There are some cracks found on No.4 and No.15 guide blades in the first routine repair after the extension of No.3 water-turbine generator set for the first time in Tian Shengqiao Second Hydroelectric Power Plant
then after the treatment
there are still some cracks found on No.4 and No.15 guide blades and new cracks found on No.12 guide blade during the second routine repair.Except that a crack on No.15 guide blade is the previous weld crack
other cracks on No.4 and No.15 guide blades are the new one.So the analysis and treatment is carried out for this situation.