Abstract: A method of flash-butt welding in which the travel speed (Vt) of the machine mobile plate and the welding voltage (U2) are changed (by preset programs) and the travel speed is controlled through negative feedback by welding current, the voltage being changed discretely for each flashing fixed interval of tm duration as a function of the increment of the actual average speed of flashing details of shortening (Va) during the previous flashing interval, Va value being maintained at the present level, lower than Vm. The invention envisages a change of the coefficient of enhancement of the negative feedback in a discrete manner for each preset flashing interval of tm duration as a function of Va increment during the previous flashing interval.

Abstract: A machine for flash-butt welding of rails, incorporates two tong-type clamping devices made in the form of two two-arm levers carried by a common central axle with insulation from each other and capable of being displaced along the axle relative to each other by two flashing-upsetting hydraulic cylinders connecting them and having bimetal current-carrying rods. Each of the two-arm levers is hinged at one end to the rod or the clamping hydraulic cylinder case, respectively, and the other end is fitted with the clamping and current-carrying jaws. Two welding transformers built into the hollow two-arm levers of one of the two tong-type clamps are joined by current-carrying jumpers through the current-carrying part of the rods of the flashing-upsetting hydraulic cylinders to the current-carrying clamping jaws. A clamping hydraulic cylinder is made with a hydraulic intensifier built into its rod.

Abstract: A method for pressure welding of parts with heating with an arc moving in magnetic field in which the parts (2,3) are placed coaxially with each other with a working gap (.delta.) between their ends magnetic field is created in the gap (67 ) and electric arc (6) is fired to heat the ends of the parts (2,3). A d-c component of voltage of the arc (6) is measured, and when this component reaches its minimum value corresponding to a temperature of the ends of the parts (2,3) at which plastic deformation of the material of the parts can occur, a pulsed increase in the arc current is carried out, with subsequent upsetting of the parts (2,3).

Abstract: The machine incorporates two clamping means, a static one fitted to a bedframe and a movable one mounted on rods which are attached to upsetting hydraulic cylinders with their ends with provision for reciprocating back and forth. Each clamping means consists of a base and a holding-down plate which is hinged to the base and displaced by a hydraulic cylinder a body of which is hinged to the base and a piston rod of which is hinged to the holding-down plate interacting with a holding down roller in clamping workpieces. The machine is provided with a fastener in the form of an inverted L-shaped lever, a means of adjusting the alignment of the workpieces for welding, and a means of setting a gap between the workpieces, made as a plunger and an adjustable stop installed coaxially.

Abstract: A method of flash-butt resistance welding of a batch of like parts in pairs consists in that during flashing off of workpieces (1,2) they are brought apart or together depending on the resulting resistance obtained by comparison of the actual resistance between the workpieces (1,2) being welded with the specific short-circuit impedance of the welding circuit, which is determined during the upsetting of the preceeding pair of workpieces (1,2) after the welding current reaches a constant level.

Abstract: A welding complex in accordance with the invention comprises a machine for resistance butt welding, means for supporting the end part of the pipeline and holding means including a platform reciprocable axially of the pipeline and a plate with a device for carrying the pipe section to be welded, rotatable by a drive between the positions of loading a pipe section and aligning it with the pipeline. For loading the holding means with the plate rotated into the loading position, by longitudinally displacing a pipe section from the accumulator, the latter is arranged alongside the platform, so that the pipe section it delivers extends at an acute angle relative to the end of the pipeline.

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: 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: The disclosed process includes the steps of and upsetting the flashing parts being welded. The flashing is conducted with concurrent measurement of useful electric power and an electric parameter of the flashing process which is related to the power by a function which maximizes the useful power at a predetermined value of said electric parameter. Then the value and sign of the power and parameter increments are determined within one and the same period of time. The parts are brought closer together up to the moment when the ratio of the power and parameter increments reverses ints sign. Then the parts begin to be separated up to the moment when the value of said ratio reaches the preset value selected to suit the welding circuit resistance and the cross sectional area of the welded parts.

Abstract: A flash-butt resistance welding process including a flashing of parts being welded and their upsetting. The direction of speed of motion of the parts during flashing is changed by converging and diverging them. The parts being welded are converged up to the moment when the total resistance of elementary contacts arising between the flashed surfaces of the parts becomes equal to 0.4-0.5 of the short-circuit impedance of the welding machine. Then the parts are diverged up to the moment when the summary resistance of elementary contacts reaches 1.4-1.6 of the short-circuit impedance of the welding machine.

Abstract: There is proposed a control device for a flash-butt resistance welding mane, which comprises a welding transformer (1) whose primary winding is in series with a welding current pickup (7) connected to an electrohydraulic drive (30) of the moving electrode of the machine via a drive control unit (12). Said drive control unit (12) comprises two input amplifiers (14) and (15), first inputs thereof being coupled with the output of the welding current pickup (7), while second inputs of the amplifier (14) and (15) are coupled to a control voltage source (13). The output of each input amplifier (14) and (15) is connected, via transistor (21) or (22) and a voltage divider, to the input of an operational amplifier (29) whose output is connected to the input of the electrohydraulic drive (30), a welding voltage stabilizing unit being inserted into the primary circuit of the welding transformer (1), the control input of said stabilizing unit (6) being connected to the secondary winding of the welding transformer (1).

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: In a resistance welding apparatus of a detachable grip type an improvement consists in that each pipe grip has a bracket (16) whereon two double-arm levers (18), one per side member (3), are pivoted. Similar arms of each lever (18) are interconnected by an extension spring (19), while the other arms are operatively associated with swinging jaws (14) adapted to abut against the pipe surface in their operating position. Each side member (3) is provided with a stop (21) for limiting the movement of the levers (18) relative the corresponding side member (3) in the direction of the action of the extension spring (19).

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: The arrangement comprises a body constructed in the form of a grip clamp arable from the vertical axis of a workpiece, and having two jaws coupled with each other in the upper portion thereof by a clamping cylinder. The arrangement further comprises cutters for deburring, and a mechanism for pressing said cutters to the workpiece surface. The cutters are mounted in the lower portion of the jaws so that cutting edges thereof form a profile of the workpiece cross-section. The cuttes disposed on the same jaw are pivotally connected with each other. The mechanism for pressing the cutters is constructed in the form of a system of hydraulic cylinders mounted on the jaws in symmetrical relationship relative to the vertical axis of the body. Said hydraulic cylinders are provided with rods operatively connected to corresponding cutters.

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: The parts to be welded together are caused to continuously approach each other and their ends are fused by an alternating current, and concurrently an oscillatory motion along the direction of approach is imparted to one of the parts, whereby additional relative movements of the parts towards and away from each other are accomplished. During the stage of a relative movement of the parts being welded together away from each other, the welding voltage is reduced to within the range of 0.7 to 0 of its working value, and during the stage of a relative movement of the parts towards each other, the voltage is restored to its initial value. Reducing the voltage is carried out in a time interval of not less than 1/8 of the period of the oscillatory motion from the beginning of the relative movement of the parts away from each other, and restoring it, in a time interval of not more than 1/8 of the period of the oscillatory motion from the beginning of the relative movement of the parts towards each other.

Abstract: The primary winding of a welding transformer is provided with controlled rectifiers and the primary winding of a current transformer. The secondary winding of the current transformer is connected to a welding current pick-up. The phase angle of opening of the controlled rectifiers is varied through a phase shifter and a programmer. A pulse shaper is provided for shaping pulses synchronized with the voltage of a supply circuit and has an output connected to a phase delay unit. An OR circuit is provided having inputs connected to the output of the welding current pick-up and to one output of the programmer, and an output connected together with the output of the phase delay unit through AND logical circuits and an inverter to the inputs of a voltage switching flip-flop having outputs each being connected in pair with another output of the programmer through additional AND circuits to corresponding inputs of the phase shifter.

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.