【摘要】 通过对轧机传动轴虎口裂纹分析，发现裂纹首先在传动轴虎口内壁形成，在后期使用过程中逐渐发生疲劳扩展，最终产生脆性断裂。金相组织观察结果表明：裂纹周围组织主要为属于脆性组织的淬火马氏体，回火屈氏体偏少，说明回火工艺不合理；存在残余组织应力，易于在使用过程中开裂。轧制过程中咬钢瞬间电流达到7 069 A,比额定电流3 096 A高出2倍以上，说明轧制过程中存在主传动轴瞬间冲击载荷过载现象。更多还原

【Abstract】 By analyzing the crack at the hub of transmission shaft on the rolling mill, it is found that the crack firstly forms in the inner wall of the transmission shaft hub, then fatigue propogation gradually occurs in the process of application, and brittle rupture happens finally.The metallographic mirostructure observation results show that the microstructure adjacent to the crack is mainly quenched martensite belonging to brittle microstructure with less quenched troostite, which indicates that the tempering process is irrational, residual microstructure stress exists, the crack probably occurred in the process of transmission shaft operation.The transient current of 7 069 A at biting-in during rolling is higher than twice of the rated current 3 096 A,indicating that instantaneous impact overload of the main transmission shaft exists during rolling.更多还原