GB384672A - Improvements in process and apparatus for welding metal stock - Google Patents

Abstract

384,672. Making tubes. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.- (Midland Steel Products Co. ; 10610, Madison Avenue, Cleveland, Ohio, U.S.A.) June 10, 1931, No. 16879. [Classes 83 (ii) and 83 (iv).] Uniting by fusion; angular bending ; rolling.-In a continuous process of welding structural members such as tubes, in which the edges, while being maintained close to each other, are passed through a longitudinally extending heating zone, such as a series of electric arcs, to raise the temperature thereof to melting-point, the molten metal is retained in the seam cleft as a long narrow pool by separate means. A strip of metal may be drawn through a series of pairs of rolls to form an open-seamed tube and then passes under a number of carbon arcs 90 or atomic hydrogen arcs 41 to heat the metal gradually between the parts 23, 24 adjacent the seam 20, 22 and finally to melt the metal at the seam 26, 27 on a retaining shoe 8 of highly refractory metal forming part of a pivoted mandrel 7. The mandrel has rollers 9 engaging the opposite side of the tube. The edges of the tube are then pushed laterally to complete the joint and exude scale by rollers 10 and the upset is then reduced by rollers 15 co-operating with the mandrel which at this point has a single upper roller 16 and a pair of lower rollers 18, 19. The electrodes of a carbon arc apparatus may be rotated on their axes so as to cause them to burn down evenly. They may contain substances to produce a non-oxidizing atmosphere. In the case of atomic hydrogen arcs they consist of a number of pairs of electrodes arranged at various angles along the seam and provided with one or more supplies of hydrogen passing through holders 42. The arcs may be held in the desired position by an electromagnet 43 carried in the welding shoe 44. In either case the electrodes may be placed so that each raises the temperature of the work 300-400‹ F. until it reaches 2700-3000‹ F. or they may be arranged so as to heat the work quickly at first and slowly subsequently or vice versa. The slow cooling after welding is stated to reduce the porosity of the joint by allowing the escape of gases absorbed during heating. By the use of eight arcs stock “" thick is stated to be welded at the rate of 25 feet per minute. The strips may be supplied in heated condition from a rolling mill from which they are transferred laterally to one or more bending and welding units according to the speed of production of the strips. In the form shown in Fig. 12, the strips are drawn from the finishing roll 50 on to a reel 53 by a motor 54, cut to length, and then transferred to arms 55 on a turret 56 from which they are removed by a travelling crane 57 on to the spindles 58 opposite the bending units 60 and welding units 61, 62, 63. The tubes are cut into lengths by travelling cutters and discharged on to tables or conveyers 65. If the temperature of the strip is too high for bending the wound strips are allowed to cool and then provided with a cover 59 to prevent further cooling. The strips from the rolling mill may first be cut to length and then transferred by a lateral conveyer into a position opposite the bending and welding units.