Patent GB-399474-A (GB)
Title: Improvements in or relating to a method of and an apparatus for electrically weldingpipe, and the welded pipe produced thereby
IPC: B23K11/06
Filed: 1932-03-24
Abstract: 399,474. Making welded tubes. REPUBLIC STEEL CORPORATION, Republic Building, Youngstown, Ohio, U.S.A. -(Assignees of Blevins, H. G.; Republic Building, Youngstown, Ohio, U.S.A.) March 24, 1932, No. 8865. Convention date, July 15, 1931. [Classes 83 (ii) and 83 (iv).] Angular bending; rolling annular bodies; rolling tubes.-In a method of electrically buttwelding the longitudinal seams of pipes, particularly pipes of gauge greater than 0À125 ins. and of diameter greater than 4 ins., e.g. up to <9>/16 ins. gauge or more and 16 ins. diameter or more, the pipe is fed past electrodes pressed on opposite sides of the seam in a plane perpendicular to the axis of the pipe, pressure is exerted in said plane against the sides of the pipe to close the seam cleft and pressure counterbalancing the electrode pressure is applied in a plane slightly beyond the first-mentioned plane. The electrode pressure is heavy so as to deform the metal of the pipe to the contour of the electrodes and a current of 130,000 amperes is used with a current density of 40,000 amperes per square inch of contact area. An open seamed pipe 3<1> is fed through two roll stands 1, 2, provided with upper rolls having fins 42 for aligning and squaring the edges of the seams to parallelism by cold working, and then passes through two pairs of feed rolls 77, 81, the upper roll of the first pair of which has a guide fin and the second pair of rolls of which bring the edges of the seam into contact and work them against each other. The pipe the passes over rolls 67<1> in a mandrel rod 5 so as to open the seam a definite amount and then passes to the welding throat where the edges are closed by side pressure rolls 105 and engage a pair of electrode rolls 17, 18. The pipe then engages a bottom pressure roll 91, situated on an axis slightly beyond that of the electrodes, so as to co-operate with the electrodes to apply contact pressure to effect the weld. Chipping of the electrodes by the end of the pipe due to the great pressure applied is thus avoided, the side pressure rolls being freely mounted on their shafts so as to float thereon. The pipe passes thence through planishing rolls and four sets of sizing rolls in stands 7,. 10. The aligning rolls, feed rolls in stand 4, planishing rolls in stand 6 and sizing rolls are driven by spindles 22, 25 through reduction-gear 24 and magneticclutch 23 from a motor 21. The upper aligning rolls each consist of two bell-shaped portions 41, Fig. 5, and a central disc 42 and the lower rolls 56 are integral. The rolls, which are removably mounted on their shafts, are driven by sliding bevel gear. The upper roll shafts are mounted in yoke members 36 adjustable by screws 35 in a frame 30, and the lower roll shafts are mounted in bearings adjustable vertically by wedges 50 through racks 51 and pinions 53. The stand is mounted on a base 28 laterally adjusted by screws 29 and an auxiliary guide roll is used to direct the pipe to the second stand 2. The mandrel rod is secured to a plate 69 attached to a bracket on the stand 2 and in addition to the roller head 67<1> has a roller head 73 co-operating with the planishing rolls 127, 128. The roll 127 is mounted in a cross-head adjustable by worm gear through a pair of screw-threaded posts and the roll 128 is adjusted by worm gear through a post 125<1>. The side pressure rolls 105, Fig. 8, are floatingly mounted on spindles carried by a pair of casings pivoted at 102 and adjusted laterally by a right and left-handed screw 107. The roll 91 is floatingly mounted on a spindle carried by a housing 90, which is vertically adjustable by a wedge and screw 96 in a carriage 87 adjustable longitudinally of the machine by a rack 94 and pinion and secured in adjusted position by clamping screws 99, 100. The electrodes 17, 18, Fig. 4, are suspended from a carriage 14 supporting a transformer 16, air cooled by a suction fan 183, and adjustable so as to vary the pressure by screws 15 in the angles of four columns 12. The screws are rotated by worm gear through couplings and reducing gear from a motor mounted on one of the cross heads 13. The sizing-roll stands comprise a pair of frames 137, 138, Fig. 12, bolted together at 139 and adjustable in guides on columns 132 and secured by bolts 158 through removable shims 159 to a housing 141 carrying a roll 156. The frames each contain a roll housing 142 adjustable by a screw 1431 and bevel gear and containing a shaft 150 adjustable by a screwed bush 151 on which a roll 153 is freely mounted. The assembly may be adjusted vertically by wedges 171 through a screw and worm gear 173 and the frames may also be adjusted by wedges 160 through racks 163 and pinions 165.