Ad hoc development of metallic powders for the application of single-layer L-DED coatings

In recent years, L-DED (Laser Directed Energy Deposition) technology has become an interesting additive manufacturing process to modify the surface properties of structural steels. This technology allows applying a stainless steel coating to improve the anti-corrosion and anti-oxidation properties of the steel, without affecting the mechanical properties of the substrate steel. During the L-DED cladding process of the coating-steel, the laser beam generates a melting pool of the cladding material, as well as a partial fusion of the substrate itself. Although the laser beam concentrates the energy at a very precise point, this superficial melting of the base metal steel may be sufficient so that the corrosive properties of the coating obtained are not exactly those of the deposited stainless steel. The strategy usually followed to solve this issue is to carry out the addition process through several steps until the substrate-layer dilution is reduced. However, considering the costs of the process, this option cannot be considered ideal. 

In this work, a new methodology for the application of a stainless steel coating is presented to overcome the dilution effect that occurs when using direct laser cladding. The methodology is based on the addition of a compensatory powder together with the clad material in the process, so that the single-layer coating has the same composition and corrosion properties as the added stainless steel. Taking into account the conditions used for the L-DED process, the compensating powder can be ad-hoc conceived depending on the coating to be added.

Acknowledgement:

Elkartek programme: REIMAGINE, KK-2023/00096, ReIMAGIN: Hybrid manufacturing technologies for a smart industry.