Fundamental Wear and Treatment Investigations of Laser-Coated Pump Parts

This paper describes the technologies and results from a study to investigate a suitable means to protect high chromium white cast iron from further wear. This work focuses on the precondition for the feasibility testing of laser cladding with metal matrix composite powders for the wear protection of impeller blades of slurry pumps. Investigations of selected powder mixtures and different treatment parameter setups were conducted using test plates. During the process of laser cladding the pumps, factors affecting success included: the very raw surface quality of the blades; very high tolerances of the parts; possible defects within the cast iron substrate; and general weldability of the cast iron material due to chemical composition. In comparison between the part surfaces as cast and after the cleaning using sandblasting, the measurements show strong differences in the chemical composition. The measurement results are strongly dependent on the measurement position, surface condition, and laser power. Based on our results, an industrial trial was conducted to compare the wear behavior of the claddings with untreated high chromium white cast iron. An evaluation of the lifetime of the laser-coated pump parts in the mineral processing industry is underway, which results will be published separately. 