Low-pressure turbine blade leading edge protection using robotic laser cladding technology

Low-pressure turbine blades are the most erosion-exposed moving parts of the steam turbine. This article brings a detailed overview of an innovative system applying a stellite coating to the leading edge of the steam turbine blades using the robotic laser cladding technology. The system is based on a software that gathers scanned data of the shape-specific workpiece from a laser profile scanner, creates a 3D model of the workpiece and generates a set of laser cladding trajectories that are used for the task of robot navigation during the laser cladding process. The navigation algorithm accounts for the workpiece-specific requirements of the laser cladding process as well as collision avoidance necessities. The shape and thickness of the resulting layer of the laser-cladded coating alloy are verified by an external 3D scanning system showing the compliance of the system with the requirements as well as a space for future development. The feasibility of the developed method is also verified by multiple material and metallographic tests.