主汽阀阀盖螺母开裂原因分析  

Analysis on Cracking of Bonnet Nut of High Pressure Main Steam Valve

作　　者：徐宝玉[1] 刘晓宏[2] 牟先红[1] XU Bao-yu;LIU Xiao-hong;MOU Xian-hong(Harbin Turbine Company Limited,Harbin 150046,China;Xi'an Thermal Power Research Institute Company Limited,Xi'an 710054,China)

机构地区：[1]哈尔滨汽轮机厂有限责任公司,哈尔滨150046 [2]西安热工研究院有限公司,西安710054

出　　处：《汽轮机技术》2021年第3期238-240,共3页Turbine Technology

摘　　要：某机组主汽阀阀盖螺母在水压试验后开裂。通过对螺母断裂位置进行宏观观察、断口宏微观分析、化学成分分析、力学性能测试以及金相分析等,并结合螺母装配工艺,最终确定了螺母的开裂原因。结果表明:主汽阀螺母断口为典型的冲击断口。开裂主要原因是冲铆过程中螺母内表面形成原始裂纹,螺母本身未经过调质处理强度较低,水压试验过程中承受冲击载荷作用时突然断裂。The cracks were found on the bonnet nut of high pressure main steam valve after hydraulic test.The fracture failure reason of the nut was analyzed by the macrostructure observation of the fracture position,the macrostructure and microstructure analysis of the fracture surface,chemical composition analysis,mechanical properties test and metallurgic examination,combining with the assembly process.Based on these experimental results,the final cracking reason of the nut was determined.The results show that the fracture of the nut was typical impact fracture morphology.The cracking of the nut mainly due to there were original cracks in the inner surface of the nut after punching-riveting process and the low strength of the nut due to unquenching and untempering.The fracture f of the nut was occurred abruptly during hydraulic test.

关 键 词：15Cr12WMoV钢 螺母 冲击断口 开裂 

分 类 号：TK264.9[动力工程及工程热物理—动力机械及工程]