Mechanical Characteristics and Microstructural Analysis of Additively Fabricated Low-Carbon Steel Structure via Direct Energy Deposition Process

The use of wire-arc additive manufacturing, an arc-based direct energy deposition (DED) process, to create different components out of structural materials has gained much traction in recent years. This experimental work focused on the use of wire-arc additive manufacturing to deposit the structure of low-carbon alloy steel (ER70S-6). The microstructure and mechanical characteristics of the deposited structure were analyzed. Microstructures consisting of polygonal ferrite in the center of the melt pools and interlayer regions of bainite, allotriomorphic ferrite, and acicular ferrite were found in the deposited structure. The microstructure showed polygonal and closed acicular phases near the grain boundary. The mechanical characteristics of the structure were examined at various orientations (i.e., horizontal, and vertical building directions). WAAM fabricated multi-layered structures have average tensile test values of ultimate tensile strength (UTS), yield strength (YS), and the percentage of elongation (EL%) are 520.25 MPa, 333.35 MPa, and 32.45%, respectively. The uniform ferritic microstructure of the structure was shown to be responsible for its improved mechanical characteristics. The results show great potential for DED as a practical and affordable process for producing precisely designed parts with remarkable strength and hardness.