Electrophysical characteristics of arc and formation of welded joints for welding with a non-consumable electrode

摘要

influence of non-consumable electrode design and shielding-gas composition on the arc force effects on a welded metal is studied here, due to their impact in improving the quality of welding processes at high currents and speeds. A physical model of the welding arc in inert gases is proposed; this model includes consideration for the working area shape of the non-consumable electrode, the dependence of the materials' thermal-physical properties on temperature, the interaction of the magnetic field produced by the electrode with the discharge self-magnetic field, and the correlation of these parameters with the force effect of the arc on the weld pool. The physical model helps to clarify the main correlations of the electrode working area construction, history of cathode processes, shielding-gas composition, and magnetic-field configuration near the cathode spot with the arc thermal-force effect on the weld pool. Experiments involving different electrode constructions and shielding-gas compositions demonstrate that, in order to avoid seam-formation defects at high welding currents and speeds, such electrodes should be used while ensuring the existence of the arc with a diffused cathode spot, and the helium concentration should be increased in the shielding gas when welding with a conical electrode. (C) 2016 Elsevier B.V. All rights reserved.