Wire Arc Additive Manufactured Radial Thin Wall: Fabrication Strategy, Macroscopic Defect Control, Microstructure, and Mechanical Properties

Abstract

The pulsed current in gas metal arc welding (GMAW) provides a smoother arc, spatter-free, proper width, and flat cap, suitable for wire arc additive manufacturing (WAAM). The heat input decreases by supporting the interpulse feature, and the deposition rate stands out more. In this study, a range of interpulse currents has been applied in four adopted strategies to create a complex radial thin-wall using the WAAM method. Microstructural characterization reveals polygonal and columnar grain growth depending on the chosen strategy and the location of the thin-wall. The hardness values are consistent with fabricating variables and the correlated thermal dissipation characteristics. The formed geometry of beads using argon shielding gas almost follows weldment produced in the cold metal transfer (CMT) process, where dilution was estimated below 25% in the presence of a spatter-free and smooth arc. The feasibility of building with a nominal current from 100 to 206 amps is well studied and demonstrated, providing a basis for economical design and implementation. Different states of equilibrium in the molten pool have been investigated and discussed. The humping phenomenon was characterized by different strategies, and the process window was analyzed statistically. A minimum melting efficiency of 0.23 was estimated during the building process.