New methodology for AC-pulsed GMAW parameterization applied to aluminum shipbuilding

Abstract

AC-pulsed gas metal arc welding may be a good option for applications that require low heat input and high productivity. The introduction of a negative polarity period assists in obtaining such characteristics, due to an increase in the wire melting rate for this polarity. The main difficulty related to the use of this version of the process is in selecting the correct welding parameters. In the scope of a medium scale (60 ft) R&D aluminum sailboat construction project, this paper deals with this issue—a tested calculation methodology for the 5087 naval aluminum alloy welding wire-electrode is proposed. By knowing the wire melting rate in both polarities, as well as the definition of some input parameters [pulse parameters, drop diameter, and negative electrode percentage (%EN)], it was possible to achieve other process variables (base current, base current time, negative current, and negative current time). The method was evaluated for different current waveforms and different negative electrode percentages. The results were satisfactory with good arc stability and the possibility of controlling the heat input in the workpiece.