Microstructures and Electrochemical Dissolution Characteristics of Additive-Manufactured Stainless Steel 304 on...

Additive manufacturing (AM) is a burgeoning technology for fabricating complex components with high efficiency and low material waste. However, the surface of AM parts is rough owing to partially melted powders and severe surface fluctuation. Electrochemical machining (ECM) is a suitable postprocessing method to finish the surface of the AM parts, and the low current density is usually employed. Our study illustrates the electrochemical dissolution characteristics of the horizontal and vertical sections of the AM SUS 304 component under a low current density and the electrochemical finishing process to obtain smooth surfaces. Linear and fan-shaped melt pools are observed on the horizontal and vertical sections, respectively. Moreover, the melt pool boundaries are vulnerable to dissolution and separate the hollows, basins, and swellings formed after electrochemical dissolution. The two sections display similar current efficiency and polarization because of the single austenitic phase and the identical and uniform elemental content distribution. The top and side surfaces of the AM sample could be efficiently smoothened via ECM by eliminating the partially melted powders and significantly reducing the surface roughness. The numerous band humps make the top surface of the AM sample difficult to smoothen compared with the side surface under the point effect of the electric field.