A high-performance WAAM process for Al–Mg–Mn using controlled short-circuiting metal transfer at increased wire feed rate and increased travel speed

Abstract

Wire Arc Additive Manufacturing (WAAM) is a method for manufacturing high-scale metal objects. This method utilizes recent developments in welding to achieve better performance and higher process rates. Higher performance requires higher metal deposition rates, which implies higher heat input that negatively affects the manufacturing process. In the present study, a high-performance controlled short-circuiting metal transfer process at a wire feed rate of 12 m/min for WAAM with an Al–Mg–Mn alloying system was developed. The arc current and voltage waveforms were studied by oscillogram processing and then modified to reduce the energy input in comparison with a self-regulated gas metal arc welding process. The newly developed process was implemented to manufacture sample parts at a travel speed of up to 150 cm/min. The modified waveforms in combination with an increased travel speed led to a decrease in heat input, which appeared to be 16% lower than that of a conventional self-regulated process. Decreased heat input led to an improved geometry preservation stability at high process rates (up to 2.2 kg/h). Study of the mechanical properties showed that the elongation of the tensile samples was up to 41%. This increase in elongation was explained through macro- and microstructure analysis.

Keywords

• Wire arc additive manufacturing
• Al–Mg–Mn alloy
• Controlled short-circuiting metal transfer
• Current and voltage waveforms
• Mechanical properties
• Microstructure evaluation