Additive Manufacturing in the Forging Process: Preform Manufacturing Through Localized Melting Material Deposition Using Low Carbon Wire

Objective: The objective of this study is to investigate the effects of hot forging on the microstructure and microhardness of a component manufactured by additive manufacturing (AM), specifically an eyebolt produced by the WAAM (Wire and Arc Additive Manufacturing) process, seeking to refine the grain size, relieve residual stresses and eliminate porosities. Theoretical Framework: Additive manufacturing (commonly called 3D printing) has been gaining ground in the manufacturing of parts and components, allowing layer-by-layer construction, useful for complex designs and rapid prototyping. The WAAM process stands out for its high material deposition rate, although it presents lower surface precision, requiring finishing by machining. The microstructure of metals printed by AM, such as carbon steel, is characterized by coarse grains, residual stresses and porosities, which can compromise the performance of the final component. Method: In this study, an eyebolt in carbon steel was manufactured by AM (WAAM process). Then, the component was subjected to hot forging. The analysis focused on evaluating the microstructure and microhardness of the samples before and after forging, seeking to verify the effect of the hybrid process (AM + forging). Results and Discussion: The microstructural analysis revealed that the forged sample presented significantly smaller grains compared to the part that was only printed. Regarding microhardness, the values ​​were also higher in the hybrid condition (207 HV) compared to the material that was only printed (161 HV), a result that was consistent with expectations, due to the grain refinement promoted by hot forging. Research Implications: The results indicate that the combination of additive manufacturing with hot forging can mitigate metallurgical deficiencies typical of printed components, such as coarse grains and porosities, in addition to improving mechanical properties, such as hardness. In addition, the use of AM allows the manufacture of preforms, reducing material waste and the need for tools in the forming process. Originality/Value: This work proposes an innovative hybrid approach, combining additive manufacturing and hot forging, as a strategy to improve the metallurgical and mechanical properties of metal components. This combination optimizes resources, promotes sustainability in the use of raw materials and expands the potential of AM for more demanding structural applications.