Robotic Terminology

Acetylene - A highly combustible gas composed of carbon and hydrogen. Used as a fuel gas in the oxyacetylene welding process.

Air-Carbon Arc Cutting (CAC-A) - An arc cutting process in which metals to be cut are melted by the heat of the carbon arc.

Alloy - A mixture with metallic properties composed of two or more elements, of which at least one is a metal.

Alternating Current - An electric current that reverses its direction at regularly recurring intervals.

Annealing - A comprehensive term used to describe the heating and cooling cycle of steel in the solid state. The term annealing usually implies relatively slow cooling.

Arc Blow - The deflection of an electric arc from its normal path because of magnetic forces.

Arc Brazing - A brazing process wherein the heat is obtained from an electric arc formed between the base metal and an electrode, or between two electrodes.

Arc Cutting - A group of cutting processes in which the cutting of metals is accomplished by melting with the heat of an arc between the electrode and the base metal.

Arc Force - Also called Dig and Arc Control. Gives a power source variable additional amperage during low voltage (short arc length) conditions while welding.

Arc Length - The distance between the tip of the electrode and the weld puddle.

Arc Voltage - The voltage across the welding arc.

Arc Welding - A group of welding processes in which fusion is obtained by heating with an electric arc or arcs, with or without the use of filler metal.

Arc-Oxygen Cutting - An oxygen-cutting process used to sever metals by a chemical reaction of oxygen with a base metal at elevated temperatures.

As Welded - The condition of weld metal, welded joints, and weldments after welding and prior to any subsequent thermal, mechanical, or chemical treatments.

Atomic Hydrogen Welding - An arc welding process in which fusion is obtained by heating with an arc maintained between two metal electrodes in an atmosphere of hydrogen. Pressure and/or filler metal may or may not be used.

Autogenous Welding - Method of uniting two pieces of metal by melting their edges together without solder or any added welding metal, as by the thermite process that employs a medium of finely divided aluminum powder and oxide or iron by which a temperature of some 2982.2°C (5400°F) is obtained.

Automatic Welding - Uses equipment which welds without the constant adjusting of controls by the welder or operator. Equipment controls joint alignment by using an automatic sensing device.

Axis Of A Weld - A line through the length of a weld, perpendicular to a cross section at its center of gravity.

Back Fire - The momentary burning back of a flame into the tip, followed by a snap or pop, then immediate reappearance or burning out of the flame.

Back Gouging - The removal of weld metal by arc gouging or grinding from the other side of a partially welded joint to assure complete penetration upon subsequent welding from that side.

Back Pass - A pass made to deposit a back weld.

Back Up - In flash and upset welding, a locator used to transmit all or a portion of the upsetting force to the workpieces.

Back Weld - A weld deposited at the back of a single groove weld.

Backhand Welding - A welding technique in which the flame is directed towards the completed weld.

Backing Strip - A piece of material used to retain molten metal at the root of the weld and/or increase the thermal capacity of the joint so as to prevent excessive warping of the base metal.

Backing Weld - A weld bead applied to the root of a single groove joint to assure complete root penetration.

Backstep - A sequence in which weld bead increments are deposited in a direction opposite to the direction of progress.

Bare Electrode - An arc welding electrode that has no coating other than that incidental to the drawing of the wire.

Bare Metal-Arc Welding - An arc welding process in which fusion is obtained by heating with an unshielded arc between a bare or lightly coated electrode and the work. Pressure is not used and filler metal is obtained from the electrode.

Base Metal - The metal to be welded or cut. In alloys, it is the metal present in the largest proportion.

Bead Weld - A type of weld composed of one or more string or weave beads deposited on an unbroken surface

Bevel Angle - The angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member.

Block Brazing - A brazing process in which bonding is produced by the heat obtained from heated blocks applied to the parts to be joined and by a nonferrous filler metal having a melting point above 800 °F (427 °C), but below that of the base metal.

Block Sequence - A building up sequence of continuous multipass welds in which separated lengths of the weld are completely or partially built up before intervening lengths are deposited.

Blowpipe - A device for mixing and burning gases to produce a flame for welding, brazing, bronze welding, cutting, heating and similar operations.

Bond - The junction of the welding metal and the base metal.

Boxing - The operation of continuing a fillet weld around a corner of a member as an extension of the principal weld.

Braze Welding - A method of welding by using a filler metal that liquefies above 450 °C (842 °F) and below the solid state of the base metals.

Brazing - A group of welding processes in which a groove, fillet, lap, or flange joint is bonded by using a nonferrous filler metal having a melting point above 800 °F (427 °C), but below that of the base metals. Filler metal is distributed in the joint by capillary attraction.

Bridging - A welding defect caused by poor penetration. A void at the root of the weld is spanned by weld metal.

Buckling - Distortion caused by the heat of a welding process.

Buildup Sequence - The order in which the weld beads of a multipass weld are deposited with respect to the cross section of a joint.

Burn Back - Fusing of the electrode wire to the current contact tube by sudden lengthening of the arc in any form of automatic or semi-automatic metal-arc welding using a bare electrode.

Butt Joint - A joint between two workpieces in such a manner that the weld joining the parts is between the surface planes of both of the pieces joined.

Butt Weld - A weld in a butt joint.

Butter Weld - A weld caused of one or more string or weave beads laid down on an unbroken surface to obtain desired properties or dimensions.

Carbide Precipitation - A condition occurring in austenitic stainless steel which contains carbon in a supersaturated solid solution. This condition is unstable. Agitation of the steel during welding causes the excess carbon in solution to precipitate.

Carbon Arc Welding - Arc welding using a carbon electrode or electrodes.

Carbon-Arc Cutting - A process of cutting metals with the heat of an arc between a carbon electrode and the work.

Carbon-Arc Welding - A welding process in which fusion is produced by an arc between a carbon electrode and the work. Pressure and/or filler metal and/or shielding may or may not be used.

Cascade Sequence - Subsequent beads are stopped short of a previous bead, giving a cascade effect.

Chain Intermittent Fillet Welds - Two lines of intermittent fillet welds in a T or lap joint in which the welds in one line are approximately opposite those in the other line.

Chain Intermittent Weld - An intermittent weld on each side of a joint (usually fillet welds in T and lap joints) arranged so that the welds lie opposite to one another along the joint.

Chamfering - The preparation of a welding contour, other than for a square groove weld, on the edge of a joint member.

Cladding - A relatively thick layer of (> 0.04" ) of material applied by surfacing for the purpose of improving corrosion resistance.

Co2 Flux Welding - Metal-arc welding in which a flux-coated or flux containing electrode is deposited under a shield of carbon dioxide.

Co2 Welding - Metal-arc welding in which a bare wire electrode is used the arc and molten pool being shielded with carbon dioxide.

Coalescence - The uniting or fusing of metals upon heating.

Commutory Controlled Welding - The making of a number of spot or projection welds in which several electrodes, in simultaneous contact with the work, progressively function under the control of an electrical commutating device.

Composite Electrode - A filler metal electrode used in arc welding, consisting of more than one metal component combined mechanically. It may or may not include materials that improve the properties of the weld, or stabilize the arc.

Composite Joint - A joint in which both a thermal and mechanical process are used to unite the base metal parts.

Concave Fillet Weld - A fillet weld in which the weld face is concave (curved inwards).

Concavity - The maximum perpendicular distance from the face of a concave weld to a line joining the toes.

Concurrent Heating - Supplemental heat applied to a structure during the course of welding.

Cone - The conical part of a gas flame next to the orifice of the tip.

Constant Current (Cc) Welding Machine - These welding machines have limited maximum short circuit current. They have a negative volt-amp curve and are often referred to as "droopers".

Constant Voltage (CV), Constant Potential (CP) Welding Machine - "Potential" and "voltage" are basically the same in meaning. This type of welding machine output maintains a relatively stable, consistent voltage regardless of the amperage output.

Constant-Feed Wire Feeder - Feeder operates from 24 or 115 VAC supplied by the welding power source.

Consumable Insert - Preplaced filler metal which is completely fused into the root of the joint and becomes part of the weld.

Continuous Weld - A weld extending along the entire length of a joint.

Convexity - The maximum perpendicular distance from the face of a convex fillet weld to a line joining the toes.

Cover Glass - A clear glass used in goggles, hand shields, and helmets to protect the filter glass from spattering material.

Covered Electrode - A metal electrode with a covering material which stabilizes the arc and improves the properties of the welding metal. The material may be an external wrapping of paper, asbestos, and other materials or a flux covering.

Crack - A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.

Crater - A depression at the termination of an arc weld.

Current - Another name for amperage. The amount of electricity flowing past a point in a conductor every second.

Cutting Electrode - An electrode with a covering that aids the production of such an arc that molten metal is blown away to produce a groove or cut in the work.

Cutting Oxygen - Oxygen used at a pressure suitable for cutting.

Cutting Tip - A gas torch tip especially adapted for cutting.

Cutting Torch - A device used in gas cutting for controlling the gases used for preheating and the oxygen used for cutting the metal.

De-Seaming - A method of metal-arc welding in which fused particles of the electrode wire in contact with the molten pool are detached from the electrode in rapid succession by the short circuit current, which develops every time the wire touches the molten pool.

Deposited Metal - Filler metal that has been added during a welding operation.

Depth Of Fusion - The distance from the original surface of the base metal to that point at which fusion ceases in a welding operation.

Die - a. Resistance Welding. A member, usually shaped to the work contour, used to clamp the parts being welded and conduct the welding current. b. Forge Welding. Devices used in forge welding primarily to form the work while hot and apply the necessary pressure.

Die Welding - A forge welding process in which fusion is produced by heating in a furnace and by applying pressure by means of dies.

Dip Transfer - A method of metal-arc welding in which fused particles of the electrode wire in contact with the molten pool are detached from the electrode in rapid succession by the short circuit current, which develops every time the wire touches the molten pool.

Direct Current (DC) - Flows in one direction and does not reverse its direction of flow as does alternating current.

Direct Current Electrode Negative (Dcen) - The specific direction of current flow through a welding circuit when the electrode lead is connected to the negative terminal and the work lead is connected to the positive terminal of a DC welding machine. Also called direct current, straight polarity (DCSP).

Direct Current Electrode Positive (DCEP) - The specific direction of current flow through a welding circuit when the electrode lead is connected to a positive terminal and the work lead is connected to a negative terminal to a DC welding machine. Also called direct current, reverse polarity (DCRP).

Ductility - The property of a metal which allows it to be permanently deformed, in tension, before final rupture.

Duty Cycle - The number of minutes out of a 10-minute time period an arc welding machine can be operated at maximum rated output.

Edge Joint - A joint between the edges of two or more parallel or nearly parallel members.

Edge Preparation - The contour prepared on the edge of a joint member for welding.

Effective Length Of Weld - The length of weld throughout which the correctly proportined cross section exits.

Electrode - A filler metal in the form of a wire or rod, whether bare or covered, through which current is conducted between the electrode holder and the arc.

Electrode Force - In spot, seam, and projection welding, the force (pounds) between the electrodes during the actual welding cycle.

Electrode Skid - The sliding of an electrode along the surface of the work during spot, seam, or projection welding.

Electron-Beam Cutting - Thermal cutting in vacuum by melting and vaporizing a narrow section of the metal by the impact of a focused beam of electrons.

Etching - A process of preparing metallic specimens and welds for macrographic or micrographic examination.

Excess Penetration Bead - Excessive metal protruding through the root of a fusion weld made from one side only.

Face Bend Test - A bend test in which a specified side of the weld Normal bend test.

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.

Face Reinforcement - Reinforcement of weld at the side of the joint from which welding was done.

Filler Metal - Metal to be added in making a weld.

Fillet Weld - A weld of approximately triangular cross section, as used in a lap joint, joining two surfaces at approximately right angles to each other.

Fixed Automation - Automated, electronically controlled welding system for simple, straight or circular welds.

Flame Hardening - A method for hardening a steel surface by heating with a gas flame followed by a rapid quench.

Flame Softening - A method for softening steel by heating with a gas flame followed by slow cooling.

Flash - Metal and oxide expelled from a joint made by a resistance welding process.

Flash Welding - A resistance welding process in which fusion is produced, simultaneously over the entire area of abutting surfaces, by the heat obtained from resistance to the flow of current between two surfaces and by the application of pressure after heating is substantially completed. Flashing is accompanied by expulsion of metal from the joint.

Flashback - The burning of gases within the torch or beyond the torch in the hose, usually with a shrill, hissing sound.

Flat Position - The position in which welding is performed from the upper side of the joint and the face of the weld is approximately horizontal.

Flexible Automation - Automated, robotically controlled welding system for complex shapes and applications where welding paths require torch-angle manipulation.

Flow Welding - A process in which fusion is produced by heating with molten filler metal poured over the surfaces to be welded until the welding temperature is attained and the required filler metal has been added. The filler metal is not distributed in the joint by capillary attraction.

Flux - A cleaning agent used to dissolve oxides, release trapped gases and slag, and to cleanse metals for welding, soldering, and brazing.

Flux Cored Arc Welding (FCAW) - An arc welding process which melts and joins metals by heating them with an arc between a continuous, consumable electrode wire and the work. Shielding is obtained from a flux contained within the electrode core. Depending upon the type of flux-cored wire, added shielding may or may not be provided from externally supplied gas or gas mixture. Consumables: contact tips, flux cored wire, shielding gas (if required, depends on wire type).

Forehand Welding - A gas welding technique in which the flare is directed against the base metal ahead of the completed weld.

Forge Welding - A group of welding processes in which fusion is produced by heating in a forge or furnace and applying pressure or blows.

Full Fillet Weld - A fillet weld whose size is equal to the thickness of the thinner member joined.

Fusion - A thorough and complete mixing between the two edges of the base metal to be joined or between the base metal and the filler metal added during welding.

Fusion Zone (Filler Penetration) - The area of base metal melted as determined on the cross section of a weld.

Gas Carbon-Arc Welding - An arc welding process in which fusion is produced by heating with an electric arc between a carbon electrode and the work. Shielding is obtained from an inert gas such as helium or argon. Pressure and/or filler metal may or may not be used.

Gas Metal Arc Welding (GMAW ) - An arc welding process in which fusion is produced by heating with an electric arc between a metal electrode and the work. Shielding is obtained from an inert gas such as helium or argon. Pressure and/or filler metal may or my not be used.

Gas Pocket - A weld cavity caused by the trapping of gases released by the metal when cooling.

Gas Tungsten-Arc Welding (GTAW) - An arc welding process in which fusion is produced by heating with an electric arc between a tungsten electrode and the work while an inert gas forms around the weld area to prevent oxidation. No flux is used.

Gas Welding - A process in which the welding heat is obtained from a gas flame.

Globular Transfer (Arc Welding ) - A type of metal transfer in which molten filler metal is transferred across the arc in large droplets.

Groove - The opening provided between two members to be joined by a groove weld.

Groove Angle - The included angle of the groove between parts to be joined by a groove weld.

Groove Weld - A weld made by depositing filler metal in a groove between two members to be joined.

Hammer Welding - A forge welding process.

Hand Shield - A device used in arc welding to protect the face and neck. It is equipped with a filter glass lens and is designed to be held by hand.

Heat Affected Zone - That portion of the base metal whose structure or properties have been changed by the heat of welding or cutting.

Heat Time - The duration of each current impulse in pulse welding.

Heat Treatment - An operation or combination of operations involving the heating and cooling of a metal or an alloy in the solid state for the purpose of obtaining certain desirable conditions or properties. Heating and cooling for the sole purpose of mechanical working are excluded from the meaning of the definition.

Heating Gate - The opening in a thermite mold through which the parts to be welded are preheated.

Hertz - Hertz is often referred to as "cycles per second".

High Frequency - Used in TIG welding for arc ignition and stabilization.

Hold Time - The time that pressure is maintained at the electrodes after the welding current has stopped.

Horizontal Weld - A bead or butt welding process with its linear direction horizontal or inclined at an angle less than 45 degrees to the horizontal, and the parts welded being vertically or approximately vertically disposed.

Horn - The electrode holding arm of a resistance spot welding machine.

Horn Spacing - In a resistance welding machine, the unobstructed work clearance between horns or platens at right angles to the throat depth.

Hygroscopic - Readily absorbing and retaining moisture.

Impregnated-Tape Metal-Arc Welding - An arc welding process in which fusion is produced by heating with an electric arc between a metal electrode and the work. Shielding is obtained from decomposition of impregnated tape wrapped around the electrode as it is fed to the arc. Pressure is not used, and filler metal is obtained from the electrode.

Induction Welding - A process in which fusion is produced by heat obtained from resistance of the work to the flow of induced electric current, with or without the application of pressure.

Inert Gas - A gas which does not normally combine chemically with the base metal or filler metal.

Intermittent Weld - A series of welds at intervals along a joint. Can also be staggered, where An intermittent weld on each side of a joint (usually fillet welds in T and lap joints) arranged so that the welds on one side lie opposite the spaces on the another side along the joint.

Interpass Temperature - In a multipass weld, the lowest temperature of the deposited weld meal before the next pass is started.

Inverter - Power source which increases the frequency of the incoming primary power, thus providing for a smaller size machine and improved electrical characteristics for welding, such as faster response time and more control for pulse welding.

Joint - The portion of a structure in which separate base metal parts are joined.

Joint Penetration - The maximum depth a groove weld extends from its face into a joint, exclusive of reinforcement.

Kerf - The space from which metal has been removed by a cutting process.

KW - Kilowatts. Primary KW is the actual power used by the power source when it is producing its rated output.

Lap Joint - A joint between two overlapping members.

Layer - A stratum of weld metal, consisting of one or more weld beads.

Leg Of A Fillet Weld - The distance from the root of the joint to the toe of the fillet weld.

Liquidus - The lowest temperature at which a metal or an alloy is completely liquid.

Manifold - A multiple header for connecting several cylinders to one or more torch supply lines.

Mash Seam Welding - A seam weld made in a lap joint in which the thickness at the lap is reduced to approximately the thickness of one of the lapped joints by applying pressure while the metal is in a plastic state.

Melting Point - The temperature at which a metal begins to liquefy.

Metal-Arc Cutting - The process of cutting metals by melting with the heat of the metal arc.

Metal-Arc Welding - An arc welding process in which a metal electrode is held so that the heat of the arc fuses both the electrode and the work to form a weld.

Metallizing - A method of overlay or metal bonding to repair worn parts.

Microprocessor - One or more integrated circuits that can be programmed with stored instructions to perform a variety of functions.

MIG (GMAW or Gas Metal Arc Welding) - An arc welding process which joins metals by heating them with an arc. The arc is between a continuously fed filler metal (consumable) electrode and the workpiece. Externally supplied gas or gas mixtures provide shielding. Common MIG welding is also referred to as short circuit transfer. Metal is deposited only when the wire actually touches the work. No metal is transferred across the arc.

Mixing Chamber - That part of a welding or cutting torch in which the gases are mixed for combustion.

Multi-Impulse Welding - The making of spot, projection, and upset welds by more than one impulse of current. When alternating current is used each impulse may consist of a fraction of a cycle or a number of cycles.

Nonferrous - Metals which contain no iron. Aluminum, brass, bronze, copper, lead, nickel, and titanium are nonferrous.

Normalizing - Heating iron-base alloys to approximately 100 °F (38 °C) above the critical temperature range followed by cooling to below that range in still air at ordinary temperature.

Nugget - The fused metal zone of a resistance weld.

Open Circuit Voltage - No current is flowing in the circuit because the circuit is open. The voltage is impressed upon the circuit so that when the circuit is completed, the current will flow immediately.

Overhead Position - The position in which welding is performed from the underside of a joint and the face of the weld is approximately horizontal.

Overlap - The protrusion of weld metal beyond the bond at the toe of the weld.

Oxidizing Flame - An oxyacetylene flame in which there is an excess of oxygen. The unburned excess tends to oxidize the weld metal.

Oxy-Hydrogen Welding - A gas welding process in which the required welding temperature is attained by flames obtained from the combustion of hydrogen with oxygen.

Oxyacetylene Welding - A welding process in which the required temperature is attained by flames obtained from the combustion of acetylene with oxygen.

Pass - The weld metal deposited in one general progression along the axis of the weld.

Peening - The mechanical working of metals by means of hammer blows. Peening tends to stretch the surface of the cold metal, thereby relieving contraction stresses.

Percussive Welding - A resistance welding process in which a discharge of electrical energy and the application of high pressure occurs simultaneously, or with the electrical discharge occurring slightly before the application of pressure.

Pitch - Center to center spacing of welds.

Plasma - The fourth state of matter following solid, liquid, and gas. Plasma is an ionized (electrified) form of gas. In plasma cutting, a gas such as Nitrogen is sent under pressure through the torch where it begins to swirl and is forced out a small orifice at which point it passes through an electric arc and the gas is ionized. The electricity "excites" the electrons of the gas atoms.

Plasma Arc Cutting - An arc cutting process which severs metal by using a constricted arc to melt a small area of the work. This process can cut all metals that conduct electricity. Miller Spectrum cutters are complete packages that contain all required equipment and torch consumables. Consumables: torch consumables, gas or compressed air supply.

Plug Weld - A weld is made in a hole in one member of a lap joint, joining that member to that portion of the surface of the other member which is exposed through the hole. The walls of the hole may or may not be parallel, and the hole may be partially or completely filled with the weld metal.

Poke Welding - A spot welding process in which pressure is applied manually to one electrode. The other electrode is clamped to any part of the metal much in the same manner that arc welding is grounded.

Porosity - The presence of gas pockets or inclusions in welding.

Positions of Welding - All welding is accomplished in one of four positions: flat, horizontal, overhead, and vertical. The limiting angles of the various positions depend somewhat as to whether the weld is a fillet or groove weld

Postheating - The application of heat to an assembly after a welding operation.

Postweld Interval - In resistance welding, the heat time between the end of weld time, or weld interval, and the start of hold time. During this interval, the weld is subjected to mechanical and heat treatment.

Power Factor Correction - Normally used on single-phase, constant current power sources, to reduce the amount of primary amperage demanded from the power company while welding.

Preheating - The application of heat to a base metal prior to a welding or cutting operation.

Pressure Controlled Welding - The making of a number of spot or projection welds in which several electrodes function progressively under the control of a pressure sequencing device.

Pressure Welding - Any welding process or method in which pressure is used to complete the weld.

Preweld Interval - In spot, projection, and upset welding, the time between the end of squeeze time and the start of weld time or weld interval during which the material is preheated. In flash welding, it is the time during which the material is preheated.

Procedure Qualification - The demonstration that welds made by a specific procedure can meet prescribed standards.

Projection Welding - A resistance welding process between two or more surfaces or between the ends of one member and the surface of another. The welds are localized at predetermined points or projections.

Pulsation Welding - A spot, projection, or seam welding process in which the welding current is interrupted one or more times without the release of pressure or change of location of electrodes.

Pulsed MIG (MIG-P) - A modified spray transfer process that produces no spatter because the wire does not touch the weld puddle.

Pulsed TIG (TIG-P) - A modified TIG process appropriate for welding thinner materials. Consumables: tungsten electrode, filler material, shielding gas.

Pulsing - Sequencing and controlling the amount of current, the polarity, and the duration of the welding arc.

Push Welding - The making of a spot or projection weld in which the force is aping current is interrupted one or more times without the release of pressure or change of location of electrodes.

Quenching - The sudden cooling of heated metal with oil, water, or compressed air.

Regulator - A device used to reduce cylinder pressure to a suitable torch working pressure.

Reinforced Weld - The weld metal built up above the surface of the two abutting sheets or plates in excess of that required for the size of the weld specified.

Resistance Brazing - A brazing process in which bonding is produced by the heat obtained from resistance to the flow of electric current in a circuit of which the workpiece is a part, and by using a nonferrous filler metal having a melting point above 800 °F (427 °C), but below that of the base metals. The filler metal is distributed in the joint by capillary attraction.

Resistance Butt Welding - A group of resistance welding processes in which the weld occurs simultaneously over the entire contact area of the parts being joined.

Resistance Spot Welding (RSW) - A process in which two pieces of metal are joined by passing current between electrodes positioned on opposite sides of the pieces to be welded. There is no arc with this process, and it is the resistance of the metal to the current flow that causes the fusion.

Resistance Welding - A group of welding processes in which fusion is produced by heat obtained from resistance to the flow of electric current in a circuit of which the workpiece is a part and by the application of pressure.

Reverse Polarity - The arrangement of direct current arc welding leads in which the work is the negative pole and the electrode is the positive pole of the welding arc.

Root Crack - A crack in the weld or base metal which occurs at the root of a weld.

Root Edge - The edge of a part to be welded which is adjacent to the root.

Root Face - The portion of the prepared edge of a member to be joined by a groove weld which is not beveled or grooved.

Root Of Joint - That portion of a joint to be welded where the members approach closest to each other. In cross section, the root of a joint may be a point, a line, or an area.

Root Of Weld - The points, as shown in cross section, at which the bottom of the weld intersects the base metal surfaces.

Root Opening - The separation between the members to be joined at the root of the joint.

Root Penetration - The depth a groove weld extends into the root of a joint measured on the centerline of the root cross section.

Scarfing - A process for removing defects and checks which develop in the rolling of steel billets by the use of a low velocity oxygen deseaming torch.

Seal Weld - A weld used primarily to obtain tightness and to prevent leakage.

Seam Welding - Welding a lengthwise seam in sheet metal either by abutting or overlapping joints.

Semiautomatic Welding - The equipment controls only the electrode wire feeding. The welding gun movement is controlled by hand.

Series Welding - A resistance welding process in which two or more welds are made simultaneously by a single welding transformer with the total current passing through each weld.

Sheet Separation - In spot, seam, and projection welding, the gap surrounds the weld between faying surfaces, after the joint has been welded.

Shielded Welding - An arc welding process in which protection from the atmosphere is obtained through use of a flux, decomposition of the electrode covering, or an inert gas.

Shielding Gas - Protective gas used to prevent atmospheric contamination of the weld pool.

Single Impulse Welding - The making of spot, projection, and upset welds by a single impulse of current. When alternating current is used, an impulse may consist of a fraction of a cycle or a number of cycles.

Size of Weld - The joint penetration depth of chamfering plus the root penetration when specified. The weld metal thickness measured at the root of the weld.

Slag Inclusion - Non-metallic solid material entrapped in the weld metal or between the weld metal and the base metal.

Slot Weld - A weld made in an elongated hole in one member of a lap or tee joint joining that member to that portion of the surface of the other member which is exposed through the hole.

Slugging - Adding a separate piece or pieces of material in a joint before or during welding with a resultant welded joint that does not comply with design drawing or specification requirements.

Soldering - A group of welding processes which produce coalescence of materials by heating them to suitable temperature and by using a filler metal having a liquidus not exceeding 450 °C (842 °F) and below the solidus of the base materials.

Spacer Strip - A metal strip or bar inserted in the root of a joint prepared for a groove weld to serve as a backing and to maintain the root opening during welding.

Spall - Small chips or fragments which are sometimes given off by electrodes during the welding operation.

Spatter - The metal particles expelled during arc and gas welding which do not form a part of the weld.

Spot Welding - A resistance welding process in which fusion is produced by the heat obtained from the resistance to the flow of electric current through the workpieces held together under pressure by electrodes. The size and shape of the individually formed welds are limited by the size and contour of the electrodes.

Spray Transfer - A type of metal transfer in which molten filler metal is propelled axially across the arc in small droplets.

Staggered Intermittent Fillet Weld - Two lines of intermittent welding on a joint, such as a tee joint, wherein the fillet increments in one line are staggered with respect to those in the other line.

Stick Welding (SMAW or Shielded Metal Arc) - An arc welding process which melts and joins metals by heating them with an arc, between a covered metal electrode and the work. Shielding gas is obtained from the electrode outer coating, often called flux. Filler metal is primarily obtained from the electrode core. An AC/DC welder is recommended for Stick. For most applications, DC reverse polarity welding offers advantages over AC, including easier starts and out-of-position welding, smoother arc and fewer arc outages and sticking.

Stored Energy Welding - The making of a weld with electrical energy accumulated electrostatically, electronagnetically, or electrochemically at a relatively low rate and made available at the required welding rate.

Straight Polarity - The arrangement of direct current arc welding leads in which the work is the positive pole and the electrode is the negative pole of the welding arc.

Stress Relieving - A process of reducing internal residual stresses in a metal object by heating to a suitable temperature and holding for a proper time at that temperature.

String Bead Welding - A method of metal arc welding on pieces 3/4 in. (19 mm) thick or heavier in which the weld metal is deposited in layers composed of strings of beads applied directly to the face of the bevel.

Stud Welding - An arc welding process in which fusion is produced by heating with an electric arc drawn between a metal studs, or similar part, and the other workpiece, until the surfaces to be joined are properly heated. They are brought together under pressure.

Submerged Arc Welding - An arc welding process in which fusion is produced by heating with an electric arc or arcs between a bare metal electrode or electrodes and the work. The welding is shield by a blanket of granular, fusible material on the work. Pressure is not used. Filler metal is obtained from the electrode, and sometimes from a supplementary welding rod.

Tack Weld - A weld made to hold parts of a weldment in proper alignment until the final welds are made.

Temper Time - In resistance welding, that part of the postweld interval during which a current suitable for tempering or heat treatment flows. The current can be single or multiple impulse, with varying heat and cool intervals.

Tempering - Reheating hardened steel to some temperature below the lower critical temperature, followed by a desired rate of cooling.

Thermite Mold - A mold formed around the parts to be welded to receive the molten metal.

Thermite Welding - A group of welding processes in which fusion is produced by heating with superheated liquid metal and slag resulting from a chemical reaction between a metal oxide and aluminum, with or without the application of pressure. Filler metal, when used, is obtained from the liquid metal.

Throat Depth - In a resistance welding machine, the distance from the centerline of the electrodes or platens to the nearest point of interference for flatwork or sheets. In a seam welding machine with a universal head, the throat depth is measured with the machine arranged for transverse welding.

Throat Of Fillet Weld - The distance from the root of the fillet weld to the center of its face.

TIG Welding (GTAW Or Gas Tungsten Arc) - Often called TIG welding (Tungsten Inert Gas), this welding process joins metals by heating them with a tungsten electrode which should not become part of the completed weld. Filler metal is sometimes used and argon inert gas or inert gas mixtures are used for shielding. Consumables: tungsten electrode, filler metal, shielding gas.

Toe Crack - A crack in the base metal occurring at the toe of the weld.

Toe Of The Weld - The junction between the face of the weld and the base metal.

Torch Brazing - A brazing process in which bonding is produced by heating with a gas flame and by using a nonferrous filler metal having a melting point above 800 °F (427 °C), but below that of the base metal. The filler metal is distributed in the joint of capillary attraction.

Touch Start - A low-voltage, low-amperage arc starting procedure for TIG (GTAW). The tungsten is touched to the workpiece; when the tungsten is lifted from the workpiece an arc is established.

Transverse Seam Welding - The making of a seam weld in a direction essentially at right angles to the throat depth of a seam welding machine.

Tungsten - Rare metallic element with extremely high melting point (3410o Celsius). Used in manufacturing TIG electrodes.

Tungsten Electrode - A non-filler metal electrode used in arc welding or cutting, made principally of tungsten.

Underbead Crack - A crack in the heat affected zone not extending to the surface of the base metal.

Undercutting - An undesirable crater at the edge of the weld caused by poor weaving technique or excessive welding speed.

Upset - A localized increase in volume in the region of a weld, resulting from the application of pressure.

Upset Welding - A resistance welding process in which fusion is produced simultaneously over the entire area of abutting surfaces, or progressively along a joint, by the heat obtained from resistance to the flow of electric current through the area of contact of those surfaces.

Upsetting Force - The force exerted at the welding surfaces in flash or upset welding.

Vertical Position - The position of welding in which the axis of the weld is approximately vertical.

Volt-Amp Curve - Graph that shows the output characteristics of a welding power source. Shows voltage and amperage capabilities of a specific machine.

Voltage - The pressure or force that pushes the electrons through a conductor.

Voltage-Sensing Wire Feeder - Feeder operates from arc voltage generated by welding power source.

Wandering Block Sequence - A block welding sequence in which successive weld blocks are completed at random after several starting blocks have been completed.

Wandering Sequence - A longitudinal sequence in which the weld bead increments are deposited at random.

Wax Pattern - Wax molded around the parts to be welded by a thermit welding process to the form desired for the completed weld.

Weave Bead - A type of weld bead made with transverse oscillation.

Weaving - A technique of depositing weld metal in which the electrode is oscillated. It is usually accomplished by a semicircular motion of the arc to the right and left of the direction of welding. Weaving serves to increase the width of the deposit, decreases overlap, and assists in slag formation.

Weld - A localized fusion of metals produced by heating to suitable temperatures. Pressure and/or filler metal may or may not be used. The filler make has a melting point approximately the same or below that of the base metals, but always above 800 °F (427 °C).

Weld Bead - A weld deposit resulting from a pass.

Weld Gauge - A device designed for checking the shape and size of welds.

Weld Metal - That portion of a weld that has been melted during welding.

Weld Symbol - A picture used to indicate the desired type of weld.

Weldability - The capacity of a material to form a strong bond of adherence under pressure or when solidifying from a liquid.

Welder Certification - Certification in writing that a welder has produced welds meeting prescribed standards.

Welding Leads - The electrical conductor between the source of the arc welding current and the electrode holder.

Welding Pressure - The pressure exerted during the welding operation on the parts being welded.

Welding Procedure - The detailed methods and practices including all joint welding procedures involved in the production of a weldment.

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

Welding Symbol - The assembled symbol consists of the following eight elements, or such of these as are necessary: reference line, arrow, basic weld symbols, dimension and other data, supplementary symbols, finish symbols, tail, specification, process, or other references.

Welding Technique - The details of a manual, machine, or semiautomatic welding operation which, within the limitations of the prescribed joint welding procedure, are controlled by the welder or welding operator.

Welding Tip - The tip of a gas torch especially adapted to welding.

Welding Torch - A device used in gas welding and torch brazing for mixing and controlling the flow of gases.

Welding Transformer - A device for providing current of the desired voltage.

Weldment - An assembly whose component parts are formed by welding.

Work Lead - The electric conductor (cable) between the source of arc welding current and the workpiece.

Workpiece Connection - A means to fasten the work lead (work cable) to the work (metal to be welded on).

Workpiece Lead - The conductor cable or electrical conductor between the arc welding machine and the work.

WPS - Weld Procedure Specification.

Yield Point - The yield point is the load per unit area value at which a marked increase in deformation of the specimen occurs with little or no increase of load.