Análise microestrutural e propriedades mecânicas de pré-formas fabricadas com consumível AWS ER 308L por manufatura aditiva com variação do tempo de interpasses

Abstract

Wire Arc Additive Manufacturing (WAAM) stands out among additive manufacturing technologies due to its high material deposition rate and more affordable investment costs. However, parts produced by WAAM often face challenges related to a complex thermal history, resulting in excessive heat buildup, which significantly affects their microstructural and mechanical characteristics. This study focuses on analyzing the time interval between deposition passes and its impact on the properties of components manufactured by WAAM, using AWS ER 308L stainless steel consumable as the deposition material. Two single-layer preforms were manufactured with different time intervals between passes (60 seconds and 300 seconds) under free cooling conditions. The influence of these intervals was evaluated by characterizing the microstructure, using techniques such as optical microscopy and SEM, as well as analyzing the mechanical properties, including tensile strength and microhardness. The results revealed that the preform produced by WAAM had a ferritic-austenitic microstructure, with different ferrite morphologies along the two deposited preforms. The microstructure is predominantly austenitic with the presence of delta ferrite, which appears at the boundaries of the austenite dendrites. Consequently, the preform with the longer cooling time showed better mechanical and microstructure results. It can therefore be concluded that using control of the time between layer deposition as a way of optimizing the cooling of preforms is a viable strategy for improving the quality of components made from 308L stainless steel using the WAAM process.