Welding Terms & Definitions Part Two

This overview (Part Two) describes the most commonly used terms in the complex metal joining process through welding.
The welding glossary, according to The American Welding Society (AWS) standard A3.0M/A3.0 includes hundreds of terms, which are presented here in a condensed and adapted form.

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

MARTENSITE
Martensite is a microconstituent or structure in quenched steel characterized by an acicular or needle-like pattern on the surface of polish. It has the maximum hardness of any of the structures resulting from the decomposition products of austenite.

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.

MELTING RANGE
The temperature range between solidus and liquidus.

MELTING RATE
The weight or length of electrode melted in a unit of time.

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.

MIG
Gas metal arc welding. Also called MIG for Metal-Inert-Gas. A gun holds the electrode which is the same as the filler rod. The filler rod is fed from a spool eliminating the need to stop and start. Used primarily for welding aluminum and steel.

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.

MULTIPASS WELDS
When multiple welds are applied to one project.

NEUTRAL FLAME
A gas flame in which the oxygen and acetylene volumes are balanced and both gases are completely burned.

NICK BREAK TEST
A method for testing the soundness of welds by nicking each end of the weld, then giving the test specimen a sharp hammer blow to break the weld from nick to nick. Visual inspection will show any weld defects.

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

NORMALIZING
Heating iron-base alloys to approximately 100 ºF (38 ºC) 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.

OFW
Abbreviation for oxy-fuel welding. There are three processes in the Oxy group including oxyacetylene, oxyhydrogen and pressure gas welding.

OPEN CIRCUIT VOLTAGE
The voltage between the terminals of the welding source when no current is flowing in the welding circuit.

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.

OXYACETYLENE CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by flames obtained from the combustion of acetylene with oxygen.

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

OXY-ARC CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by means of an arc between an electrode and the base metal.

OXY-CITY GAS CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by flames obtained from the combustion of city gas with oxygen.

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 GOUGING
An application of oxygen cutting in which a chamfer or groove is formed.

OXY-HYDROGEN CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by flames obtained from the combustion of city gas with oxygen.

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.

OXY-NATURAL GAS CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by flames obtained by the combustion of natural gas with oxygen.

OXY-PROPANE CUTTING
An oxygen cutting process in which the necessary cutting temperature is maintained by flames obtained from the combustion of propane 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.

PENETRANT INSPECTION
A non-destructive testing method that detects surface flaws using either fluorescent or dye penetrants. Fluorescent penetrants glow under black light, while dye penetrants produce bright red indications when drawn to the surface by a developer. The process involves cleaning the surface, applying the penetrant, waiting for it to be absorbed, removing excess penetrant, and applying the developer to reveal any defects.

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.

PERLITE
Perlite is the lamellar aggregate of ferrite and iron carbide resulting from the direct transformation of austenite at the lower critical point.

PITCH
Center to center spacing of welds.

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, brazing, soldering, thermal spraying, or cutting 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.

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.

PUSH WELDING
A technique in welding where the welding gun is pushed forward in the direction of the weld, resulting in better visibility and control over the weld. This technique is commonly used in Gas Metal Arc Welding (GMAW) and is preferred for creating clean, spatter-free welds.

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

REACTION STRESS
The residual stress which could not otherwise exist if the members or parts being welded were isolated as free bodies without connection to other parts of the structure.

REDUCING FLAME
See CARBURIZING FLAME.

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.

RESIDUAL STRESS
Stress remaining in a structure or member as a result of thermal and/or mechanical treatment.

RESISITANCE 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 ºF (427 ºC), 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)
Uses electrical current which is passed through the metal. It does not require a filler rod. The process is easy to automate and requires low heat input.

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.

ROCKWELL HARDNESS TEST
In this test a machine measures hardness by determining the depth of penetration of a penetrator into the specimen under certain arbitrary fixed conditions of test. The penetrator may be either a steel ball or a diamond spherocone.

ROOT
See ROOT OF JOINT and ROOT OF WELD.

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.

SCARF
The chamfered surface of a joint.

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.

SELECTIVE BLOCK SEQUENCE
A block sequence in which successive blocks are completed in a certain order selected to create a predetermined stress pattern.

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 surrounding 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.

SHOULDER
See ROOT FACE.

SHRINKAGE STRESS
See RESIDUAL STRESS.

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 size of weld refers to the dimensions of the weld, typically its diameter or width and depth, depending on the type of weld. For fillet welds, the size is often described by the leg length, which is the distance from the joint root to the toe of the weld. For groove welds, the size could refer to the depth of penetration or the thickness of the weld bead. The size of the weld plays a critical role in determining the strength and performance of the welded joint.

SKIP SEQUENCE
See WANDERING SEQUENCE.

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. The hole may be open at one end and may be partially or completely filled with weld metal. (A fillet welded slot should not be construed as conforming to this definition.)

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.

SMAW
Shielded metal (stick) arc welding uses a consumable electrode that has a solid metal rod in the core. The rod and electrode melt down and become part of the weld. The electrode is flux coated to protect the weld from contamination.

SOLDERING
A group of welding processes that produce coalescence of materials by heating them to a suitable temperature and by using a filler metal having a liquidus not exceeding 450 ºC (842 ºF) and below the solidus of the base materials. The filler metal is distributed between the closely fitted surfaces of the joint by capillary action.

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

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. This problem is especially common with heavy-coated electrodes.

SPATTER
The metal particles expelled during arc and gas welding 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.

SPRAY WELDING
another term for spray arc welding or GMAW.

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.

STORED ENERGY WELDING
The making of a weld with electrical energy accumulated electrostatically, electromagnetically, 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. This treatment may be applied to relieve stresses induced by casting, quenching, normalizing, machining, cold working, or welding.

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 stud, 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 shielded 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.

SURFACING
The deposition of filler metal on a metal surface to obtain desired properties or dimensions.

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

TEE JOINT
A joint between two members located approximately at right angles to each other in the form of a T.

TEMPER COLORS
The colors which appear on the surface of steel heated at low temperature in an oxidizing atmosphere.

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. The object of tempering a steel that has been hardened by quenching is to release stresses set up, to restore some of its ductility, and to develop toughness through the regulation or readjustment of the embrittled structural constituents of the metal. The temperature conditions for tempering may be selected for a given composition of steel to obtain almost any desired combination of properties.

TENSILE STRENGTH
The maximum load per unit of original cross-sectional area sustained by a material during the tension test.

TENSION TEST
A test in which a specimen is broken by applying an increasing load to the two ends. During the test, the elastic properties and the ultimate tensile strength of the material are determined. After rupture, the broken specimen may be measured for elongation and reduction of area.

THERMIT CRUCIBLE
The vessel in which the thermit reaction takes place.

THERMIT MIXTURE
A mixture of metal oxide and finely divided aluminum with the addition of alloying metals as required.

THERMIT MOLD
A mold formed around the parts to be welded to receive the molten metal.

THERMIT REACTION
The chemical reaction between metal oxide and aluminum which produces superheated molten metal and aluminum oxide slag.

THERMIT 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
This term encompasses two measurements. The theoretical throat is the perpendicular distance from the root of the joint to the hypotenuse of the largest inscribable right triangle within the fillet-weld cross-section. The actual throat, on the other hand, refers to the distance from the root of the fillet weld to the center of its face. Both measurements are crucial in determining the strength and quality of the weld.

TIG
TIG is another name for GTAW (gas tungsten arc welding). This process uses a non-consumable tungsten electrode and an air cooled or water cooled torch. The process uses an electrical arc to generate heat, costs more than other processes, but is significantly cleaner.

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
See CUTTING TORCH or WELDING TORCH.

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 ºF (427 ºC), but below that of the base metal. The filler metal is distributed in the joint of capillary attraction.

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 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.

UNDERCUT
A groove melted into the base metal adjacent to the toe or root of a weld and left unfilled by weld 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. Pressure is applied before heating is started and is maintained throughout the heating period.

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. In pipe welding, the pipe is in a vertical position and the welding is done in a horizontal position.

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 metal has a melting point approximately the same or below that of the base metals, but always above 800 ºF (427 ºC).

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.

WELDER PERFORMANCE QUALIFICATION
The demonstration of a welder’s ability to produce welds meeting prescribed standards.

WELDING LEADS:
a. Electrode lead. The electrical conductor between the source of the arc welding current and the electrode holder.
b. Work lead. The electrical conductor between the source of the arc welding current and the workpiece.

WELDING POSITIONS
There are four welding positions including flat, horizontal, overhead and vertical.

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.

WIRE FEED SPEED
The rate of speed in mn/sec or in./min at which a filler metal is consumed in arc welding or thermal spraying.

WORK LEAD
The electric conductor (cable) between the source of arc welding current and the workpiece.

X-RAY
A radiographic test method used to detect internal defects in a weld

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; in other words, the yield point is the stress at which a marked increase in strain occurs with little or no increase in stress.

The above data, some modified by the owner of wermac.org, comes from the WeldGuru by Jeff Grill

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