Research on the sidewall penetration mechanisms of cable-type welding wire narrow gap GMAW process

A method of narrow gap gas metal arc welding (NG-GMAW) with a self-rotating arc was established using cable-type welding wire. The wire melting speed, metal deposition, and welding seam thermal cycles of cable-type welding wire (CWW) GMAW and single-wire GMAW at the same welding parameters were studied and analyzed. The microstructural characteristics and mechanical properties of the weld were analyzed. The results showed that CWW was highly efficient and exhibited satisfactory sidewall penetration in the welding process. With its special structure, the surface area and the heating provided by the electrical resistance of CWW were distinctly higher than those of the single wire, thus resulting in CWW GMAW exhibiting higher efficiency than single-wire GMAW. The sidewall penetration of CWW NG-GMAW was analyzed in terms of arc rotation, droplet transfer motion, and regular molten pool flow. The combination of the arc rotating force and droplet transfer force on the molten pool promoted heat transfer to both sidewalls, affecting the features of the sidewall and the bottom width of the molten pool.