针对某电厂多层焊接不锈钢波纹管发生开裂的情况，采用宏观观察、能谱分析、金相检验、显微硬度测试等方法，分析了波纹管开裂的原因。结果表明：波纹管的失效形式为疲劳开裂，失效原因为纵焊缝余高超标，加大了该部位的塑性变形和硬化程度，降低了抗疲劳性能，柴油机运行中波纹管的振动诱发了疲劳开裂。

Aiming at the situation of cracking of multilayer welded stainless steel bellows in a power plant, the cracking reasons of the bellows were analyzed by macroscopic observation, energy spectrum analysis, metallographic examination, microhardness testing and so on. The results show that:the failure type of the bellows was fatigue cracking; the failure reason was that the welding reinforcement was over standard; the plastic deformation and the hardening degree were increased and the fatigue resistance performance was reduced, and the vibration of bellows during operation of the diesel engine gave rise to the fatigue cracking.