Re-Melting Characteristics of a Stellite21 Deposited Part by Direct Energy Deposition Process Using a Pulsed Plasma Electron Beam with a Large Irradiation Area

Several re-melting type post-processing technologies were developed to improve surface qualities and properties of the fabricated part by a metal additive manufacturing process. The aim of this paper is to investigate re-melting characteristics of the Stellite21 deposited part using a pulsed plasma electron beam with a large irradiation area for the improvement of surface characteristics and material usage ratio of the deposited part by a direct energy deposition (DED) process. The influence of process parameters, including acceleration voltage and the number of beam irradiations, on the roughness, the hardness, the thickness, and the morphology of the re-melted region is examined using results of re-melting experiments. Using the experimental results, a novel post-processing method, including a mechanical subtractive process and a re-melting process using a pulsed plasma electron beam, is proposed. The results of post-processing experiments confirm that the proposed method can significantly improve the surface characteristics and the material usage ratio of the DED part.