800MW汽轮机高压转子围带脱落原因分析及处理

On Cause Analysis and Treatment of High-voltage Rotor Shroud Drop of 800 MW Turbine

对绥中发电有限责任公司2号机组汽轮机高压转子2级动叶4条围带断裂原因从宏观、断口形貌、现场光谱分析和汽轮机运行角度进行分析,认为铆钉在脱落的汽封和汽流波动共同作用下发生疲劳断裂;疲劳源从铆钉的根部应力集中处开始;铆钉疲劳断裂导致围带断裂。利用激光熔铸的方法再生铆钉头,将受损的围带进行整片更换并与铆钉采用铆接连接后,再利用激光熔铸补强,此方法工艺上可行、质量可靠。

Analysis is made,from the point of macro,and fracture appearance,field spectral analysis and turbine operation,on the causes of four shroud break of the second moving blade for turbine high pressure rotor in Suizhong Power Generating Co.,Ltd.It is found that fatigue rupture occurs to rivets under common effect of the dropped shaft gland and current fluctuation.Fatigue source originates from the roots of rivets where stress concentrates.And the rivet fatigue rupture induces shroud break.Rivet head can be reproduced by way of laser melt-casting method.The damaged shrouds will be replaced and welded to the rivets.This Technique is feasible and the quality is reliable.