Study of the Attachment Stage of a Welding Arc Discharge of Direct-Current Straight Polarity on Aluminum Surface

The results of a study on aluminum welding by direct-current straight polarity arc in a protective gas environment (argon, helium) are presented. The welding arc burns in aluminum vapor; the condensation products consequently lower the temperature of the welding column in the anode region. The condensation products of aluminum are formed by the cluster mechanism with the formation of fractal thread-like structures. The clustering mechanism is characterized by the release of nondissociated molecular blocks of aluminum into the vapor state. They form a morphologically complex composition of the alumina film on the surface of the weld pool during condensation.