Systems, methods, and apparatus to preheat welding wire are disclosed. An example welding assembly for a welding torch includes: a first contact tip configured to conduct welding current to a consumable electrode; a second contact tip configured to conduct preheating current to the consumable electrode; and a cooling body configured to transfer heat from at least the first contact tip to coolant and to conduct the welding current.

Embodiments of welding systems and methods with coordinated dual power outputs supporting a same welding process or a same AC output process are disclosed. One embodiment of a welding system includes an engine and a generator operatively connected to the engine, where the engine is configured to drive the generator to produce electrical input power. The welding system also includes a power supply operatively connected to the generator and having at least one controller. The power supply is configured to convert the electrical input power to form two power outputs that are coordinated with each other, at least in time, via the controller to support a same welding process. The same welding process may be, for example, a hotwire welding process, a tandem metal inert gas (MIG) welding process, or an alternating current (AC) output process.

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 aluminum. In one aspect, a welding wire comprises a sheath having a steel composition and a core surrounded by the sheath. The core comprises aluminum (Al) at a concentration between about 3 weight % and about 20 weight % on the basis of the total weight of the welding wire, where Al is in an elemental form or is alloyed with a different metal element. The disclosed technology also relates to welding methods and systems adapted for using the aluminum-comprising electrode wires.

Systems, methods, and apparatus to control weld current in a preheating system are disclosed. An example preheating power supply includes power conversion circuitry configured to output welding-type power via a first output power connector and a second output power connector, and a bypass path prevention circuit configured to prevent less than a threshold voltage applied to the first output power connector and the second output power connector from a different power supply from causing current to flow between the first output power connector and the second output power connector.

Systems, methods, and apparatus to preheat weld wire are disclosed. An example contact tip includes: an inner bore configured to conduct current to a consumable welding electrode; screw threads on an exterior of the contact tip; and a head opposite the screw threads on an exterior of the contact tip to enable threading and dethreading of the contact tip.

An example welding apparatus includes a welding power source configured to output current between a consumable electrode and a workpiece; a feeding apparatus configured to move the consumable electrode toward the workpiece; and circuitry. The circuitry is configured to: control the welding power source to repeat a sequence including: outputting a positive peak current from the workpiece to the consumable electrode during a positive peak period; outputting a first base current between the consumable electrode and the workpiece during a first base period following the positive peak period, an absolute value of the first base current being less than the positive peak current; and outputting a negative peak current from the consumable electrode to the workpiece during a negative peak period following the first base period, an absolute value of the negative peak current being greater than the absolute value of the first base current. The circuitry is further configured to control the feeding apparatus to move the consumable electrode close to the workpiece so as to temporarily short circuit the consumable electrode and the workpiece during the first base period.

An example welding torch includes: a first contact tip configured to conduct welding current to a consumable electrode; a second contact tip configured to conduct preheating current to the consumable electrode; a cooling assembly configured to transfer heat from at least the first contact tip to coolant and to conduct the welding current through the cooling assembly; wherein the first contact tip and the cooling assembly are removable from the welding torch as a single unit.

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.

Systems, methods, and apparatus to control weld current in a preheating system are disclosed. An example preheating power supply includes power conversion circuitry configured to output welding-type power via a first output power connector and a second output power connector, and a bypass path prevention circuit configured to prevent less than a threshold voltage applied to the first output power connector and the second output power connector from a different power supply from causing current to flow between the first output power connector and the second output power connector.

Systems, methods, and apparatus to preheat weld wire are disclosed. An example contact tip includes: an inner bore configured to conduct current to a consumable welding electrode; screw threads on an exterior of the contact tip; and a head opposite the screw threads on an exterior of the contact tip to enable threading and dethreading of the contact tip.