Desempenho mecânico de ligas de aço-carbono fabricadas por Manufatura Aditiva por Deposição a Arco (MADA)

Abstract

In a context of accelerated technological evolution in terms of sustainable manufacturing of mechanical and structural components, the process of Additive Manufacturing by Arc Deposition (AMAD) has stood out, which, cunningly taking advantage of processes originally designed for joining (welding) and parts, so widely known and consolidated, it is configured as a disruptive additive manufacturing technique that, together with other pillars, builds the possible and probable “new era” of the industry: the fourth industrial revolution, the Industry 4.0. However, like any innovation process, there are inherent challenges and uncertainties, for which there must be quick and assertive responses that guarantee the much-desired consolidation as an alternative option to conventional manufacturing processes, which have proven to be inefficient and environmentally unsustainable in a scenario of climate crisis that requires broad attention from the scientific community, as well as large corporations. Therefore, as it is a developing process based on technology, equipment and consumables used in welding, it is important to know and understand how they behave, especially consumables, specifically filler metals, under AMAD conditions. For that reason, the objective of the present work as a form is to elucidate practical issues regarding the application of this technology, through the deposition of preforms of simple geometry (walls) of approximately 300 mm in length by 220 mm in height by 18 mm in width, using as filler metals the electrode wires of classes ER70S-3, ER70S-6, G4Si1, ER80S-G, ER80S-B2 and ER110S-1, with 1.20 mm nominal diameter, so that they could be evaluated and analyzed the mechanical properties of such materials when applied in the construction of components via AMAD. In addition, we sought to establish a methodology that would allow the comparison of the mechanical performance of these materials in relation to available data on their respective, well-known, welding applications, as well as the comparison between them, in terms of resistance to traction, impact and fatigue, with data regarding the structural integrity, hardness and metallurgy of the materials resulting from AMAD deposition being collected and analyzed. In general, the assessment is that these materials showed considerably ductile behavior, exceeding the deformation requirements established by the respective manufacturing standards, accompanied by a drop in yield stress and resistance limit, having, in addition, demonstrated a low or non-existent degree of anisotropy. In agreement, high impact resistance was noted, showing high energy absorption capacity, even at very low temperatures (-50 °C). Added to this, the hardness values far exceed those found when testing structural steels of similar chemical composition manufactured by conventional means, presenting metallurgical aspects that, although complex, demonstrated good homogeneity, without the presence of deleterious phases and /or undesirable, even under critical thermodynamic conditions (intense and successive thermal cycles). Finally, the ER110S-1 material showed surprising results in fatigue tests, with comparison only possible with steels with predominantly austenitic structure.