The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. The tubular welding wire is configured to form a weld deposit on a structural steel workpiece, wherein the weld deposit includes less than approximately 2.5% manganese by weight.

A welding device for gas shielded arc welding includes: a portable welding robot mounted with a welding torch including a nozzle that guides jetting of shielding gas and a contact tip that performs energization on a consumable electrode; a feeding device that supplies the consumable electrode to the welding torch; a welding power source that supplies electric power to the consumable electrode via the contact tip; a gas supply source that supplies the shielding gas to be jetted from a nozzle end; and a control device that controls the portable welding robot. When the welding torch is seen from a side of jetting of the shielding gas, the contact tip is placed in an inside of an opening of the nozzle, the nozzle and the contact tip have a relatively movable structure, and an inner diameter of the nozzle end is within a range of 10-20 mm.

A method of manufacturing a metallic part in a weldable material by solid freeform fabrication unrestricted in size and open to the ambient atmosphere. The method comprises generating a computer-generated, three dimensional model of the part, slicing the computer-generated three dimensional model into a set of computer-generated, parallel, sliced layers and then dividing each layer into a set of computer-generated, virtual, one-dimensional pieces and, with reference to layered weld-bead geometry data, forming a computer-generated, direction specific, layered model of the part. The method also comprises uploading the direction specific, layered model of the part into a welding control system able to control the position and activation relative to a support substrate, of an electric arc delivered by a high energy tungsten arc welding torch, a plasma transferred arc welding torch, and/or a gas metal arc welding torch, and a system for feeding a consumable wire placed in an open area build space relevant to the substrate unrestricted in size and open to the ambient atmosphere. The method also comprises directing the welding control system to deposit a sequence of one-dimensional weld beads of the weldable material onto the supporting substrate in a pattern required to form a first layer of the computer-generated, direction specific, layered model of the part, and depositing a second welded layer by sequencing one-dimensional weld beads of the weldable material onto the previous deposited layer in a configuration the same as the second layer of the computer-generated direction specific layered model of the part, and repeating each successive weld bead layer of the computer-generated, direction specific, layered model of the part until the entire part is completed. The method further includes one or both of displacing the atmosphere within the immediate vicinity of the heat source with an inert gas atmosphere which produces a required flow rate, and in which that inert atmosphere contains a maximum oxygen concentration, wherein the inert gas is delivered by an apparatus through a matrix of individual gas diffusers and/or a filter; and engaging an induction heating and closed loop cooling apparatus synergic to a welding control system and pre-heating the substrate material including the deposited weld beads, relevant to the type of weldable material, wherein induction heating and cooling cycles are applied constantly or pulsed from the first layer to the final layer, where optimal heating and/or cooling cycles of the weldable material are relative to the final desired part shape and microstructure.

The invention relates to a forming device (200) for supplying at least one root protection gas to the root side of at least one region (11) of at least one pipe (10) to be connected, comprising at least one root protection gas supply device (220) for supplying the root protection gas and comprising at least one root protection gas conducting device (210) for conducting or deflecting the supplied root protection gas in an axial direction along the inner wall of the pipe (10) along the root side of the region (11) to be connected, wherein the root protection gas conducting device (210) has a cylindrical shape and can be inserted into the pipe (10) in a centered manner, and the root protection gas supply device (220) is arranged within the root protection gas conducting device (210). The invention additionally relates to a method for forming or supplying at least one root protection gas to the root side of at least one region (11) of at least one pipe (10) to be connected. The supplied root protection gas is guided, conducted, or deflected in the direction along the inner face of the pipe (10) along the root side of the region to be connected, and the root protection gas is additionally guided in the radial direction such that when the pipe region is connected to a pipe bend (12), the root protection gas is guided along the curvature of the pipe bend (12) in the axial direction.

A purge system useful in welding applications to provide a shielding or purging gas to a weld site, preferably of a tube, pipe or construction, while also providing controlled release of an exhaust gas and pressure relief through the use of a permeable body. The purge system is also flame resistant allowing use in close proximity to the weld site. The design facilitates ease of insertion, holding and retraction in a tube, pipe or other construction.

A weld is formed in a workpiece such as a pipeline by first activating a melting device, such as a laser, to form a molten weld pool in the workpiece and then activating a welding device, such as a GMAW torch, to initiate a weld in the weld pool. The weld therefore incorporates the weld pool homogeneously. Relative movement between the activated welding device and the workpiece continues and completes the weld while the melting device remains deactivated.

The method can include inserting a first portion of a backing device into a fluid aperture of a first conduit component, inserting a second portion of the backing device into a fluid aperture of a second conduit component, and bringing the second conduit component adjacent the first component over the backing device, fusion welding the first conduit component to the second conduit over the backing device, and removing the backing device by circulating a fluid inside the welded conduit components. The backing device can be made of a soluble material.

The present invention provides a repairing method for a hydraulic-end valve cage cavity. First, a to-be-repaired hydraulic-end valve cage cavity is mechanically processed to reserve a unilateral repair size of the cavity; shot blasting and cleaning are performed on the cavity; basic repairing is performed on the cavity to form a backing welding layer, and welding and cladding repairing are performed on the backing welding layer for n layers, to form n repair-welding layers; and finally machine finishing is performed on the cavity having undergone welding repair. The repairing method is also applicable to repairing of a plunger-end seal hole. The repairing method provided in the present invention is simple and is easy to be controlled, and a repaired hydraulic-end valve cage and plunger-end seal hole can be used in on-site fracturing construction in a condition of 50 MPa to 100 MPa for 200 h. By repairing the hydraulic-end valve cage and the plunger-end seal hole, equipment costs for oil fracturing can be significantly reduced.

The disclosed technology generally relates to consumable electrode wires and more particularly to consumable electrode wires having a core-shell structure, where the core comprises chromium. In one aspect, a welding wire comprises a sheath having a steel composition and a core surrounded by the sheath. The core comprises chromium (Cr) at a concentration between about 12 weight % and about 18 weight % on the basis of the total weight of the welding wire, manganese (Mn) at a concentration between about 12 weight % and about 18 weight % on the basis of the total weight of the welding wire, nickel (Ni) at a concentration between zero and about 5 weight % on the basis of the total weight of the welding wire, and carbon (C) at a concentration greater than zero weight %, wherein concentrations of Ni, C and Mn are such that [Ni]+30[C]+0.5[Mn] is less than about 12 weight %, wherein [Ni], [C], and [Mn] represent weight percentages of respective elements on the basis of the total weight of the welding wire. The disclosed technology also relates to welding methods and systems adapted for using the chromium-comprising electrode wires.

The invention relates to a welding nozzle assembly and method of use thereof. The welding nozzle assembly has a first or upper guide body and a second or lower guide body configured to accurately insert and position the nozzle assembly between two adjacent arms of a V-shaped refractory anchor assembly. The method of using the welding nozzle assembly forms a welding pool dam for attaching the V-shaped refractory anchor assembly to a surface.