Mild steel metal rotating spray transfer behavior in magnetically controlled gas metal arc welding

Abstract

Welding efficiency is important for the development of the manufacturing industry. Gas metal arc welding (GMAW) is a popular welding method, and a reasonable approach for increasing the wire melting rate is to increase the welding current. However, the metal transfer mode changes from stable free-flight transfer to unstable rotating spray transfer, which worsens the welding quality. In this study, alternating axial magnetic fields were applied to control the metal rotating angle, frequency, and spatter by acting with the radial current in the conductive metal liquid column. Using the experimental high-speed photograph method and numerical simulation method, a three-dimensional rotating spray transfer model considering the applied external alternating axial magnetic field, main acting forces such as gravity, electromagnetic forces, plasma shear stress, and surface tension on the molten metal is established. Additionally, two-dimensional axial symmetry models of globular and spray transfer are provided for verification. By utilizing the externally applied electromagnetic forces, the rotating motion of the metal liquid column is constricted and mildly controlled, and the control mechanism is revealed in the numerical analysis. The advantages and disadvantages of the simplified numerical model compared with the mass–heat fully coupled model are examined.