Abstract: Francis turbine runner’s welding temperature field and stress field are simulated on basis of realizing the welding thermal source’s movement along any complicated spatial route and solving the problem of heat conduction between blade and crown or band. The simulation result shows that welding residual tensile stress appears on the weld and nearby while the peak value of residual tensile stress appears on the blade’s outlet edge of weld area. Moreover, the contrast of residual tensile stress between different welding sequences shows that the evener the filler metal of weld during the welding process is filled, the less the peak value of residual tensile stress is.

Key words: Blade, Residual stress, Runner, Welding sequence