A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

The disclosed technology relates generally to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding. In one aspect, an electrode assembly for submerged arc welding (SAW) comprises a head portion and an extension portion that are arranged serially to feed a consumable electrode therethrough such that, during SAW, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode. The head portion includes a contact tip configured to electrically contact the consumable electrode to deliver power thereto. The extension portion is formed of a single piece insulating article configured for the consumable electrode to finally pass through before the arcing tip is exposed.

A system and method for dual-twin SAW cladding is disclosed. The method includes arranging a first twin SAW head in close proximity to a second twin SAW head, delivering electroslag flux to a surface of a workpiece to create a layer of electroslag flux atop the workpiece, directing two first consumable wires through the first twin SAW head towards the surface of the workpiece, directing two second consumable wires through the second twin SAW head towards the surface of the workpiece, introducing the two first consumable wires and the two second consumable wires into a molten slag pool formed on the surface of the workpiece to melt the two first consumable wires and the two second consumable wires via resistive heating, and translating the first twin SAW head and the second twin SAW head together to form a cladded deposit on the workpiece.

An electric arc welding system for depositing weld metal along a groove between two edges of a metal workpiece where the system contains a first power supply and a second power supply, each providing a welding waveform to respective welding electrodes. The positive output terminals of both power supplies are coupled to the same contact tip and the negative output terminal of one of the power supplies is not coupled to the workpiece.

A multi-electrode submerged arc welding method enables, in multi-electrode submerged arc welding using five or six electrodes, a deep penetration and a large amount of deposit metal to be obtained by supplying a large current, and enables stable arc to be generated by respective electrodes by suppressing magnetic interference. Welding defects can be prevented, beads with a good shape or appearance can be obtained, and the welding speed can be increased.

The present invention provides a submerged arc welding method attempting to enhance toughness of a welded zone with low heat input and capable of achieving deep penetration and a sufficiently wide bead width in welding a thick material at a weld speed of 3 m/min or less. In the submerged arc welding method, a first electrode at the head in a welding direction has a wire diameter of 3.9 to 4.1 mm, two electrodes are arranged on both sides holding a weld line therebetween at the tail end in the welding direction, the wire tip positions of the two electrodes on a surface of the steel plate are arranged on the same line vertical to the weld line, and a distance W (mm) between each of the wire tip positions and the weld line is 5 to 20 mm.

The disclosed technology generally relates to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding. In one aspect, an electrode assembly for submerged arc welding comprises a contact tip portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough. During welding, the contact tip portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode. The extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material surrounding the consumable electrode.

The disclosed technology relates generally to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding. In one aspect, an electrode assembly for submerged arc welding (SAW), the electrode assembly comprising a head portion comprising a contact nozzle and an extension portion removably and serially attached to the contact nozzle and disposed to be proximal to an arcing tip of a consumable electrode relative to the contact nozzle. The extension portion comprises a ceramic sleeve configured to slidingly feed the consumable electrode therethrough, and a pair of metallic sheaths covering opposing ends of the ceramic sleeve.

The present application relates to an arc welding arrangement and an electric arc welding method to be used with the arc welding arrangement. The arc welding arrangement comprising a first power source, a first electrode connected to say first power source, and a second electrode, said first electrode being adapted to generate a weld pool via a first electric arc present within a first arc region. The second electrode is operated at welding parameters adapted to ensure that excess energy from at least said first electrode is required to maintain said second arc ignited. The method comprises the step of feeding said second electrode so that it is allowed to consume excess energy from said first electrode to maintain said second arc ignited.

A method for producing a steel material for line pipes which has a tensile strength of 570 MPa or more, a compressive strength of 440 MPa or more, and a thickness of 30 mm or more, the method including heating a steel having a specific composition to a temperature of 1000° C. to 1200° C.; performing hot rolling such that a cumulative rolling reduction ratio in a non-recrystallization temperature range is 60% or more, a cumulative rolling reduction ratio in a temperature range of (a rolling finish temperature +20° C.) or less is 50% or more, and a rolling finish temperature is the Ar.sub.3 transformation point or more and 790° C. or less; and subsequently performing accelerated cooling from a cooling start temperature of the Ar.sub.3 transformation point or more, at a cooling rate of 10° C./s or more, until the temperature of a surface of a steel plate reaches 300° C. to 500° C.