Welding terminology

Welding terminology shown below are the typical ones. (Refer to A3.0 for the AWS
standard.)
(1) General
Technical term

Definition

deposited
metal test

A test specimen with alldepositedmetal testing section.

specimen

root bend
specimen

face bend
specimen

side bend
specimen

guided bend
test

A butt weld joint bend specimen whose root side is bent in tension.

A butt weld joint bend specimen whose surface side is bent in tension.

A bend specimen for testing the weld cross section.

A bending test in which the specimen is bent to a definite shape by using a set of male and female dies.

A bending test in which the specimen is placed across the supports of rollers as shown in the figure
below and is bent by the force of plunger.

roller bend
test

A bending test in which the lengthwise ends of a specimen are bent to an initial angle and then the
free bend test

specimen is bent freely by applying forces on both of the ends without using a set of male and female
dies or aset of rollers.

multilayer
welding

A weld consisting of multiple layers of beads.

pit

A small hole occurred in the weld surface.

surfacing

A welding technique to lay a desired deposited metal on ametal surface.

hardfacing

notch
brittleness

crater

residual
stress

crack
sensitivity

weldability

A welding technique to lay a hard deposited metal on a metal surface.

Even if a particular metal has sufficient ductility when it contains no notch, the metal can be brittle to
become fractured when it contains a notch. Such a brittle characteristic is referred to as notch
brittleness.

A depression in the weld surface at the termination of an arc weld bead.

Stresses remained in a structure or its component.

Easiness of weld cracking.

The welding suitability of the base metal quality.

consumable
nozzle
electroslag

An electroslag welding process that uses a consumable nozzle.

welding

spring

An arc welding process in which a dedicated electrode is kept contact at a certain low angle with respect

contact arc

to the welding line during welding by using the spring force of the dedicated device placed on the

welding

weldment.

oneside

A butt joint welding variation in which the welding is completed from the singlegroove side of the joint

welding

makingameltthrough weld with a backing material.

(2) Welding design

welded joint

Definition

A joint welded.

A lap joint variation in which the thicknesswise surfaces of splice plates are fillet welded with the
surface of the components to be joined.
strapped joint

A weld joint variation in which two members are partly overlapped to fillet weld one members surface
and the other members thicknesswise surface.

lap joint

A weld joint variation in which a single groove is prepared on the oneside surface of the members to be
joined ; the basic groove shapes are as follows.

single groove
joint

A weld joint variation in which double grooves are prepared on doubleside surfaces of the members to
be joined ; the basic groove shapes are as follows.

double
groove joint

A lap joint variation in which one members edge is formed with joggling to make the two members
joggled lap

aligned in the same plane, which is also known as offset lap joint.

joint
(Offset lap
joint)

edge joint

A weld joint between the edges of two or more parallel or nearly parallel members.

butt joint

A weld joint between two members aligned approximately in the same plane.

A weld joint between two members located approximately at right angles to each other in the form of an
L, the corner of which is welded.

corner joint

A weld joint between two members located approximately at right angles to each other in the form of a T,
in which one members edge is put on the other members surface.

tee joint

welding
groove

A groove prepared between two members to be welded ; the typical grooves are as follows.

The total included angle of the groove between two parts to be joined by a groove weld.

groove angle

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

bevel angle

The distance from the root of the joint to the toe of the fillet weld.

leg length

size of fillet

The size of fillet weld (S1, S2, S3) is specified for designing the weldment. The triangle determined with

weld

the sizes must be inscribed within the fillet weld cross section.

For a fillet weld, the shortest distance, measured in its cross section, from the root of weld to its face. For
a butt weld, the smallest thickness measured through the root of weld in its cross section.
actual throat,
(actual throat
of fillet weld),
(actual throat
of butt weld)

throat

Refer to theoretical throat and actual throat.

theoretical
throat,
(theoretical

For a fillet weld, the distance from the root of the joint perpendicular to the hypotenuse of the right

throat of fillet

triangle determined with the fillet weld sizes. For a butt weld, the thickness of the components to be

weld),

joined. When the components have different thicknesses, the thinner one is taken as the theoretical

(theoretical

throat.

throat of butt
weld)

root of weld

In the cross section of a weld, the points at which the bottom of the weld intersects the base metal.

root of joint

For butt welding, that portion of a joint to be welded where the members approach closest each other.

(root of butt

For fillet welding, that portion of a joint to be welded where two members intersect each other.

welded joint),
(root of fillet
welded joint)

The separation between the members to be joined at the bottom of the welding groove.

root opening
(root gap)

The radius of the bottom of a J,U, and Hgroove.

root radius

The upright face at the bottom of a welding groove.

root face

The junction between the face of weld and the base metal.

weld toe

welding
symbol

fillet welded
joint

A symbolic representation of welds on drawings.

A joint welded by fillet welding.

A joint welded by fillet welding the members assembled to a cross shape as shown in the figure below.
cruciform
joint
(cross
shaped joint)

The distance from the surface of a base metal to the bottom of the welding groove prepared between
two members to be joined.

groove depth

groove face

scarf joint

That surface of a member included in the groove for welding.

A joint variation in which the members to be joined are prepared with singlebevel edges arranged with
parallel groove faces to create a wide faying surface, which is used mainly for brazing and forging.

(3) Welding fabrication

weaving

Definition

A type of welding manipulation in which the electrode is oscillated transversely as the welding is
progressed.

backing

A technique to support molten metal by placing a metal or a refractory against the backside of the weld.

backing strip

A metallic strip for backing.

back chipping

The removal of weld metal and base metal from the backside of a butt welded joint to remove incomplete
penetration or the root pass weld to assure complete penetration upon subsequent welding from that

side.

magnetic arc
blow

The deflection of an electric arc from its normal path because of electromagnetic force.

(Arc blow)

layer

A layer of weld metal consisting of one pass or multiple passes

pass (run)

A single welding operation in the progression direction along a joint.

The position in which welding is performed from the underside of a joint whose weld axis and face are
kept in almost horizontal.
overhead
position

The position in which welding is performed from the lateral side of a joint whose weld axis is kept in
almost horizontal and, for butt welding, the weld face is kept in almost vertical.
horizontal
position

The position in which welding is performed from the face of a joint whose weld axis is kept in almost
vertical.

vertical
position

flat position

The position in which welding is performed from the top side of a joint whose weld axis and face are kept
in almost horizontal.

welding line

welding
current

weld length

effective
length of weld

The line showing the direction of a bead, fillet weld, or butt weld.

An electric current to generate a heat needed for welding.

The length of a continuous weld excluding its start and crater portions.

The entire length of a weld, throughout which the intendedsize cross section exists.

The largest distance the weld metal extends from the surface of the base metal or the groove face.

penetration
(weld
penetration)

weld
reinforcement

Weld metal in excess of the size required for a groove weld or a fillet weld.

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

undercut

The protrusion of weld metal beyond the weld toe or weld root, which is not fused with the base metal.

overlap

fisheye

A fisheyelike area of silver gray in color, which may appear in the fracture surface of a weld metal.

slag

A nonmetallic product generated on a weld.

slag inclusion

A discontinuity consisting of slag entrapped in weld metal or at the weld interface.

spatter

The metal or slag particles expelled during arc welding and oxyfuel gas welding.

spatter loss

Metal loss due to spatter.

blowhole

Cavity type discontinuities formed by gas entrapment in the weld metal during solidification.

underbead

A crack occurred generally in the heataffected zone, near the bead, which generally not extends to the

crack

surface of the base metal.

deposition
rate

deposition
efficiency

The mass of deposited metal in a unit of time.

The ratio of the mass of deposited metal to the net mass of welding consumables consumed, exclusive
of stubs. For covered electrodes, the mass of its covering is included normally, but excluded for a
specific purpose.

weld bead

A weld resulting from a weld pass.

melting rate

The mass or length of electrode, wire, or rod melted in a unit of time.

weld pool
(molten pool)

The depressed local area of molten metal due to the welding arc heat.

preheating

The heating of the base metal prior to welding or oxyfuel gas cutting.

postheating

The application of heat to an assembly after welding or oxyfuel gas cutting.

(immediate

The postheating that is applied to an assembly immediately after welding to remove diffusible hydrogen

postheating,

from the weld and to prevent cold cracking is called as immediate postheating. The postheating that is

postweld heat

applied to an assembly after welding to remove residual stresses and to improve mechanical properties

treatment)

and corrosion resistance is called as postweld heat treatment.

weld metal
zone

deposited
metal

weld zone
(weld)

weld metal

That portion of the weld area that was fused and solidified.

The metal that has been deposited on the base metal by welding with a filler metal.

The general term for the weld metal plus the heataffected zone.

Metal included in a weld that was fused and solidified during welding.

heataffected

The portion of base metal that was not melted but its mechanical properties and microstructure have

zone

been altered by the heat of welding or thermal cutting.

Fillet welds having a convex weld face.

convex fillet
weld

Fillet welds having a concave weld face.

concave fillet
weld

continuous
fillet weld

slot weld

A fillet weld with a continuous weld length.

A weld made in an elongated hole in one of the two lapped members of a joint.

A weld made by filling a circular hole with a filler metal in one member of a joint, fusing that member to
another member.

plug weld

A weld made in the flare groove of two members of a joint.

flare groove
weld

butt weld

A weld made in a butt joint.

seal weld

Any weld intended only to provide a specific degree of tightness against leakage of a liquid.

buildup

A surfacing variation in which surfacing material is deposited to achieve the required dimensions on a

welding

substrate that is worn or lacking in dimension.

A surfacing variation that deposits a dissimilar metal on the groove surface of a base metal to prevent
buttering

the chemistry effect of the base metal on the weld metal that is to be deposited subsequently by butt
welding.

underlaying

A surfacing variation that deposits a lowcracksensitive metal to prevent cracking or disbonding prior to
the buildup welding on the base metal.

A fanshaped opening made in a member to avoid crossing the welding line of the member with that of
another associated member.

scallop

back run

backing weld

groove weld

A weld made at the back of a single groove weld, which is laid after the face side welding.

A backing variation in which a weld is laid on the backside of a groove in advance to prevent excessive
meltthrough in the arc welding of the face side.

A weld made in a groove. Typical groove weld variations

Ugroove weld,
Jgroove weld,
Xgroove weld,
Hgroove weld,
Kgroove weld,
DoubleJ groove weld.

backhand
welding

forehand
welding

tack welding

skip welding

fillet weld

A welding technique in which the welding torch is directed opposite to the progress of welding.

A welding technique in which the welding torch is directed toward the progress of welding.

A welding variation in which a weld is made to hold the parts of a weldment in proper alignment until the
main welds are made.

A welding technique in which intermittent welds are laid first and then the skipped areas are welded after
the intermittent welds are cooled sufficiently, the main purpose of which is to minimize welding distortion.

A weld of approximately triangular cross section jointing two surfaces approximately at right angles to
each other in a lap joint, Tjoint, and corner joint.

front fillet

A fillet weld variation in which the fillet weld axis is almost normal to the direction of applied shear

weld

stresses.

side fillet

A fillet weld variation in which the fillet weld axis is almost parallel to the direction of applied shear

weld

stresses.

intermittent
fillet weld

A weld in which the continuity is interrupted by recurring unwelded spaces.

An intermittent fillet weld on both sides of a Tjoint in which the weld increments on one side are
alternated with respect to those on the other side.
staggered
intermittent
fillet weld

backstep

A welding technique in which the electrode manipulation direction for each pass is opposite to the entire

welding

progress of welding.

A deposition sequence variation for a multipass weld in which separated increments are welded with
several layers before intervening increments are welded.
block
sequence
(block
welding)

The continuation of a fillet weld around the corner of a member as an extension of the principal fillet
weld.

boxing

weld tab,
runoff weld
tab
(runoff
plate),
starting weld

Additional material that extends beyond either end of the joint, on which the weld is started on the
starting weld tab or terminated on the runoff weld tab.

tab
(runon
plate)

burnthrough
(excessive
meltthrough
)

Dropping of molten metal to the opposite side of a groove through the root of the joint.

preset

The artificial angular distortion provided in a base metal toward the reverse direction before welding to

distortion

an extent which is expected to be induced by the face side welding.

gravity
welding

arc striking

A shielded metal arc welding variation in which a covered electrode is held by the dedicated device, and
the welding is progressed automatically as the holder slides down by the gravity while the electrode
consumes contacting to the welding line and keeping a certain angle with respect to the base metal.

To initiate an arc or to generate it momentary on a base metal followed by immediate putting out.

(4) Arc welding

AC arc
welding.

DC arc
welding.

Definition

A welding variation in which AC current is used to generate an arc.

A welding variation in which DC current is used to generate an arc.

automatic arc

Arc welding with equipment in which welding wire is fed automatically and the welding is progressed

welding

continuously without manual control.

semiautomati

Arc welding with equipment which controls the welding wire feed while the welding torch is manipulated

c arc welding

manually.

electrode

The arrangement of direct current arc welding leads in which the electrode is the negative pole and the

negative

workpiece is the positive pole of the welding arc.

electrode

The arrangement of direct current arc welding leads in which the electrode is the positive pole and the

positive

workpiece is the negative pole of the welding arc.

arc voltage

A voltage supplied between both poles of an arc.

arc length

The distance between both poles of an arc.

workpiece
cable
connection

exposed core

The electrical connection of the workpiece cable with a base metal or other metallic body to which the
base metal contacts.

The uncoated part of a covered electrode for holding with a electrode holder.

consumable
electrode

An electrode that is fused and consumed in the arc during arc welding and arc cutting.

nonconsum
able

An electrode that is hard to be consumed by the arc heat due to high melting point.

electrode

electrode
diameter

droplet

The diameter of the core wire of a covered electrode.

Molten metal particles that transfer from the tip of the welding electrode to the base metal.