Abstract: The machine of the invention, intended for resistance butt welding of pipes, comprises two semi-housings mounted externally on the pipes to be welded to the opposite sides of a joint and interconnected by the flash and upset drive, a clamping device mounted in each semihousing, including radially arranged hydraulic cylinders with clamping shoes, and a control system of the hydraulic cylinders.The control system of the hydraulic cylinders includes control valve units structurally associated with the piston rods of the hydraulic cylinders. The control valve units include follow-up spool valves interconnected by their common actuator linkage.

Abstract: A mobile arrangement for laying a continuous pipeline comprises a resistance welding apparatus, an outer flash trimmer, and at least one pipe-laying means. A jib of the pipe-laying means has a longitudinal support structure suspended therefrom. A suspension is attached to this longitudinal support structure. The front end of said longitudinal support structure carries an outer flash trimmer, and the rear end of said longitudinal support structure carries an inductor for thermal treatment of the weld.

Abstract: A method and apparatus for welding girth joints in pipelines using two welding heads comprises the steps of moving each of the welding heads upwards around the pipeline along the respective section of the girth joint, feeding a welding wire to each of the welding heads so that the welding wire is fed substantially tangentially with respect to the surface of the pipe, and forming a circumferential weld by moulding it to hold the molten metal of the welding bath in the welding zone. An apparatus for carrying out the method for welding girth joints in pipelines comprises an annular track structure having at least two carriages mounted thereon which are connected with drives adapted to impart a translatory motion to the carriages. Each of the carriages carries a welding head provided with a welding wire feeder and a weld moulding member arranged opposite to the joint being welded.

Abstract: A welder arranged inside pipes to be welded comprises a housing with the longitudinal axis thereof matched with the axis of the pipes. On the housing are a welding transformer and two mechanisms clamping the pipes, each having a drive moving the mechanism along the axis of the housing, and each being electrically connected to the transformer. The housing has mounted thereon a pipe flashing and upsetting mechanism with its own hydraulic drive, kinematically coupled to one of the pipe clamping mechanisms, a hydraulic pump supplying fluid to the drives, and a mechanism driving the welder along the pipes' axis. The housing carries two bearing discs secured at opposite ends and three clips mounted on roller supports and movable along the housing's axis. Two clips are incorporated in the first and second clamping mechanisms, respectively, and the third is part of the flashing and upsetting mechanism.

Abstract: A welding bulge removing apparatus comprises a ring-shaped carrier adapted to be placed by means of rollers on welded pipes at the weld bulge, and being provided with a circumferential guideway and gear rim. It also comprises motor-operated carriages each having a driving gear wheel and support rollers. Mounted on the carriages are milling cutter units movable to and from the weld bulge. The gear wheel and the support rollers are brought respectively into engagement with the gear rim and the circumferential carrier.

Abstract: A welding bulge removing apparatus comprises a U-shaped carrier adapted to be placed by means of rollers on welded pipes at the weld bulge, and being provided with an arcuate guideway and a toothed segment. It also comprises a motor-operated carriage having a driving gear wheel and support rollers. Mounted on the carrier are cutting tool holders movable to and from the weld bulge. The gear wheel and the support rollers of the carriage are respectively brought into engagement with the toothed segment and the arcuate guide-way of the carrier. The carriage is adapted to be rigidly connected to a lifting mechanism of a vehicle used for raising and carrying the welding bulge removing apparatus, whereby rotation of the carrier is effected, while the carriage remains immobilized.