GB1352580A - Flash-butt welding machine - Google Patents

Abstract

1352580 Welding by pressure V S LIFSHITS V I GRIGORIEV G N PETROV and O S PAPKOV 17 June 1971 28346/71 Heading B3R A flash butt welding machine comprises a welding transformer 2, a rod in two connected sections 4, 5, a clamp A fixed on the section 4, a fixed clamp C on the rod section 5 and a movable clamp B on the rod section 5, the clamp B being between the clamps A and C and a piston and cylinder 12, 15, the cylinder 12 being connected to the clamp B and the piston 15 being secured to the rod section 5, the clamp A clamping the rod section 4 within a pipe section 1<SP>1</SP> and the clamps B, C clamping the rod section 5 within a pipe section 1. In the embodiment the transformer 2 is arranged about the pipes to supply welding current thereto. The rod parts 4, 5 are separated by an insulator 6 and the clamps A, C each comprises a cylinder 7 secured to the rod section and housing a sliding tapered piston 8 in engagement with radially movable clamping elements 9. Intermediate clamp B is similar to clamps A and C but its cylinder is secured to the cylinder 12 and its piston 15 is moveable on the rod section 5. In operation the rod portion 5 is located inside the pipe 1 with clamp B adjacent the pipe end to be welded, oil is supplied to cavity 18 of clamp C which causes the elements 9 to be urged outwardly to clamp the pipe and oil is supplied to cavity 17 to move elements 14 outwardly to clamp the pipe, oil being supplied to both chambers 19 and 20 of cylinder 12. Thereafter oil is released from chamber 20 but supplied to chamber 19 to compress the pipe 1 and extend the rod portion 5. The pipe 1<SP>1</SP> is then lightly abutted with pipe 1 and clamp A is actuated to clamp the pipe by elements 9. Welding current is supplied to the pipe ends to effect arcing between the ends and oil is released from chamber 19 and supplied to chamber 20 to bring the pipes into upsetting relation by the extension of the pipe 1 and contraction of rod 5.