Additive Manufacturing of Metal Products via Filler Wire Arc Welding (Review)

Abstract

The paper presents a state-of-the-art review of additive manufacturing and summarizes its development trends. It considers mainstreams of this technology and outlines its methods. The study highlights importance and prospects of the process based on electrode wire arc welding (GMAW and GTAW). It proposes a layered electric arc deposition by a consumable electrode in shielding gases. A peculiarity of this procedure is that a wire is preheated to a temperature of 400-600°С before fed into a zone where metal products are formed. Wire preheating is realized by an additional power supply placed at a distance of 250-400 mm from a wire end to conduct a preheating current. It is suggested this process is suitable for manufacturing metal products in principle. The study has revealed a gradient structure of product walls manufactured using this technology. It is an upper deposited layer only that has a dendrite structure. Layers below it are subject to repeated thermal treatment caused by heat liberation from the upper layer. As a result, a grain tends to the refinement up to 10 μm depth wise. The most important outcome to emerge from the study is that a 4 mm thick frame structure free of defects may be built given that deposition is carried out by a material with a diameter of 1.2 mm in the conditions: current force 120-140А, voltage 22-24 V, deposition rate 300 mm/min.