混流式转轮焊接残余应力测试新装置与新方法
New equipment and method for measuring welding residual stress in Francis runner
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摘要: 混流式转轮叶片出水边焊接接头区域存在的较高残余应力是导致转轮疲劳开裂的重要原因,混流式转轮焊后及热处理后的焊接残余应力测试已经成为转轮制造过程中的必要工艺,其测试精度及效率对转轮制造质量及效率有重要影响.根据转轮的结构特点研发了新型残余应力测试装置,并根据转轮疲劳开裂的特点确定了针对混流式转轮焊接残余应力测试的新方法,实际应用试验结果表明测试所得结果能够真实反映热处理前后转轮易开裂区域的残余应力分布情况.新型测试设备及方法完全适用于混流式转轮的残余应力测试,而且具有非常高的测试精度及效率.Abstract: The high welding residual stress in the welded joint in the outlet of blade is one of the major reasons leading to the fatigue failure of Francis turbine runners. The welding residual stress test in as-welded and after post-weld heat treatment has been the necessary process during the manufacture of the runner. The test precision and efficiency have an important influence on the manufacture quality and schedule of runner. According to the structural characteristics of the runner,new test equipment was developed,and the welding residual stress test method for Francis runner was determined. The experimental results show that the test results could truly reflect the distribution of welding residual stress in the runner before and after heat treatment. The new test equipment and method could be applied to the test of welding residual stress in Francis runner with high precision and efficiency.