Analysis on runner welding residual stress affected by local heating

According to the property of weld formation, local heating method was brought out to improve the distribution of welding residual stress in of runner blade. Moreover, on the basis of local heating's reasonable position attained by plane experiment, regulating and controlling on some hydroelectric station's runner welding residual stress field was researched by means of local heating. The result shows that for the plane whose dimension is 500 mm × 500 mm × 16 mm, local heating can decrease residual stress and the best opsition is 60 mm or so away from the edge of heating area; transverse residual stress engenders in the dangerous area of blade of runner by means of local heating. Moreover, from the view of the effect on decreasing residual stress near blade outlet, the effect of local heating processing after heat treatment excels that of before heat treatment.