Ribbed tube production method by induction heating and welding of strip

摘要

The method is applied to a tube (1) e.g. of stainless steel around which a helical strip (2) of the same material is wound tangentially. The welding is performed with pulsed DC applied through a sliding contact (3) to the outer surface of the rotated tube and a similar contact (4) to both faces of the strip. The effect is enhanced by a removable ferrite core (5) centred in the tube to concentrate the pulsed DC into the region of contact with the strip. Very good results are reported with 50-100 kW pulses of 5-15 V DC supplied at a repetition rate of 200-500 kHz.