A 3D printer can print a structure by depositing material into a weld pool that is moving relative to a workpiece. A multi-wire process may be utilized to increase the deposition rate of the 3D printer. An electrode wire can supply energy to the weld pool while being fed at a first feed rate into the weld pool. A second wire can be fed into the weld pool at a second feed rate to deposit additional material and thereby speed up the overall material deposition rate. All of the energy in the weld pool may be supplied by the electrode wire. Different materials may benefit from different orientations of the electrode wire and the second wire.

The present application relates to an electric arc welding method to be used with an arc welding arrangement (1) comprising a first power source, a first electrode (2) connected to said first power source, and a second electrode (7), said first electrode (2) being adapted to generate a weld pool (28) via a first electric arc present within a first arc region (31) and said second electrode (7) being adapted to generate said weld pool via a second electric arc present within a second arc region. The first electrode (2) is operated at welding parameters adapted to maintain said first arc ignited. The second electrode (7) is operated at welding parameters adapted to ensure that excess energy from at least said first electrode (2) is required to maintain said second arc ignited. The method comprises the step of feeding said second electrode (7) so that it is allowed to consume excess energy from said first electrode (2) to maintain said second arc ignited. The invention also relates to an arc welding arrangement (1) for carrying out the method.

A system and method of welding or additive manufacturing is provided where at least two welding electrodes are provided to and passed through a two separate orifices on a single contact tip and a welding waveform is provided to the electrodes through the contact tip to weld simultaneously with both electrodes, where a bridge droplet is formed between the electrodes and then transferred to the puddle.

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO.sub.2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF.sub.2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

The pulsed arc welding method supplies a pulsed current to a welding electrode and performs welding while the welding electrode is relatively moved with respect to a workpiece 40. The welding electrode includes a main electrode 13 and a sub electrode 23. The sub electrode 23 is arranged on the back side of the main electrode 13 in the moving direction, the sub electrode 23 is moved along with the main electrode 13 above a molten pool 41 formed by the main electrode 13, and a second pulsed current P2 that is asynchronous with a first pulsed current P1 to be supplied to the main electrode 13 is supplied to the sub electrode 23.

A welding or additive manufacturing contact tip includes an electrically-conductive body extending from a proximal end of the body to a distal end of the body. The body forms a first bore terminating at a first exit orifice at a distal end face of the body, and a second bore terminating at a second exit orifice at the distal end face of the body. The first and second exit orifices are separated from each other by a distance configured to facilitate formation of a bridge droplet between a first wire electrode delivered through the first bore and a second wire electrode delivered through the second bore during a deposition operation.

A system and method of welding or additive manufacturing is provided where at least two welding electrodes are provided to and passed through a two separate orifices on a single contact tip and a welding waveform is provided to the electrodes through the contact tip to weld simultaneously with both electrodes, where a bridge droplet is formed between the electrodes and then transferred to the puddle.

A system and method of welding or additive manufacturing is provided where at least two welding electrodes are provided to and passed through a two separate orifices on a single contact tip and a welding waveform is provided to the electrodes through the contact tip to weld simultaneously with both electrodes, where a bridge droplet is formed between the electrodes and then transferred to the puddle.

A mobile factory of steel sheet coil helical pipe includes a factory for the production of helical pipes that can be mounted on trailers, rafts, or container-type structures that is distinguished by its high production speed and use of steel sheet coils of up to 1 possible thanks to the use of an optional coil driver, a beveler and a wire welding system that may contain two, three, four, or five welding wires per pass (internal and external).

A method and related system and apparatus for refurbishing worn rail transit rails to a desired refurbished rail surface profile substantially similar to the surface profile of a newly-manufactured rail, comprising: depositing a first line of fill material along a lower-inside section to be refurbished; in N1 successive iterations thereafter, progressing circumferentially from the lower-inside section to be refurbished to an upper-outside section to be refurbished, depositing an n+1.sup.th line of fill material adjacent an n.sup.th line of fill material wherein the n.sup.th line of fill material substantially provides a flow barrier against the n+1.sup.th line of fill material flowing past the n.sup.th line of fill material.