Component repair using laser direct metal deposition

Abstract

Recent studies have indicated that laser direct metal deposition can be used for repairing deep or internal cracks and defects in metallic components. In order to implement the method, it is necessary to machine a groove or slot to the depth of the defect and refill it. This work investigates advantages and potential problems with the technique and compares the results from using two different slot geometries: one rectangular and one triangular in cross-section. H13 hot-work tool steel components are used and H13 powder is deposited using a 1.5 kW diode laser and lateral nozzle. Different combinations of deposition parameters are tested and each sample is analysed in terms of mass deposition rate, deposition microstructure, evidence of porosity, size of the heat-affected zone, and microhardness. Results are evaluated using statistical techniques and the important parameters that control each variable are identified. The work provides evidence that the method can produce high-quality repairs, but porosity at the boundaries between the original part and the added material is a problem.