Wire Arc Additive Manufacturing of 308L Stainless Steel: Dimensional Characterization, Arc Stability, Microstructural Evolution, and Mechanical Anisotropy in Thin-Wall Structures

In this work, 308L stainless steel was deposited via wire arc additive manufacturing, identifying how process variables (voltage, wire feed speed, and travel speed) influence the geometry of the deposit in terms of arc stability, the resulting microstructure, and mechanical properties. Deposits were obtained by varying the voltage from 16 to 20V, the wire feed speed between 4 and 6 m/min, and the travel speed between 240 and 540 mm/min, in order to assess their importance in deposit quality and in the occurrence of defects such as porosity and inclusions. By varying the aforementioned parameters, the response values of the deposit (height and width) were obtained, which is crucial for understanding and controlling the material deposition layer by layer, as well as for properly planning process trajectories. Proper control of welding conditions allows for uniform layers with lower porosity, better internal quality, and an austenitic matrix microstructure with delta ferrite, whose morphology varies with heat input. Finally, through the effective control of height and width, we obtained a thin wall was obtained to evaluate its mechanical behavior. The results demonstrated proper interlayer adhesion as well as anisotropy, particularly regarding tensile strength and ductility, depending on the orientation of the specimens relative to the deposition direction.