通过宏观分析、化学成分分析、力学性能试验、金相检验、断口扫描电镜及能谱分析等方法分析了某船用艉轴断裂失效的原因。结果表明：该船用艉轴的化学成分、力学性能均符合相关标准和规范的要求，显微组织为正常的铁素体+珠光体，断口形貌具有疲劳断裂特征，电偶腐蚀疲劳是造成该船用艉轴断裂的主要原因。

The causes of fracture failure of a marine stern shaft were analyzed by macroscopic analysis, chemical composition analysis, mechanical property test, metallographic examination, fracture scanning electron microscopy analysis and energy spectrum analysis. The results show that both the chemical compositions and the mechanical properties of the marine stern shaft met the requirements of relevant standards and specifications, and the microstructure was normal ferrite+pearlite. The fracture morphology had fatigue fracture characteristics, and the galvanic corrosion fatigue was the main cause for the fracture of the marine stern shaft.