Axial-flow rotary propeller type water turbine runner blade crackle treating method

The invention discloses a crack treating method for an axial turning blade hydro-turbine runner, wherein the runner can be repaired in situ without being hoisted out from a runner chamber. 'R' value of round corner of one front side of the blade on exit edge which is connected with a root flange is enlarged intentionally; crack arrest holes are drilled on end part of crack, with different shaped groove for different crack, and the preheat, patch weld and heat preservation are carried out based on predetermined process order. The invention has the following advantages: construction on-the-spot, restoration in short period, avoided miscellaneous disassembly and assembly work, saved transportation cost, good weld restoration strength and stiffness, strong crack resistance, thus the invention can satisfy the work requirement of the axial turning blade hydro-turbine runner after repairing the crack.