Author(s): Guangfu Cheng; Song Wei; Daowei Wen; Zheng Li; Peng Zhao
Linked Author(s):
Keywords: Francis runner; Easily crack region; Welding residual stress; Test techniques
Abstract: The fatigue failure of Francis turbine runners usually happens in the welding joints of blade outlet and has important relationship with the distribution of welding residual stress. The hole drilling method is usually used to test the welding residual stress during the runner manufacture. And the test precision and efficiency has important impact on the quality and efficiency of the runner manufacture. In order to improve the residual stress test precision and efficiency, the new test method for the easily crack region of Francis runner and the new type of magnetic suction welding residual stress test devices have been researched and developed. The test method and the test devices have been practically used on many large hydropower stations, such as The Three Gorges, Yantan, Longkaikou, Jinghong, Xiluodu, Nuozhadu, etc. The application results show that the new test method greatly reduces workload and test time, and the test results truly reflect the welding residual stress distribution in the easily crack region of Francis runner. The new test devices have the features of easy operation, flexible regulating, high precision, and broad application range. It also solves the problem of testing blind zone in the residual stress test of Francis runners. And test efficiency can reach three times more than the original device. The new type of test method and the test devices are complete suitable for the welding residual stress test of Francis runners. So the production efficiency and quality of the runner have been improved significantly.
Year: 2013