Welding Terms & Definitions

In order to become a successful welder, first you need to learn some technical vocabulary (language) of welding. The sections in this chapter will introduce you to some of the general terms of the welding language.

Once you are familiar with the language of welding you will be able to interpret and convey welding information accurately.

welding terms that start with 1-9

1F, PIPE. A welding test position designation for a circumferential fillet weld applied to a joint in a pipe, with its axis approximately at a 45° angle from horizontal, in which the weld is made in the flat welding position by rotating the pipe about its axis.

1F, PLATE. A welding test position designation for a linear fillet weld applied to a joint in which the weld is made in the flat welding position.

1G, PIPE. A welding test position designation for a circumferential groove weld applied to a joint in a pipe, in which the weld is made in the flat welding position by rotating the pipe about its axis.

1G, PLATE. A welding test position designation for a linear groove weld applied to a joint in which the weld is made in the flat welding position.

2F, PIPE. A welding test position designation for a circumferential fillet weld applied to a joint in a pipe, with its axis approximately vertical, in which the weld is made in the horizontal welding position.

2F, PLATE. A welding test position designation for a linear fillet weld applied to a joint in which the weld is made in the horizontal welding position.

2FR, PIPE.As shown in the table, the FMA welding test positions utilized within the welding industry designate those positions in which a joint can be welded.

1G, PIPE. A welding test position designation for a circumferential fillet weld applied to a joint in a pipe, with its axis approximately horizontal, in which the weld is made in the horizontal welding position by rotating the pipe about its axis.

2G, PIPE. A welding test position designation for a circumferential groove weld applied to a joint in a pipe, with its axis approximately vertical, in which the weld is made in the horizontal welding position.

2G, PLATE. A welding test position designation for a linear groove weld applied to a joint, in which the weld is made in the horizontal welding position.

3F, PLATE. A welding test position designation for a linear fiilet weld applied to ajoint, in which the weld is made in the vertical welding position.

3G, PLATE. A welding test position designation for a linear groove weld applied to a joint, in which the weld is made in the vertical welding position.

4F, PIPE. A welding test position designation for a circumferential fillet weld applied to a joint in a pipe, with its axis vertical, in which the weld is made in the overhead welding position.

4F, PLATE. A welding test position designation for a linear fillet weld applied to a joint in which the weld is made in the overhead welding position.

4G, PLATE.5F, PIPE. This is a welding test position designation for a circumferential fillet weld applied in the overhead welding position to a joint in a pipe with its axis approximately horizontal. The pipe remains stationary until the weld is finished.

5G, PIPE. This is a welding test position designation for a circumferential groove weld applied in the flat, vertical and overhead welding positions to a joint in a pipe with its axis horizontal. The pipe remains stationary until the weld is finished.

6F, PIPE. This is a welding test position designation for a circumferential fillet weld applied in the flat, vertical, and overhead welding positions to a joint in a pipe with its axis approximately 45° from horizontal. The pipe remains stationary until the weld is finished.

6G, PIPE. This is a welding test position designation for a circumferential groove weld applied in the flat, vertical, and overhead welding positions to a joint in a pipe with its axis horizontal. The pipe remains stationary until the weld is finished.

6GR, PIPE. This is a welding test position designation for a circumferential groove weld applied in the flat, vertical, and overhead welding positions to a joint in a pipe with its axis approx. 45° from horizontal. In this case a restriction ring is added adjacent to the joint to restrict access to the weld. The pipe remains stationary until the weld is finished.

welding terms that start with A

ABRASION SOLDERING: A variation of soldering in which abrasion to the faying surfaces enhances surface wettability.

ABRASIVE BLASTING: A cleaning or surface roughening process using a stream of abrasive particles that are forced and projected.

ABSORPTIVE LENS: A filter lens that reduces the effect of transmitted light and light reflected from a surface.

ACCEPTABLE WELD: A weld that meets the applicable requirements.

ACETYLENE FEATHER: The intense white, feathery edge made of the cone of a carburizing oxyacetylene flame.

ACID CORE SOLDER: A solder wire or bar that is inlaid with acid flux as a core.

ACTIVATED ROSIN FLUX: A rosin-based flux with an additive to enhance the solder’s wetting.

ACTIVE FLUX, SUBMERGED ARC WELDING: A flux formulated to yield a weld metal composition is dependent upon the welding parameters, but especially arc voltage.

ACTUAL THROAT: The shortest distance between the weld root and the face of a fillet weld.

ADHESIVE: A polymeric material that has chemical and physical properties that differ from those of the base materials, is placed at their faying surfaces, to join the materials as a result of the attraction of this polymeric material.

ADHESIVE BOND: An attraction, generally physical in nature, between an adhesive and the base materials.

ADHESIVE BONDING (AB): A joining process where, an adhesive is placed between faying surfaces, and solidifies to form an adhesive bond.

AGGLOMERATED FLUX, SUBMERGED ARC WELDING: A granular flux was formed by sintering a charge composed of powdered materials and binding materials at a temperature that is capable of evaporating water, and further processing yielding the particle size desired.

AIR ACETYLENE WELDING (AAW): This oxyfuel gas welding process utilizes an air-acetyiene flame and performed without pressure, this process is no longer actively used and is considered obsolete.

AIR CAP: A nonstandard name for the nozzle of a flame-spraying gun for wire or ceramic rod.

AIR CARBON ARC CUTTING (CAC-A): is a type of carbon arc cutting process that expels molten metal with a stream of air. air carbon arc cutting torch: is an apparatus for supplying current to a fixed cutting electrode and providing positioning ability and directed air flow.

AIR FEED: A type of thermal spraying process that uses a stream of air to transport powder surfacing material through a gun and into the heat source.

ALIGNED DISCONTINUITIES: Three or more discontinuities aligned approximately parallel to the weld axis that are sufficiently distanced apart that they may be treated as a single intermittent discontinuity. aligned porosity. An oriented localized array of porosity in a lne.

ALLOY: A substance that possesses metallic qualities and is made from two or more chemical elements, one of which is a metal.

ALLOY FLUX, SUBMERGED ARC WELDING: A flux consisting of materials that interact with the filler metal to achieve the desired alloying composition in the weld metal.

ALLOY POWDER: Particulate material derived from either a homogeneous molten alloy or the solidified product of a homogeneous alloy.

ARC BRAZE WELDING (ABW): A form of braze welding that uses an electric arc to produce the heat.

ARC CHAMBER: An informal term for a plenum chamber arc cutting.

ARC CUTTING (AC): A group of thermal cutting processes in which the material is removed by melting using heat produced from an arc between the electrode and the work. arc cutting gun. A device that supplies current to an automatically fed cutting electrode, stablizes positions and directs the cutting electrode, and provides directional shielding gas.

ARC GOUGING: Thermal gouging, a type of arc cutting process that uses an arc process to machine a bevel or groove into a surface.

ARC LENGTH: The distance from the point of the welding electrode to the closest point on the surface of the weld pool.

ARC PLASMA: A gas heated by an arc, up to or at least in a partially ionized state which is used for current carrying.

ARC SPRAYING (ASP): A thermal spraying process where the heat source is an arc established between two consumable electrodes of surfacing materials and a source of compressed gas is used to atomize and propel the surfacing materials onto the base substrate surfaces.

ARC STRIKE: An interruption caused by an arc, which is any localized remelted metal, heat-affected metal, or a change in surface profile of any metal component.

ARC STUD WELDING (SW): An arc welding process in which an arc is struck between a metal stud, or similar part, and the other workpiece. The process is applied without filler metal, with or without shielding gas or flux, with or without partial shielding from a ceramic or graphite ferrule surrounding the stud, and by applying pressure after the faying surfaces have been sufficiently heated. arc time. That portion of time during which an arc is sustained in the process of making an arc weld.

ARC VOLTAGE: The electrical potential between electrode and workpiece.

ARC WELDING (AW): A group of welding processes that produce coalescence of workpieces by melting them with an arc. The processes are used with or without the application of pressure and with or without filler metal.

ARC WELDING ELECTRODE: A component of the welding circuit through which current is conducted and that terminates at the arc.

ARC WELDING GUN: A device for transferring current to a continuously fed consumable electrode, guiding the electrode, and directing shielding gas.

ARC WELDING TORCH: A device for transferring current to a fixed welding electrode, positioning the electrode, and directing the shielding gas.

ARM: A beam extending from the frame of resistance welding machine whereby the electrode force is transmitted and welding current may also be conducted.

ASSEMBLY: One or more components, members, or parts fitted together in preparation for joining. assist gas. A gas used to blow molten metal away to form the kerf in laser beam inert gas cutting, or to blow vaporized metal away from the beam path in laser beam evaporative cutting.

ATOMIC HYDROGEN WELDING (AHW): An arc welding process that uses an arc between two metal electrodes in a shielding atmosphere of hydrogen and without the application of pressure. This is an obsolete or seldom-used process.

welding terms that start with B

BACK BEAD. A weld bead resulting from a previous back weld pass.

BACK CAP. A device used to apply pressure to the collet and create a seal before filling the back of the gas tungsten arc welding torch so no air enters the back of the torch.

BACK WELD. A weld made in the back of a single groove weld.

BACKFIRE. The momentary retreat of the flame back into the torch, potentially leading to a flashback or sustained backfire. This is usually indicated by a popping sound, after which the flame may go out or reappear at the end of the tip.

BACK GOUGING. The removal of weld metal and base metal from the weld root side of a welded joint to allow complete fusion and complete joint penetration when welding from that side in the future.

Backhand Welding. A welding technique where the end of the welding torch (or gun) is facing in the opposite direction of the welding progress.

BACKING. A material or device held against the back side of the joint very close to the joint root, or, in the cases of electro slag and electro gas welding, held to both sides of a joint; used to hold molten weld metal during welding, and/or to contain molten weld metal during the process. A backing may either be partially fused or remain unfused during the process and can be either a metal or nonmetal material.

BACKING GAS. Backing by way of a shielding gas for protecting the welding process for mainly providing a protective to adjoin backing materials.

BACKUP ELECTRODE. An electrode that has a wide electrode face resisting the conditions of the welding force by balling up, brazing, and soldering. The creation of globules of molten filler metal or flux as a result of inadequate wetting of the base metal.

BARE ELECTRODE. A filler metal electrode can be produced as wire, strip or bar and is not coated or covered with anything except that which is incidental to manufacture or preservation.

BARE METAL ARC WELDING (BMAW). An arc welding process using an arc between a bare or slightly coated electrode and the weld pool. The process is used without shielding, no pressure applied, and the filler metal is provided from the electrode. This process is obsolete or very rarely used.

BASE MATERIAL. The material being welded, brazed, soldered, or cut. See also base metal and substrate.

BASE METAL. The metal or alloy that is welded, brazed, soldered, or cut. See also base material and substrate.

BASE PLATE. A nonstandard term when used in base metal.

BEAM DIVERGENCE. The spreading of the cross-section of a beam originating from the source.

BEND TEST. A test in which a specimen is bent to a specified bend radius. See also face bend test, root bend test, and side bend test.

BEVEL ANGLE. The angle between the bevel of a joint member and a plane perpendicular to the surface of the member.

BEVEL EDGE SHAPE. A kind of edge preparation wherein the prepared surface or surfaces is at a more acute than perpendicular angle to the surface of the material involved.

BLANKET BRAZING. A type of brazing process using a flexible blanket(s) heated by resistance as the heat source.

BLIND JOINT. A joint where no part of the joint is visible.

BLOCK BRAZING (BB). A process of brazing using heated blocks as the heat source. An obsolete or infrequently used process.

BLOCK SEQUENCE. A sequence combining a longitudinal and a cross-sectional way to have one continuous (in a sense) pass of weld by having separated blocks be completely or partially welded before the segments that intervene are welded.

BLOWHOLE. A nonstandard term when used for porosity.

BONDING. A nonstandard term used when referring to brazing, soldering, and welding.

BOTTLE. A nonstandard term used for gas cylinders.

BRAZE WELDING (BW). A joining process in which the brazing filler metal is deposited in the joint and neither capillary action nor melting of base material occurs.

BURNER. A nonstandard term used for oxyfuel gas cutter.

BURNING. A nonstandard term used for oxyfuel gas cutting.

BURN-THROUGH. A hole or hollow in the root bead of a single groove weld due to excess penetration.

BUTT JOINT. A type of joint when the butting ends of one or more workpieces are parallel aligned in approximately the same plane.

BUTT WELD. A nonstandard term for a weld in a butt joint.

BUTTERING. A surfacing phase depositing surfacing metal on one or more surfaces to provide metallurgically compatible weld metal in the completion of a weld. See buildup, cladding, and hard facing.

BUTTING MEMBER. A joint member prevented by the other member from movement in one direction, perpendicular to its thickness dimension. For example, both members of a butt joint, or one member of a T-joint or corner joint.

BUTTON. In the destructive testing of projection, seam, or spot welds to describe as the part of a weld that is torn out (all or part of the nugget).

welding terms that start with C

CAPILLARY ACTION – The force by which liquid in contact with a solid is distributed between the closely fitted faying surfaces of the joint to be brazed or soldered.

CARBON ARC BRAZE WELDING (CABW) – A variation of the braze welding process, CABW uses an arc between a carbon electrode and the base metal as the heat source.

CARBON ARC BRAZING (CAB) – A brazing process using heat from a carbon arc. This is a now-obsolete, or seldom-used process.

CARR BURIZING FLAME – A reducing oxyfuel gas flame in which there is an excess of fuel gas, resulting in a carbon-rich zone extending around and beyond the cone.

CARRIER GAS – The gas which transports powdered material from the feeder or hopper to the thermal spraying gun or thermal cutting torch.

CASCADE SEQUENCE – A combined longitudinal and cross-sequence in which weld beads are made in overlapping layers.

CERAMIC ROD FLAME SPRAYING – A thermal spraying process variation in which the material used for surfacing is in rod form.

CHAIN INTERMITTENT WELD – An intermittent weld on both sides of a joint in which the weld segments on one side are approximately opposite those on the other side.

CIRCULAR ELECTRODE – A rotatable electrode with the contacting surface at the periphery, welding current and force are applied to the workpieces.

CLAD METAL -A laminar composite is a metal or metal alloy with a metal or metal alloy of a different chemical composition, bonded using casting, drawing or rolling, surfacing, chemical deposition or electroplating either on one side or more than one side.

CLUSTER POROSITY. Refers to a localized cluster of porosity that is randomly geometric.

COATED ELECTRODE. A nonstandard term for covered electrode or lightly coated electrode.

COATING. A nonstandard term when referred to as thermal spray deposit.

COATING DENSITY. A nonstandard term when talking about spray deposit density ratio.

COEXTRUSION WELDING (CEW). A solid-state welding process that produces a weld by applying a simultaneous heating of the material to the welding temperature and forcing the materials through an extruder die.

COIL WITH SUPPORT. A packaging configuration for filler metal that includes one cylinder wound wire or strip without flanges.

COLD SOLDERED JOINT. A soldered joint having an incomplete metallic bond due insufficient heating of the base material during the soldering process.

COLD WELDING (CW). Cold welding is a solid-state welding process that uses pressure to produce a weld at room (ambient) temperature and with significant deformation at the weld.

COLLAR. The reinforcing metal in a non-pressure thermite weld.

COLLET, gas tungsten arc welding, plasma arc cutting, plasma arc welding and thermal spraying. A mechanical device used to clamp the electrode in position in the welding cutting or spraying torch.

COMPLETE FUSION. fusion through the entire face of the fusion and between all the adjoining weld beads.

COMPLETE JOINT PENETRATION (CJP). A groove weld where the weld metal runs through the full joint thickness.

COMPOSITE ELECTRODE. A generic term for a multicomponent filler metal electrode that can exist in multiple physical forms including stranded wires, tubes and covered wire.

CONCURRENT HEATING. Adding supplemental heat to a structure at the same time the welding or cutting is happening.

CONSTRICTING NOZZLE. The device at the exit end of a plasma arc torch or plasma spraying gun that contains the constricting orifice.

CONSUMABLE ELECTRODE. An electrode used to provide filler metal.

CONTINUOUS WELD. A weld that extends from one end of a joint to the other end without interruption. If the joint is essentially circular this means a weld that extends around the entire joint.

COVER PLATE. A replaceable sheet of clear glass, plastic-coated glass, or plastic used to cover the filter plate to protect from weld spatter, pitting or scratching.

COVERED ELECTRODE. A composite filler metal electrode consisting of a bare or metal-cored electrode which has a flux covering that is of sufficient size to produce a slag layer and/or alloying elements.

welding terms that start with D

DEFECT. A discontinuity or defect that, by nature or cumulative effect, makes a part or product fail to meet minimum applicable acceptance standards or specifications. The term refers to reject ability. See also discontinuity and flaw.

DEPOSITED METAL, brazing, soldering, and welding. A filler metal that is added to the welded joint during brazing, soldering, or welding.

DEPOSITION RATE. The weight of material deposited per unit time.

DEPTH OF BEVEL. The perpendicular distance from the base metal surface to the root edge or beginning of the root face.

DEPTH OF FUSION. The distance that fusion extends into the base metal or previous bead from the surface melted while welding.

DIFFERENTIAL THERMAL EXPANSION. The dimensional effects associated with differences in expansion coefficients and/or thermal gradients within a workpiece or assembly.

DIFFUSION BRAZING (DFB). A brazing process that uses a brazing filler metal or an in-situ liquid phase that diffuses with the base material(s) to produce joint properties that are approaching that of the base material(s). Pressure may or may not be applied.

DIFFUSION WELDING (DFW). A solid-state welding process that produces a weld by pressure at elevated temperature with no macroscopic deformation or relative motion of the workpieces. A solid filler metal can be inserted between the faying surfaces.

DISCONTINUITY. An interruption of the usual structure of a material, like lack of homogeneity in its mechanical, metallurgical, or physical characteristics. Not all discontinuities are defects.

DISSOLUTION, brazing. Dissolving of the base material into the filler metal, or the filler metal into the base material.

DOUBLE ARCING. A condition where the welding or cutting arc of a plasma arc torch does not pass through the constricting orifice but transfers to the inside surface of the nozzle, while simultaneously establishing a secondary arc between the outside surface of the nozzle and the workpiece.

DOUBLE-BEVEL EDGE SHAPE. A bevel edge shape with two prepared surfaces adjacent to opposite sides of the material.

DOVETAILING, thermal spraying. A method of surface roughening with angular undercutting to interlock the thermal spray deposit.

DRAG, thermal cutting. The measured offset distance between the actual gas stream or cutting beam exit point and a straight line drawn on the exit surface of the base metal.

DRAG ANGLE. The travel angle when the electrode is pointed in an opposite direction to the welding progression. The drag angle can be used to partially define the position of guns, torches, rods, and beams.

DYNAMIC ELECTRODE FORCE, resistance welding. The actual force applied to the workpieces by the electrodes when welding.

welding terms that start with E

EDGE EFFECT, thermal spray. The loosening of the bond of thermal spray deposit and substrate at the edge of the thermal spray deposit.

EDGE JOINT. A joint in which the non-butting ends of one or more workpieces are roughly parallel.

EDGE LOSS, thermal spray. Thermal spray deposit lost as overspray beyond the edge of the workpiece.

EDGE PREPARATION. The preparation of the edges of joint members, by cutting, cleaning, plating or otherwise preparing the joint edges.

EDGE WELD. A weld in an edge joint, a flanged butt joint, or a flanged corner joint in which the full thickness of the members is melted together.

ELECTRODE. A component of the secondary circuit ending at the arc, molten conductive slag, or base metal.

ELECTRODE ADAPTER; resistance welding. A fitting used to adapt an electrode to an electrode holder.

ELECTRODE CAP. A replacement electrode adapter tip used when resistance spot welding.

ELECTRODE EXTENTION. Length of electrode that extends the holder or cutting torch.

ELECTRODE HOLDER, A device used to mechanically hold and conduct current to an electrode or electrode adapter.

ELECTRODE INDENTATION, an indentation in the surface of the workpiece formed by an electrode.

ELECTRODE LEAD, a secondary circuit conductor which conveys energy from the power source to the electrode holder, gun or torch.

ELECTRO GAS WELDING (EGW).A process in which the molten weld metal is confined by backing in an approximately vertical welding progression and through an arc between a continuous filler metal electrode and the weld pool. The process can be used with or without supplied shielding gas, and without applied pressure.

ELECTRON BEAM BRAZING (EBB). A brazing process using the heat from a slightly defocused or oscillating electron beam.

ELECTRON BEAM WELDING (EBW). A welding process producing coalescence by a concentrated beam consisting primarily of high-velocity electrons acting on the joint. The process is used without shielding gas and without applied pressure.

ELECTROSLAG WELDING (ESW). A welding process producing coalescence of metals with molten slag that melts filler metal and the surfaces of the components being welded. The weld pool is shielded by this slag, which flows over the full cross-section of the joint as welding proceeds. The process begins with an arc that melts the slag, and then the conductive properties of the slag extinguish the arc and keep it flowing in a molten state based on its resistance to the electric current travelling through the electrode and workpieces.

ELECTROSLAG WELDING ELECTRODE. Filler metal portion of the welding circuit by which current passes through to the molten slag from electrode guiding member.

ELONGATED POROSITY. A type of porosity having a length in excess of its width that lies approximately parallel of the weld axis.

EMISSIVE ELECTRODE. A filler metal electrode containing a core of a bare electrode or a composite electrode to which a very light coating has been applied to give a stable arc.

EXPLOSION WELDING (EXW). A solid-state welding process produces a weld by the high-velocity impact of the components as a result of detonation.

welding terms that start with F

FACE OF WELD: The exposed welding surface made by an arc or gas welding operation, on the side from which the welding was made.

FILL PASS: A non-standard term when used for intermediate weld pass

FILLER MATERIAL: The material to be added in making a brazed, soldered, or welded joint.

FILLER WIRE: A non-standard term for welding wire.

FILLET: The weld metal in the internal vertex, or corner, of the angle formed by two pieces of metal, added to further strengthen the joint against unusual stresses.

FILLET WELD: A weld with approximately triangular cross section joining two surfaces approximately at right angles to each other in a lap joint, T-joint or corner joint.

FILTER LENS: A colored glass used in goggles, helmets, and shields to exclude harmful light rays.

FLASHBACK ARRESTOR: Device generally used in oxy-fueled welding and cutting, to stop flame from burning back into equipment and causing damage, including explosion. Firepower recommends to use flashback arrestors wherever possible.

FLAT POSITION: The position of the weld, used to weld from the upper side of the joint; the face of the weld is approximately horizontal.

FLUX: An agent or substance for preventing, or controlling the formation, of oxides and other undesirable means in the molten metal and on solid metal surfaces, and/or help with the dissolving or other means of removal of such undesirables.

FLUX CORED ARC WELDING (FCAW): An arc welding process that uses an arc between a consumable continuous filler metal electrode and the weld pool. The process is used with shielding gas from a flux contained within the tubular electrode, and with or without additional shielding from an externally supplied gas and without the application of pressure.

FLUX CORED ELECTRODE: A composite tubular filler metal electrode consisting of a metal sheath and core of various powdered materials that result in an extensive slag cover on the face of a weld bead.

FOREHAND WELDING (NON-STANDARD TERM: PUSH TECHNIQUE): A welding technique whereby the welding torch or gun is directed toward the direction of progress of the welding.

FORGING: Metallic shapes are derived by either hammering or squeezing the original piece of metal to the desired shapes or thicknesses.

FULL PENETRATION: A non-standard term for complete joint penetration.

FUSION: The melting together of filler metal and base metal in the process of welding; or only base metal material to produce a weld.

welding terms that start with G

GAS: The state of matter in which molecules are free to move, allowing it to expand completely to fit any space.

GAS CYLINDER: A portable vessel for the transport and storage of compressed gas.

GAS LENS: One or more fine mesh screens are placed in the gas nozzle to create a stable stream of shielding gas. It is primarily used for gas tungsten arc welding.

GAS METAL ARC WELDING (GMAW): Arc welding process using an arc between a continuous filler metal electrode and the weld pool. The process takes place with the benefit of shielding from external supplied gas and without application of pressure.

GAS NOZZLE: A device at the exit end of the torch or gun that directs shielding gas.

GAS POCKETS: Cavities in weld metal due to entrapping gas (porosity).

GAS REGULATOR: A device to control the delivery of gas at some substantially constant pressure.

GAS SHIELDED ARC WELDING: A family of processes which includes, 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 variation of the flux cored arc welding process where shielding gas is sourced from the gas nozzle in addition to that obtained from the flux in the electrode.

GAS TUNGSTEN ARC WELDING (GTAW): An arc welding process using an arc between a tungsten electrode (non-consumable) and the welding pool. The process is conducted 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.

GOUGING: A thermal cutting process variation using melting or burning to remove the whole portion of the material being removed to form a bevel or groove. See Gouging Techniques for Specific Materials for additional gouging information.

GROOVE ANGLE: The included angle between the groove faces of a weld groove.

GROOVE WELD: A weld made in a weld groove on a surface of a workpiece, between the workpiece edges, surfaces of the workpiece, or between one or more edges or surfaces of the workpiece.

GROUND CLAMP: A non-standard and incorrect term for workpiece connection.

GROUND CONNECTION: The electrical connection of the welding machine frame to the earth as a safety measure.

GROUND LEAD: A non-standard and incorrect term for workpiece lead.

welding terms that start with H

HARD FACING (NON-STANDARD TERM: HARD SURFACING): A type of surfacing where surfacing material is deposited to diminish wear

HEAT CONDUCTIVITY: The velocity and efficiency of the travel of heat energy through a substance

HEAT INPUT: The energy added by the welding arc to the work piece. That part of the base metal that is not melted but is altered by the heat of welding, cutting, or heating and whose mechanical properties or microstructure have been affected.

HEAT-AFFECTED ZONE (HAZ): The part of the base metal whose mechanical properties or microstructure have been altered by the heat of welding, brazing, soldering or thermal cutting.

HEATING: A heating process for different metals through direct application of single or multiple flames to reach a desired high temperature to perform metal fabrication processes such as: bending or straightening, stress relief, flame hardening or flame shrinking.

HORIZONTAL POSITION: A position in which welding is performed on the upper side and approximately horizontal surface and against an approximately vertical surface.

HOSE: A flexible medium used to transport gases from the regulator to the torch. The hose is made of interleaved rubber or neoprene material, placed on top of a braided inner section.

HOT PASS: A non-standard term used in pipe welding when referring to the weld pass immediately after the root pass.

HOT START CURRENT: A very brief current pulse when the arc is started in order to initiate the arc quickly and stabilize.

HYDROGEN: A gas made of the single element hydrogen and is one of the most reactive gases. When combined with oxygen, it will form a very clean flame.

welding terms that start with I

IGNITION: The act of igniting an explosive combination of gases or vapors using flame, electric spark, heating, or rapid rise in pressure.

INCLUDED ANGLE: The angle of the groove made between two pieces of the material that they are welded to. An uncommon term when referring to groove angle.

INCLUSION: Entrapped foreign solid materials in a weld, such as slag.

INCOMPLETE FUSION: A weld discontinuity that the fusion was incomplete between the weld metal and fusion faces or fused weld beads.

INERT GAS: A gas that normally would not react chemically with the materials (Argon and Helium are inert gases).

INSIDE CORNER WELD: Completely fused two metals while one metal is held at a 90° axis to the other. The fusion occurs in the vertex of the angle.

INTERMEDIATE WELD PASS: A single progression of welding along a joint following the root pass and preceding the cover pass.

INTERMITTENT WELD: A weld where continuity is broken with repeating unwed intervals.

INTER PASS TEMPERATURE: In a multi-pass weld, the temperature at the weld area between the weld passes.

welding terms that start with J

JOINING: The process of connecting two pieces of base metal (i.e. copper tubing) together using a capillary fitting, whereby the pieces will be sealed together with a filler that will be melted by heating the base metal with a torch.

JOINT: The joining of members or if the edges of members, which are to be joined, or have been joined.

JOINT CLEARANCE: The distance between the faying surfaces of a joint.

JOINT EFFICIENCY: The ratio of strength of a joint to the strength of the base metal expressed in percent.

JOINT PENETRATION: The distance a weld extends from its face into a joint, exclusive of reinforcement.

JOINT TYPE: A designation of a weld joint based on the relative position of the members being joined. Five basic joint types include butt joint, corner joint, edge joint, lap joint and T-joint.

welding terms that start with K

KERF: The resulting gap produced by the cutting process;

KEYHOLE WELDING: A welding procedure in which a concentrated heat source is moved partially through, or completely through, a work piece while forming a “hole” (keyhole) at the front of the weld pool (during the rotation of the keyhole). This pool fills in behind the hole and completes the weld bead;

KINDLING TEMPERATURE: The temperature at which a material will ignite and burn (ignition point);

KNEE: The upper arm of the lower arm in a resistance welding machine;

KNURLING: A method for providing a roughened surface by upsetting the surface with a knurling tool.

welding terms that start with L

LAND: A non-standard term for root face.

LAP JOINT: A joint formed by two overlapping members in parallel planes.

LAYER: A thickness of weld metal, made up of one or more passes.

LENS: (See Filter Lens) Liquefied Gas: Any substance which is normally a gas at ambient temperature and pressure, but has been converted to a liquid state by changing its temperature or pressure. If the critical temperature for the substance is above ambient temperature it can be liquefied by simply lowering the temperature or increasing the pressure. If the critical temperature is below ambient temperature, it cannot be liquefied by pressure alone. It requires cooling as well.

LIQUIDUS: The temperature of the liquidus is the higher temperature at which the filler metal is completely molten. This is the minimum temperature that the brazing will occur.

welding terms that start with M

MANUAL WELDING: The procedure of welding wherein the torch, gun, or electrode holder is held and manipulated with a hand (also known as SMAW or GTAW).

MECHANIZED WELDING: The procedure of welding with equipment that requires the manual adjustment of the equipment controls based on visual observation of the welding process, and where the torch, gun, or electrode holder is held by a mechanical device.

MELTING RANGE: The melting range is defined by the difference between the solidus and liquidus temperatures. The melting range is the working range for the filler metal and whether the filler metal will freeze at a speed that will allow it to bond after brazing. Some filler metals will have narrow melting ranges whether they have silver or not; these will freeze quickly and thus, the introduction of heat must be applied cautiously.

METAL CORED ELECTRODE: A composite tubular filler metal electrode consisting of a metal sheath and core containing various powdered materials, producing at most, slag islands on the face of the weld bead.

METAL ELECTRODE: A filler (or non-filler) metal electrode used in arc welding or arc cutting, which consists of a metal wire or rod that has been produced by any process or combination of processes and that is either bare or covered.

MIG WELDING: A non-standard term for flux cored arc welding or gas metal arc welding, abbreviation for metal inert gas.

MIXING CHAMBER: That part of the welding or cutting torch in which the fuel gas and oxygen are mixed.

welding terms that start with N

NEUTRAL FLAME: An oxy-fuel gas flame wherein the region being used is neither oxidizing nor reducing.

NFPA: Abbreviation for “National Fire Protection Association”. Fuel gas flame wherein the region being used is neither oxidizing nor reducing.

NONDESTRUCTIVE EXAMINATION (NDE): The process of determining the acceptability of some material or component for intended use, using techniques that will not adversely affect its usefulness.

NOZZLE: The device at the exit end of the gun that direct the atomizing air or other gas.

welding terms that start with O

OPEN CIRCUIT VOLTAGE (OCV): The voltage measured at the output terminals of the power source when no current is delivered to the torch or gun.

OPEN ROOT JOINT: A joint that has not been welded with no backing or consumable insert.

ORIFICE: Opening through which the gas flows. This is usually the last opening controlled by a valve.

OSHA: Acronym for “Occupational Safety and Health Administration”.

OUTSIDE CORNER WELD: Where two pieces of metal are fused together at a seam with the fusion taking place under the seam.

OVERHEAD POSITION: A position where the welding is completed from below the joint.

OVERLAP: The weld metal which protrudes beyond the weld toe or weld root.

OXIDIZING: The combining of oxygen with any other substance. For example, a metal is oxidized when the metal is burned (oxygen is combined with all of the metal or a portion of it).

OXIDIZING FLAME: An Oxy-fuel gas flame having an oxidizing effect resulting from excess oxygen.

OXY-ACETYLENE CUTTING: An Oxy-fuel gas flame having an oxidizing effect resulting from excess oxygen.

OXY-ACETYLENE WELDING: An Oxy-fuel gas cutting process employed to burn metals through the reaction of oxygen with the base metal at elevated temperatures. The necessary temperature is maintained by gas flames resulting from the combustion of acetylene with oxygen.

OXY-FUEL CUTTING: The method employed to sever metals through the reaction of oxygen with the base metal at elevated temperatures. The necessary temperature is maintained by gas flames resulting from the combustion of a fuel combined with oxygen.Oxy-fuel gas welding is a process of melting metals using gas flame or flames produced through the controlled burning of acetylene and oxygen. This process can be used with or without pressure, and with or without a filler metal.

OXY-FUEL CUTTING TORCH: A device used for controlling the preheat flame produced by the controlled burning of fuel gases and directing and controlling cutting oxygen.

OXYGEN: A gas made up of the element of oxygen. When oxygen vigorously supports combustion, it is referred to as burning, however, when oxygen is slowly combined with other substances, it is called oxidizing.

OXYGEN CUTTING: A process used to cut ferrous metals through the chemical action of oxygen on elements in the base metal at high temperatures.

OXYGEN CYLINDER: (See Gas Cylinder) Oxygen Hose: (See Hose) Oxygen Hydrogen Flame: The chemical process of joining oxygen with the fuel gas of hydrogen.

OXYGEN L.P. GAS FLAME: Chemical reaction that combines Oxygen with L.P. fuel gas. (liquefied petroleum).

OXYGEN REGULATOR: A device used to reduce cylinder pressure to torch pressure and to maintain constant pressure. These are never intended for use as fuel gas regulators.

welding terms that start with P

PENETRATION: A non-standard term for joint penetration.PILOT ARC: A low current arc produced between the electrode and constricting nozzle of the plasma arc torch for gas ionization, to initiate the welding or plasma cutting arc.

PLASMA ARC CUTTING (PAC): An arc cutting process that uses a constricted arc where the molten metal is removed by a high velocity jet of ionized gas that issues from the constricting orifice.

PLUG WELD: A weld made within a circular hole in one member of a joint to fuse that member to another member.

POLARITY: See direct current electrode negative and direct current electrode positive.

POROSITY: Cavity type discontinuities that are formed from gas entrapment during solidification.

POROSITY: Cavity Type discontinuities that are formed from gas entrapment during solidification or from gas entrapment in a thermal spray deposit.

POST FLOW TIME: The time interval in seconds from current shut off to either shielding gas or cooling water shut off.

POST HEATING: The application of heat to an assembly, after welding, cutting or heating.

POUNDS PER SQUARE INCH (PSI): A measure equivalent to a mass or weight that is applied to one square inch of surface area.

POWER SOURCE: A device that supplies current and voltage for welding, thermal cutting or thermal spraying.

PRECOATING: Coating the base metal in the joint before soldering or brazing.

PRE-FLOW TIME: The time interval (in seconds) between start of shielding gas flow and start of arc.

PREHEAT TEMPERATURE: The temperature of the base metal at the volume surrounding the welding point immediately before welding started. In a multi-pass weld, the temperature immediately before an initiation of the second and subsequent arcs, also.

PREHEATING: The application of heat immediately before welding or cutting to the base metal.

PROPANE: A fuel gas. It is a member of the paraffin family. A hydrocarbon molecule associated with three carbon atoms and eight hydrogen atoms, C3H8.

PROPYLENE: A fuel gas. It is a member of the olefin family. A hydrocarbon molecule associated with three carbon atoms and six hydrogen atoms, C3H6. There is a double covalent bond formed with two pairs of electrons shared by two of the carbon atoms.

PUDDLE: A non-standard term referring to the welding pool.

PULSED GAS METAL ARC WELDING (GMAW-P): A variation of gas metal arc welding process in which the current is pulsed.

PULSED GAS TUNGSTEN ARC WELDING (GTAW-P): A variation of gas tungsten arc welding process in which the current is pulsed.

PUSH ANGLE: The travel angle when the electrode is pointing in the direction of weld progression. This angle may also be used to partially define the relative positions of guns, torches, rods and beams.

PWG WELD: A welding in circular hole in one member of a joint to fuse that member to another member.

welding terms that start with R

REDUCED FLAME: A flame which has a reducing effect from excess fuel gas.

REVERSE FLOW CHECK VALVES: Used to prevent reverse flow of gases moving past the check vlave. Firepower recommends to use them wherever possible.

ROOT BEAD: A weld bead that is into or includes some or all of the joint root.

ROOT OF WELD: (See Weld Root) Rosebud: Term for a multi-flame heating nozzle.

welding terms that start with S

SELF-SHIELDED FLUX CORED ARC WELDING (FCAW-S): A flux cored arc welding process where shielding gas is derived only from the flux of the electrode.

SEMI-AUTOMATIC WELDING: Manual welding using a machine that automatically controls one or more welding conditions.

SHIELDED METAL ARC WELDING (SMAW): An arc welding process having an arc, with a covered electrode, between the electrode and the weld pool, using shielding obtained from the decomposition of the covering of the electrode, with the addition of filler metal from the electrode, without the use of pressure.

SHIELDING GAS: Protective gas used to help prevent or reduce the entry of atmospheric contaminants into the weld.

SHORT CIRCUITING TRANSFER, GAS METAL ARC WELDING: Metal transfer where there are intermittent short circuits, during which molten metal from a consumable electrode is deposited in the weld pool, during the repeated short circuits.

SLAG: A nonmetallic product resulting from the melting together of flux with nonmetallic impurities as part of certain welding and brazing processes.

SLAG INCLUSION: Nonmetallic solid material entrapped in the weld metal or between the weld metal and base metal.

SOLDERING: Soldering is a group of welding processes that join two pieces of metal, but like traditional welding, add only metal. However, the added metal has a melting temperature lower than that of the work. Thus, only the added metal is melted, while the workpiece only gets warm. Soldering occurs below temperatures of 800°f (427°c) and normally utilizes metal at these melting points, which is distributed between closely fitted surfaces of the joint by capillary action.

SOLIDUS: The temperature at which a metal or an alloy is completely solid.

SPATTER: Metal particles expelled during fusion welding that do not form part of the molten weld.

SPOT WELD: A weld made between or onto overlapped members, in which coalescence may begin and occur on the faying surfaces or may begin and occur from the outer surface of either member.

SPRAY TRANSFER, GAS METAL ARC WELDING: Metal transfer, whether produced by arc spray or spray arc welding, whereby molten metal from the consumable electrode is propelled axially across the arc in small droplets.

STANDARD CUBIC FEET PER HOUR (SCFH): The USC unit measurement of the volumetric flow rate of air or gas (free air or gas) at a temperature of 15.6°c (60°f) and absolute pressure of 101.3 KPA (14.7 psi), expressed in cubic feet per hour.

STICKOUT, GAS METAL ARC WELDING AND GAS: The length of unmelted electrode extending beyond the end of the gas nozzle when the gas-shielded flux cored arc welding.

STICKOUT, GAS TUNGSTEN ARC WELDING: The length of tungsten electrode extending beyond the end of the gas nozzle.

STINGER: A term used for stick electrode holder.

STRAIN: Reaction of an object to stress.

STRESS: Load imposed on an object.

STRESS RELIEVING: Uniform heating of a structure to a temperature below critical followed by slow and uniform cooling.

welding terms that start with T

TACK WELD: A weld made to hold the parts of a weldment in position and proper alignment until final welds are made.

TENSILE STRENGTH: Maximum pull strength which is capable of being sustained by a specimen.

THROAT OF A FILLET WELD: Distance from the weld root to the weld face.

TIG WELDING: Non-standard way of saying gas tungsten arc welding, it stands for tungsten inert gas.

TINNING: Non-standard way of saying precoating.

TIP: The end of the torch where the gas burns to create a high-temperature flame, regulates and directs the flame.

TOE OF WELD: (See Weld Toe) Joint formed by placing one metal against another at an angular position of 90°. One edge of one metal contacts the surface of the other metal.

TUNGSTEN ELECTRODE: A non-filler metal electrode used in arc welding, arc cutting, and plasma spraying, made primarily of tungsten.

TUNGSTEN INCLUSION: A discontinuity containing tungsten that was entrapped in the weld metal.

welding terms that start with U

UNDERCUT: A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal.

welding terms that start with V

VERTICAL POSITION: The position of welding in which the weld axis is approximately vertical.

welding terms that start with W

WELD AXIS: A line through the length of the weld that is perpendicular to the weld face and through the geometric center of the cross section of the weld.

WELD BEAD: A weld deposit from a pass.

WELD FACE: The exposed surface of weld on the side of the weld pool from which welding was initiated.

WELD METAL: Metal in a fusion weld that consists of that portion of the base metal and filler metal that is melted throughout the welding process.

WELD PASS: A single progression of welding or surfacing along a joint or substrate. The weld bead or layer is the physical total of that pass.

WELD POOL: The local volume of molten metal as a weld prior to its solidification as weld metal.

WELD REINFORCEMENT: Weld metal in excess of the total amount required to fill a joint.

WELD ROOT: The points, as shown in the cross-section, where the back of the weld intersects the base metal.

WELD TOE: The junction of the weld face and the base metal.

WELDING: A joining process in which coalescence occurs through the heating of two or more materials, with or without the application of pressure, and with or without the use of filler metal. The materials are heated to the welding temperature.

WELDING ARC: A controlled electrical discharge between the electrode and the workpiece that is formed and sustained by the establishment of a gaseous conductive medium, called arc plasma.

WELDING ELECTRODE: The element of the welding circuit in which current is conducted and ends at the arc, molten conductive slag, or base metal.

WELDING HELMET: A device with a filter plate designed to be worn on the head in order to protect the eyes, face, and neck from arc radiation, radiated heat, spatter, or substances volatile from the type of welding or cutting process.

WELDING LEADS: The work lead and the electrode lead of an arc welding circuit.

WELDING POWER SOURCE: A machine supplying current and voltage for welding.

WELDING PROCEDURE SPECIFICATION (WPS): A document to inform of the required welding variables for a given application to permit the repeatability by properly qualified and trained welders and welding operators.

WELDING ROD: Filler metal in the form of a wire or rod, is used in the gas welding and brazing processes and in those arc welding processes in which the electrode does not supply the filler metal.

WELDING SEQUENCE: The chronological order of making welds in a weldment.

WELDING TORCH: A tool used in gas cutting to control the gases used for preheating the metal and the oxygen that is being used to cut the metal.

WELDING WIRE: Metal wire that is melted to produce the necessary increase in bead size to the welding puddle.

WELDMENT: The assembly of component parts that are joined together by welding.

WHIPPING: A manual welding technique whereby the arc or flame is oscillated forwards and backwards in the direction of travel, as it moves along the weld path.

WIRE FEED SPEED: The amount of wire that is consumed as it travels in arc welding.

WIRE STICK OUT: Distance from the contact tip of a MIG gun to the end of the welding electrode (that is sticking out of the gun).

WORK LEAD: A non-standard term for work lead.

WORKPIECE: The piece that is being welded, brazed, soldered, thermally cut, or thermally sprayed.

WORKPIECE CONNECTION: The connection of the work leads to the work piece.

WORKPIECE LEAD: The electrical conductor that lies between the arc welding current source and workpiece connection.

welding terms that start with Y

YIELD STRENGTH: Stress at which a specimen assumes a permanent set.

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