A pipe-laying vessel for S-laying a pipeline is provided, the vessel defining a pipe-laying path extending along the vessel. The vessel includes one or more track tensioners disposed along the pipe-laying path, and a travelling clamp assembly, including a clamp mounted for movement along a length of the pipe-laying path. The vessel may also include a fixed clamp assembly located on the pipe-laying path for clamping the pipeline in a fixed position on the pipe-laying path. At least one of the clamp assemblies may include a load bearing structure and a clamp wherein a downstream-facing portion of the clamp is in an abutting relationship with an upstream-facing portion of the load bearing structure such that a downstream force exerted, in use, by the pipeline on the clamp is transmitted to the load bearing structure.

Underwater pipe-laying

The present invention is directed to a system for welding together segments of a pipeline. The system includes an external alignment mechanism for externally supporting and manipulating the orientation of pipe segments in order to align relative segments. The system also includes an internal welding mechanism for applying a weld to an interior face joint of the two abutted pipe segments. The internal welding mechanism including a torch for applying a weld, a laser for tracking the weld profile and guiding an articulating head of the torch, and a camera for visually inspecting the weld after the weld is applied.

Laser controlled internal welding machine for pipelines

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° to 135° of its welding pass around the weld joint.

Adjustable welding torch mounting

A system for welding two pipes includes a first pipe clamp, a second pipe clamp, a weld torch, an inspection detector, a motor, one or more processors, and a grinder. The weld torch is configured to create a weld joint between the pipes at an interface region between the pipes. The inspection detector is configured to emit an inspection beam of radiation. The motor is operatively associated with the inspection detector to direct the inspection beam of radiation along the weld joint between the pipes. The one or more processors are operatively associated with the inspection detector to determine a profile of the weld joint between the pipes. The grinder is configured to grind at least a portion of the weld joint between the pipes based on the profile of the weld joint between the pipes.

Systems and methods for use in welding pipe segments of a pipeline

A welding apparatus for pipes which provides for a guide means which is to be fixedly secured to the pipe adjacent the welding area, a first carriage and a second carriage is movably supported upon the guide means with each of the carriages supporting a pair of spaced apart welding heads. Attached to the guide means is a driving chain. Mounted on each of the carriages are motor means which, in turn, operate through the driving chain to move the carriages in a prescribed manner with respect to the guide means. The welding heads of each of the carriages move within the same plane but each are movable in a separate one hundred and eighty degree arc thereby forming a continuous circle. Associated with each welding head is a weld groove tracking system which automatically maintains each welding head correctly aligned within the welding groove. The entire apparatus of this invention, when combined with appropriate electronic computer equipment, automatically welds an adjoined pair of piping sections.

Apparatus for welding pipes

A traveling electric arc welding apparatus using gas shielded consumable wire electrode, comprises a welding head mounted on a traveling carriage. The mounting means provide for angular shifting of the head about two different axes. Both such axes are in or near and closely parallel to the plane of the weld; e.g., in welding pipeline girth joints one axis lying as nearly as convenient in the plane of the weld is also as nearly as convenient tangential to the weld circle and thus passes near or, if desired, through the locus of the arc. The direction of feeding electrode material with respect to the weld plane is accurately set by movement about this first axis. The other axis is perpendicular to the first and lies generally in the weld plane. Means are provided for accurately aligning and setting the welding head laterally with respect to the plane of the joint; i.e., along the axis of the work in the case of a pipeline joint, by shifting the head about the second axis. Other positioning means are provided to adjust, pre-set and fix the distance or spacing of the welding nozzle from the noint. Means which can be inactivated, if desired, are included for oscillating the head back and forth across the weld path as for filling a wider gap or for capping. Quick release means permit raising the head from the work and returning it to a precisely determined working position.

Apparatus and method for welding joints between metal shapes

Apparatus and method for welding girth joints in pipelines and similar structures, of the general type described and claimed in U.S. Pat. No. 3,806,694, is improved by adding to the normal or conventional head, on its frame, a second or supplemental welding head with its own independent wire electrode, electric power and shielding gas supply. The second head is mounted on an adjustable support for accommodating work pieces of different radius or for varying arc positions. Oscillating means for spreading the molten metal across the width of the joint, as normally provided for the single welding head in the patent mentioned, are adapted to operate the second head as well and to vary its amplitude of movement. Separate means are provided for adjusting the spacing between each head and the work and also for lateral adjustment to align the heads with the plane of the joint. By these means, the number of stations required for a multiple pass operation, on thick wall pipe, for example, may be reduced. By operating two welding heads on each of two or more carriages, welding equipment requirements may be cut nearly in half, with beneficial effects on the weld, due to improved thermal effects. Either head may precede the other; cantilever means provide stability for the head mounted most remotely from the frame.

Multiple arc welding device and method

A series of torches mounted on a single traveling carrier and spaced apart in sequence are passed along a newly welded joint such as a girth joint in a pipeline to heat the metal and relieve high hardness commonly found in the zone adjacent deposited weld metal. The invention is used especially to relieve heat induced stresses in electric arc welding of large work pieces, such as thick walled pipes. Acetylene or other high energy fuel is supplied at a closely controlled rate to each torch. All torches are carried along the joint in a group at a predetermined and controlled rate. Spacing between each torch and the work is carefully adjusted and maintained to control the sequential heat inputs into the interior of the work metal. The first torch applies high intensity heat preferably directly on the weld with succeeding torches apply progressively softer flames. The critical area along the weld thus is quickly brought to austenitic temperature range, followed by slower heating and then by slow cooling, to relieve stress and/or to correct grain growth and related crystalline conditions in the metal. A series of four torches attached to a self-propelled and track-guided carrier are preferred. Since the torches are spaced progressively farther and farther from the work surface, the breadth of heat application by successive torches is progressively widened while heat intensity is reduced. At all times the surface temperature remains within tolerance limits.

Method and apparatus for heat treating welded joints

For oscillating the welding torch or head, in apparatus for arc welding metal shapes such as large pipes together, variably adjustable eccentric means, are secured under spring pressure to a rotary driver driven by an appropriate motor. A micrometer screw means mounted on the rotary driver has a circumferentially grooved head engaging a flange on the eccentric. As this screw is turned in or out the eccentricity of the variable eccentric is set with accuracy. This micrometer screw is mounted for radial movement on the rotary driver member adjacent and facing the eccentric. The eccentric in turn drives a gyrating member which does not rotate but whose radius of gyration corresponds to the adjusted eccentricity. The gyrating member rocks a follower arm mounted on a rock shaft which shaft also supports the welding head for reciprocating motion. By separate adjusting means, the welding head may be aligned with the weld line independently of its amplitude of reciprocation.

Oscillating apparatus for arc welding equipment

1285285 Welding by fusion CRC-CROSE INTERNATIONAL Inc 4 June 1970 [4 June 1969] 26984/70 Heading B3R A MIG butt welding apparatus comprises a carriage movable along a guide track capable of being secured adjacent the line of the joint to be welded and a welding head movable transversely of the joint. The apparatus is particularly for use in butt welding of pipes but may also be used for butt welding flat plates. In Figs. 1, 3 a transversely oscillatable and adjustable welding head 61 is supported on a carriage 21, on the one hand via a stiffly resilient coiled metal spring wire guide 104 tending to centre, but permitting transverse deflection of, the head, and on the other hand via a bracket 57 pivoted on the carriage. The bracket 57 has adjustably slidable thereon a plate 140 having arms 134, 136 provided with cam followers 137 selectively engageable, by means of knobcontrolled eccentric 164, with cam grooves disposed on opposite sides of a cam 130, each cam providing a different amplitude of head oscillation. The cam 130 is rotatable, via a gear reducer (128), by a motor 126 which is connected to the carriage by a screw 120 adjustment of which varies the general transverse position of the head. Consumable electrode wire from a reel 72 is taken through flexible and semiflexible tubes 60, 102, motor-driven and spring- pressed feed rollers (82, 84) and the wire guide 104. The carriage has grooved rollers 23, 25 engaging a flexible guide track 27 held by tension on the workpiece surface. One or more carriages may be used on tracks 27, 33 on either side of the joint. The carriage, controlled from a box 39, is propelled by one or more of the grooved rollers driven by an electric motor 43. A connection 70 to the welding heads supplies welding current and shielding gas (e.g. nitrogen, argon). With neither cam follower 137 engaging a cam groove, the head is held by the guide tube and does not oscillate. In Fig. 10, a pivoted welding head supporting bracket 57a is axially movable, against a spring 300, by a face cam 130b to provide for longitudinal reciprocation of the head. Transverse oscillation may be added to the longitudinal oscillation to achieve more complex weaving patterns. In Fig. 13 (not shown), the reciprocation cam is double acting so that the spring 300 may be dispensed with. In Figs. 6-8 (not shown), a screw directly transversely adjusts a pivoted bracket 57 supporting the welding head, no provision being made for oscillation. Welding of thick-walled pipes may comprise the following steps: (i) making an initial inner pass manually or automatically and preferably internally, (ii) making one or more rapid " hot " passes using heavy current, from the outside, to fuse into the inner pass and the workpieces, and (iii) making one or more cooler, slower, oscillated head, passes, the latter acting as a corrosion resistant cover for the corrosion susceptible austenitic conditions created by the " hot " passes. The hot pass step may be effected, using the apparatus of the invention, by making one or more vertical electrode feed passes, one or more angled passes, or a combination thereof. When making angled passes, the weld gap may be filled by alternate side corner passes, as by alternately using separate heads respectively on tracks mounted one on each side of the joint. The joint preparation may comprise, from inside to outside, a small V, a narrow land where the adjoining pipe ends actually or nearly abut, a perpendicular or nearly perpendicular wall stepped back, say 1/32-1/8 inch, in one or both pipe ends, and a wide V.

Randolph James B

Papers

Apparatus and method for welding joints between metal shapes

Multiple arc welding device and method

Method and apparatus for heat treating welded joints

Oscillating apparatus for arc welding equipment

Travelling arc-welding apparatus