GB234373A - A process and apparatus for electric welding and brazing - Google Patents

Abstract

234,373. Schr÷der, E. Nov. 8, 1924. Welding; brazing.-In a process of electric welding or brazing in which currents are induced in the zone of the seam by passing the parts through an alternating magnetic field, high-frequency current is used in conjunction with a field of restricted crosssectional area so that the points of crossing of the circle of induced current lie near one another in the immediate neighbourhood of the seam and thus conjoin their heating zones. Plates P, P<1> are held in contact by holders H, H<1> between the poles F of a magnetic field. The surface area of the poles is limited, being one square centimetre for plates one to two millimetres in thickness. With a field intensity of 7000-8000 lines per square centimetre, a high-frequency field current having a frequency of about 5000-7000 is used. The flow of induced current'in the work thus passes through the welding zone twice. By moving the plates between the poles the zone may first be given a preliminary heating and then a subsequent heating to welding temperature. The poles of the magnetic field may be arranged as shown in Fig. 3, the field being closed by a holder K. In welding tubes, the weld may be completed and the tubes fed by rollers. Currents of frequency up to 10,000 or 12,000 may be used. In brazing, the brazing material is put on the seam in the form of wire, tape or powder.