Abstract: Disclosed is a machine for flash butt welding of pipes located in the bore of the pipes welded together, a housing (2) whereof is provided with rigidly attached thereto a first supporting disc (3) and a second supporting disc (4) and with a pipe flashing-and-upsetting means (5) which has a carrier (7) and a hydraulic actuator (6) for displacing said means along the housing (2) and also has two pipe clamping means (9, 10) each whereof is provided with a carrier (12 and 13) and self-contained hydraulic actuators (11) imparting axial motion to this clamping means.

Abstract: An internal apparatus for flash welding pipes together in end to end relationship both under factory conditions and in the field, for example in laying trunk pipelines, comprises an elongate supporting member carrying an axially movable clamping assembly with electrode jaws for clamping one pipe, an axially immovable clamping assembly with electrode jaws for clamping the other pipe, and a doughnut-type welding transformer. The welding transformer is disposed at the side of the axially immovable clamping assembly, which is distant from the joint. The axially immovable clamping assembly is mounted on the elongate supporting member in a manner to provide an annular clearance therebetween such that there are extending therethrough two coaxial contact tubes, which are electrically insulated from one another and connect the welding transformer with the electrode jaws, whereby in operation a welding circuit is established.

Abstract: Disclosed are welding current pick-ups which are switched into welding circuits. Outputs of these pick-ups are connected to inputs of a logical coincidence unit having its output connected to a control input of a welding program control unit whose output is connected with a drive adapted for moving the workpieces being welded.

Abstract: A pipe resistance butt welding apparatus comprises a body with an elongated arrying member and two internal expanding clamps including current-feeding shoes. One of the clamps is rigidly attached to the body, whereas the other is movably mounted on the elongated carrying member and connected with a drive intended to communicate reciprocating motion to the other clamp. A trimming mechanism for removing flash is mounted on at least one of the internal expanding clamps. The body of the apparatus mounts centering supporting rollers and driving wheels, the former and the latter being secured thereto by means of spring-loaded levers. The driving wheels are connected with a rotation drive intended to rotate the wheels. The body carries a powder cylinder and spring-loaded three-arm rockers, the latter being turnably mounted. The first arm of each of said three-arm rockers carries a driving wheel, the second arm carries an additional supporting roller, and the third arm is connected with a rod of the power cylinder.

Abstract: An apparatus comprises a body having V-shaped two-arm levers mounted thereon. Around the periphery of the body there are mounted cutting tool holders pivoted each to one arm of each of the levers. Secured to the body are drives for turning the levers and each connected with the other arm of each of the levers. On the front and rear ends of the cutting tool holders there are mounted rollers in contact with the inside surface of the pipe. Rigidly attached to the cutting tool holders are cutting tools.

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.