Overlay Dilution Prevention Method in a Single Step L-DED Process

L-DED presents an interesting approach to modify the surface of standard structural steel with stainless steel. By employing L-DED to deposit stainless steel on structural steel it is possible to maintain the properties of the base material with enhanced anti-corrosion and anti-oxidation properties in the coated areas. Furthermore, it allows the modification of the surface morphology to create specialized surface geometries with a high degree of precision. The L-DED procedure involves the fusion of the applied material with the partial melting of the substrate material. Consequently, the chemical composition of the surface is a mixture of the powder with the substrate, potentially modifying the properties of the stainless steel coating. The commonly applied corrective method to address the described dilution effect and maintain the surface properties involves the addition of additional layers of stainless steel through a subsequent L-DED deposition process. However, this solution is not optimal as it forces the application of additional L-DED processes, which, under ideal conditions, would not be necessary. This paper presents a method for obtaining an additive coating on stainless steel by deposition in a single coating process. The method of the present invention allows to compensate for the dilution effect by incorporating a counteracting powder into the stainless steel during the L-DED process and thus to obtain the target chemical composition of the stainless steel coating. The counteracting powder is specifically designed for the target stainless steel selected in each process.