An apparatus and method of short circuit 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 cycle which comprises a transfer portion and a plasma portion. The plasma 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. The apparatus and method has a selector to control the polarity of the individual cycles of a total welding procedure.

Short circuit welder

A method and apparatus for feeding wire in a welding system include one or more motors disposed adjacent the wire to drive it. A wire feed motor is also disposed along the wire path, and is closer to the source of wire than the torch, and closer to the source than the one or more motors. The motors may be a pair motors disposed on opposite sides of the wire and move the wire to and away from an arc end of a torch. They preferably reversing the direction of the wire within one process cycle. The or more motors may be a stepper motor, a servo motor, a zero backlash motor, a gearless motor, a planetary drive motor, or a linear actuator (such as a piston), in various embodiments.

Method and apparatus for feeding wire to a welding arc

An electric arc welder powered by a plurality of liquid organic fuel cells The fuel cells use a methanol/water mixture as the organic feed The fuel cells produce carbon dioxide as a reactive product which is used an a shielding gas during the arc welding process The fuel cells are stacked together to produce the desired arc voltage and current between an electrode and the workpiece The arc welder includes a welding current to control the current wave shape through the electrode and to control or increase the voltage through the electrode

Fuel cell operated welder

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.

Method and apparatus for electric arc welding

An electric arc welder operated to perform a short circuit welding process between an electrode and a workpiece, where the process comprises a succession of alternate short circuit conditions and arc conditions, with a first current waveform during the short circuit condition and a second voltage waveform during the arc condition. A first waveform generator constructs the first waveform from a series of current pulses controlled by a pulse wave modulator operated at a rate greater than 18 kHz and a second waveform generator constructs the second waveform from a series of current pulses controlled by a pulse wave modulator operated at a rate greater than 18 kHz. The second waveform generator has a circuit to generate the second waveform with a generally constant arc parameter, generally voltage.

Short circuit arc welder and method of controlling same

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.

Elliott K. Stava

Papers

Short circuit pipe welding