联合循环机组高压主汽阀阀碟失效分析

Failure Analysis of High Pressure Main Steam Valve Disc in Combined Cycle Unit

通过断口宏观分析,利用金相显微镜和扫描电镜等失效分析手段研究某电厂检修时发现的高压主汽阀阀碟裂纹,分析发现,出现裂纹原因是阀碟表面在渗氮处理前存在原始裂纹,并提出具体控制措施,防止裂纹的再次发生。

Through macroscopic fracture analysis, failure analysis methods such as metallographic microscopy and scanning electron microscopy（SEM） are used to study the cracks of the high pressure main steam valve disc found during maintenance of a power plant. It is found that the crack is caused by the presence of original cracks on the surface of the valve disc before nitriding. Specific control measures are proposed to prevent the recurrence of cracks.