Influence of Interlayer Temperature and Deposition Method on the Wall Geometry and Vickers Microhardness Profile of ER70S-6 Parts Manufactured by Additive Manufacturing Using CMT

Wire and arc additive manufacturing (WAAM) stands out from other deposition techniques for being able to produce bigger parts and with higher deposition rates. However, due to the high thermal input, it is necessary to carefully select the deposition strategy and parameters to achieve good geometry, low defects and adequate mechanical properties. As a recent technology, different studies have been developed comprehending the deposition approach, aiming to achieve parts with specific characteristics, usually evaluating the geometry, microstructure and mechanical properties, such as yield and tensile strengths, residual stresses and microhardness; however, the last is usually presented by mean values, requiring more details to comprehend its behavior further. In this sense, this work aims to evaluate the microhardness variation on walls of ER70S-6 deposited by WAAM-CMT in detail, with different deposition strategies, unidirectional and bidirectional, and with and without interlayer temperature control. The wall’s geometry was also assessed in terms of height and width. The results showed that both bidirectional deposition and temperature control contributed to improving the wall’s geometry. Combining methods led to a 26% increase in the wall width and 9% in the height; combining both methods also led to a more homogeneous distribution of microhardness throughout the wall with less than 15 HV variation. For all the deposition strategies, the wall region influenced the microhardness, and relatively higher values were obtained on the upper region of the wall, followed by the central and lower regions.