Additive manufacturing of novel metals has received much attention as an alternative to traditional subtractive manufacturing because of its high material efficiency (cost reduction in terms of material efficiency or the Buy-to-Fly ratio), shorter lead time and higher design flexibility (new design possibilities). When compared with the laser and powder additive manufacturing, the arc and wire additive manufacturing is known to have higher material efficiency, higher deposition rate, and cheaper investment and maintenance. Therefore, in this work, we used cold metal transfer (CMT) gas metal arc welding (GMAW) for arc and wire additive manufacturing of STS 316L and perform a parametric study. It was found that the cooling time for the interpass temperature to cool down to 350℃ is dependent on the number of the deposition layer and the travel speed. We also investigate the effect of the travel speed, the travel direction, the contact tip to work distance (CTWD) and number of the deposition layer on the characteristics of the deposited sample. The spatial inconsistencies of the tensile strength and the hardness are observed to increase as the travel speed is increased. Finally, we find that anisotropic metallurgical properties are observed throughout the deposited STS 316L.

This study addressed the gas metal arc welding (GMAW) of Al 5183 aluminum alloy using variable polarity (VP). The effects of the electrode negative (EN) pulsing ratio and repetition frequency on the geometrical features and microstructural evolution of the deposited materials were investigated and discussed. The current and voltage were manually controlled independently for each phase to evaluate the effect of the polarity change. The influence of phase and its changing frequency on the geometrical features and microstructure evolution were observed. The phase of the electrode affected the arc concentration and changed the amount of the deposited material and the dilution between the substrate. The EN phase is beneficial for making a finer structure than the electrode positive (EP) phase because of the lower heat input per unit mass. In addition, the size of the grains decreased as the phase change frequency increased. When the number of repetitions frequency increased within a cycle, the size of the microstructure was reduced. Consequently, strategies can be established to minimize the microstructure with VP-GMAW welding using a high EN pulsing ratio and low repetition conditions.