电站汽轮机低压转子叶片裂纹形成原因分析  

Cause Analysis of Blade Fracture for Steam Turbine Low-pressure Rotor in One Power Plant

作　　者：刘文生 LIU Wen-sheng(Central-China Electric Power Research Institute,China Datang Corporation Science and Technology Research Institute,Zhengzhou 450000,China)

机构地区：[1]中国大唐集团科学技术研究院有限公司华中电力试验研究院,郑州450000

出　　处：《汽轮机技术》2021年第2期157-160,共4页Turbine Technology

摘　　要：对某电厂汽轮机低压转子末3级含裂纹叶片取样,进行宏观观察、光谱分析、力学性能试验、显微硬度检验、显微组织及能谱等分析。试验结果表明:叶片的合金成分符合相关要求,叶片材料的强度、塑性和韧性等相关指标均符合标准要求;裂纹起源及裂纹尖端未见腐蚀性元素。叶片热处理工艺控制不佳,出汽侧边缘硬度和组织不均匀,存在较大的残余应力,材料的抗疲劳性能降低,塑韧性变差,在离心力和蒸汽压力等周期性交变应力作用下发生疲劳开裂。实现叶片出汽侧边缘硬化层的无损检测是未来发展的一个重要方向。Macroscopic observation,spectral analysis,mechanical property test,micro-hardness test,microstructure and energy spectrum analysis were carried out which taken from the last 3rd stage fractured blades of a steam turbine low-pressure rotor in a power plant.The results show that the alloy composition of the blade meets the relevant requirements,and the strength,plasticity and toughness of the blade meet the requirements of the standard.Meanwhile no corrosive elements were found at the crack origin and crack tip.The hardness and microstructure of the outlet side edge are not uniform because of the improper heat treatment.This leads to the large residual stress,the lower fatigue resistance andpoor plastic toughness.So the fatigue crack occurred under the action of periodic alternating stresses such as centrifugal force and steam pressure.And it is an important direction for the future development to realize the non-destructive testing of the hardened layer in the outlet side edge of blade.

关 键 词：低压转子叶片 出汽侧边缘 硬度不均匀 疲劳开裂 

分 类 号：TG142.73[一般工业技术—材料科学与工程]