CW Certified Welder key terms

An arc welding process in which a consumable, flux-covered electrode carries the current and melts to supply filler metal, while the decomposing coating creates shielding gas and slag.

An arc welding process that uses a continuously fed solid wire electrode and an externally supplied shielding gas to protect the molten weld pool from the atmosphere.

An arc welding process using a continuous tubular wire filled with flux; the flux provides shielding and slag, and an auxiliary gas may also be supplied.

An arc welding process that uses a nonconsumable tungsten electrode to establish the arc, with filler metal added separately and an inert gas shielding the weld area.

The current-carrying component that terminates the arc; in SMAW it is consumable and coated, melting to become part of the weld.

Gas supplied around the arc and molten pool to exclude air, preventing contamination such as oxidation and nitrogen absorption that cause porosity or brittle welds.

A mineral-based material that melts during welding to generate protective gas, dissolve oxides, and form a slag layer over the cooling bead.

The amperage flowing through the welding circuit; it largely determines heat input, deposition rate, and depth of penetration, and must be set within the electrode's range.

The direction of current flow in a direct-current welding circuit, described as electrode positive or electrode negative; it affects penetration, deposition, and arc stability.

The distance between the electrode tip and the surface of the molten weld pool; maintaining a consistent length controls voltage, bead shape, and spatter.

The rate at which the arc moves along the joint; too fast can cause undercut and lack of fusion, too slow can cause excessive reinforcement and burn-through.

A nonmetallic, glassy byproduct formed from flux that covers the finished bead; it protects the cooling metal but must be removed before the next pass.

The first pass deposited in a groove weld, made at the joint root; it establishes penetration and fusion and is often the most critical pass for soundness.

A welding position in which the work is horizontal and welding is done from above, letting gravity hold the molten pool in place; designated 1G for groove and 1F for fillet.

A position where the weld axis is roughly horizontal and the weld face lies in a vertical plane; molten metal tends to sag downward, requiring controlled technique. It is designated 2G or 2F.

A position in which the weld axis is vertical and the weld face lies in a vertical plane, so the welder progresses either upward or downward along the joint. It is designated 3G or 3F.

A position in which welding is performed from beneath the joint, with the weld face horizontal and facing downward; gravity works against the pool, demanding short arcs and lower current.

Vertical welding performed with progression from the bottom to the top of the joint; it generally gives deeper penetration and higher quality but is slower and harder to control.

Vertical welding that progresses from top to bottom; it is faster and suits thin material, but reduced penetration makes it unsuitable for many thick groove welds.

A weld made in a channel formed between two members, such as a beveled, V, U, or J preparation; it usually requires multiple passes to fill.

A weld of roughly triangular cross section joining two surfaces that meet at an angle, such as a lap or T joint; its size is measured by leg length.

A pipe test position in which the pipe is fixed at about 45 degrees to horizontal and cannot be rotated, so the welder must deposit metal in all positions around the circumference.

A flat rolled metal product of uniform thickness, usually tested in butt joints; plate coupons are common for qualifying welders on material thicker than sheet.

A hollow cylindrical product joined by welding around its circumference; test pipes are classified as small or large diameter based on nominal size and are usually fixed for qualification.

The thickness of the pipe wall, which governs joint preparation, required root penetration, number of passes, and the range of material thickness a welder is qualified for.

An angled cut or grind on the edge of a member that creates the groove for a butt weld; the bevel angle and root face control access and penetration.

The gap left between the two members at the bottom of a groove before welding; it allows root penetration and must be held uniform during fit-up.

The alignment and spacing of parts before welding, including gap, mismatch, and bevel condition; poor fit-up causes defects such as lack of fusion or burn-through.

A small temporary weld used to hold parts in alignment until the permanent weld is made; tacks must be sound because they become part of the finished joint.

Material placed behind the joint root to support the molten pool and help control penetration; it may be permanent (steel) or removable (ceramic, copper).

Inspection of the completed weld using the eye, alone or with aids such as a flashlight and mirror; it detects surface discontinuities, profile problems, and size errors before other testing.

A groove melted into the base metal along the weld toe or root that is left unfilled by weld metal; it reduces thickness and concentrates stress, so depth limits apply.

Cavities or holes in the weld caused by gas trapped as the metal solidifies; surface porosity is visible, while internal porosity requires radiographic or ultrasonic inspection.

A discontinuity in which weld metal fails to fuse to the base metal or to a previous pass; it creates a planar defect that sharply reduces joint strength.

Nonmetallic slag trapped inside the weld or between passes, usually because slag was not fully removed or the arc failed to float it out.

A fracture-type discontinuity with a sharp tip that propagates under stress; cracks are generally unacceptable in a test weldment regardless of size or location.

Weld metal that extends above the base metal surface on the face side, or beyond the root on the back side; excessive reinforcement creates a stress concentration and may exceed limits.

The specified limits that define whether a completed test weld passes inspection, covering discontinuity type, size, location, and required weld dimensions.

A small area of melted or discolored base metal where the arc was accidentally initiated outside the weld joint; it can cause hardening or cracking and is often rejected.