Introduction
Mastering Welding Language
Welcome to our comprehensive Welding course! In this segment, we will explore the fundamental terms and definitions crucial for mastering the art of Welding. From the basics like Welding, fusion, and base metals to more specialized terms like P numbers, Group numbers, and F numbers, we cover it all. Our interactive and easily digestible content ensures that learning is both engaging and efficient.
Dive into our Welding blogs to unlock the secrets of Welding terminology, paving the way for your success in this dynamic industry. Stay tuned for regular updates as we guide you through every aspect of Welding, making complex concepts simple and accessible.
Welding Terminology
Speak the Language of Welding
In this page, we have provided some important Welding terms and definitions to enhance your understanding of the craft. However, to delve even deeper into Welding terminology, we recommend downloading standards such as AWS A3.0 and BS499. These standards serve as invaluable resources for gaining comprehensive knowledge and understanding of Welding terminology, ensuring you are well-equipped to excel in the field.
So, explore the terms provided here and take your Welding knowledge to the next level by delving into the detailed standards available for download.
What is Welding ?
According to Codes
According to American Welding Society (AWS) A3.0
A joining process producing 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.
According to British Standards Institute (BSi) BS499-1
Joining process in which two or more parts are united producing a continuity in the nature of the workpiece material(s) by means of heat or pressure or both, and with or without the use of filler material.
According to The Welding Society
Welding is a fabrication process whereby two or more parts are fused together by means of heat, pressure or both forming a joint as the parts cool.
Some Important Definitions
the letter 'A'
actual throat
The shortest distance between the weld root and the face of a fillet weld.
arc voltage
The electrical potential between the electrode and workpiece.
arc welding
A group of welding processes producing 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 torch
A device used to transfer current to a fixed welding electrode, position the electrode, and direct the shielding gas.
as-welded
Pertaining to the condition of weldments prior to subsequent thermal, mechanical, or chemical treatments.
autogenous weld
A fusion weld made without filler metal.
automatic process
An operation performed with equipment requiring occasional or no observation and no manual adjustment during its operation.
the letter 'B'
back-chipping (back-gouging)
The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side.
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 electroslag 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 (such as inert gases like Helium or Argon) employed primarily to provide a protective atmosphere.
backing ring
Backing in the form of a ring, generally used in the welding of pipe.
bare electrode
A filler metal electrode produced as a wire, strip, or bar with no coating or covering except one incidental to its manufacture or preservation.
base material
The material being welded, brazed, soldered, or cut.
base metal
The metal or alloy being welded, brazed, soldered, or cut.
bend test
A test in which a specimen is bent to a specified bend radius.
bevel angle
The angle between the bevel of a joint member and a plane perpendicular to the surface of the member.
bevel face
The prepared surface of a bevel edge shape.
bevel radius
The radius used to form a J-edge shape.
brazing
A group of joining processes producing the bonding of materials by heating them to the brazing temperature in the presence of a brazing filler metal having a liquidus above 450°C [840°F] and below the solidus of the base metal. The brazing filler metal is distributed and retained between the closely fitted faying surfaces of the joint by capillary action.
braze welding
A joining process in which the brazing filler metal is deposited in the joint without capillary action or melting of the base material.
braze
A bond produced as a result of heating an assembly to the brazing temperature using a brazing filler metal distributed and retained between the closely fitted faying surfaces of the joint by capillary action.
brazing wire
A solid or flux cored form of brazing filler metal supplied on coils or spools.
buildup
A surfacing variation in which surfacing material is deposited to achieve the required dimensions.
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 (or up to 30°).
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.
the letter 'C'
cap
A nonstandard term for the final layer of a groove weld.
caulking
Plastic deformation of weld and adjacent base metal surfaces by mechanical means to seal or obscure discontinuities.
cladding
A surfacing variation depositing or applying surfacing material usually to improve corrosion or heat resistance.
cluster porosity
A localized array of porosity having a random geometric distribution.
complete fusion
Fusion over the entire fusion faces and between all adjoining weld beads.
complete joint penetration
A groove weld condition in which weld metal extends through the joint thickness.
concavity
The maximum distance from the face of a concave fillet weld perpendicular to a line joining the weld toes.
constant current power source
An arc welding power source with a volt-ampere relationship yielding a small welding current change from a large arc voltage change.
constant voltage power source
An arc welding power source with a volt-ampere relationship yielding a large welding current change from a small arc voltage change.
consumable electrode
An electrode providing filler metal.
consumable insert
Filler metal placed at the joint root before welding, and intended to be completely fused into the joint root to become part of the weld.
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.
crack
A fracture-type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.
crater
A depression in the weld face at the termination of a weld bead.
crater crack
A crack initiated and localized within a crater.
the letter 'D'
defect
A discontinuity or discontinuities that by nature or accumulated effect render a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates rejectability.
deposited metal
Filler metal added during brazing, soldering, welding or surfacing.
deposition rate
The weight of material deposited in a unit of time.
downhill
Welding with a downward progression.
direct current electrode negative (DCEN)
The arrangement of direct current arc welding leads in which the electrode is the negative pole and workpiece is the positive pole of the welding arc.
direct current electrode positive (DCEP)
The arrangement of direct current arc welding leads in which the electrode is the positive pole and the workpiece is the negative pole of the welding arc.
discontinuity
An interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics. A discontinuity is not necessarily a defect.
duty cycle
The percentage of time during a specified test period that a power source or its accessories can be operated at rated output without overheating.
the letter 'E'
elongated porosity
A form of porosity having a length greater than its width that lies approximately parallel to the weld axis.
the letter 'F'
face bend test
A test in which the weld face is on the convex surface of a specified bend radius.
Ferrite Number (FN)
An arbitrary, standardized value designating the ferrite content of an austenitic or duplex ferritic-austenitic stainless steel weld metal based on its magnetic properties.
field weld
A weld made at a location other than a shop or the place of initial construction.
filler material
The material to be added in making a brazed, soldered, or welded joint.
filler metal
The metal or alloy to be added in making a brazed, soldered, or welded joint.
fillet weld
A weld of approximately triangular cross section joining two surfaces approximately at right angles to each other in a lap joint, T-joint, or corner joint (generally more than 30°).
flaw
An undesirable discontinuity.
fusion
The melting together of filler metal and base metal, or of base metal only, to produce a weld.
the letter 'G'
groove weld
A weld in a weld groove on a workpiece surface, between workpiece edges, between workpiece surfaces, or between workpiece edges and surfaces.
ground-connection
An electrical connection of the welding machine frame to the earth for safety.
the letter 'H'
hard-facing
A surfacing variation in which surfacing material is deposited to reduce wear.
heat input
The energy applied to the workpiece during welding.
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.
hybrid welding
The combination of two or more welding processes applied concurrently to produce a weld bead or nugget.
the letter 'I'
inclusion
Entrapped foreign solid material, such as slag, flux, tungsten, copper or oxide.
incomplete fusion (lack of fusion)
A weld discontinuity in which fusion did not occur between the weld metal and the fusion faces or the adjoining weld beads.
incomplete joint penetration (lack of penetration)
A joint root condition in a groove weld in which weld metal does not extend through the joint thickness.
inert gas
A gas that does not react chemically with materials.
interpass temperature
In a multipass weld, the temperature of the weld area between weld passes.
the letter 'J'
joint
The junction of the workpiece(s) that are to be joined or have been joined.
joint design
The shape, dimensions, and configuration of the joint.
the letter 'L'
lamellar tear
A subsurface terrace and step-like crack in the base metal with a basic orientation parallel to the wrought surface caused by tensile stresses in the through-thickness direction of the base metals weakened by the presence of small dispersed, planar shaped, non-metallic inclusions parallel to the metal surface.
lamination
A type of discontinuity with separation or weakness generally aligned parallel to the worked surface of a metal.
lap joint
A joint type in which the non-butting ends of one or more workpieces overlap approximately parallel to one another.
linear discontinuity
A discontinuity with a length substantially greater than its width.
linear indication
A test result in which a discontinuity in the material being tested is displayed as a linear or aligned array.
longitudinal crack
A crack approximately parallel to the joint axis or the weld axis.
the letter 'M'
macro-etch test
A test in which a specimen is prepared with a fine finish, etched, and examined using no magnification or low magnification.
macro-examination
A metallographic examination in which a surface is examined using no magnification or low magnification.
manual process
An operation with the torch, gun, or electrode holder held and manipulated by hand.
micro-etch test
A test in which the specimen is prepared with a polished finish, etched, and examined under high magnification.
micro-examination
A metallographic examination in which a prepared surface is examined at high magnification.
multi-pass weld
A fusion weld produced by more than one progression of the arc, flame or energy source along the joint.
the letter 'O'
open circuit voltage
The voltage between the output terminals of the power source when the rated primary voltage is applied and no current is flowing in the secondary circuit.
oscillation
An alternating pattern of motion relative to the direction of travel in a welding, brazing or soldering process.
overlap
A nonstandard term when used for incomplete fusion.
the letter 'P'
peening
The mechanical working of metals using impact blows.
penetration
A nonstandard term when used for depth of fusion, joint penetration, or root penetration.
porosity
Cavity-type discontinuities formed by gas entrapment during solidification.
preheat
The heat applied to the workpiece(s) to attain and maintain the preheat temperature prior to joining, thermal cutting, or thermal spraying.
preheat temperature
The temperature of the base material 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.
Prequalified Welding Procedure Specification (PWPS)
A welding procedure specification in compliance with the stipulated conditions of a particular welding code or specification and therefore acceptable for use under that code or specification without a requirement for qualification testing.
procedure
The detailed elements of a process or method used to produce a specific result.
purge
The introduction of a gas to remove contaminants from a system or provide backing during welding.
the letter 'R'
residual stress
Stress present in a joint member or material that is free of external forces or thermal gradients.
root bend test
A test in which the weld root is on the convex surface of a specified bend radius.
root face
The portion of the groove face within the joint root.
root pass
A weld pass made to produce a root bead.
root opening (root gap)
A separation at the joint root between the workpieces.
the letter 'S'
semi-automatic process
An operation performed manually with equipment controlling one or more of the process conditions.
side bend test
A test in which the side of a transverse section of the weld is on the convex surface of a specified bend radius.
sidewall
A nonstandard term when used for bevel face or groove face.
slag
A non-metallic product resulting from the mutual dissolution of flux and non-metallic impurities in some welding and brazing processes.
slag inclusion
A discontinuity consisting of slag entrapped in weld metal or at the weld interface.
soldering
A group of joining processes in which the workpiece(s) and solder are heated to the soldering temperature to form a soldered joint.
spatter
The metal particles expelled during fusion welding that do not form a part of the weld.
stub
The short length of filler metal electrode, welding rod, or brazing rod remaining after its use for welding or brazing.
surface preparation
The operations necessary to produce a desired or specified surface condition.
surfacing
The application by welding, brazing, or thermal spraying of a layer, or layers, of material to a surface to obtain desired properties or dimensions, as opposed to making a joint.
the letter 'T'
tack weld
A weld made to hold the parts of a weldment in proper alignment until the final welds are made.
tension test
A test in which a specimen is loaded in tension until failure occurs.
theoretical throat
The distance from the beginning of the joint root perpendicular to the hypotenuse of the largest right triangle that can be inscribed within the cross section of a fillet weld. This dimension is based on the assumption that the root opening is equal to zero.
transverse crack
A crack with its major axis oriented approximately perpendicular to the weld axis.
tungsten electrode
A non-filler metal electrode used in arc welding, made principally of tungsten.
tungsten inclusion
A discontinuity consisting of tungsten entrapped in weld metal.
the letter 'U'
undercut
A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal.
underfill
A groove weld condition in which the weld face or root surface is below the adjacent surface of the base metal.
uphill
Welding with an upward progression.
usability
A measure of the relative ease of application of a welding filler metal to make a sound weld.
the letter 'W'
weld (weld-joint / weld-seam)
A localized coalescence of metals or nonmetals produced either by heating the materials 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 material.
weld bead (weld layer)
The result of a weld pass is a weld bead or layer.
weaving
A welding technique in which the thermal source is oscillated transversely as it progresses along the weld path.
weld face
The exposed surface of a weld on the side from which welding was done.
weld gauge
A device designed for measuring the shape and size of welds.
weld groove
A channel in the surface of a workpiece or an opening between two joint members providing space to contain weld metal.
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 along a joint.
weld pass sequence
The order in which the weld passes are made.
weld pool
The localized volume of molten metal in a weld prior to its solidification as weld metal.
weld reinforcement (capping)
Weld metal in excess of the quantity required to fill a weld groove.
welding symbol
A graphical representation of the specifications for producing a welded joint.
weld toe
The junction of the weld face and the base metal.
weldability
The capacity of material to be welded under the imposed fabrication conditions into a specific, suitably designed structure performing satisfactorily in the intended service.
welder
One who performs manual or semiautomatic welding.
welding arc
A controlled electrical discharge between the electrode and the workpiece formed and sustained by the establishment of a gaseous conductive medium, called an arc plasma.
welding generator
A generator used for supplying current for welding.
welding head
The part of a welding machine in which a welding gun or torch is incorporated.
welding machine
Equipment used to perform the welding operation.
welding operator
One who operates adaptive control, automatic, mechanized, or robotic welding equipment.
welding position
The relationship between the weld pool, joint, joint members, and welding heat source during welding.
welding power source
An apparatus for supplying current and voltage suitable for welding.
welding procedure
The detailed methods and practices involved in the production of a weldment.
Welding Procedure Qualification Record (PQR)
A record of welding variables used to produce an acceptable test weldment and the results of tests conducted on the weldment to qualify a welding procedure specification.
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 rectifier
A device in a welding power source for converting alternating current to direct current.
welding technique
Details of the welding operation controlled by the welder or welding operator.
welding test position
The orientation of a weld joint for welding procedure or welder qualification testing.
welding transformer
A transformer converting input power into useable levels of voltage and current for welding at a rated duty cycle.
