某电厂中调门预启阀碟断裂原因分析  

Crack Cause Analysis of Pre-Opening Valve Disc of Intermediate Control Valve in Thermal Power Plant

作　　者：王天鹏 张显武 曹琳 王宇楠 WANG Tianpeng;ZHANG Xianwu;CAO Lin;WANG Yunan(Electric Power Research Institute of State Grid Liaoning Electric Power Co.,Ltd.,Shenyang,Liaoning 110006,China;Liaoning Dongke Electric Power Co.,Ltd.,Shenyang,Liaoning 110179,China)

机构地区：[1]国网辽宁省电力有限公司电力科学研究院,辽宁沈阳110006 [2]辽宁东科电力有限公司,辽宁沈阳110179

出　　处：《东北电力技术》2024年第7期54-57,共4页Northeast Electric Power Technology

摘　　要：某火电机组中调门预启阀碟发生断裂,采用宏观形貌、力学性能测试、化学成分分析、金相组织观察和扫描电镜等试验方法对其断裂原因进行分析。研究表明,阀碟材料的化学成分、强度、组织等指标均满足要求,延伸率、冲击韧性值均低于要求值。分析显示σ相析出对材料的基体产生了明显弱化作用,降低了构件整体强度。由于阀杆与防旋转销子存在微动摩擦及碰撞,且销子和阀碟径向间隙变小产生附加应力,预启阀碟在销孔内应力集中区域发生开裂,并呈现脆性扩展趋势。随着裂纹不断扩展,最终导致阀碟断裂。该研究可为存在类似问题的电厂提供参考。The pre-opening valve disc of intermediate control valve of some thermal power plant units causes cracks,which is analyzed by means of macroscopic morphology observation,mechanics performance testing,chemical composition analysis,metallographic structure observation and scanning electron microscope.The results indicate that the chemical composition,intensity,and microstructure of valve disc materials follow the standard requirements,but the elongation after crack and impact toughness values are lower than the required values.Further analysis shows that the precipitation ofσphases has a significant weakening effect on the matrix of the material,reducing the overall strength of the component.Due to the micro friction and collision between the valve stem and the anti rotation pin,and the reduced radial clearance between the pin and the valve disc,additional stress is generated.The pre opening valve disc crackes in the stress concentration area inside the stop rotation pin hole and shows a trend of brittle expansion.As the cracks continues to propagate,it ultimately leds to the crack of the valve disc.It can provides reference for other power plants with similar problems.

关 键 词：中调门 预启阀碟 失效分析 

分 类 号：TM62[电气工程—电力系统及自动化]