Published Paper Details:

WAAM is a form of Direct Energy Deposition that 3D prints metal parts using an arc welding process. Unlike other conventional AM methods, WAAM uses an electric arc to melt metal wire. The procedure is guided by a robotic arm, where the shape of the product is created on a substrate material. When the wire is melted, it is extruded into beads on the substrate. The beads bind together, forming a coating of metal. The process is repeated in a layer-by-layer fashion until the required metal part is finished. In the present study, a rectangular slab of dimensions 300 x 200 x 20 mm3 was fabricated using 4043 MIG filler wire via wire arc additive manufacturing (WAAM). The effect of welding current (heat input) on the weld microstructure and mechanical properties of 4043 WAAM alloy was investigated. Three weld joints were produced by varying the welding current from 140 to 160 A for the other welding parameters kept at constant value. The experimental findings reveal that all the weld joints were defect free and the strength of the weld decreased for the increase in the welding current. A highest joint strength of 120 MPa (119% of the base WAAM strength) was achieved in case of lower heat input(140A) weld joint. The significant strength is due to presence of more refined equiaxed dendritic microstructure and smaller size of fusion boundary. The toughness of the weld joints were 10, 11 and 12 Joules for low, medium and high heat input respectively. The toughness of the weld joints shows an increasing trend for the increase in the welding current. More softening of the weld joint has resulted in higher ductility and toughness. The results of pitting corrosion studies reveal that overall, a better and similar corrosion behaviour was achieved in all the weld joints, owing to presence of more Si in the Al matrix. The difference in the heat input and grain coarsening in the weld microstructure has attributed to variation in the corrosion resistance of the weld joints. However, the corrosion resistance of the weld joints are within the acceptable limit of the industry standards.