Abstract
ABSTRACT The electromagnetic nature of the arc pressure, which is the result of the pinch effect, i.e. compression under the action of its own magnetic field, is confirmed. The pinch effect and compression are greater at the electrode; therefore, powerful plasma flows appear, directed from the electrode to the workpiece, and the pressure of the welding arc is created, which is determined by the current and the contraction coefficient. When welding with a composite electrode the arc pressure is asymmetric with a maximum in the rear part of the active spot, the active spot size increases, the pinch effect decreases. As a result the speed of plasma flows and arc pressure decrease, which ensures high-quality formation of a reverse bead at one-sided high-speed welding on a flux cushion. A process of one-sided high-speed welding by using a composite electrode is developed. This process provides a fourfold decrease in the speed of plasma flows and arc pressure in comparison with a wire electrode, high-quality formation of seams on a flux cushion with fine-grained glassy flux and an increase in the impact strength of welded joints by 2–2.5 times.
Published Version
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