Abstract: An apparatus and method for depositing an overlay material onto a metal surface. An electroslag strip overlaying process which distributes flux through a trailing flux tube and a forward flux tube eliminates many of the problems associated with electroslag overlaying techniques. The apparatus and method significantly improves the quality of the overlay surface, and permits overlays to be made within the small confines of pipes and pipe fittings having straight or curved surfaces.

Abstract: The present invention relates generally to an apparatus and method for performing tube-to-tubesheet welding within box headers and, in more particular, to a GTAW welding gun that has a long generally tubular barrel which is small enough in diameter to pass through the plug holes on one side of a box header and long enough to reach over to the point of connection on the opposite tubesheet. Additionally, and as a critical part of the instant invention, the torch is fitted with a semi-automatic cold wire feeding apparatus and an associated wire feed liner that is constrained to be proximate to the exterior of that tube throughout said barrel's length. Thus, both the barrel of the welding torch and its accompanying wire feed liner are sized to fit within and pass through a plug hole.

Abstract: A device for internally butt-welding pipes, of the type comprising a support and guide frame (2) for an annular welding member (3), rotatable coaxially to the pipes (1) to be welded and carrying a plurality of welding units (4) each comprising support means (13, 14; 40, 41; 40A, 41A; 45, 46) for a spool (8, 8A, 8B) on which welding wire (7) is wound, and means (26) for automatically feeding said wire. The support means (13, 14; 40 41; 40A; 41A; 45, 46) are removably connected to walls (10A, B) of a support frame (10) for the welding units (4) so as to enable said means to be replaced and spools of different type to be used.

Abstract: A gas shield strip cladding welding system including a workpiece, a strip of welding material, an enclosure having an opening through which the strip of welding material passes, a feeder for controllably passing the strip of welding material into the enclosure through the opening, a gas delivery conduit connected to the enclosure so as to pass a shielding gas into the enclosure adjacent to the strip of material, and a power supply electrically connected to the strip of welding material and to the workpiece such that an arc is produced when the strip of welding material comes into close proximity to the workpiece. A mechanism is connected to the enclosure so as to move the enclosure continuously relative to the workpiece so as to deposit the welding material in a desired pattern. The shield gas includes an inert gas.

Abstract: A new system for welding sections of pipe together to form a long, continuous pipeline. A welding bug is mounted on a guide track which goes around the circumference of the pipe. The welding bug is provided with a wire feeder, a motor to drive the wire feeder, and driving motor for driving the bug around the track. One may vary the speed of the bug and the wire feeder while the bug is continuously driven around the track. The welding head on the welding bug is powered by a surface-tension-transfer power source. The initial or root pass is made external of the pipe. In one embodiment there is a dual welding wire feeder for driving two welding wires simultaneously at the same speed.

Abstract: A weld head assembly which, in one embodiment, includes a mounting ring subassembly and a faceplate subassembly is described. The mounting ring subassembly includes a mounting ring configured to be mounted to one of the pipes to be welded. At least one motor is mounted to the mounting ring and the motor includes an output shaft having a rotatable spur gear mounted thereto. A plurality of bevel rollers are mounted, at spaced locations, to the mounting ring and each of the rollers is mounted along a same radial path. The faceplate subassembly is secured to the mounting ring subassembly and includes a faceplate ring, a bevel ring and a spur gear mounted to the faceplate ring. Wire spool holders, wire feeders, a welding torch, and cameras are secured to the rotatable faceplate ring.

Abstract: An improved plasma arc welding arm method and apparatus for keyhole welding rotating workpieces has an arcuate gear track supporting a corresponding arcuate geared cart bearing a plasma arc welding torch prevents voids in keyhole weld starts and finishes. The gear track is mounted on a manipulator arm for positioning the welding torch in proximity to a rotating workpiece to be welded. The torch may be rotated on the cart and gear track in the same direction and at the same rotational speed as the workpiece.

Abstract: A welding method for steel reinforcements, wherein electric current flows through the reinforcements, an electroslag pool formed from a solder melted by an electric arc generates a lot of heat to melt the reinforcements, pressure is applied to combine the same; the method uses a clamping device, wherein a sliding chuck is adjustably rotated by means of a bolt handle thereon to enhance a movable clamping seat to clamp the upper reinforcement, then a fixed chuck is adjustably rotated by means of another bolt handle to enhance another movable clamping seat to clamp the lower reinforcement, a crank provided at one side of a main body can be optionally rotated forwardly or backwardly to raise or lower the upper reinforcement, or the upper and the lower reinforcements can be compressed for combining.

Abstract: The system comprises: a distance sensing device for sequentially acquiring, during the welding process or before it, individual transverse profiles of the welding gap by gauging its various depths; electronic units for parametrically reconstructing, by combined numeric and vector calculation, the parametric and topological features of the welding gap starting from the various depths acquired by gauging points; electronic circuits that are adapted to compare the features of the acquired welding gap profile and the stored features of the profile of a corresponding nominal ideal welding gap and to infer corresponding data for varying the parameters of the welding process; and control subsystems using, selectively or in combination, one or more of the variation data to adapt corresponding welding parameters.

Abstract: A welding apparatus and method is provided for automatically welding a stack of two or more metal tubes together. The tubes are stacked such that there is a pair of opposed longitudinal interfaces (or seams) between each tube in the stack. The welding apparatus broadly comprises: a stationary welding means for forming welds along the seams between each tube; a drive means for linearly advancing the stack of tubes relative to the welding means and for preventing separation of the tubes as the welds are being formed; and an alignment means for continuously and accurately keeping the stack of tubes in proper alignment as the drive means advances the tubes. The welding method broadly comprises: aligning the tubes in accurate stacked relation; holding the tubes together in stacked relation; advancing the tubes relative to a stationary welding means while maintaining the tubes in stacked relation; and welding the opposed longitudinal interfaces between each tube as the tubes are moved relative to the welding means.

Abstract: A method and apparatus for use in welding pipe. The apparatus includes means for viewing the interior of the pipe, means for establishing a predetermined atmosphere in the weld zone and means for clearing liquid from the interior of the pipe.

Abstract: A system for automatically tracking a surface for performing a welding operation comprises a frame and pair of ring gears movably mounted to the frame. The ring gears are spaced apart from each other. Three weld heads are movably mounted to each ring gear. Each weld head has a welding torch for providing a weld and a laser scanning device for scanning a surface and for measuring distances over the surface. A control system communicates with the laser scanner for receiving the measured distances and for controlling the movement of the ring gears and the weld heads.

Abstract: A method and apparatus for welding a branch tube to a header tube includes a fixture having a pair of clamps for supporting the fixture on the header tube. A welding head on the fixture includes a clamp to hold the branch tube in place relative to the header tube. The welding head also includes a collet extending into contact with the header tube. The header tube, the collet and the welding head form a limited volume chamber that contains shielding gas in the vicinity of the joint between the branch tube and the header tube. The welding head includes a mechanism for rotating a tungsten welding electrode around the intersection of the branch tube and the header tube to form the welded joint.

Abstract: An automatic welding system uses an anti-gravitational welding controller to minimize or eliminate the undercutting and concavity of the roots of the welds caused by gravitational effects. The pressure within the pipes to be welded is continually changed as the welder orbits the pipes. At the upper section of the weld, positive pressure is applied to the pipes to eliminate undercutting at the upper surface of the weld and negative pressure (vacuum) is applied to the lower section of the weld to eliminate concavity of the root of the weld. In one mode, the internal pressure within the pipes is varied as a function of the position of the orbital welder. In another mode, the arc voltage at the tip of the weld, i.e., the distance between the tip of the weld and the surface of the weld, is maintained constant by varying the pressure within the pipes. The system allows for the completion of high quality welds with less weld material, less passes, and less time.

Abstract: A device for flooding a weld junction between two devices with a protective gas has a double wall body received in the pipes and bridging the junction with sealing rings received in end chambers of the body braced against inner surfaces of the pipe. An intermediate chamber is bounded outwardly by a cylindrical shell of fine-pore sintered metal and has an inner wall provided with at least one fitting for connecting a supply pipe for the protective gas thereto. Between the intermediate chamber and at least one of the end chambers, at least one outlet chamber is formed to discharge excess protective gas through a throttle on an inner wall of the outlet chamber.

Abstract: Automatic welding apparatus of the type comprising a carriage self-propelled along a guide track encircling end-to-end adjoining metal tube sections through a welding pass therearound for forming a weld bead joint therebetween is provided with a welding head pivotally mounted on the carriage for pivotal movement thereon in the plane of the weld joint, about a pivot point located approximately at the tip end of the wire electrode projecting from the nozzle end of the welding head, between an initial forwardly inclined drag angle welding position at the top of the adjoining horizontally disposed tube sections to a rearwardly inclined push angle welding position when the welding head reaches around 120.degree. to 135.degree. of its welding pass around the weld joint.

Abstract: A device for hindgas coverage in welding tube pieces (2,3) together comprises two sealing devices (5,6) connected by a rod (7). The sealing devices comprise a first web part (10) with sealing means (8) and a supply duct (11) for hindgas, and a second web part (9) with sealing means (8,25) and discharge ducts (19,20) for controlled outflow of gas to the surroundings. Some of the surfaces of each web part have a two-dimensional curvature (26) for forming the sealing means (8), e.g. rubber discs.

Abstract: A torch assembly for TIG relaxing an inner surface of a tube to be removed from a tube sheet which comprises a conductive base containing passages for cooling water and for inert gas. A sheath is rotatably mounted to the base and contains a drive shaft fixed to the base. A torch head is fixed to an opposite end of the drive shaft and the drive shaft is embraced by a conductive braid so that electrical power applied to the base is conveyed to the torch head. A torch tip extends radially from the torch head and is used to strike an arc with the inner surface of the tube to be TIG relaxed. Inert gas is supplied through the sheath and to a space around the head which is confined by a gas cap. A hole in the gas cap receives the end of the torch tip so that inert gas bathes the annular space around the tip to protect the arc.

Abstract: A welding apparatus is disclosed for seal welding closed the bore of a sealing plug which is positioned adjacent the end of a hollow tube and where the bore defines an axis in communication with the tube. The apparatus includes a head with an end stop member rotatably mounted thereto. The end stop member is movable between an extended position where the front sealing plug engaging end is extended for engaging and supporting a sealing plug during girth welding, and a retracted position where the end stop member is retracted. A seal welding electrode is supported in an axial passage of the end stop member and is movable therein between a retracted non-welding position and an extended seal welding position where the electrode tip extends outward beyond the front opening of the end stop member for permitting the seal welding closure of the sealing plug axial bore.

Abstract: A purge block with non-inflatable, disc-like seals removably mounted on either end of an elongate tube. In one embodiment, the tube is rigid and hollow and forms part of a conduit for argon or other inert gas through one of said seals to a set of discharge ports adjacent the near end of the other seal. A vent tube extends separately through the first seal. In a second embodiment, the elongate tube is semi-rigid, and a passageway is provided through each seal to discharge ports located adjacent the inner end of each seal to permit gas to flow outside the tube from the inlet end seal of the purge block to and through the outlet end seal.

Abstract: An automatic welder is used in an internal welder unit which travels along the interior of a pipeline and provides the interior weld passes at the junction of abutting pipe joints. The internal welder unit has an electronic control system which includes a plurality of microprocessor control units, each of which performs specific functional operations for the internal welder unit. The microprocessor control units are interconnected by a serial communication link which permits the transmission of commands and data between all of the microprocessor control units. The control system includes a back end control unit positioned in the internal welder unit, a front end control unit with a panel in the weld unit, a reach rod control unit at the end of a reach rod and a power supply control unit adjacent the arc power supply. The control system directs the operation of orbiting internal welders to have a zero or slow travel speed at a start point to ensure a high reliability of arc initiation.

Abstract: A continuous manufacturing method for a metal welded tube and a manufacturing apparatus therefor, which obtains a tubular member by continuously passing a metal band coil through molding rollers, guides the tubular member to abutting rollers to bring the edges thereof in slight contact with each other so as to form a V-throat having the vertex of an edge contact portion at the upstream side of the abutting rollers, disposes an inductor of a high frequency preheating unit aiming at edge preheating at the outer periphery in front of the abutting point of the V-throat and at need disposes an impeder also at the inner surface of the V-throat, and further disposes welding torches in a single or double rows of a welding unit for melting and welding the tubular member by welding high density energy at the upstream side of the abutting rollers including the line connecting the centers thereof.

Abstract: In a device for welding together pipe ends of pipes held mutually in line, a fixing band is first clamped around a pipe and a ring frame for opening and closing is then arranged therearound which is provided with a guide rail for guiding at least one welding carriage along the periphery of a ring weld.

Abstract: A device for hindgas coverage in welding tube pieces (2,3) together comprises two sealing devices (5,6) connected by a rod (7). The sealing devices comprise a first web part (10) with sealing means (8) and a supply duct (11) for hindgas, and a second web part (9) with sealing means (8,25) and discharge ducts (19,20) for controlled outflow of gas to the surroundings. Some of the surfaces of each web part have a two-dimensional curvature (26) for forming the sealing means (8), e.g. rubber discs.

Abstract: An apparatus and a method for welding joint fixtures to either end of a pipe at a given angles of attachment. A retaining mechanism on both the driver side and the follower side for joint fixtures is provided on either end of a horizontally elongated table on which a pipe is to be horizontally placed. The joint fixtures are secured on the opposing inner ends of the retaining mechanisms via clamping devices to receive the pipe therebetween. The retaining mechanism for the joint fixture on the driver side includes a device for establishing the angle of attachment of the joint fixture so that the joint fixture can be turned to a predetermined angular position. After the angle of attachment of the joint fixture to the pipe is determined, the junctions between the joint fixtures and the pipe on either end are held in place by gripping devices for tentative welding using welding torches.

Abstract: A pipe welding connector for joining pipe sections that have been internally coated with a heat sensitive coating material. The connector is arranged so that during the welding process, the coating remains below its degradation temperature. The connector has a first fixture at the end of one pipe section and a second fixture at the end of another pipe section. The first and second fixtures, when brought into abutting relationship, can be butt welded together to form the pipe welding connector. The second fixture is a cylinder that outwardly diverges into a bell and the opposed marginal end is of constant inside diameter and is attached about the exterior of a pipe section. Part of the pipe section extends from the belled marginal end and forms a stinger. The first fixture has an enlarged interior that telescopingly receives the stinger therein and further includes a belled marginal terminal end of a diameter equal to the diameter of the belled marginal end of the second fixture.

Abstract: An end stop is adapted for engaging the sealing plug positioned in the end of a nuclear fuel rod and so as to permit the evacuation of the fuel rod to facilitate girth welding of the plug onto the rod, and to permit pressurization of the fuel rod and an enclosing welding chamber to facilitate the seal welding closure of the axial opening in the end stop. The end stop includes an axial passage extending therethrough having a welding electrode coaxially positioned therein to facilitate the seal welding closure of the fuel rod sealing plug. An air channel extends between the axial passage and an outlet on the surface of the end stop. A one-way valve is positioned in the air channel for permitting the free passage of a gas from the axial passage to the outlet into the welding chamber while precluding passage of a gas in the reverse direction.

Abstract: An apparatus and a method for automatically welding a T-junction connector to a main pipe are disclosed. The apparatus includes a rotatable frame which is provided with a movable bracket for supporting a welding gun. The frame is preferably attached by a vertical shaft to a portable framework having a wheeled leg and a pair of spaced apart horizontal handles. The portable framework may be moved from one location to another on its wheeled leg. The frame is rotated about the shaft by a computer controlled motor. Two other motors mounted to the frame are interconnected with the bracket for supporting a welding gun or torch, and adapted to move the welding gun along axes parallel with and normal to a T-junction connector supported in a preformed hole in a main pipe.

Abstract: A device for forming a closed chamber inside a set of two metal pieces of pipework (1) to be interconnected by arc welding under a protective gas, the device comprising a first hollow element made of elastomer disposed inside the first piece of pipework and a second hollow element made of elastomer disposed inside the second piece of pipework, both hollow elements being inflatable to close the corresponding piece of pipework. Each of the hollow elastomer elements comprises a toroidal inflatable tube (2) having a disk (3) fixed to the internal equatorial meridian thereof by gluing, said disk withstanding the pressure difference between the ambient atmosphere and the desired internal pressure inside the closed chamber, said disk being of a proper diameter necessary to cause the zone of the inflatable tube adjacent to said internal equatorial meridian to be concave.

Abstract: In a vessel, two tubes are mutually spaced apart by a given distance, are to be welded together at ends of the tubes, are accessible with difficulty or not at all, and one of them is introduced into the vessel through an opening in a wall of the vessel. A method and apparatus for forming a partial protective-gas atmosphere for the two tubes includes a sheath brought to a welding location through one of the tubes or through the opening for the tube in the wall of the vessel. Both of the tube ends are overlapped with the sheath or one of the tube ends is overlapped with the sheath and the sheath is placed above the opening in the wall of the vessel for the other tube. This forms a chamber about the welding location. The two tube ends are subsequently pushed toward each other until only a slight intermediate space remains therebetween. A protecive gas is subsequently introduced into the chamber through the intermediate space. The tubes are subsequently centered in a desired position for welding.

Abstract: An apparatus method for pipe end preparation and end to end welding of pipes comprises a stationary annular clamp (4) for both clamping and round up of pipes (2). It also has one or two rotating tool carrier rings (5) mounted at one or both sides of the clamp (4) on a track (6). The rotating ring may have thereon devices for cutting, machining of grooves, welding and non-destructive testing (NDT). The round up of the pipe is performed via 6 or more clamping shoes independently operated by screw jacks (18), a wedge mechanism (15) or directly acting hydraulic cylinders.

Abstract: A welding apparatus includes a housing defining a welding chamber and an access opening at one end thereof. The access opening allows an end of a tube fitted with an end plug to pass into and from a welding position within the chamber. An end stop for supporting the end plug at the welding position is rotatably mounted to the housing and disposed in the chamber opposite from and axially aligned with the chamber access opening. The end stop has an annular collar-like portion adapted to fit over and engage the exterior of the end plug. The end stop also has an inner hollow tube-like portion adapted to fit into a central passage of the end plug and engage the interior of the end plug. The end stop has an orifice adapted to supply flow of inert cover gas into the end plug central passage and therefrom into the tube interior to purge air therefrom.

Abstract: A welding apparatus has a welding chamber with an access opening allowing passage of a cladding tube end fitted with an end plug to a welding position therein. A rotatable end plug stop assembly disposed in the chamber and axially aligned with the access opening is adapted to engage the end plug when inserted in the welding chamber. An end of a electrode of a girth welding assembly disposed in the welding chamber adjacent to the rotatable end plug and tube end and in generally orthogonal relation thereto is operable to form a girth weld circumferentially joining the end plug and cladding tube end. An end seal welding assembly mounted to the end plug stop assembly and having an electrode with an end disposed adjacent to and in axial alignment with an axial bore of the end plug is operable to form an end seal weld therein.

Abstract: There is disclosed a method and apparatus for manufacturing a small diameter, thick walled, cable sheath by controllably driving a metal strip in a longitudinal direction while it is trimmed and formed into a hollow tubular member; continuously welding the longitudinal abutting edges of the hollow tubular member in association with cooling the tubular member in the vicinity of the welding by surrounding at least 60% of its circumference with a coolant, while maintaining the resulting longitudinal welded seam free of the coolant; and continuously drawing the cooled hollow tubular member in the same direction as the metal strip is driven.

Abstract: Flashing for a pipe is produced by joining a lead sheet having a hole in it for passing over the pipe, and a lead cylinder which is to surround the pipe and be bent into the top thereof. The joint is formed by producing mating flares on the lead sheet and cylinder and welding the two together. The weld is performed in the presence of an inert gas by drawing an arc between an electrode and the joint. The portion of the joint being welded is brought to a horizontal orientation by having the flares at a 45 degree angle and supporting the two parts on a rotating table inclined at 45 degrees.

Abstract: An apparatus for circumferentially and longitudinally positioning a weld head or other tool with respect to the surface of a pipe. A first annular ring is affixed to the pipe. A longitudinally movable annular indexing track is also circumferentially fitted about the pipe and rides upon a plurality of support rods mounted to the indexing track. The support rods are slidably received within corresponding holes in the clamping ring and extend longitudinally and parallel to the outer surface of the pipe. A motor mounted to the fixed ring drives a ring gear concentric to the fixed ring to reciprocate a ball screw which moves the second longitudinally moveable ring toward and away from the fixed ring. An orbitally moveable third annular ring is circumferentially mounted to the second ring, and a second motor mounted to the fixed ring drives a telescoping drive shaft which rotates the orbital third ring.

Abstract: Welding tongs for connecting two abutting pipe ends to each other by arc welding, includes two rigid jaws, a clamping device in the form of two symmetrical clamping jaws guided in the rigid jaws in radial direction of the surface of a pipe, the clamping jaws having contact surfaces adapted to the surface of a pipe for holding at least one pipe end, two angle levers each being connected to a respective one of the clamping jaws, a tie rod connected to the angle levers, a pair of levers connected to the tie rod and operating in vicinity of an extended position thereof, an operating handle connected to the pair of levers, a spring member biased between the clamping jaws and the pair of levers, a track, a welding electrode disposed on the track, and a motor connected to the electrode for moving the electrode along the track.

Abstract: The invention relates to a machine for automatically welding and/or cutting the junction point between a main pipe and a secondary branch pipe placed thereon. This machine comprises a positioning support on which the main pipe is placed. The positioning support comprises two servomotors which drive the main pipe in rotation about the longitudinal axis of the pipe and about a second horizontal axis perpendicular to said longitudinal axis. The machine comprises a travelling gantry crane which bears three carriages movable by three servomotors along three axes rectangular with each other, one of which is vertical. One of the carriages bears a welding or cutting head.

Abstract: A pipe welder for the automatic welding of joints between end abutting stationary sections of pipe which uses a welding head assembly mounted on a track which is mounted about the pipe. The welding head is low frictionally supported by a roller assembly connected between edges of the track. The track includes gear engaging slots. A drive gear is to engage with the gear engaging slots. The drive gear is flexibly mounted on the welding head housing so as to be continuously biased into positive engagement with the gear engaging slots.

Abstract: A method for restarting the longitudinal welding seam when producing thin-walled tubes from a metal tape comprises the steps of starting welding with the tape in motion and the welding current amperage being gradually raised from zero to the steady state values, a steady state step in which the longitudinal welding seam is continuously produced and the welding current amperage is at its steady state value, a third step in which the welding is stopped and the welding current amperage is gradually decreased from its steady state value to nearly zero, and a restarting stage in which the welding seam is overcast partially behind the point at which it had been stopped and the welding current amperage is gradually raised from nearly zero to the steady state value once again. An apparatus for performing the method is also disclosed.

Abstract: Method for manufacturing a large-sized, cylindrical, metal casing by welding successive cylindrical sections, characterized in that metal in the form of a strip is unwound continuously and at a uniform speed from a coil (6) and in that, as the strip (16) is fed through, crushing (15) or breaking of the fibre, pulling (13), polishing (17) and measuring of the length are continuously performed, in that at the same time the strip (30) thus unwound is continuously arranged on turntable (2) comprising a rotating table (26) the speed of rotation of which corresponds to the feeding speed of the strip at the radius of the cylindrical section being made, and then in that, when the length corresponding to the spread-out form of the cylindrical section has been obtained, unwinding of the strip is stopped, the cylindrical section (30) is cut off from the remainder of the strip (16) and is wound onto the turntable, in that the structure being assembled is then brought into position above this cylindrical section (30) and

Abstract: A partially consumable spacer chill or welding ring includes a generally cylindrical non-consumable base metal ring having an outside diameter of such a size as to snugly fit the inside diameter of the pipe end to be welded. A circular consumable filler metal spacer ring is medially attached to the outer periphery of the base metal ring and extends peripherally radially outwardly to function as a spacing device between adjacent ends of two lengths of pipe to be joined. The consumable spacer ring may be affixed to the base metal ring in a plurality of circularly offset locations by spot welding or may be press-fitted in an alignment groove in the base ring. The consumable spacer ring becomes filler metal during welding.

Abstract: A method for performing automatic circumferential welding around the circumference of a butt joint of a fixed pipe or the like. First, an initial set-up operation is performed wherein a welding head is moved around the welding circumference while producing pulses indicative of the amount of movement of the welding head. The number of pulses required to move the welding head one complete revolution is counted. Next, angles at which the welding conditions are to be changed are specified. These angles are converted to the form of pulses from a start point using the number of pulses previously counted. For the actual welding operation, pulses are again counted while moving the welding head. Each time the pulse count reaches one of the specified angles, a controller instructs a new set of welding conditions to the welding head.

Abstract: Voltage in a transfer arc power supply of a plasma jet cleaning apparatus employed to induce a cathode workpiece current for cleaning a surface of the workpiece includes apparatus for cyclically varying the applied voltage between at least two negative levels which are effective to induce two levels of workpiece current. The more negative voltage is effective to produce a large workpiece current and to clean dielectric impurities from the surface of the workpiece. The less negative voltage is effective to maintain current flow but to permit enhanced motion of the plasma jet over the workpiece surface so that any tendency for sticking of cathode spots on the workpiece during existence of the more negative voltage is counteracted.

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 large generally cylindrical workpiece is supported for rotation and driven by a set of axially spaced floor supported units each including a pair of parallel spaced cradle rolls. The cradle rolls of each unit are supported by a surrounding frame, and a pair of trunnions support each frame and cradle rolls for tilting movement on a transverse axis. Each unit also has a set of power operated screw jacks which precisely position the cradle rolls at a selected elevation, and the cradle rolls of one unit have resilient outer surfaces and are driven by an endless chain drive system. The cradle rolls of another unit are positioned within a cooling liquid to prevent overheating of the rolls by a heated workpiece, and each unit carries air inflatible flotation cells to facilitate moving the unit. A horizontal track extends parallel to the cradle rolls and supports a carriage having a portion projecting cantileveredly above the workpiece.

Abstract: An automatic valve seat build-up welding apparatus for a Y-type main steam isolation globe valve used in an atomic power station is disclosed which is characterized in that the valve seat can be build-up welded on the spot by the welding torch introduced into the valve box with the welding operation being carried out remotely from the spot and viewed by an image sensor positioned near the welding torch so that the exposure of an operator to a radioactive environment is prevented.

Abstract: An improved welding method for welding an inner seam of a longitudinally welded steel pipe along an inner groove by welding electrodes held by a boom which is supported by a tracing roller moving along the inner groove of the steel pipe. According to the invention, at least one metal plate is urged against at least one end of the steel pipe after tack welding the seam on an opposite side of the inner groove of the steel pipe to be welded. Lateral angular deformations of the end of the steel pipe are prevented on both sides of the seam. Such deformations are due to the load of the boom when the tracing roller leaves the end of the steel pipe for the metal plate. Thus, the invention provides for prevention of hot cracking at the end of the pipe.

Abstract: Internal pipe welding apparatus, including a pair of internal pipe clamps between which is disposed a rotative welding head support. The welding wire and gas feed conduits are disposed through passages through the central hub of one of the clamps. The welding head support is rotated by a ring gear engaged by a gear carried by a shaft disposed through a passage of the central hub of the other clamp. The gear engagement with the ring gear is adjustable to minimize vibration and chatter. The welding wire feeders are mounted on a block support at the front of the first mentioned central hub.

Abstract: An automatic welding machine for arc-welding stator core laminations is disclosed. The machine carries singular or plural workpieces which are fixtured on a vertical slideway. A slide moves past relatively stationary welding guns which are independently adjusted and independently activated for the weld process. The workpieces may be indexed for desired weld spacing. In one embodiment the indexing may be manual or power actuated. In another embodiment the guns may be varied as to radial position as the workpiece is moved, to weld non-constant cross-sectioned parts.