某公司生产的34CrNi3Mo钢制轧辊在使用过程中发生断裂，通过宏观分析、化学成分分析、力学性能试验、断口分析以及金相检验等方法对轧辊断裂原因进行了分析。结果表明：该失效轧辊的断裂模式为疲劳断裂。在复杂交变应力作用下，尺寸变化较大的变径位置处应力集中严重，同时心部组织不均匀促进了疲劳裂纹的扩展，最终导致轧辊失效断裂。

The 34CrNi3Mo steel roll produced by a company cracked during using. The causes for fracture failure of the roll were analyzed by macroscopic analysis, chemical composition analysis, mechanical property test, fracture analysis and metallographic examination. The results show that the failure mode of the roll was fatigue fracture. Under the complex alternating stress, the stress concentration was serious at the diameter variation position with large size change. The inhomogeneous central microstructure promoted the propagation of fatigue cracks and eventually led to fracture failure of the roll.