Overview of Weld Types 221

arc length

The distance from the electrode to the workpiece in an arc welding application. Arc length helps to determine the concavity or convexity of a weld.

arc welding

A fusion welding process that uses electricity to generate the heat needed to melt the base metals. Arc welding is the most common form of welding, as it is portable and economical.

back-gouging

The removal of weld metal and base metal from the side opposite a partially welded joint. Back-gouging is typically used to allow complete joint penetration.

base metals

The two or more metals to be welded together to form a joint. The composition of the base metals can greatly influence the strength of the final joint.

bead

The line of filler metal created by welding. An even weld bead with good penetration will create a strong weld.

butt joint

A type of joint between two metal parts that lie in the same plane. A butt joint is the most common joint type.

chipping

The act of cutting or breaking small pieces, or chips, with an edged tool. Chipping is often used to prepare a joint for welding.

complete joint penetration

Extending the weld metal throughout the full thickness of the base metal in a joint with a groove weld. Complete joint penetration is more difficult but generally creates a strong weld.

complete-penetration weld

A weld that penetrates all the way through the joint. Complete-penetration welds are stronger than partial-penetration welds.

concave

Curving inward. A concave fillet weld face results when a welder runs a bead too quickly or sets voltage too high.

convex

Curving outward like the exterior part of a circle. A convex fillet weld face results when a welder runs a bead too slowly or sets voltage too low.

corner joint

A type of joint that fuses two metal parts to form a right angle. Corner joints are very common in welding.

defects

A weld discontinuity that is so severe it compromises the integrity of the weld. Weld defects must be repaired, or the welded part must be discarded.

double-fillet welds

A weld which consists of two fillet welds on either side of the joint. Double-fillet welds are especially useful in T-joints.

double-groove weld

A weld that has two groove welds on both sides of the joint. Double-groove welds are ideal for welding large or thick workpieces.

double-groove welds

A weld that consists of a groove weld on both sides of a joint. Double-groove welds are strong and often require less weld metal than single-groove welds.

edge joint

A type of joint that fuses the surfaces of two parallel parts. Edge joints appear at the common edges of the parts.

electrode

A device that conducts electricity. In welding, the electrode also can act as the filler metal.

fast-fill

When a joint requires a large amount of weld metal. Fast-fill electrodes lay a heavy weld bead in a short amount of time.

fast-follow

When a weld requires molten metal to follow the arc at a rapid speed. Fast-follow electrodes are often required for welds that must be completed in a single pass.

fast-freeze

When a joint requires quick weld metal solidification. Fast-freeze electrodes are necessary to prevent molten metal from leaving the area of out-of-position welds.

filler metal

A metal that may be added to a joint during welding. Filler metal adds to the strength and mass of the welded joint.

fillet weld

A type of weld that is triangular in shape and joins two surfaces at right angles to one another. Fillet welds are the most common types of welds.

flat-position welding

Welding from the upper side of a joint. In flat-position welding, the face of the weld is horizontal.

gouging

The act of scooping out larger pieces of metal with a tool. Gouging is used to allow complete joint penetration or to prepare a surface for welding.

grinding

The use of an abrasive to wear away the surface of a workpiece and change its shape. Grinding often uses a rapidly rotating abrasive wheel tool.

groove weld

A type of weld that consists of an opening between two part surfaces that provides space to contain weld metal. Groove welds are used on all joints except lap joints.

groove welds

A type of weld that consists of an opening between two part surfaces, which provides space to contain weld metal. Groove welds are used on all joints except lap joints.

horizontal-position welding

In horizontal-position welding, the axis of the weld is horizontal. Horizontal-position welding is a common welding position used for fillet and groove welds.

inadequate joint penetration

Weld metal penetration that is less than specified in the joint design. Inadequate joint preparation may result from insufficient heat or poor control of the arc.

incomplete fusion

A weld discontinuity which leaves a space or spaces between the weld metal and base metal or adjoining weld beads. Incomplete fusion can result from insufficient current, joint access, or joint preparation.

J-groove weld

A type of groove weld with an opening in the shape of the letter "J." One edge of a J-groove weld is concave, and the other is square.

joint

The meeting point of two materials that are fused together. Welding creates a permanent joint.

joint penetration

The depth that weld metal extends into the face of a joint. Joint penetration is an important factor in the strength of a joint.

joint preparation

Preparing base metals before welding. Joint preparation can involve preheating and cutting.

joint preparation

The creation of the appropriate opening for a groove weld before welding takes place. Joint preparation may include grinding or machining the edges to create the appropriate space.

joint type

The configuration in which two or more workpieces are joined. Common joint types for welding include butt, corner, edge, lap, and T-joints.

lap joint

A type of joint that fuses two overlapping metal parts in parallel planes. Lap joints are often used to weld pipe or sheet metal.

legs

The distance from the root to the toe of a fillet weld. Leg length determines the size of a fillet weld.

legs

The portions of the weld from the toe to the root. The length of the legs is a determinant of the strength of the weld.

machining

The process of removing metal through the use of cutting tools. Machining is often used to remove excess weld metal from the surface of a completed part.

overhead-position welding

Welding from the underside of a joint. Overhead-position welding is the most difficult welding position.

overlap

A weld discontinuity in which the weld metal protrudes beyond the weld toe or weld root. Overlap is nearly always unacceptable in a finished weld.

partial joint penetration

Extending the weld metal through only part of the joint in a groove weld. Partial joint penetration is intentionally less than complete.

penetration

The depth to which weld metal extends into the joint. Some joints require only shallow penetration because the base metals are thin and others require deep penetration to ensure the strength of the joint.

perpendicular

An angle formed by two lines at a right angle. T-joints are composed of two perpendicular workpieces.

plane

A flat surface that extends infinitely in any direction in three dimensions. Most welded surfaces can be measured on a plane.

plug weld

A type of weld made by joining one metal part with a circular hole to another metal part positioned directly beneath it. Plug welds are commonly used to weld sheet metal parts.

porosity

Cavity-shaped discontinuities or bubbles formed by gas entrapment during solidification of the weld metal. Porosity significantly weakens the finished weld.

resistance welding

A group of welding processes that join parts using the heat obtained from the resistance to the flow of electric current. Resistance welding uses pressure to weld the parts together.

right angle

An angle that is exactly 90 degrees. Two perpendicular objects form a right angle.

right triangle

A triangle with a 90° angle, also known as a right angle. Right triangles are often drawn with a square in the 90° corner of the triangle.

root opening

The separation at the joint root between the base metals. The size of the root opening determines how much weld metal is needed to obtain fusion at the root.

root opening

The separation at the root of a joint between the base metals. The size of the root opening determines how much weld metal is needed to obtain fusion at the root.

seam weld

A type of continuous weld made between or upon overlapping metal parts. Seam welds are used in a variety of different applications, including automobile fuel tanks and steel drums.

single bevel-groove weld

A type of groove weld with one edge shaped like the V-groove weld and one edge that is square. This weld requires less preparation and weld metal.

skips

An area of a weld joint that has not been welded. Skips are often unintentional, but can also be used intentionally to save weld metal.

slag inclusion

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

slot weld

A type of weld made by joining one metal part with an elongated hole to another metal part positioned directly beneath it. A slot weld is very similar to a plug weld, but the elongated hole allows for greater strength.

spot weld

A small welded area between or upon overlapping metal parts. Multiple spot welds are generally required to join parts.

square-groove weld

A type of groove weld with a slight separation at the edges of the base metal parts. Square-groove welds are the most economical groove weld to prepare.

strength

A material's ability to resist outside forces that attempt to bend, break, or deform it. Greater strength is generally preferred in a finished weld.

thermal cutting

A group of industrial processes that use heat to cut or shape metal. Thermal cutting processes include oxyfuel, air-carbon arc, and plasma cutting.

T-joint

A type of joint produced when two metal parts are perpendicular to each other. A T-joint resembles the shape of the letter "T."

U-groove weld

A type of groove weld with an opening in the shape of the letter "U." The edges of a U-groove weld are concave.

undercut

A groove melted into the base material, usually along the toes of the weld, that produces a weak spot in the weld. Undercut can be caused by excessive current, poor welding technique, or incorrect filler metal.

undercut

A groove melted into the base material, usually along the toes of the weld, which produces a weak spot in the weld. Undercut can be caused by excessive current, poor welding technique, or incorrect filler metal.

underfill

A depression on the weld face or root surface that extends below the adjacent surface of the base metal. Underfill is the result of a welder's failure to properly fill a joint with metal.

vertical-position welding

Welding an upright workpiece surface. Vertical-position welding is more difficult than flat- or horizontal-position welding.

V-groove weld

A type of groove weld with an opening in the shape of the letter "V." V-groove welds require more joint preparation but less weld metal.

voltage

A measure of electrical pressure or potential known as electromotive force. Voltage is measured in volts.

weld

A mixture of metals that joins at least two separate parts. Welds can be produced by applying heat, pressure, or a combination of these.

weld axis

An imaginary line through the length of the weld perpendicular to its cross-section. The weld axis runs parallel to the joint.

weld backing

A strip of metal located opposite the weld that provides a surface for depositing the first layer of metal. Weld backing is used to prevent molten metal from escaping through the joint in complete penetration welds.

weld crown

The raised surface of a weld, extending beyond a line drawn between the weld toes. In welds in which the welded pieces lie on the same plane, the crown is often ground off to create a smooth surface.

weld defect

A weld discontinuity that compromises the integrity of the weld. Weld defects must be repaired or the welded part must be discarded.

weld discontinuities

An interruption in the typical structure of a weld. A discontinuity is not necessarily a defect.

weld face

The exposed surface of a weld. The weld face may be convex, concave, or flush with the workpiece.

weld metal

Metal or metals which are welded together. Weld metal is an important determinant of weld strength.

weld metal

The portion of a weld that has been melted during welding. Weld metal may be composed either of base metal or from a combination of base metal and filler metal.

weld root

The point at which the back of the weld intersects the base metal surfaces. A complete-penetration weld may have two weld roots.

weld throat

The shortest distance between the weld root and a line drawn between the weld toes. The throat determines a weld's size and strength.

weld toes

The point at which the weld face and the base metal meet. Incomplete fusion along the weld toe results in undercut.

welder

The person who performs a weld. Some reference materials may also refer to the power source used for arc welding as a welder.

welding

A joining process that uses heat, pressure, friction, or a combination of methods to fuse two materials together permanently. Welding is used in a variety of industries from auto manufacturing to aerospace engineering.

welding codes

Standards used to govern welding processes and ensure safe welding practices and high-quality welds. Most welding codes are published by the American Welding Society.

welding positions

The angle from which the welder performs a weld. The different welding positions include overhead, vertical, flat, and horizontal-position welding.