超超临界汽轮机高压旁路阀B446材质螺栓断裂失效分析及工程改造  

Fracture Failure Analysis and Engineering Reform of B446 Material Bolt of an Ultrasupercritical Steam Turbine High-pressure Bypass Valve

作　　者：彭以超 严鸿平 楼玉民 PENG Yichao;YAN Hongping;LOU Yumin(Zhejiang Zheneng Electric Power Engineering Technology Co.,Ltd.,Ningbo,Zhejiang 315103,China;Zhejiang Zheneng Technology Research Institute Co.,Ltd.,Hangzhou,Zhejiang 311121,China;Zhejiang Key Laboratory of High Efficiency,Energy Saving and Pollutant Control Technology Research for Thermal Power Generation,Hangzhou,Zhejiang 311121,China)

机构地区：[1]浙江浙能电力工程技术有限公司,浙江宁波315103 [2]浙江浙能技术研究院有限公司,浙江杭州311121 [3]浙江省火力发电高效节能与污染物控制技术研究重点实验室,浙江杭州311121

出　　处：《山西电力》2023年第3期56-60,共5页Shanxi Electric Power

摘　　要：某超超临界机组高压旁路阀B446材质螺栓在服役1a后发生瞬间全部断裂,对断裂螺栓进行了理化性能检验,并对螺栓断裂问题进行了系统分析,结果发现:B446材质高温屈服强度偏低,安全余量低;断裂螺栓为粗腰刚性结构,导致服役受力时螺栓的应力集中显著;高压旁路阀密封形式设计不合理导致服役条件恶劣,在诸多因素作用下螺栓发生屈服变形以至最终断裂。对高压旁路阀进行了2次工程改造,一是将螺栓升级为细腰结构的Inconel 718材质螺栓,二是将高压旁路阀升级为带自密封结构形式的阀门,彻底消除了依靠高旁阀螺栓紧力密封阀盖和阀体时螺栓易断裂的安全隐患。All the bolts of B446 material of the high-pressure bypass valve of an ultra-supercritical unit broke instantaneously after one year of service.The physical and chemical properties of the broken bolts are tested,and the fracture of bolts is analyzed systematically.The results show that the high-temperature yield strength of B446 material is comparatively low and the safety margin is also low.The fracture bolts have a rigid structure with thick waist,which leads to the significant stress concentration of the bolt forces during service.The improper seal design of high-pressure bypass valve leads to poor service conditions,and the bolts yield,and then are deformed and finally break under the action of many factors.The high-pressure bypass valve has been renovated for two times.Firstly,the bolts are upgraded to Inconel 718 material bolts with narrow waist structure;secondly,the high-pressure bypass valve is up-graded into a self-sealing structure valve,which completely eliminates the safety hazard that the bolt is very likely to break when relying on high-pressure bypass valve tightening force to seal valve cover and valve body.

关 键 词：高压旁路阀 螺栓 B446材质 Inconel 718材质 失效分析 自密封结构 

分 类 号：TM621.3[电气工程—电力系统及自动化]