PLASMA ARC WELDING METHOD AND APPARATUS FOR PRACTISING THE SAME

摘要

A plasma arc welding method characterized by the steps of thermally melting a part of an upper work with a plasma arc to form a molten basin, bringing this molten basin, which is retained by surface tension, into contact with a part of a lower work by the pressures of the plasma arc and sealed gas, and melting the contacting part of the lower work by the conduction of heat to weld these two works to each other, a swirling force being applied to the plasma gas in the plasma gas. A plasma arc welding apparatus used for this plasma arc welding method, characterized in that the apparatus is provided with a plasma torch having a plasma ejection port from which a plasma gas of a plasma arc is ejected as it is swirled toward a space around an electrode.