Chapter 3: Welding Terms

root pass

1. An initial weld pass that provides complete penetration through the thickness of a joint member. 2. A weld pass made to produce a root bead.

electrode

A component of a welding circuit that conducts electrical current to a weld area.

crater

A depression at the termination of the weld bead.

fixture

A device used to maintain the correct positional relationship between weldment components as required by print specifications.

lamination

A discontinuity or defect that is aligned parallel to the working direction of a metal.

arc strike

A discontinuity resulting from an arc, consisting of any localized remelted metal, heat affected metal, or change in the surface profile of any metal object.

positioner

A mechanical device that supports and moves weldments for maximum loading, welding, and unloading efficiency.

base metal

A metal or alloy that is to be welded.

weld pass

A single progression of welding along a weld joint.

root bead

A weld bead that extends into or includes part or all of a joint root.

cold roll

A weld discontinuity that results in excessive weld on weld face; caused by incorrect personal speed (usually too fast) or machine settings; "muffin top" (as Liam said :-))

spatter

Droplets of molten metal or non-metallic material that are scattered or splashed during the welding process

weld toe

Junction of the base metal and the weld face

filler metal

Metal deposited in a welded, brazed, or soldered joint during the welding process.

slag inclusion

Non-metallic solid material entrapped in weld metal or between weld metal and base metal. Cause: not removing all slag or weld not cleaned out properly.

face reinforcement

Reinforcement on the same side as the welding.

root reinforcement

Reinforcement on the side opposite the one on which welding took place.

weld reinforcement

The amount of weld metal in excess of that required to fill the joint.

weld root

The area where filler metal intersects base metal and extends the furthest into the weld joint.

weld type

The cross-sectional shape of a weld.

root opening

The distance between joint members at the root of a weld before welding.

theoretical throat

The distance from the joint root, perpendicular to the hypotenuse of the largest right-angle triangle that can be inscribed within the cross section of a fillet weld.

weld width

The distance from toe to toe across the face of a weld.

depth of fusion

The distance that fusion extends into a base metal from the surface melted during welding.

weld face

The exposed surface of a weld, bounded by the weld toes on the side on which welding was done.

lack of fusion

The failure to melt into the surface or root edges of a joint; also called "lack of penetration" or "lack of drop-through"

effective throat

The minimum distance, minus convexity, between the weld face and the weld root.

root face

The portion of a groove face within a joint root.

slag

The residue or mass of metal left after smelting; worthless matter; the solidified remaining flux after the weld area cools.

ripple

The shape within the deposited bead caused by the movement of the welding heat source.

actual throat

The shortest distance from the face of a fillet weld to the weld root after welding.

faying surface

The surface of a joint member that is in contact with, or in close proximity to, the member to which it will be joined.

nugget

The weld metal that joins the members in spot, seam, and projection welds.

porosity

Weld metal contamination in the form of a trapped gas

overlap

When molten metal flows over the surface of the base material and then cools without fusing with the base material

undercut

When the edge of a weld has an inverse U shape