Abstract: The invention relates to a finned tube (1), a process for its manufacture and a device for performing the process. The process involves at least one endless strip (4), forming the fins, being wrapped around a rotating tube body (2) in roughly helical fashion and the narrow side of the strip (4) facing the tube body (2) being joined to the tube surface by means of a welding device (7).

Abstract: An electric arc welding apparatus for depositing molten metal from an advancing welding wire into a weld puddle in an open root between two juxtapositioned plates where the root extends in a welding path and is formed by converging walls terminating in generally parallel walls spaced to define a gap, which apparatus comprises a contact holder with a wire outlet, a switching power supply directing welding current to the wire as the wire passes from the outlet toward the open root, with the advancing wire defining an electrode stick out between the contact holder and the weld puddle, a circuit for sensing the length of the stick out, and control means for adjusting the welding current as a function of the sensed stick out length.

Abstract: The invention relates to a finned tube (1), a process for its manufacture and a device for performing the process. The process involves at least one endless strip (4), forming the fins, being wrapped around a rotating tube body (2) in roughly helical fashion and the narrow side of the strip (4) facing the tube body (2) being joined to the tube surface by means of a welding device (7).

Abstract: Applicant's invention includes an apparatus and associated method for precisely aligning two pieces of weldable material and welding the two pieces, the apparatus contains means for independently securing the two pieces of weldable material and for centering the junction of the two pieces in line with the welding electrodes.

Abstract: An apparatus and a method for controlling a welding robot is disclosed. In the method, an initial welding is performed under initial welding conditions while moving a welding object and a welding torch relatively to each other along a predetermined welding line. Then, a change point at which at least one of the welding conditions should be changed, and a change value of the welding condition, are determined. The welding conditions are changed to the change value at the change point while the welding operation and the relative movement of the welding object and the welding torch are continued. Thus, the welding operation is not stopped during the real-time change of the welding conditions such as welding voltage, welding current, welding speed and the like. Thus, working efficiency and the welding quality are improved, and the discontinuity of the welding bead does not occur.

Abstract: An internal spacer and expander clamp for use when welding two sections of pipe together. There are two spider rings supported from a frame, one in one section of pipe and the other across the joint in the other pipe. Each spider ring has a plurality of holes with a piston with a pipe contacting pad in each hole. A rotor is supported within said spider ring. A linkage bar is pivotally connected at one end to the piston and at the other end to a pin in a cut-out in the rotor. The convex ends of the linkage bar mates with a concave cut-out in the piston and the other end in a concave cut-out in the rotor. A power linkage rotates the rotor such that in a first position the longitudinal axis of the piston is out of alignment with the longitudinal axis of the linkage bar and in a second rotational position thus are aligned forcing the shoe against the inner surface of the pipe with great force.

Abstract: A method for manufacturing a fuel rod of the present invention includes a welding step of welding a cladding tube of said fuel rod to a plug by arc discharge; and a post welding step of subsequently discharging an arc to a welded portion by a predetermined arc current lower than that of the welding step. In the welding step and in the post welding step, the cladding tube and the plug are rotated with respect to an electrode for discharging the arc. The rotation speed of the cladding tube and the plug in the post welding step is higher than that in the welding step.

Abstract: A method of welding the ends of two pipes at the open root between the spaced ends by an STT electric arc welder, which comprises: selecting a welding wire having 0.06-0.15% by weight carbon, 0.90-1.40% by weight manganese, and 0.45-0.75% by weight silicon, as well as phosphorous, copper, stainless steel alloys and sulfur; maintaining the sulfur at a given percentage level of the selected wire in the specific range of 0.015 to 0.035% by weight; and maintaining said phosphorous at a given percentage level of said selected wire in the specific range of less than about 0.015%.

Abstract: The machined ends of two parts (2, 4) are arranged in facing positions to form a welding bevel (6) between the parts (2, 4). A series of layers of filler metal are deposited one on top of the other in the welding bevel (6) in a direction thereof corresponding to the width of the parts (2, 4), by melting a wire (14) supplied at a predetermined feed rate to an electric arc between the parts to be welded and an electrode (13) supplied with a predetermined welding current and voltage. Each layer of filler metal essentially consists of a single weld bead across the full width of the bevel (6). The electric welding current and voltage and the feed rate of the wire (14) are predetermined in accordance with the width of the bevel (6).

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 device and a method of manufacturing a metal tube made from a metal sheet with two substantially straight and parallel longitudinal edges, in which method the two longitudinal edges of the metal sheet are welded together using a welding method employing at least one electric arc between at least one electrode (Ei) and the metal sheet in contact with at least one ground lead (PMi), in which the plane of each ground lead (PMi) is positioned a distance (e.sub.i) of between -5 mm and +25 mm with respect to the plane of each corresponding electrode (Ei), the positive direction being the direction of relative travel of the metal sheet with respect to the at least one electrode (Ei).

Abstract: A vertical pipe column assembly procedure involves the simultaneous welding and ultrasonic testing activity by using a plurality of welders progressing peripherally around a joint with the ultrasonic testing work similarly progressing peripherally around the joint between the welders. The temperature rise from welding activity is reduced by only partially completing the weld at a selected joint, then lowering the joint by the usual process of lowering or driving it downward one section length and completing the weld deposit at a lower work station. At the lower work station, ultrasonic testing again proceeds simultaneously between the peripherally progressing welders. An optional step used to improve joint strength, usable at selected joints needing the most strength, involves the application of an axial pull on the section above the finish welding activity. This axial pull places an axial stress in the partially completed weld.

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 welding method in which the outer-most surfaces of ferritic stainless steel contains chromium oxide surfaces with no iron oxides. The welding method includes flowing a gas having an oxidizing activity over the welded part while applying an arc to the welded part, which is insufficient to melt the welded part. The resulting welded stainless steel is suitable for use as clean room gas supply lines.

Abstract: A process for automatically welding parts consisting of a number of tubular members (2, 3, 4 and/or 5) cut out and welded together to form a pipe (1). A previously welded part is positioned and secured using a securing jaw. The part is suspended every time from its center of gravity (G) using the securing jaw (50) and a cable (52) stretched between the two securing points, as well as a suspension joint (37), so that the part lifted by means of a lifting apparatus can be moved along about its center of gravity (G). The previously welded part and as standardized spare part are then welded using a welding robot (30) along the contact line between the two tubular parts.

Abstract: An apparatus and method of short circuiting arc welding two spaced ends of two pipe sections at a groove between the two pipe sections. The method and apparatus include the use of a cored metal electrode and moving the electrode toward the groove as the electrode is moved along the groove and about the outer peripheral surface of the pipe sections during the welding operation. The cored electrode is melted by an electric wave which comprises a transfer portion and a controlled melting portion. The melting portion is controlled to bridge the gap between the pipe sections for laying a root bead along the groove. The cored electrode is preferably a self-shielding electrode and includes alloying components in the core to form a root bead having a substantially similar composition as the composition of the two pipe sections.

Abstract: A method and device for welding pipe onto a piping network at a joint comprising introducing an inert purging gas under pressure at a substantially constant flow rate at one end of the pipe away from the weld joint, providing a flow restriction at the end of the piping network away from the weld joint, diverting a minor portion of the inert purging gas flowing through the piping network into and through a constant back pressure maintaining device for maintaining a substantially constant back pressure on the inert purging gas in the piping network during the welding, whereby any changes in back pressure occurring in the piping network cause a greater or lesser amount of the inert purging gas to flow through the constant back pressure maintaining device, thereby enabling production of precise and highly reproducible welds with an orbital welder.

Abstract: A steel material and a steel pipe each exhibiting an excellent corrosion resistance in an environment containing a wet carbon dioxide and a small amount of hydrogen sulfide are produced at low cost and with high productivity, a steel slab which contains, in wt %, 0.01 to 0.6% of Si, 0.02 to 1.8% of Mn, 7.5 to 14.0% of Cr, 1.5 to 4.0% of Cu and 0.005 to 0.1% of Al, which reduces C to not more than 0.02%, N to not more than 0.02%, P to not more than 0.025% and S to not more than 0.01%, and whose balance consists of Fe and unavoidable impurities, is heated to a temperature of 1,100.degree. to 1,300.degree. C., hot rolling is finished at a rolling finish temperature of not less than 800.degree. C. and a cumulative rolling reduction quantity at a temperature not more than 1,050.degree. C. is at least 65%, and cooling is carried out at a cooling rate of less than 0.02.degree. C./sec to at least 500.degree. C. so as to substantially convert the metallic structure to ferrite.

Abstract: Utilizing a low-oxygen welding flux, and a low carbon welding wire, seam welding is conducted by submerged arc welding so that the resulting weld metal has a chemical composition, in which P.sub.WM value defined as below is in a range of from 0.18 to 0.33, and a micro-structure containing acicular ferrite not less than 55% by area ratio:P.sub.WM =P.sub.cm +3.19Ti-1.020where,P.sub.cm =C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5BFurthermore, when cracking resistance is required, submerged arc welding is conducted such that the chemical composition of the weld metal satisfies P.sub.rh value of less than 2.8, in addition to fulfilling the above conditions:P.sub.cm =C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B.

Abstract: Automatic orbital welding system for welding conduit sections. The system may include a weld head having a clamping assembly for aligning the conduit sections. The weld head may include an electrode for applying heat to the conduit sections. Inert purge gas is preferably passed through the conduit sections while the orbital weld is formed to exclude contaminants from the weld area. A purge assembly is preferably connected to one of the conduit sections. The purge assembly preferably includes a purge restrictor having a valve disposed therein to allow the pressure within the conduit sections to be precisely controlled within a predetermined range during welding to promote the formation of a suitable weld.

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 tube such as a nozzle to be repaired or tubular sections to be repaired or connected to each other, are welded using a backing ring having a groove in the area to be welded. The groove forms a purge space for purge gas between the ring and the tube to establish an inert atmosphere on both inner and outer surfaces of the tube during the welding operation. The ring is removed by making a bore in the ring having a diameter larger than the diameter of the groove but smaller than the diameter of the ring. In this way, the ring is divided into two portions which are easily removed from the tube.

Abstract: A process for buttwelding metal workpieces having bevelled joint preparations using an automatic GTAW welder using filler wire includes preparing the bevelled workpiece with bevelled joint areas having minimal land thickness at the root extremities; placing the prepared workpiece joint sections together with an open gap between their adjacent root extremities, the gap having a minimum dimension that avoids harmful compression stress between the workpieces due to weld shrinkage and a maximum dimension that avoids filler wire penetration of the gap; fusion welding the open root area of the adjacent workpieces with a root pass weld using an automatic GTAW welder supplied with filler wire and a shield gas including 1 to 10% hydrogen and the balance inert gas; and then promptly overlaying the root pass weld with at least one additional filler weld pass using an automatic GTAW supplied with filler wire and hydrogen-free shield gas.

Abstract: Applicant's invention includes an apparatus and associated method for precisely aligning two pieces of weldable material and tack welding the two pieces together. The apparatus contains means for independently securing the two pieces of weldable material and for centering the junction of the two pieces in line with the tack welding electrodes.

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.

Abstract: A control rod tube and end plug are disposed in a weld chamber. A fixed welding torch with a tungsten electrode is disposed adjacent the weld area. A collet grips the tube and an inflatable seal seals the weld chamber. By rotating the collet, the tube and end plug are seal-welded to one another without loss of fusion, porosity or suck-back effects. The weld chamber is maintained under a positive pressure of between 5 to 10 psi gauge.

Abstract: A drive shaft assembly includes an aluminum torque tube and aluminum yokes that are arc welded to the ends of the torque tube. The torque tube has a hollow cylindrical end portion at each end that is pressed onto an annular end portion of the respective yoke to form a narrow annular slit. The two parts are then arc welded together by forming an electric arc between the parts at the narrow annular slit and a consumable aluminum based electrode. The electric arc is sustained with a pulsed high amperage direct current to fill the narrow annular slit with aluminum based material from the consumable electrode in a single pass.

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: A superpure purity gas supply system adapted to prevent a semiconductor device of high cleanliness, into which a gas is introduced through a gas supply pipe system, from being contaminated with the metal s or the like deposited during the welding thereof, and a method of installing such a gas supply pipe system. The superhigh purity gas supply system according to the present invention is a pipe system consisting of gas supply pipe system parts welded portions, characterized in that the gas supply pipe system parts having such welded portions are washed with super high purity water before, during or after the installation of the pipe system.

Abstract: In a method for overlap welding the inner surface of an elbow pipe, the elbow pipe is first divided axially into several pieces. These pieces are then stacked such that the inner arc of any piece is continuous with the outer arc of neighboring piece(s) to form an elbow piece stack. The inner surface of this stack may then be automatically overlap welded to a high uniformity of thickness using a relatively simple welding method. By fixing a short straight end tube to each end of the elbow piece stack it becomes possible using a relatively simple welding method to automatically overlap weld the entire surface area of the inner surface of the elbow piece stack continuously and to a high uniformity of thickness thus further improving productivity and quality of finish. The welded stack of elbow pieces is then dismantled and the elbow pipe is reassembled from the separate pieces.

Abstract: A welding system for superhigh purity gas supply system, capable of removing easily and completely the metals deposited, during the installation of the superhigh purity gas pipe system, on the outer surfaces of the portions of the pipes which are closed to the portions to be welded thereof and on the inner portions of these pipes, and capable of setting up a superhigh purity gas supply system in a short period of time.

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: In a process and an apparatus for the longitudinal-side welding of tubes (1) to flat steel bars (2), in which the welding in each case is carried out on the top side and on the underside of the flat steel bars (2), the welding torches (4) are arranged in a fixed position, the parts (1, 2) to be joined are pressed against one another before the welding and are moved in the longitudinal direction by means of a conventional transport device (10) during the welding operation, and the welding is carried out on the top side in a known manner by means of a SAW process, combined pulse oscillation GMAW is carried out on the underside at the same time as the SAW carried out on the top side, during which pulse oscillation GMAW the torches (11) are set in very rapid lateral motion by means of an oscillation device (15), the oscillating speed for guiding the welding torches (11) being coordinated with the feed rate of the parts (1, 2) to be welded.

Abstract: A method of joining metal parts by fusion arc welding in a weld of small volume includes the steps of providing the metal parts to be joined having a first side which accessible to a welding operation and a second side opposite the first side. The metal parts have welding surfaces shaped to have a first flank adjacent the first side and a second flank adjacent the second side, a step joining the flanks. Each part has a relief bulge formed in the second side adjacent the second flank, and a centering offset at the second flank to position the metal parts relative to one another for welding. The relief bulge is provided to ensure that the centering offsets melt during welding, and is shaped to have a sufficient size so that a predetermined melt-through point develops for melting of the centering offset during welding.

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 weld shield apparatus provides an atmosphere of inert gas within a conduit in an underbead region where an external weld joint is to be produced. The weld shield apparatus includes a diffuser structure having a convex exterior surface that is defined by a wall structure, the convex exterior surface is shaped to fit within the conduit and to be separated from an inner wall of the conduit by a clearance space. The diffuser wall structure is comprised of a porous material which enables gas communication between an inlet to the diffuser and the convex exterior surface. A seal is positioned immediately upstream from the diffuser structure and is positioned to engage the inner walls of the conduit so as to prevent the passage of gas in an upstream direction. A source of gas is coupled to the inlet to the diffuser structure and enables inert gas to pass through the porous material and to flow in a laminar manner, via the clearance space, past the underbead region and into the downstream region of the conduit.

Abstract: A method for manufacturing a welded metal container by first arc welding a branch pipe to a trunk pipe. The arc welding of the pipes together causes both of the pipes to be thermally deformed. The end surfaces of the pipes are then cut by a laser cutting or mechanical cutting process so that the ends of the trunk pipe are in parallel and perpendicular to the end of the branch pipe. Subsequently flanges are laser welded to the ends of the pipes without further thermally deforming the pipes. The metal container made by this process can be used as a sheath for a gas insulated switch gear.

Abstract: A welding speed-dependent voltage (11) is added to a variable fixed voltage (13), to control the welding current as a function of welding speed in DC arc welding equipment, for the continuous welding of longitudinal seams of tube-shaped metal bands. In addition, the sum (15) of speed-dependent voltage (11) and variable fixed voltage (13) is superimposed by a pulsed DC voltage by a summing amplifier (28).

Abstract: In an arc welding process for welding pipes used to convey high purity gas, dispersion of particles into the pipes during welding is reduced by discharging an inert back shielding gas into one end of one pipe and holding the welding current at less than the normal welding current for a specified interval after the start of arc, the welding current thereafter being increased to its normal level.

Abstract: Duplex stainless steel having about 25% chrome, 7% nickel and 3.5% molybdenum content included in its chemical composition is gas tungsten arc welded by a manual procedure wherein a continuous or segmented root pass weld is made with a filler metal rod of a first diameter and plural cover passes are made in segments or continuously using a filler metal rod of a larger diameter. The weld may be cooled by demineralized water between passes to limit the interpass temperature of the weld to about 300.degree. F. or less. The use of a larger diameter filler rod for the cover passes with a 300.degree. F. temperature limit between passes and segment welds in intermediate and cover passes of 180.degree. reduces time to complete circumferential girth welds for duplex stainless steel pipe by more than 50 percent.

Abstract: The welding electrode rotates at variable speed about the axis of the cylindrical part so as to lay down successive superposed layers, each covering the entire width of the bevel. The electrode is moved translationally in the direction of the axis of the cylindrical part. The device includes arrangements for adjusting the speed of rotation of the electrode and for moving it in the direction of the axis. The method may be used for welding a replacement adaptor onto the vessel head of a nuclear reactor.

Abstract: A process to avoid or limit corrosion at the junction of two piping comprising devices welded together, said piping comprising devices being adapted to flow corrosive gases through them, said process comprising the steps of:a) providing a first piping comprising device and connecting it to an inert gas source;b) purging it with an inert gas comprising substantially not more than 10 ppb of an oxidizing gas selected from the group consisting of oxygen, carbon dioxide, water vapor or mixtures thereof, said inert gas flowing from a first opening to a second opening of said piping comprising device;c) providing a second pipe comprising device in flow communication with the first one, while continuing to purge the first piping comprising device;d) welding the two piping comprising devices, said welding being carried out under an inert gas atmosphere; ande) repeating steps c and d if necessary.

Abstract: A Cr-Mo steel pipe having a wall thickness of 5 to 25 mm consisting essentially of 0.03 to 0.10 wt. % C, 0.5 to 1.0 wt. % Si, 0.3 to 0.6 wt. % Mn, 0.02 wt. % or less P, 0.007 wt. % or less S, 1.0 to 1.5 wt. % Cr, 0.45 to 0.65 wt. % Mo, 0.002 to 0.1 wt. % Al, 0.002 to 0.01 wt. % N, and the balance being Fe and unavoidable impurities. In the method of welding the Cr-Mo steel pipe, the Cr-Mo steel pipe is welded by shielded metal arc welding without a preheat treatment and/or a post weld heat treatment.

Abstract: An improved welding method is provided for repairing broken rotors. The welding method preferably employs a 2.25Cr-1.0Mo-0.3V-type filler metal, preferably deposited using a narrow groove welding technique. The broken pieces are aligned end to end. A narrow groove is formed to substantially remove the end surfaces. The groove is preheated, filled with the welding filler metal, and postheated, resulting in a strong, high temperature resistant, long lasting weld.

Abstract: A method of welding metal products, at least one of which is made of nickel or a nickel alloy, comprises the steps of generating an arc between the products to be welded, serving as a positive pole, and a tungsten electrode held by a welding torch, serving as a negative pole. A shielding gas is emitted, consisting of an argon-based mixed gas containing one or both of hydrogen and helium, from a confining gas nozzle concentric with the tungsten electrode, thus confining the apparent flaring angle of the arc within 80 degrees. The welding torch is moved along the weld line while feeding the tip of a filler wire to a part of the molten pool directly below the arc. This method is applicable to the welding of metal products, at least one of which is made of nickel or a nickel alloy.

Abstract: A machine for continuously producing metal tubing from a flat metal strip in which the welder, weld closing rolls, and seam guide are attached to a base plate slidably attached to a support structure. The base plate is displaceable relative to the support structure between an operating position and a start position. The base plate may be displaced by a manually operated actuator or by an electromechanical mechanism. The base plate is placed in the start position when the machine is stopped and is slowly displaced to the operating position when the machine is restarted. During displacement of the base plate to the operation position, the welder overwelds a portion of the seam previously welded. The seam weld during a restart transition of the base plate from the start to the operating position produces a defect-free seam weld.

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: Disclosed is a gas-shield arc welding method in which chemical components of base material and weld material (gas-shield arc welding wire), chemical component ranges of weld metal based on the base material and the weld material, especially, difference (.DELTA.(Cu+Ni), .DELTA.Mo) of Cu, Ni and Mo between the weld metal and the base material, and welding conditions are limited for the purpose of improvement preferential corrosion resistance, toughness and crack resistance of the weld metal in circumferential welding of a pipe exposed into a corrosion environment including CO.sub.2.