Tool wear assessment when drilling AISI H13 tool steel multilayered claddings

Laser cladding is a layer-by-layer metal deposition technique often used to deposit high-quality metallic coatings on poorly performant metal alloy surfaces. Nevertheless, to reach the desired surface finish and geometrical tolerances, machining operations after laser cladding may become necessary, whose performances can be significantly affected by the deposition parameters. While the outcomes of milling operations carried out on multi-layered claddings in terms of tool wear and surface integrity have been recently investigated, the same is not available in literature in case of drilling, which is particularly challenging when the drilling operation in-tersects several layers. In this paper, C45 steel substrates were laser cladded with multiple AISI H13 tool steel layers using different powder size and laser power. The laser cladded samples were characterized on the basis of their microstructural features and micro-hardness. Afterward, drilling trials were conducted on these samples to evaluate the drill bit wear. The effect of the laser cladded-induced microstructure on the tool wear was then assessed at varying deposition parameters. Moreover, the quality of the drilled holes in terms of hole internal surface roughness and hole edge contour was investigated and related to the tool wear. The obtained results showed that, when drilling laser cladded AISI H13 tool steel, the microstructural features induced by the deposition process significantly affect the tool wear and, in turn, the hole quality.