局部加热法影响转轮焊接残余应力的试验分析

针对焊缝成形的特点,提出了改善叶片焊接残余应力分布状态的局部加热法,并在利用平板试验得到局部加热合理位置的基础上,利用局部加热法对某水电站转轮的焊接残余应力场进行了调控.结果表明,对于500 mm×500 mm×16 mm的平板,局部加热法降低残余应力效果最好的位置是在距加热区域边缘约60 mm处;局部加热法可以使叶片的危险区域产生残余压应力;从降低叶片出水边附近焊接残余应力的效果来看,热处理后进行局部加热的效果要优于热处理前进行的局部加热.

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.