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.

Welding wire preheating systems and methods are disclosed. An example welding method includes: receiving a signal indicative of initiation of welding process; prior to initiating a welding arc based on the received signal, controlling voltage or current applied to a welding electrode to preheat the electrode to a temperature above an ambient temperature but below a melting point of the welding electrode; monitoring feedback voltage to determine a termination of preheating; and terminating preheating prior to initiating the welding arc in accordance with a welding protocol.

A method and a welding torch for gas tungsten arc welding is provided for, wherein an electric arc burns between a non-consumable electrode and a workpiece. The interior of the electrode has a cavity through which an electrically conducting filler is fed in the direction of the workpiece, the filler being energized.

Submerged arc welding torches and systems to resistively preheat electrode wire are disclosed. A disclosed example submerged arc welding torch includes: a first contact tip configured to transfer weld current and preheating current to the wire; a second contact tip configured to conduct the preheating current to the wire; an air-cooled first conductive body portion configured to receive the weld current and to conduct the weld current and the preheating current to the first contact tip; an air-cooled second conductive body portion configured to receive the preheating current and to conduct the preheating current to the second contact tip; and an insulator coupled between the first and second conductive body portions.

An apparatus and system for preheating and removing surface oxidation of welding wire using electric arcs one via one or more tungsten electrodes is disclosed. The preheating and cleaning electric arcs may occur between tungsten electrodes, or between one or more tungsten electrodes and welding wire. Electric arc preheating of welding wire allows increased efficiency and deposition rates.

Embodiments of systems and methods of additive manufacturing are disclosed. One embodiment includes an additive manufacturing system configured to deposit a metal powder, having a first chemical composition, onto a substrate or a previous layer of a part being additively manufactured, and tacking tracks of the metal powder to the substrate or the previous layer according to a pattern of a present layer of the part by applying a first energy along the tracks of the metal powder to sinter the tracks. The system is configured to deposit a metal wire, having a second chemical composition, along the tracks of the metal powder. Depositing the metal wire includes applying a second energy to the metal wire and the tracks of the metal powder, as sintered, to form a specified homogenous alloy of the first chemical composition and the second chemical composition as at least a portion of the present layer.

In a method for regulating or controlling the conveyance speed of a wire composed of consumable material during a laser soldering or welding method, the wire is melted by a laser beam from a laser unit and is conveyed at a mean conveyance speed toward a workpiece to be processed, wherein a voltage between the wire and the workpiece is measured. A laser soldering or laser welding device carries out this method. In order to avoid at least relatively lengthy short-circuit breaking between the end of the wire and the workpiece, the conveyance speed of the wire, as a function of the measured voltage, is temporarily increased to a predetermined boost speed by increasing the conveyance speed to the predetermined boost speed when a defined voltage limit value is exceeded, and the conveyance speed is reduced again at the latest when the voltage limit value falls below.

Systems, methods, and apparatus to provide preheat voltage feedback loss protection are disclosed. An example welding-type system includes a welding-type power source configured to provide welding-type power to a welding-type circuit, the welding-type circuit comprising a welding-type electrode and a first contact tip of a welding torch; an electrode preheating circuit configured to provide preheating power through a first portion of the welding-type electrode via a second contact tip of the welding torch; a preheat feedback circuit configured to measure a preheat voltage; and an electrode preheat control circuit configured to: control the preheating power based on the preheating voltage; and control the electrode preheating circuit to reduce the preheating power in response to detecting an invalid preheat voltage measured by the preheat feedback circuit.

The present invention discloses build-up welding methods for repair by low power density laser direct energy deposition upon a substrate to be welded, which do not necessarily require preheating of the substrate. The present invention further discloses welded regions formed by such methods, and products comprising such welded regions. Moreover, the present invention relates to laser additive welding methods and processes using a filler wire for various welding positions and orientations.

A welding-type system includes a welding torch comprising a contact tip to provide an electrode wire. A secondary contact in electrical contact with the electrode wire, the secondary contact located along a length of the electrode wire and before the contact tip. Each of the contact tip and the secondary contact are connected to a welding-type power source. A current limiting device coupling located between the welding-type power source and the secondary contact and configured to limit a current at the secondary contact.