Many of the terms here have been reprinted or adapted with permission fromAWS A3.0:2001, Standard Welding Terms and Definitions.
Alloy: A substance with metallic properties and composed of two or more chemical elements of which at least one is a metal.
Arc length:The distance from the tip of the welding electrode to the adjacent surface of the weld pool.
Arc voltage: The electrical potential between the electrode and workpiece.
Arc welding: A group of welding processes that produces fusion of workpieces by heating them with an arc. The processes are used with or without the application of pressure and with or without filler metal.
Arc welding (MIG) gun: A device used to transfer current to a continuously fed consumable electrode, guide the electrode, and direct the shielding gas.
Arc welding (TIG) torch: A device used to transfer current to a fixed welding electrode, position the electrode and direct the shielding gas.
Air carbon arc cutting (CAC-A): A carbon arc cutting process that removes molten metal with a jet of air.Also referred to as air carbon arc gouging.
Autogenous weld: A fusion weld made without filler metal.
Automatic welding: Welding with equipment that requires only occasional or no observation of the welding, and no manual adjustment of the equipment controls.
Backgouging: The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side.
Backhand welding: A welding technique in which the welding torch or gun is directed opposite to the progress of welding.
Backing gas: Backing in the form of a shielding gas employed primarily to provide a protective atmosphere.
Backstep sequence: A longitudinal sequence in which weld passes are made in the direction opposite to the progress of welding.
Base metal: The metal or alloy that is welded, brazed, soldered, or cut.
Butt joint: A joint between two members aligned approximately in the same plane.
Cap: A nonstandard term for the final layer of a groove weld.
Carbon electrode: A non-filler metal electrode used in arc welding and cutting, consisting of a carbon or graphite rod, which may be coated with copper or other materials.
Coalescence: The growing together or growth into one body of the materials being joined. See fusion.
Cold crack: A crack which develops after solidification
Cold lap: A non-standard term. A joint with incomplete coalescence (fusion) caused by insufficient application of heat to the base metal.
Collet: A mechanical clamping device used to hold the electrode in position within the welding, cutting or spraying torch.
Constant current (CC) power source: An arc welding power source with a volt-ampere relationship yielding a small welding current change from a large arc voltage change.
Constant voltage (CV) power source: An arc welding power source with a volt-ampere relationship yielding a large welding current change from a small arc voltage change.
Contact tip: A component of a MIG gun that delivers welding current to, and guides, a continuous electrode.
Covered electrode: A composite filler metal electrode consisting of a core of a bare electrode or metal cored electrode to which a covering sufficient to provide a slag layer on the weld metal has been applied. The covering may contain materials providing such functions as shielding from the atmosphere, deoxidation, and arc stabilization, and can serve as a source of metallic additions to the weld.
Crack: A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.
Crater: A depression in the weld face at the termination of the weld bead.
Crater fill time: The time interval following weld time but prior to melt back time during which arc voltage or current reach a preset value greater or less than welding values. Weld travel may or may not stop at this point.
Defect: Adiscontinuity or discontinuities that by nature or accumulated effect render a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates rejectability. See also discontinuity and flaw.
Deposition rate: The weight of material deposited in a unit of time.
Direct current electrode negative (DCEN): The arrangement of direct current arc welding leads in which the electrode is the negative pole and workpiece is the positive pole of the welding arc.
Direct current electrode positive (DCEP): The arrangement ofdirect current arc welding leads in which the electrode is the positive pole and the workpiece is the negative pole of the welding arc.
Discontinuity: An interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical or physical characteristics. A discontinuity is not necessarily a defect.
Drag angle: The travel angle when the electrode is pointing in a direction opposite to the progression of welding. This angle can also be used to partially define the position of guns, torches, rods, and beams.
Downslope time: The time during which the current is changed continuously from final taper current or welding current to final current.
Dross: The remaining solidified oxidized metallic material adhering to the workpiece adjacent to the cut surface.
Duty cycle: The percentage of time during a specified test period that a power source or its accessories can be operated at rated output without overheating.
Electrode: Acomponent of the electrical circuit that terminates at the arc, molten conductive slag or base metal.
Electrode extension (see also stickout): The length of electrode extending beyond the end of the contact tip.
Filler material: The material to be added in making a brazed, soldered or welded joint.
Fillet weld.: A weld of approximately triangular cross section joining two surfaces approximately at right angles to each other in a lap joint, T-joint or corner joint.
Fill pass: A nonstandard term when used for intermediate weld pass.
Forehand welding(non-standard: push technique): A welding technique in which the welding torch or gun is directed toward the progress of welding.
Flux cored arc welding (FCAW): Anarc welding process that uses an arc between a continuous filler metal electrode and the weld pool. The process is used with shielding gas from a flux contained within the tubular electrode, with or without additional shielding from an externally supplied gas and without the application of pressure.
Flux: A material used to hinder or prevent the formation of oxides and other undesirable substances in molten metal and on solid metal surfaces, and to dissolve or otherwise facilitate theremoval of such substances.
Flux cored electrode: A composite tubular filler metal electrode consisting of a metal sheath and a core of various powdered materials, producing an extensive slag cover on the face of a weld bead.
Full penetration: A nonstandard term for complete joint penetration.
Fusion: The melting together of filler metal and base metal, or of base metal only, to produce a weld.
Gas cylinder: A portable container used for transportation and storage of compressed gas.
Gas lens: One or more fine mesh screens located in the gas nozzle to produce a stable stream of shielding gas. This device is primarily used for gas tungsten arc welding.
Gas metal arc welding (GMAW): An arc welding process that uses an arc between a continuous filler metal electrode and the weld pool. The process is used with shielding from an externally supplied gas and without the application of pressure.
Gas nozzle: A device at the exit end of the torch or gun that directs shielding gas.
Gas regulator: A device for controlling the delivery of gas at some substantially constant pressure.
Gas shielded arc welding: A group of processes including, flux cored arc welding, gas metal arc welding, gas tungsten arc welding and plasma arc welding.
Gas shielded flux cored arc welding (FCAW-G): A flux cored arc welding process variation in which shielding gas is supplied through the gas nozzle, in addition to that obtained from the flux within the electrode.
Gas tungsten arc welding (GTAW): An arc welding process that uses an arc between a tungsten electrode (non-consumable) and the weld pool. The process is used with shielding gas and without the application of pressure.
Globular transfer, gas metal arc welding: The transfer of molten metal in large drops from a consumable electrode across the arc. See also short circuiting transfer and spray transfer.
Groove weld: A weld in a weld groove on a workpiece surface, between workpiece edges, between workpiece surfaces, or between workpiece edges and surfaces.
Ground connection: An electrical connection of the welding machine frame to the earth for safety.
Ground clamp: A nonstandard and incorrect term for workpiece connection.
Ground lead: A nonstandard and incorrect term for work-piece lead.
Hardfacing (non-standard term: hard surfacing): A surfacing variation in which surfacing material is deposited to reduce wear.
Heat-affected zone (HAZ): The portion of base metal whose mechanical properties or microstructure have been altered by the heat of welding, brazing, soldering or thermal cutting.
Heat input: The energy supplied by the welding arc to the workpiece.
Hot pass: A nonstandard term when used in pipe welding for the weld pass subsequent to the root pass.
Hot start current: Avery brief current pulse at arc initiation to stabilize the arc quickly.
Included angle: A nonstandard term when used for groove angle.
Inclusion: Entrapped foreign solid material, such as slag.
Incomplete fusion: A weld discontinuity in which fusion did not occur between weld metal and fusion faces or adjoining weld beads.
Inert gas: A gas that normally does not combine chemically with materials (argon and helium are inert gases).
Intermediate weld pass: A single progression of welding along a joint subsequent to the root pass(es) and prior to the cover pass(es).
Interpass temperature: In a multi-pass weld, the temperature of the weld area between weld passes.
Joint type: A weld joint classification based on the relative orientation of the members being joined. The five basic joint types are: butt, corner, edge, lap and T-joint.
Kerf: The gap produced by a cutting process.
Land: A nonstandard term for root face.
Lap joint: A joint between two overlapping members in parallel planes.
Manual welding: Welding with the torch, gun, or electrode holder held and manipulated by hand (SMAW and GTAW are common manual processes).
Mechanized welding: Welding with equipment that requires manual adjustment of the equipment controls in response to visual observation of the welding, with the torch, gun, or electrode holder held by a mechanical device.
Metal cored electrode: A composite tubular filler metal electrode consisting of a metal sheath and a core of various powdered materials, producing no more than slag islands on the face of a weld bead.
Metal electrode: A filler or non-filler metal electrode used in arc welding and cutting that consists of a metal wire or rod that has been manufactured by any method and that is either bare or covered.
MIG Welding: A nonstandard term for flux cored arc weldingor gasmetal arc welding. It stands for Metal Inert Gas.
Nondestructive examination (NDE): The act of determining the suitability of some material or component for its intended purpose using techniques that do not affect its serviceability.
Nozzle: A device at the exit end of the gun that directs the atomizing air or other gas.
Open circuit voltage: The voltage between the output terminals of the power source when no current is flowing to the torch or gun.
Open root joint: An un-welded joint without backing or consumable insert.
Oxy-fuel gas cutting torch: A device used for directing the preheating flame produced by the controlled combustion of fuel gases and to direct and control the cutting oxygen.
Oxygen cutting: A group of thermal cutting processes that severs or removes metal by means of the chemical reaction between oxygen and the base metal at elevated temperature. The necessary temperature is maintained by the heat from an arc, an oxy-fuel gas flame or other source.
Pilot arc: A low current arc between the electrode and the constricting nozzle of the plasma arc torch to ionize the gas and facilitate the start of the welding or plasma cutting arc.
Power source: An apparatus for supplying current and voltage suitable for welding, thermal cutting or thermal spraying.
Plasma arc cutting (PAC): An arc cutting process that uses a constricted arc and removes the molten metal with a high-velocity jet of ionized gas issuing from the constricting orifice.
Plug weld: A weld made in a circular hole in one member of a joint fusing that member to another member.
Polarity: See direct current electrode negative and direct current electrode positive.
Porosity: Cavity-type discontinuities formed by gas entrapment during solidification or in a thermal spray deposit.
Postflow time: The time interval from current shut off to either shielding gas or cooling water shut off.
Preflow time: The time interval between start of shielding gas flow and arc starting.
Preheat temperature: The temperature of the base metal in the volume surrounding the point of welding immediately before welding is started. In a multipass weld, it is also the temperature immediately before the second and subsequent passes are started.
Puddle: A nonstandard term when used for weld pool.
Pulsed gas metal arc welding (GMAW-P): Agas metal arc welding process variation in which the current is pulsed.
Pulsed gas tungsten arc welding (GTAW-P): Agas tungsten arc welding process variation in which the current is pulsed.
Push angle: The travel angle when the electrode is pointing in the direction of weld progression. This angle can also be used to partially define the position of guns, torches, rods and beams.
Root bead: A weld bead that extends into or includes part or all of the joint root.
Self-shielded flux cored arc welding (FCAW-S): A flux cored arc welding process variation in which shielding gas is obtained exclusively from the flux within the electrode.
Semiautomatic welding: Manual welding with equipment that automatically controls one or more of the welding conditions.
Shielded metal arc welding (SMAW): An arc welding process with an arc between a covered electrode and the weld pool. The process is used with shielding from the decomposition of the electrode covering, without the application of pressure and with filler metal from the electrode.
Shielding gas: Protective gas used to prevent or reduce atmospheric contamination.
Short circuiting transfer, gas metal arc welding: Metal transfer in which molten metal from a consumable electrode is deposited during repeated short circuits.
Slag: A nonmetallic product resulting from the mutual dissolution of flux and nonmetallic impurities in some welding and brazing processes.
Spatter: The metal particles expelled during fusion welding that do not form a part of the weld.
Spot weld: A weld made between or upon overlapping members in which coalescence may start and occur on the faying surfaces or may proceed from the outer surface ofone member. Spray transfer, gas metal arc welding: Metal transfer in which molten metal from a consumable electrode is propelled axially across the arc in small droplets.
Stickout, gas metal arc welding and gas-shielded flux cored arc welding: The length of unmelted electrode extending beyond the end of the gas nozzle.
Stickout, gas tungsten arc welding: The length of tungsten electrode extending beyond the end of the gas nozzle.
Tack weld: A weld made to hold the parts of a weldment in proper alignment until the final welds are made.
TIG welding: A nonstandard term for gas tungsten arc welding. It stands for Tungsten Inert Gas.
T-joint: A joint between two members located approximately at right angles to each other in the form of a T.
Tungsten electrode: A nonfiller metal electrode used in arc welding, arc cutting, and plasma spraying, made principally of tungsten.
Tungsten inclusion: A discontinuity consisting of tungsten entrapped in weld metal.
Undercut: A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal.
Welding: A joining process that produces coalescence of materials by heating them to the welding temperature, with or without the application of pressure or by the application of pressure alone, and with or without the use of filler metal.
Weld metal: Metal in a fusion weld consisting of that portion ofthe base metal and filler metal melted during welding.
Welding arc: controlled electrical discharge between the electrode and the workpiece that is formed and sustained by the establishment ofa gaseous conductive medium, called an arc plasma.
Welding electrode: A component of the welding circuit through which current is conducted and that terminates at the arc, molten conductive slag, or base metal.
Welding procedure specification (WPS): A document providing the required welding variables for a specific application to assure repeatability by properly trained welders and welding operators.
Welding helmet: A device equipped with a filter plate designed to be worn on the head to protect eyes, face, and neck from arc radiation, radiated heat, spatter or other harmful matter expelled during some welding and cutting processes.
Welding leads: The workpiece lead and electrode lead of an arc welding circuit.
Welding power source: An apparatus for supplying current and voltage suitable for welding.
Weldment: An assembly whose component parts are joined by welding.
Weld metal: Metal in a fusion weld consisting of that portion of the base metal and filler metal melted during welding.
Whipping: A manual welding technique in which the arc or flame is oscillated backwards and forwards in the direction of travel as it progresses along the weld path.
Wire feed speed: The rate at which wire is consumed in arc welding.
Wire stick out: The distance from the contact tip of a MIG gun to end of the welding electrode protruding from it.
Work lead: A nonstandard term for workpiece lead.
Workpiece: The part that is welded, brazed, soldered, thermal cut or thermal sprayed.
Workpiece connection: The connection of the workpiece lead to the workpiece.
Workpiece lead: The electrical conductor between the arc welding current source and workpiece connection.