Providing tube with welded fins - by applying successively electric current to fins located on the tubes

摘要

A process for welding elements such as fins on workpieces such as tubes, involves providing slots by cutting on a position of the length of a strip so as to provide on the length of the strip a cut portion and a non-cut portion. The strip is folded so that the fold is approximately parallel to at least one of the edges of the strip. The strip is rolled around a tube to be provided with fins, the non-cut part of the strip being applied at the workpiece periphery to constitute the base of the fin so that the cut part is opened in the form of a fan so as to form segmented fins. A roll is supported on the base of a fin so as to impart successively to the base of each fin and to the tube an electric current from a generator. Another roll is supported on the base of another fin in contact with the tube so as to close the circuit to the generator. The rolls and tube are rotated relative to each other so that the heat produced in each successive contact of the fin and tube provides welding of the fin on the tube. The invention avoids the formation of a deposit of copper on the tube.