High deposition wire arc additive manufacturing of mild steel: Strategies and heat input effect on microstructure and mechanical properties

Wire Arc Additive Manufacturing (WAAM) is a layer-by-layer production concept that is proposed as a promising alternative to traditional subtractive techniques due to its potential to manufacture large metallic components of medium geometrical complexity. In recent years, this technology has created interest due to the advantages it proposes, such as a low cost and high deposition rates in comparison with other Additive Manufacturing (AM) techniques. In this study, the Gas Metal Arc Welding (GMAW)-based WAAM system was developed to deposit mild steel material. To that end, a comprehensive methodology to understand the main process variables and their influence in the final component properties is shown. The aim of the present study was to compare the influence of oscillatory and overlapping deposition strategies in terms of productivity, growth per layer, obtained microstructure and mechanical properties using the control volume concept to compare volume-dependent parameters. Although some characteristics of these strategies have been documented in literature, the heat input influence has not yet been comprehensively demonstrated and understood. For example, heat input, analyzed deeply in the present study, is a critical factor for the stability of the WAAM process, influencing the mechanical properties and microstructural evolution of as-fabricated parts. The results indicate that the oscillated strategy increases productivity.