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

L-DED presents an interesting approach for the surface modification of standard structural steel with stainless steel. By employing L-DED to deposit stainless steel onto structural steel, it becomes possible to maintain base material properties with enhanced anti-corrosive and anti-oxidative properties in the overlay areas. Furthermore, it allows the modification of 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 partial fusion of the substrate material. Consequently, the chemical composition of the surface is a mix of the powder with the substrate, which potentially modifies the properties of the stainless steel overlay. The commonly applied corrective method to maintain the surface properties to address the described dilution effect, involves the addition of further stainless steel layers through subsequent L-DED deposition process. However, this solution is not the optimal, as it forces to apply additional L-DED processes, which, in ideal conditions, would not be required. A method for obtaining a stainless steel additive coating by deposition in a single coating process is presented in this work. The method of the present invention allows to compensate the dilution effect by incorporating a counteract powder to the stainless steel during the L-DED process and, thus, obtaining the target chemical composition of the stainless steel coating. The counteract powder is specifically tailored for the selected target stainless steel in each process.