42CrMo4钢板冷弯曲中断裂原因分析

Analysis on Cold-bended Fracture of 42CrMo4 Steel Plate

利用金相显微镜和扫描电镜等分析方法,对42CrMo4钢板冷弯曲中断裂原因进行分析。结果表明,断裂钢板内部存在严重的组织缺陷,钢板局部区域存在马氏体组织、孔洞、严重的组织偏析和较大尺寸的钛颗粒夹杂,这些因素导致该区域组织应力和脆性较大,成为钢板内部的裂纹源,在弯曲成形过程中的拉应力作用下产生裂纹,并不断扩展导致钢板断裂。

Causes to the cold-bended fracture of 42CrMo4 steel plate are analyzed by means of metallographical and scanning electron microscopes. Results show that severe microstructure defects are existing in the broken steel plate and such a few factors as the martensite microstructure, pores, severe microstructure segregation and big Ti inclusion particles inevitably result in higher microstructure stress and brittleness in steel plate and in turn lead to occurrence and expansion of cracks during the cold-bending process.