GB669890A - Improvements in methods of and apparatus for welding - Google Patents

Abstract

669,890. Uniting by fusion. LINCOLN ELECTRIC CO., Ltd. May 4, 1950, No. 11088/50. Class 83 (iv). A method of forming a welded seam between two juxtaposed metallic work-pieces comprises simultaneously traversing and heating the line of juncture between the edges with an electric arc applied to opposite sides of the seam to be formed whereby such edges are fused to form a common pool of fused metal. A tube P is supported for longitudinal traverse on rollers R, Fig. 1, with electrodes on each side of the seam to be welded. Each weld rod W is drawn from a reel 1 by gripping rolls 2 driven by motor 3 through a gear-box 4 whereby the rate of feed may be adjusted. The welding current is taken from terminals 6 and 7 the former being connected to the pipe P. The terminal 7 is connected to flexible tubular welding rod guides T. Operation of the motor 3 is controlled by the welding current through a relay 10 and a switch 11 in one of the armature leads 12 and a push button switch 13 enables the rod to be fed when not welding. The guide T consists of an inner flexible coil of hardened steel wire 15, a multi-strand copper wire sheath 16, and an outer rubber sheath 17. The outlet from each guide T comprises a core 21 carrying a curved tube 22 with a conical extension 23 electrically connected to the sheath 16. The terminal fittings are supported by beams 25 parallel to the seam s both inside and outside the pipe P. During the welding operation the electrodes are immersed in powdered or granular flux carried by inclined endless asbestos belts 27, Fig. 3, forming open trough-like supports supplied with flux from hoppers 30 which are adjustable to determine the depth of the flux layer. Plates 23a prevent the flux from spilling over the edge of the belt. The belts are driven by an electric motor 35 so that the upper rim of the belt travels in the same direction and at the same speed as the workpiece. The inclination of the belts may be varied so that the flux is squeezed against the welded seam to modify the form of the seam surface. Circumferential seams between justaposed ends of the two pipes may be welded by this method, in which case the pipe will be rotated about its axis and the flux will be carried in relatively stationary box-like containers instead of travelling belts. One electrode may be located slightly in advance of the other along the seam and a gaseous protective medium may be used instead of granular flux. Carbon electrodes may be substituted for the metallic electrodes or one or more of each may be used on either side of the seam to be welded.