Abstract: A system for deploying a coil of spoolable pipe from a vessel includes a first tower configured to move longitudinally and transversely along a first track coupled to the vessel, a second tower configured to move longitudinally along a second track coupled to the vessel, and a coil drum assembly coupled to the first tower. The first tower is configured to insert the coil drum assembly transversely into an interior channel of the coil when the coil drum assembly is in a retracted position, the coil drum assembly is configured to support the coil when the coil drum assembly is in an extended position and rotate during deployment of the spoolable pipe, and the first tower and the second tower are configured to move the coil drum assembly vertically.

Abstract: The present disclosure provides a system and method of repairing a flange of an engine case having a damaged section of attachment tabs and/or flange region. One or more damaged attachments tabs extending away from a flange are removed along with a first portion of the flange, thus leaving a second portion of the flange. A replacement component is produced comprising a replacement flange portion and one or more replacement tabs. The replacement flange portion is placed in contact with the second portion of the flange and the replacement flange portion is secured to the second portion of the flange.

Abstract: A combustor may comprise a combustion chamber encapsulated by a combustor casing, wherein the combustor casing comprises a casing forward portion, a casing radially inward portion, a casing radially outward portion, and a casing aft portion. The casing radially inward portion may comprise a dirt collector system comprising a hot panel adjacent to the combustion chamber; a cold shell panel coupled to the hot panel such that the hot panel is between the combustion chamber and the cold shell panel; and a dirt collector panel coupled to the cold shell panel such that the cold shell panel is between the hot panel and the dirt collector panel. The cold shell panel and the dirt collector panel at least partially define a dirt collecting space.

Abstract: A tube assembly includes at least first and second tubes configured for coupling at respective ends. The first and second tubes each include a base material, and a weld interface at the respective end. The weld interface is proximate to an inner diameter and an outer diameter of the first and second tubes, and includes a weld interface segment extending therebetween. A work hardened weld assembly couples the base material of each of the first and second tubes. The work hardened weld assembly includes a weld fusion zone between the weld interfaces of the first and second tubes and the weld interface segments of the first and second tubes. The weld fusion zone is work hardened and at least the weld interface segments of the first and second tubes are work hardened between the work hardened weld fusion zone and the base material of the first and second tubes.

Abstract: Closure element for a vacuum valve having a valve disk realized for the gas-tight closure of a process volume by means of interaction with a vacuum valve opening of the vacuum valve provided for the process volume, wherein the valve disk comprises a closure side and an oppositely situated rear side which is substantially parallel thereto and a first sealing face which is assigned to the closure side and corresponds to a second sealing face of the vacuum valve opening, in particular with regard to form and size, with cured-on sealing material, wherein the second sealing face runs around the vacuum valve opening, and a cross carrier with a receiving means for a drive component transversely with respect to an extension direction of the cross carrier, wherein the cross carrier is connected to the valve disk on the rear side of the valve disk at at least one connection point. The connection of the cross carrier to the valve disk comprises a friction stir welding connection at the at least one connection point.

Abstract: A welding system for welding a first elongated element and a second elongated element together by a laser beam that is emitted from a laser welding head after the ideal welding center point of the aligned first and second elongated elements has been positioned at a focal point of the laser beam that is emitted from the laser welding head.

Abstract: A welding unit for welding together two rails of a track includes two rail clamping assemblies which can be moved towards one another in a longitudinal direction of the rail along unit guides by compression cylinders. Each rail clamping assembly is equipped with clamping jaws which are displaceable in pairs in a pressing plane and each of which has a contact surface provided for application to a rail web. The clamping jaws are each constructed as clamping levers which are pivotable in the pressing plane about a lever pivot axis. The contact surface intended for application to the rail web is disposed at a first lever end spaced apart from the lever pivot axis. The two contact surfaces of each rail clamping assembly are each positioned closer to the oppositely disposed rail clamping assembly than the two lever pivot axes.

Abstract: A gas turbine engine includes a combustor having a dual-wall impingement convention effusion combustor tile assembly. The dual-wall tile assembly provides a cooling air flow channel and attachments for securing the tile to the cold skin liner of the combustor. Cooling is more efficient in part due to the dual wall construction and in part due to reduced parasitic leakage, and the design is less sensitive to attachment features which operate at lower temperatures.

Abstract: A welding assembly includes a tip dress unit for dressing an electrode tip and a tip cleaning unit having a brush rotating during a cleaning operation. The tip cleaning unit is used to clean the electrode tip prior to the electrode tip being moved to the tip dress unit. The brush may be a wire brush. The brush may clean multiple electrode tips simultaneously. The brush may remove debris, such as sealer, oil, or particles from the electrode tip. The tip cleaning unit may include a shield at least partially surrounding the brush.

Abstract: A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

Abstract: A vibration dampening device for the manufacture by rotational friction welding of a turbomachine rotor including a first disc and a second disc each having a hub with an internal surface is provided. The device includes a first clamping device configured to be positioned coaxially to the hub of the first disc and having a pair of radially opposite jaws suited to come into contact with the internal surface of the hub of the first disc.

Abstract: A shear bonding device and a shear bonding method of metal plates are disclosed.

Abstract: A system of forming a bimetal medical device from dissimilar metal components includes a first metal component, a second metal component, a retaining device, a compression mechanism, and an energy source. A method of forming the bimetal medical device with the system includes applying a first pulse of laser energy to a joint formed between the first and second metal components retained by the retaining device and compressing the first and second metal components together with the compression mechanism to form a welded region.

Abstract: A wire butt welding apparatus includes at least two clamps, individual ones of the at least two clamps configured to hold a respective wire. The individual ones of the at least two clamps are positioned within the wire welder such that the ends of individual ones of the respective wires, when held by the respective clamps, will contact each other. One or more individual ones of the at least two clamps are associated with an adjustment axis about which the individual ones of the at least two clamps are configured to rotate. An adjustment mechanism is operatively coupled to fix one or more of the at least two clamps corresponding to the associated adjustment axis at an angular orientation with respect to a second clamp.

Abstract: Nickel-base radiant tube includes straight and curved elbow tube sections. The straight tube section has constant inner and outer radii. The elbow tube section has a constant inner radius and variable outer radius. The inner diameter of the elbow tube section is equal the inner radius of the straight tube section. Mating end portion of the elbow tube section has an outer radius equal to the outer radius of the straight tube section. Method for making the radiant tube comprises the steps of positioning a mating end portion of the straight tube section adjacent to and aligned with the mating end portion of the elbow tube section so that end faces of the straight and elbow tube sections face each other to define a circumferentially extending weld groove, and butt welding the mating end portions of the straight and elbow tube sections together at the weld groove.

Abstract: The present invention provides a high strength welded steel pipe superior in weld zone embrittlement crack characteristics and a method of production of the same, that is, a method of production of a welded steel pipe superior in hydrogen embrittlement cracking resistance of weld metal characterized by seam welding from the inner and outer surfaces by a tensile strength of 850 MPa or more, then expanding or reducing the size of the pipe for correction, which method of production of welded steel pipe characterized in that the hydrogen concentration of the preceding weld metal is 0.2 cc or less per 100 g at ordinary temperature.

Abstract: An improved method for executing a flash butt weld to join first and second rail segments includes applying a voltage to the first rail segment and the second rail segment to establish a voltage difference between the first and second rail segments. The rail end faces are brought into contact, resulting in an electrical current between the first rail end face and the second rail end face, resistively heating material at the interface. As material burns off at the interface, the power consumed at the rail end interface as a function of rail displacement is periodically sampled. If the comparison indicates that the power per unit of rail displacement is not increasing from sample to sample, the burn-off process is terminated. In a further aspect, if the power per unit of rail displacement exceeds a predetermined threshold, the burn-off process is terminated.

Abstract: The invention relates to a method of providing a duplex stainless steel strip for an armouring layer of a flexible pipe, said method comprising providing at least two duplex stainless steel pieces each having an end-face, welding said end-faces of said two pieces of duplex stainless steel together to form a welded interface section using resistance welding, such as dual upset welding or flash welding, and providing a controlled cooling of said welded interface section. The duplex stainless steel strip should preferably be heated to a temperature of at least about 1100° C., preferably at least about 1200° C., such as at least about 1500° C. in said interface section, and the controlled cooling of said welded interface section preferably comprises prolonging the cooling of the interface section preferably at least for the cooling from about 800° C. to about 600° C., more preferably at least for the cooling from about 1100° C. to about 600° C.

Abstract: In resistance welding, an end portion and a flange portion are welded together at contact surfaces thereof by applying a voltage between two electrodes a while an inner casing and a main metal piece are pressed in directions toward each other. When a shearing stress due to the pressure is applied to a ceramic guide pin, the guide pin is more resistant to wear as compared to a phenolic resin guide pin, for example. In addition, a clearance is provided between a large-diameter portion of the guide pin and an inner surface of a guide-pin insertion hole. Accordingly, the guide pin is capable of tilting in the radial direction, to partially absorb the shearing stress. Therefore, the guide pin is more resistant to breakage compared to a non-tilting ceramic guide pin. Thus, the life of the guide pin used in the resistance welding process can be prolonged.

Abstract: In working equipment comprising a table, a positioning station for fixing a workpiece on the table, and a working station for performing a working process on the workpiece, the table includes a stopper for the workpiece to contact, a pressing member for pressing and thereby bringing the workpiece into contact with the stopper, and a fixing device for fixing the workpiece to the table, and the positioning station includes a pressing actuator for moving the pressing member.

Abstract: A weld fairing apparatus and a welding method using the apparatus effectively prevent a weld metal zone from forming a humping bead. The welding method includes: butting first and second object pieces together; heating the butted first and second object pieces using a heating device, thus forming a weld metal zone; and placing a fairing device such that the fairing device comes into contact with the weld metal zone and fairs the weld metal zone.

Abstract: A device for the linear butt welding of thin metal sheets without weld filler materials comprising movable welding heads, a clamping device having at least two pressing elements which operate independently of one another at least one of the pressing elements being suitable for applying two or more distinct pressure levels and additional horizontal pressing elements are further provided in order to press the metal sheets to be welded against one other while being deformed, until full-area contact of the metal-sheet edges butting against one another is achieved as well as a welding method making use of the device.

Abstract: Plate members 17 are respectively rested on first and second tables 1A and 1B relatively movable toward and away from each other. The plate members 17 are caused to abut against reference positioning members 16a and 16b of reference positioning devices protruded ahead of and over opposing ends 1? of the tables 1A and 1B so that opposing ends of the plate members 17 are positioned ahead of the opposing ends 1? of the tables 1A and 1B, and the plate members 17 are positioned laterally. Then, the positioned plate members 17 are locked on the tables 1A and 1B. After the reference positioning devices are retracted, the tables 1A and 1B are relatively moved toward each other to cause the opposing ends of the plate members 17 to abut together for formation of weld line X.

Abstract: The seam welding apparatus welds a workpiece held by a robot while delivering the workpiece between a pair of electrode rolls. The seam welding apparatus includes a load cell mounted on the robot, for detecting a load imposed along a Y direction which is perpendicular to a pressing direction Z along which the electrode rolls press the workpiece at a weld point and a delivering direction X along which the robot delivers the workpiece at the weld point, a robot controller and an arithmetic unit, a turning mechanism for turning the electrode rolls about the pressing direction Z, and a control device for controlling the turning mechanism to operate depending on the magnitude of the load in the Y direction detected by the load cell.

Abstract: The present invention provides a high strength welded steel pipe superior in weld zone embrittlement crack characteristics and a method of production of the same, that is, a method of production of a welded steel pipe superior in hydrogen embrittlement cracking resistance of weld metal characterized by seam welding from the inner and outer surfaces by a tensile strength of 850 MPa or more, then expanding or reducing the size of the pipe for correction, which method of production of welded steel pipe characterized in that the hydrogen concentration of the preceding weld metal is 0.2 cc or less per 100 g at ordinary temperature.

Abstract: A butt welding apparatus and a butt welding method where end faces of at least one plate member to be welded are butted to each other to form a butt portion, and butt welding can be performed on respective plate members which have various thickness sizes on both side portions of the butt portion with electric resistance heat by a pair of electrode members which are common to the respective plate members. At least one electrode member (1) is provided on an outer face thereof with a convex portion (1A) which gradually retreats from one plate member (31) of two plate members (31, 32) as it extends from an intermediate portion, in a thickness direction, of the one electrode member (1) along the one plate member (31).

Abstract: A forced-insertion welded structure is provided which is formed by welding members making up a metal component and which is easy to manufacture and has low cost, a good finish precision and a high bonding strength. The forced-insertion welded structure comprises: a first member 2 with a hole 13 which has the same geometry as a cross section of a forcibly inserted portion of a second member; and the second member 4 having a constant cross section over its length which is similar in shape to the hole 13; wherein a press-fit interference of the second member 4 relative to the hole 13 of the first member 2 is set to 0.

Abstract: An improved method for joining together the edge portions of first and second panels includes applying a heat curable adhesive along the edge portion of the first panel and then abutting the edge portion of the second panel with the edge portion of the first panel so that the adhesive is interposed between the edge portions of the first and second panels and the adhesive spaces the panels apart and provides a gap between the panels. A brazing material is melted and fills the gap and the heating of the panels by the brazing causes at least partial curing of the adhesive so that the panels are joined together by both brazing and adhesive bonding.

Abstract: A shear-assisted solid state welding method for joining of metal parts, involves a first step of heating opposing surfaces in a non-passivating environment to a temperature in the hot working temperature range of the metal. A second step involves bringing the opposing surfaces into contact while still in the hot working temperature range, and applying compressive stress sufficient to substantially prevent sliding in response to shear displacement, causing plastic flow in the hot layers. A third step involves imposing relative shear displacement of the metal work pieces without disengaging the opposing surfaces. The shear displacement induces plastic shear strain within the hot layers to progressively induce bonding.

Abstract: A butt welding apparatus, a butt welding method, and a product manufactured by the butt welding method involves two electrode rollers disposed on both the front and back sides of a thick sheet member and a thin sheet member whose end surfaces are butted. The electrode rollers bridge across the sheet members and are composed of small diameter portions on the side of the thick sheet member and large diameter portions on the side of the thin sheet member. The small diameter portions come into contact with and press the thick sheet member before the large diameter portions come into contact with the thin sheet member. Thus, the end surface of the thick sheet member swells and deforms toward the thin sheet member and reliably comes into contact with the end surface of the thin sheet member, and power is applied between the end surfaces, even if not polished.

Abstract: An automated method for forge welding tubulars including heating the tubular ends to be joined in a welding chamber while the heated tubular ends are maintained aligned and parallel relative to each other and at a small spacing, whereupon the heated tubular ends are pressed together while a reducing shield gas is injected into the chamber.

Abstract: The invention concerns a method for controlling the butt welding, by flash welding, of two metallic parts (A, A?) in a welding machine of the type comprising two pairs of clamping dies (2, 2?) mounted respectively on a fixed frame (1) and on a mobile frame (1?) for contacting rear (3) and front (3?) ends of both parts (A, A?) and the flow of an electric welding current. According to the invention, on the one hand a set of electric parameters including at least the voltage (Us) and the intensity (Is) of the welding current and on the other hand the relative position of the mobile frame (1?) with respect to the fixed frame (1) are measured at any moment and the travel of the mobile frame (1?) is regulated in position from at least one of the measured value of said electric parameters, in order to control the closing-in speed v(t) of the ends (3, 3?) of both parts (A, A?) taking in account the progress of the welding process, during at least a portion thereof.

Abstract: An apparatus and method for supplying a continuous source of wire includes a base supporting at least first and second sources of wire, a wire joining apparatus adjacent the base configured to weld a first wire from the first source with a second wire from the second source and a swing arm apparatus adjacent the first and second sources of wire. The swing arm apparatus may comprise a swing arm assembly configured to position a source cover over the second source of wire upon depletion of a feed wire in the first source of wire.

Abstract: A method of welding an axle housing surface to a blank surface includes generated heat in one of the two components. Heat is generated from at least one of these surfaces at their interface sufficient to weld them together. The surfaces are then applied together.

Abstract: A method and machine for deburring the burr which is formed when wires are butt welded is disclosed. The machine comprises a deburring head which has a pair of opposed deburring rollers mounted thereon. Each of the rollers has a milled surface formed therein. A linkage is connected to the rollers to cause the rollers to rotate when the linkage is moved between first and second positions. When the linkage is in its first position, the milled surfaces of the rollers face one another to enable the wires and burr to be positioned therebetween. As the linkage moves to its second position, the circumferences of the rollers engage the burr to roll out the same, thereby providing a substantially smooth, cylindrical surface where the burr was located. The method of deburring is also disclosed.

Abstract: To provide a seam welding apparatus and a seam welding method that may operate at a low pressure to obtain a suitable overlapped alignment amount. In the seam welding apparatus, a trailing plate clamp moving means is provided with link mechanisms for overlapping and aligning a leading end of a trailing plate with a trailing end of a leading plate and a link drive source for operating the link mechanisms under an extended condition. The link mechanisms are arranged in parallel along both side edges of the trailing plate. The pair of link mechanisms are connected to a link drive source to form a parallel link mechanism assembled through a coupling link. Also, a movable portion of the leading plate clamp means has a tilt pivot. This tilt pivot is adapted to be movable so that the overlapped alignment amount may be adjusted.

Abstract: A band saw strip manipulator is arranged to receive a toothed metal strip for welding from a cut to length machine. The strip is moved into the band saw strip manipulator by powered rollers. The strip extends between a first edge detector at one side of the manipulator and a second edge detector at the opposite side of the manipulator. First and second end clamps are located to either side of a carriage mounted for vertical movement. When the strip has been approximately centrally located in the manipulator the carriage moves upwardly thereby pulling the strip upwardly until the edge detectors detect the ends of the strip. The first and second end clamps are then closed and pivoted about first and second guide rollers so that the two ends of the strip are located in close proximity for welding together.

Abstract: A flash butt rail welding welderhead combines in a single unit, the ability for the three functions of rail pulling, flash butt forging and maintaining the “after forged” displacement without any change in platen position such that shearing may be accomplished in three stages, a single stage, multiple stages or a progressive stage, all while maintaining clamping and stretching force on the rails.

Abstract: A continuous hot rolling mill with a metal block conveying apparatus and a metal block joining apparatus which moves with the metal blocks along the metal block conveying apparatus to conform a joining operation. The metal block conveying apparatus uses rollers supported by cylinders with a common hydraulic circuit which allows the cylinders to follow guide rails on the metal block joining apparatus and lower out of the path of the metal block joining apparatus and then return to a metal block support position after the metal block joining apparatus' passage without individual control circuits and valves for each of the cylinders.

Abstract: The present invention is an improved welding technique that provides real-time control of the servo valve to account for the changing conditions of the parts being welded. The present invention may be implemented within any electrical welder having at least one movable platen for carrying a part to be welded, at least one hydraulic cylinder coupled to the movable platen, the hydraulic cylinder having a first chamber and a second chamber, and a servo valve coupled to the hydraulic cylinder. The present invention includes means for making instantaneous pressure measurements within the first and second chambers of the hydraulic cylinder. Also included is a force control module that reacts to the pressures within the first and second chambers to control the servo valve. The force control module receives the instantaneous pressure information from the first and second chambers of the hydraulic cylinder and determines whether the platen is moving and how far the servo valve is from its target force.

Abstract: An improved method for welding and passivation forms a chromium oxide passivated film over the welded portion during the welding process. In a shielding step, a backshield gas, preferably argon, is flowed around the welding site. In a welding step, an arc gas, preferably argon with approximately 10% hydrogen and less than 1 ppm moisture content, is flowed through the welding head and a welded joint is formed, for example by high speed tungsten-inert gas (TIG) orbital welding. In the passivation step, a process gas, preferably argon with approximately 30-100 ppm of oxygen and less than 1 ppm moisture content, and preferably less than 1 ppb moisture content, is flowed over the welded portion to form a chromium oxide passivated film on the welded portion. The process gas is passed through a gas purifier prior to being flowed over the welded portion to maintain its moisture level at less than 1 ppb.

Abstract: The present invention is an improved butt welding technique that provides adaptive control of force that is applied to a part during a welding process to enable a maintained joint resistance across joint. The force may be adjusted to account for the changing conditions of the part. The present invention may be implemented within any electrical welder having at least one movable platen for carrying a part to be welded, at least one hydraulic cylinder coupled to the movable platen, the hydraulic cylinder having a first chamber and a second chamber, and a servo valve coupled to the hydraulic cylinder. The present invention includes means for making voltage drop measurements across the joint to be welded. The voltage measurements provide feedback as to whether the force should be adjusted. A force control module may be implemented to provide controlled force to the part.

Abstract: A device for welding together elongated work pieces such as railroad track, is provided with controls to eliminate pre-existing angles that exist between each work piece prior to joining.

Abstract: A welding method and apparatus for flash butt welding adjacent ends of axially aligned railway rails includes a base frame and fixed and movable platens supported on the base frame. The platens support rail sections and are under the control of controller means operative to automatically move the movable platen through a predetermined distance/velocity relation as electrical power is inputted into the rail ends during straight flashing, preheating, flashing and upsetting phases of a welding cycle. The controller includes PID feedback loops operative to maintain the predetermined platen distance/velocity relation with entry of a single parameter by the operator. Significantly improved quality and repeatability of rail welds are obtained.

Abstract: An apparatus for connecting strips, in which a rear end portion of a preceding strip and a front end portion of a succeeding strip are cut and brought into contact to each other so that a butt welding of the contacted portions may be carried out to connect both the strips. A carriage is provided for carrying a cutting device for cutting the end portions of both the strips. A finish-machining device is provided for finish-machining the cut end faces of both the strips and a welding device for butt welding both the strips along a contacting line of both the strips is installed so as to be movable in a line substantially parallel with the contacting line of both the strips. Die wears and burrs incidental to cut faces can be prevented from forming and the highly accurate contacted state of strips can be achieved, thereby improving the quality of the welded portion.

Abstract: An electronic proximity switch adapted to be operated in a non-contact mode for use in a welding zone of welding facility, with the switch being employed for, for example, controlling welding tongs and/or checking a position of welding electrodes. The electronic proximity switch includes a housing provided on at least a portion of a surface thereof exposed to, for example, floating welding globules with an anti-stick coating. A ceramic disk may be provided at a responsive-sensitive end face of the switch, with the ceramic disk also being provided with an anti-stick coating.

Abstract: A pair of clamping electrodes for use in flashless D.C. butt welding of aluminum and the like are disclosed. Each clamping electrode is provided with a clamping face for engaging opposed major surfaces of a work piece. The electrodes are configured so that, when a pair of opposed clamping electrodes are clamped around a workpiece having a pair of opposed major surfaces and a pair of opposed minor surfaces, the electrodes form opposed containment walls adjacent to the minor surfaces of said workpiece. The pair of opposed clamping electrodes preferably include pinching surfaces adjacent to each of the containment walls and the clamping surfaces. According to a preferred embodiment, a first clamping electrode is provided with a flat clamping surface and a second, opposed clamping electrode has a compound clamping surface including a flat clamping surface for engaging a major surface of a workpiece and two opposed containment walls adjacent the flat clamping surface.

Abstract: A cylindrical wheel rim blank has a longitudinal seam defined by a pair of longitudinal edge portions each of which is clamped between upper and lower jaws of a respective clamping assembly. The two clamping assemblies are urged laterally together to press the two longitudinal edge portions together, and welding current is introduced at the seam through the lower jaws to effect the weld. The upper jaws are at the bottom of cantilevered horn members around which the rim blank is mounted. The lower jaws are urged upwardly toward the cantilevered upper jaws to effect the clamping function. Structure is provided to equalize the clamping pressure exerted against the upper jaw along the length thereof and, if desired, to introduce a bias into the upward pressure exerted through the lower jaw. There is a mechanism to provide different, predetermined spacings between the clamping assemblies as different steps in the operation. Circuitry is provided to produce a reversing, pulsating DC welding current.

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.