Welding Terms & Definitions

To become a skilled welder, you first need to learn the technical vocabulary ‘(language)of welding. The sections in this chapter introduce you to some of the basic terms of the welding language.

Once you understand the language of welding, you will be prepared to interpret and communicate welding information accurately.

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 45° 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. 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 fillet weld applied to a joint 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. A welding test position designation for a linear groove weld applied to a joint in which the weld is made in the overhead welding position.

5F, 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, vertical, and overhead welding positions. The pipe remains fixed until the welding of the joint is complete.

5G, PIPE. A welding test position designation for a circumferential groove weld applied to a joint in a pipe with its axis horizontal, in which the weld is made in the flat, vertical, and overhead welding positions. The pipe remains fixed until the welding of the joint is complete.

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

6G, PIPE. A welding test position designation for a circumferential groove weld applied to a joint in a pipe, with its axis approximately 45° from horizontal, in which the weld is made in the flat, vertical, and overhead welding positions. The pipe remains fixed until welding is complete.

6GR, PIPE. A welding test position designation for a circumferential groove weld applied to a joint in a pipe, with its axis approximately 45° from horizontal, in which the weld is made in the flat, vertical, and overhead welding positions. A restriction ring is added, adjacent to the joint, to restrict access to the weld. The pipe remains fixed until welding is complete.

A

ABRASION SOLDERING. A soldering process variation during which surface wetting is enhanced by abrading the faying surfaces.

ABRASIVE BLASTING. A method of cleaning or surface roughening by a forcibly projected stream of abrasive particles.

ABSORPTIVE LENS. A filter lens is designed to attenuate the effects of transmitted and reflected light.

ACCEPTABLE WELD. A weld meeting the applicable requirements.

ACETYLENE FEATHER. The intense white, feathery-edged portion adjacent to the cone of a carburizing oxyacetylene flame.

ACID CORE SOLDER. A solder wire or bar containing acid flux as a core.

ACTIVATED ROSIN FLUX. A rosin-based flux containing an additive that increases wetting by the solder.

ACTIVE FLUX, SUBMERGED ARC WELDING. A flux is formulated to produce a weld metal composition dependent on the welding parameters, especially arc voltage.

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

ADHESIVE. A polymeric material having chemical and physical properties differing from those of the base materials is placed at their faying surfaces, to join the materials together as a result of the attractive forces 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 in which an adhesive, placed between faying surfaces, solidifies to produce an adhesive bond.

AGGLOMERATED FLUX, SUBMERGED ARC WELDING. A granular flux produced by baking a pelletized mixture of powdered ingredients and bonding agents at a temperature sufficient to remove the water, followed by processing to produce the desired particle size.

AIR ACETYLENE WELDING (AAW). An oxyfuel gas welding process using an air-acetylene flame. The process is used without the application of pressure. This is an obsolete or seldom used process.

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

AIR CARBON ARC CUTTING (CAC-A). A carbon arc cutting process variation removing molten metal with a jet of air. air carbon arc cutting torch. A device used to transfer current to a fixed cutting electrode, position the electrode, and direct the flow of air.

AIR FEED. A thermal spraying process variation in which an air stream carries the powdered surfacing material through the gun and into the heat source.

ALIGNED DISCONTINUITIES. Three or more discontinuities aligned approximately parallel to the weld axis, spaced sufficiently close together to be considered a single intermittent discontinuity. aligned porosity. A localized array of porosity oriented in a line.

ALLOY. A substance with metallic properties and composed of two or more chemical elements of which at least one is a metal.

ALLOY FLUX, SUBMERGED ARC WELDING. A flux containing ingredients reacting with the filler metal to establish a desired alloy content in the weld metal.

ALLOY POWDER. Powder is prepared from a homogeneous molten alloy or from the solidification product of such an alloy.

ARC BRAZE WELDING (ABW). A braze welding process variation using an electric arc as the heat source.

ARC CHAMBER. A nonstandard term for plenum chamber. arc cutter.

ARC CUTTING (AC). A group of thermal cutting processes severing or removing metal by melting with the heat of an arc between an electrode and the workpiece. arc cutting gun. A device used to transfer current to a continuously fed cutting electrode, guide the electrode, and direct the shielding gas.

ARC GOUGING. Thermal gouging uses an arc-cutting process variation to form a bevel or groove.

ARC LENGTH. The distance from the tip of the welding electrode to the adjacent surface of the welding pool.

ARC PLASMA. A gas heated by an arc to at least a partially ionized condition, enabling it to conduct an electric current.

ARC SPRAYING (ASP). A thermal spraying process using an arc between two consumable electrodes of surfacing materials as a heat source and a compressed gas to atomize and propel the surfacing material to the substrate.

ARC STRIKE. A discontinuity resulting from an arc, consisting of any localized remelted metal, heat-affected metal, or change in the surface profile of any metal object.

ARC STUD WELDING (SW). An arc welding process using an arc between a metal stud, or similar part, and the other workpiece. The process is used 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 with the application of pressure after the faying surfaces are sufficiently heated. arc time. The time during which an arc is maintained in making an arc weld.

ARC VOLTAGE. The electrical potential between the electrode and workpiece.

ARC WELDING (AW). A group of welding processes produces 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 used to transfer current to a continuously fed consumable electrode, guide the electrode, and direct the shielding gas.

ARC WELDING TORCH. A device used to transfer current to a fixed welding electrode, position the electrode, and direct the shielding gas.

ARM. A beam extends from the frame of a resistance welding machine to transmit electrode force and sometimes conduct welding current.

ASSEMBLY. One or more components, members, or parts fit 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 using 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.

B

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

BACK CAP. A device used to exert pressure on the collet in a gas tungsten arc welding torch and create a seal to prevent air from entering the back of the torch.

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

BACKFIRE. The momentary recession of the flame into the torch, potentially causes a flashback or sustained backfire. It is usually signaled by a popping sound, after which the flame may either extinguish or reignite 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 facilitates 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. A material or device placed against the back. side of the joint adjacent to the joint root, or at both sides of a joint in electro slag and electro gas welding, to support and shield molten weld metal. The material may be partially fused or remain unfused during welding and may be either metal or nonmetal.

BACKING GAS. Backing in the form of a shielding gas is employed primarily to provide a protective atmosphere.

BACKUP ELECTRODE. An electrode has a large electrode face opposing the welding force. balling up, brazing, and soldering. The formation of globules of molten filler metal or flux due to insufficient base metal wetting.

BARE ELECTRODE. A filler metal electrode is produced as a wire, strip, or bar with no coating or covering except one incidental to its manufacture or preservation.

BARE METAL ARC WELDING (BMAW). An arc welding process using an arc between a bare or lightly coated.

ELECTRODE AND THE WELD POOL. The process is used without shielding, without the application of pressure, and filler metal is obtained from the electrode. This is an obsolete or seldom-used process.

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

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

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

BEAM DIVERGENCE. The expansion of a beam’s cross-section as the beam emanates from its source.

BEND TEST. A test in which a specimen is bent to a specified bend radius. See also the 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 type of edge shape in which the prepared surface or surface lies at some angle other than perpendicular to the material surface.

BLANKET BRAZING. A brazing process variation employing a flexible, resistance-heated blanket(s) as the heat source.

BLIND JOINT. A joint, no portion of which is visible.

BLOCK BRAZING (BB). A brazing process employing heated blocks as the heat source. This is an obsolete or seldom-used process.

BLOCK SEQUENCE. A combined longitudinal and cross-sectional sequence for a continuous multiple-pass weld in which separated segments are completely or partially welded before intervening segments are welded.

BLOWHOLE. A nonstandard term when used for porosity.

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

BOTTLE. A nonstandard term when used for gas cylinders.

BRAZE WELDING (BW). A joining process in which the brazing filler metal is deposited in the joint without capillary action or melting of the base material.

BURNER. A nonstandard term when used for oxyfuel gas cutter.

BURNING. A nonstandard term when used for oxyfuel gas cutting.

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

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

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

BUTTERING. A surfacing variation depositing surfacing metal on one or more surfaces to provide metallurgically compatible weld metal for the subsequent completion of the weld. See also buildup, cladding, and hard facing.

BUTTING MEMBER. A joint member is 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. Part of a weld, including all or part of the nugget, is torn out in the destructive testing of projection, seam, or spot welds.

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 braze welding process variation using 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 an obsolete or seldom-used process.

CARBURIZING 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 is used to transport powdered material from the feeder or hopper to a thermal spraying gun or a thermal cutting torch.

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

CERAMIC ROD FLAME SPRAYING. A thermal spraying process variation in which the surfacing material 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 through which welding current, and force are applied to the workpieces.

CLAD METAL. A laminar composite consisting of a metal or alloy, with a metal or alloy of different chemical composition applied to one or more sides by casting, drawing, rolling, surfacing, chemical deposition, or electroplating.

CLUSTER POROSITY. A localized array of porosity having a random geometric distribution.

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

COATING. A nonstandard term when used for thermal spray deposit.

COATING DENSITY. A nonstandard term when used for spray deposit density ratio.

COEXTRUSION WELDING (CEW). A solid-state welding process producing a weld by heating to the welding temperature and forcing the workpieces through an extrusion die.

COIL WITH SUPPORT. A filler metal packaging configuration in which the wire or strip is wound around a cylinder without flanges.

COLD SOLDERED JOINT. A soldered joint with incomplete metallic bonding due to insufficient heating of the base material during soldering.

COLD WELDING (CW). A solid-state welding process in which pressure is used to produce a weld at room temperature with substantial deformation at the weld.

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

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

COMPLETE FUSION. Fusion over the entire fusion faces and between all adjoining weld beads.

COMPLETE JOINT PENETRATION (CJP). A groove weld condition in which weld metal extends through the joint thickness.

COMPOSITE ELECTRODE. A generic term for multicomponent filler metal electrodes in various physical forms such as stranded wires, tubes, and covered wire.

CONCURRENT HEATING. The application of supplemental heat to a structure during welding or cutting.

CONSTRICTING NOZZLE. A device at the exit end of a plasma arc torch or plasma spraying gun, containing the constricting orifice.

CONSUMABLE ELECTRODE. An electrode provides filler metal.

CONTINUOUS WELD. A weld extends continuously from one end of a joint to the other. Where the joint is essentially circular, it extends completely around the joint.

COVER PLATE. A removable pane of colorless glass, plastic-coated glass, or plastic covers the filter plate and protects it from weld spatter, pitting, or scratching.

COVERED ELECTRODE. A composite filler metal electrode consisting of a bare or metal-cored electrode with a flux covering sufficient to provide a slag layer and/or alloying elements.

D

DEFECT. A discontinuity or discontinuity that by nature or accumulated effect renders a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates reject ability. See also discontinuity and flaw.

DEPOSITED METAL, brazing, soldering, and welding. Filler metal is added during brazing, soldering or welding.

DEPOSITION RATE. The weight of material deposited in a unit of time.

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

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

DIFFERENTIAL THERMAL EXPANSION. Dimensional effects result from differences in expansion coefficients and/or thermal gradients within a workpiece or assembly.

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

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

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.

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

DOUBLE ARCING. A condition in which 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. A secondary arc is simultaneously established between the outside surface of the nozzle and the workpiece.

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

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

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

DRAG ANGLE. The travel angle is 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.

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

E

EDGE EFFECT, thermal spraying. Loosening of the bond between the thermal spray deposit and the substrate at the edge of the thermal spray deposit.

EDGE JOINT. A joint type in which the non-butting ends of one or more workpieces lie approximately parallel.

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

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

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 fused.

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

ELECTRODE ADAPTER, resistance welding. A device used to adapt an electrode to an electrode holder.

ELECTRODE CAP. A replaceable electrode adapter tip is used for resistance spot welding.

ELECTRODE EXTENSION. The length of the electrode extends beyond the electrode holder or cutting torch.

ELECTRODE HOLDER, A device used for mechanically holding and conducting current to an electrode or electrode adapter.

ELECTRODE INDENTATION, A depression formed on the surface of the workpiece by an electrode.

ELECTRODE LEAD, A secondary circuit conductor transmitting energy from the power source to the electrode holder, gun, or torch.

ELECTRO GAS WELDING (EGW). An arc welding process using an arc between a continuous filler metal electrode and the weld pool, employing approximately vertical welding progression with backing to confine the molten weld metal. The process is used with or without an externally supplied shielding gas and without the application of pressure.

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

ELECTRON BEAM WELDING (EBW). A welding process produces coalescence with a concentrated beam, composed primarily of high-velocity electrons, impinging on the joint. The process is used without shielding gas and without the application of pressure.

ELECTROSLAG WELDING (ESW). A welding process produces coalescence of metals with molten slag, melting the filler metal and the surfaces of the workpieces. The weld pool is shielded by this slag, which moves along the full cross-section of the joint as welding progresses. The process is initiated by an arc that heats the slag. The arc is then extinguished by the conductive slag, which is kept molten by its resistance to electric current passing between the electrode and the workpieces.

ELECTROSLAG WELDING ELECTRODE. A filler metal component of the welding circuit through which current is conducted from the electrode guiding member to the molten slag.

ELONGATED POROSITY. A form of porosity having a length greater than its width that lies approximately parallel to the weld axis.

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

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

F

FACE OF WELD: The exposed surface of a weld, made by an arc or gas welding process, on the side from which welding was done.

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: Weld metal in the internal vertex, or corner, of the angle formed by two pieces of metal, giving the joint additional strength to withstand unusual stress.

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.

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

FLASHBACK ARRESTOR: A device commonly used in oxy-fueled welding and cutting to stop the flame from burning back up into the equipment and causing damage or explosion. Firepower recommends the use of these devices whenever possible.

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

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 the removal of such substances.

FLUX CORED ARC WELDING (FCAW): An arc 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 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.

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

FORGING: Metallic shapes being derived by either hammering or squeezing the original piece of metal into 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, or of base metal only, to produce a weld.

G

GAS: The state of matter in which molecules move freely, allowing it to expand completely to fill any space that it occupy.

GAS CYLINDER: A portable container used for transportation and storage of compressed gas.

GAS LENS: One or more fine mesh screens are 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 POCKETS: Cavities in weld metal caused by entrapping gas (porosity).

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 welding 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.

GOUGING: A thermal cutting process variation that removes metal by melting or burning the entire removed portion, to form a bevel or groove. For more information on gouging techniques, see Gouging Techniques for Specific Materials.

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

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

GROUND CONNECTION: An electrical connection of the welding machine frame to the earth for safety.

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

H

HARD FACING (NON-STANDARD TERM: HARD SURFACING): A surfacing variation in which surfacing material is deposited to reduce wear.

HEAT CONDUCTIVITY: Speed and efficiency of heat energy movement through a substance.

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

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.

HEATING: A process of heating various metals with direct application of single or multi-flames to a desired elevated temperature in order to perform the following metal fabrication processes: straightening or bending, stress relieving, flame hardening or flame shrinking.

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

HOSE: Flexible medium used to carry gases from the regulator to the torch. Constructed of continuous layers of rubber or neoprene material over a braided inner section.

HOT PASS: A non-standard term when used in pipe welding for the weld pass subsequent to the root pass.

HOT START CURRENT: A very brief current pulse at arc initiation to stabilize the arc quickly.

HYDROGEN: A gas formed of the single element hydrogen. It is considered one of the most active gases. When combined with oxygen, it forms a very clean flame.

I

IGNITION: The action of firing an explosive mixture of gases or vapors by means of a flame, electric spark, heating of sudden pressure change.

INCLUDED ANGLE: The angle of the groove between the two work pieces that are welded together. A non-standard term when used for groove angle.

INCLUSION: Entrapped foreign solid material in a weld, 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).

INSIDE CORNER WELD: Two metals fused together; one metal is held 90° to the other. The fusion is performed inside the vertex of the angle.

INTERMEDIATE WELD PASS: A single progression of welding along a joint subsequent to the root pass(es) and prior to the cover pass(es).

INTERMITTENT WELD: A weld which the continuity is broken by recurring unwed spaces.

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

J

JOINING: Connecting two pieces of base metal (e.g. copper tubing) with a capillary fitting, sealing those pieces with a filler that is melted by heating the base metal with a torch.

JOINT: The junction of members, or 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 depth a weld extends from its face into a joint, exclusive of reinforcement.

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.

K

KERF: The gap produced by a cutting process.

KEYHOLE WELDING: A technique in which a concentrated heat source penetrates partially or completely through a work piece, forming a hole (keyhole) at the leading edge of the weld pool. As the heat source progresses, the molten fills in behind the hole to form the weld bead.

KINDLING TEMPERATURE: The temperature at which a substance will catch on fire and continue to burn, also referred to as the “ignition point”.

KNEE: The supporting structure of the lower arm in a resistance welding machine.

KNURLING: A method of surface roughening in which the surface is upset with a knurling tool.

L

LAND: A non-standard term for root face.

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

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

LENS: (See Filter Lens) Liquefied Gas: A substance which is gaseous at ambient temperature and atmospheric pressure but has been transformed into liquid by changing its temperature and/or pressure. If the critical temperature for the substance is above the ambient temperature it can be liquefied by either lowering the temperature or increasing the pressure. If it’s critical temperature is below ambient it cannot be liquefied by applying pressure alone, it must also be cooled.

LIQUIDUS: The liquidus temperature is the higher temperature at which the filler metal is completely melted. This is minimum temperature at which brazing will take place.

M

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.

MELTING RANGE: The difference between solidus and liquidus temperatures is how the melting range is determined. This is the working range for the filler metal and the speed with which the filler metal will become solid after brazing. Filler metals with narrow ranges, with or without silver, solidify more quickly and therefore require careful heat application.

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 non-standard term for flux cored arc welding or gas metal arc welding. It stands for metal inert gas.

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

N

NEUTRAL FLAME: An Oxy-fuel gas flame in which the portion used is neither oxidizing nor reducing.

NFPA: Abbreviation for “National Fire Protection Association”. Fuel gas flame in which the portion used is neither oxidizing nor reducing.

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.

O

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

OPEN ROOT JOINT: An unwelded joint without backing or consumable insert.

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

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

OUTSIDE CORNER WELD: Fusing two pieces of metal together with the fusion taking place on the underside of the seam.

OVERHEAD POSITION: The position in which welding is performed from the underside of the joint.

OVERLAP: The protrusion of weld metal beyond the weld toe or weld root.

OXIDIZING: Combining oxygen with any other substance. For example, a metal is oxidized when the metal is burned, i.e., oxygen is combined with all the metal or parts of it.

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

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

OXY-ACETYLENE WELDING: An Oxy-fuel gas cutting process used to burn metals by means of 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 process used to sever metals by means of the reaction of oxygen with the base metal at elevated temperatures. The necessary temperature is maintained by gas flames resulting from the combustion of fuel with oxygen. An Oxy-fuel gas welding process produces fused metals by heating them with a gas flame or flames obtained from the combustion of acetylene with oxygen. The process may be used with or without the application of pressure and with or without the use of a filler metal.

OXY-FUEL 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: A gas formed of the element oxygen. When oxygen actively supports combustion, it is called burning; when oxygen is slowly combined with a substance it is called oxidation.

OXYGEN CUTTING: A process of cutting ferrous metals by means of the chemical action of oxygen on elements in the base metal at elevated temperatures.

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

OXYGEN L.P. GAS FLAME: Chemical combining of oxygen with the fuel gas L.P. (liquefied petroleum).

OXYGEN REGULATOR: A device used to reduce cylinder pressure to torch pressure and to keep the pressure constant. They are never to be used as fuel gas regulators.

PENETRATION: A non-standard term for joint penetration.

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.

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.

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

POST FLOW TIME: The time interval 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 measurement equal to a mass or weight applied to one square inch of surface area.

POWER SOURCE: An apparatus for supplying current and voltage suitable for welding, thermal cutting or thermal spraying.

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

PRE-FLOW 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 multi-pass weld, it is also the temperature immediately before the second and subsequent passes are started.

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

PROPANE: A fuel gas. A member of the paraffin family. A hydrocarbon molecule comprising three carbon atoms and eight hydrogen atoms, C₃H₈.

PROPYLENE: A fuel gas. A member of the olefin family. A hydrocarbon molecule comprising three carbon atoms and six hydrogen atoms, C₃H₆. Two of the carbon atoms form a double covalent bond in which two pairs of electrons are shared.

PUDDLE: A non-standard term for welding pool.

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

PULSED GAS TUNGSTEN ARC WELDING (GTAW-P): A gas 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.

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

R

REDUCING FLAME: A flame having a reducing effect due to excess fuel gas.

REVERSE FLOW CHECK VALVES: Helps to prevent the reverse flow of gases from traveling past the check valve. Firepower recommends the use of these devices whenever possible.

ROOT BEAD: A weld bead that extends into or includes part or the entire joint root.

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

S

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.

SEMI-AUTOMATIC 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 non-metallic product resulting from the mutual dissolution of flux and non-metallic impurities in some welding and brazing processes.

SLAG INCLUSION: Non-metallic solid material entrapped in the weld metal or between weld metal and base metal.

SOLDERING: A group of welding processes, soldering uses metal to join two pieces of metal. However, the metal added during the process has a melting point lower than that of the work piece, so only the added metal is melted, not the workpiece. Soldering uses metals with a melting point below 800°f (427°c). The filler metal is distributed between the closely fitted surfaces of the joint capillary action.

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

SPATTER: The metal particles expelled during fusion welding 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 of one 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.

STANDARD CUBIC FEET PER HOUR (SCFH): USC unit for a volumetric flow rate of air or gas (same as free air or free gas) at a temperature of 15,6°c (60°f) and an absolute pressure of 101,3 KPA (14,7 psi), expressed in cubic feet per hour.

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 the tungsten electrode extends beyond the end of the gas nozzle.

STINGER: Term used for stick electrode holder.

STRAIN: Reaction of an object to stress.

STRESS: Load imposed on an object.

STRESS RELIEVING: Even heating of a structure to a temperature below the critical temperature followed by a slow, even cooling.

T

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

TENSILE STRENGTH: Maximum pull strength which a specimen is capable of withstanding.

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

TIG WELDING: A non-standard term for gas tungsten arc welding. It stands for tungsten inert gas.

TINNING: A non-standard term for precoating.

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

TOE OF WELD: (See Weld Toe) Joint formed by placing one metal against another at an angle of 90°. The 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 principally of tungsten.

TUNGSTEN INCLUSION: A discontinuity consisting of tungsten entrapped in the weld metal.

U

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

V

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

W

WELD AXIS: A line through the length of the weld, perpendicular to and at the geometric center of its cross-section.

WELD BEAD: A weld deposit resulting from a pass.

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

WELD METAL: Metal in a fusion weld consisting of that portion of the base metal and filler metal melted during welding.

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

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

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

WELD ROOT: The points, as shown in the cross-section, at which 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 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.

WELDING ARC: 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: A component of the welding circuit through which current is conducted and that terminates at the arc, molten conductive slag, or base metal.

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.

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

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

WELDING TORCH: A device used in gas cutting for controlling the gases used for preheating and the oxygen used for cutting the metal.

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

WELDMENT: Assembly of component parts joined together by welding.

WHIPPING: A manual welding technique in which the arc or flame is oscillated backward 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 the end of the welding electrode protruding from it.

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

WORKPIECE: The part that is welded, brazed, soldered, thermal cut, or thermal sprayed.

WORKPIECE CONNECTION: The connection of the workpiece leads to the workpiece.

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

Y

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

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