The Welding Residual Stress Test and Analysis of the Runner for Xiluodu Hydropower Plant

The distribution of welding residual stress has a major impact on the fatigue restraint ability of Francis runners.The welding residual stress test after welding and heat treatment has been the necessary process during the manufacture of the runner.Blind hole method has been taken to test and analysis the residual stress after welding and heat treatment of the Xiluodu runner.And the test area include weld zone,fusion zone and heat affect zone of the joints between blade inlet edge and crown,outlet edge and band,and outlet edge and crown.The results show that there is significant effect after the heat treatment of the runner.The level of residual stress reduced effectively.After the runner being welded,the peak value of residual stress was very high and distributed unevenly.After heat treatment,the peak value of residual stress reduced significantly.And the distribution tended to equality.The heat treatment has achieved excellent effects.