Robot Narrow Gap Welding of Water Turbine Impeller
The main difficulty in the welding of water turbine impeller lies in the complex molded lines, narrow space, high section thickness, and variable thickness size. This is a big challenge for multilayer surfacing. Using many external axis robots carrying narrow gap GMAW welding heads for layer-by-layer surfacing is a good choice. Due to the complex trajectory and thickness changes, the most critical technology is the planning and design of welding path which requires our professional planning software calculation to split the entire filling surface and design the filling and grouping of each region by analog simulation until the complete welding seam is achieved. At the same time, it requires stable welding process support and prediction from the system on the accumulative errors which can be reflected in our process expert library.
GMAW Technology
The filling area can be reduced by about 50% via the application of narrow gap GMAW technology compared with the existing conventional technology. With lower welding heat input planned to use, the welding residual stress can be greatly reduced and process quality can be more easily guaranteed. Lower welding heat input will make smaller joints and narrower NAZ in as-welded condition, and thus will result in better mechanical properties, higher welding productivity, and significantly lowered welding production cost.
