Effect of Preheat Temperature and Welding Sequence on the Temperature Distribution and Residual Stress in the Weld Overlay Repair of Hydroturbine Runner.

The hydroturbine runner is the core of the whole hydroelectric generating unit, which is employed to transform water energy into mechanical energy. In the process of service, the runner frequently suffers from abrasion due to erosion and cavitation. Defects are usually repaired by welding.