某电厂高压调节汽门消音器开裂失效原因分析

Failure Analysis on Cracking of High Pressure Regulating Valve Silencer in Nuclear Power Plant

某电厂维修人员在大修期间对一高压调节汽门解体检修时发现其消音器表面一圈存在不同程度的裂纹,个别裂纹已贯穿消音器。通过宏观观察、化学成分分析、微观组织检验、拉伸测试和断口微观形貌观察等测试手段,发现断口微观形貌上存在疲劳条纹,基体材质不合格,同时结合其实际运行工况中存在一定的振动判断其失效是由于进气量的变化而产生的载荷及振动导致的疲劳开裂,材质的不合格加速了疲劳开裂过程。

The maintenance personnel of the nuclear power plant found cracks of varying degrees on the surface of the muffler when disassembling and overhauling a high-pressure governing valve during the overhaul.By means of macroscopic observation,chemical composition analysis,microstructure inspection,tensile test and fracture micro morphology observation,it was found that there were fatigue stripes on the fracture surface,and the chemical elements did not meet the design standards.According to the actual operating conditions,it was judged that the failure was caused by the load and vibration caused by the change of air intake,which lead to its fatigue cracking.The unqualified material promoted the occurrence of fatigue cracks.