Controlling weld pool shape by a travelling magnetic field - to nullify influence of gravity and increase welding speeds

摘要

A travelling magnetic field is used near the molten metal pool in a welding process, so that an eddy current is induced in the pool, and the shape of the pool is controlled by the electromagnetic driving force during welding. V)rtical welding is pref. carried out while the travelling magnetic field moves upwards near the pool, whereas in overhead welding the field travels near the pool in the welding direction. For horizontal welding on a vertical workpiece, the field pref. travels upwards at 90 degrees to the welding direction, an for horizontal fillet welding an inclined upward travel of the field is used. Pref. appts. uses the principle of a linear induction motor to produce an electro-magnetic force corresp. with Fleming's left hand rule. Process is used in welding all metals, e.g. iron, steel, alloy- or stainless-steels, Cu, Al, or Ni. The detrimental influence of gravity is nullified, e.g. in upwards vertical- or overhead-welding, so higher speeds and better quality is obtd. than in conventional welding processes.