采用宏观形貌观察、化学成分分析、显微组织观察、断口形貌分析、显微硬度测试、示波冲击试验等方法，分析了工程机械用Q960高强度钢板在冷折弯过程中出现开裂的原因。结果表明：Q960高强度钢板冷折弯处的开裂性质为拉应力诱发的微裂纹萌生及扩展。在冷折弯过程中钢板折弯外圆面受到拉应力而在原板坯中大尺寸TiN夹杂物处萌生裂纹，裂纹沿横向和纵向扩展导致钢板开裂。通过将钛质量分数由0.18%降至0.15%，氮质量分数控制在不高于0.003%的范围内来降低大尺寸TiN夹杂物的析出量，避免类似失效再次发生。

The cracking causes of Q960 high strength steel plate for construction machinery during cold bending process were analyzed by macromorphology observation, chemical composition analysis, microstructure observation, fracture morphology analysis, micro-hardness test, and instrumented impact test. The results show that the cracking property at the cold bending location of Q960 high strength steel plate was microcrack initiation and propagation induced by tensile stresses. During the cold bending process, the bending circular surface of the steel plate was subjected to tensile stresses, so cracks were initiated at the large TiN inclusions in the original slab. The cracks propagated along the transverse and longitudinal directions, leading to cracking of the steel plate. To avoid the recurrence of similar failure, the titanium mass fraction should be reduced from 0.18% to 0.15%, and the nitrogen mass fraction should be controlled within the range of no more than 0.003% to reduce the amount of large TiN inclusion precipitate.