanked edges of the 1.5 GPa sheet is highly tensile, whereas the residual stress at the laser-blanked edges is compressive. The high tensile residual stress causes the occurrence of hydrogen-induced delayed cracking and the reduction in fatigue strength. In press blanking of the 1.5 GPa sheet, considerably high compressive stress was generated under the punch corner just before the separation due to a small critical punch stroke, and high tensile residual stress on the fracture surface of the blanked edge was induced by releasing this high compressive stress for the separation. Not only the high strength of the 1.5 GPa sheet but also the low ductility influences the generation of the high tensile residual stress on the fracture surface because of the small critical stroke. On the other hand, the compressive residual stress at the laser-blanked edges of the 1.5 GPa sheet was generated by the volume increase of the martensite transformation at a comparatively low temperature. In addition, an approach for determining the allowable amount of hydrogen for the occurrence of delayed cracking at the edges was proposed, and the relationship between the critical residual stress and the amount of hydrogen for the 1.5 GPa sheet was obtained.

研究了1.5GPa超高强度马氏体钢板冲压冲切和激光冲切边缘残余应力的产生机制。1.5 GPa 板材冲压边缘处的残余应力是高度拉伸的，而激光冲压边缘处的残余应力是压缩性的。较高的拉伸残余应力导致氢致延迟裂纹的发生和疲劳强度的降低。在对 1.5 GPa 板材进行冲压冲裁时，由于冲头临界冲程小，在即将分离之前的冲头角部下产生了相当高的压缩应力，通过释放该高压力，在冲裁边缘的断裂面上产生了高拉伸残余应力。分离的压应力。1.不仅强度高。5 GPa 薄板和低延展性也影响了断裂表面高拉伸残余应力的产生，因为它的临界冲程小。另一方面，1.5 GPa 薄板激光冲切边缘的压缩残余应力是由于马氏体相变在较低温度下的体积增加而产生的。此外，提出了确定边缘出现延迟裂纹的许用氢量的方法，得到了1.5GPa片材的临界残余应力与氢量之间的关系。5GPa片材是在较低温度下马氏体相变体积增加而产生的。此外，提出了确定边缘出现延迟裂纹的许用氢量的方法，得到了1.5GPa片材的临界残余应力与氢量之间的关系。5GPa片材是在较低温度下马氏体相变体积增加而产生的。此外，提出了确定边缘出现延迟裂纹的许用氢量的方法，得到了1.5GPa片材的临界残余应力与氢量之间的关系。