BTEB Welding Exam key terms

A fabrication process that joins metals by heating their edges to a molten state, with or without pressure or filler metal, so the parts fuse into one continuous piece.

The state in which the base metal and any filler metal melt together and merge into a single liquid pool that solidifies as one joint.

The parent material being joined. Its thickness, composition and surface condition determine the electrode size, current and preparation needed before welding begins.

Additional metal added to the joint to fill the gap and build up the weld. It may be supplied as a coated electrode, bare wire or rod matching the base metal.

The localized volume of molten metal formed at the joint during welding. Its size and fluidity show whether current and travel speed are correctly set.

A sustained electrical discharge across a small air gap between the electrode and the work. The arc produces the intense heat that melts the metal.

Any welding process in which the heat of an electric arc between an electrode and the workpiece melts the joint, usually with a filler metal fed into the arc.

Shielded metal arc welding, commonly called stick welding. A flux-coated consumable electrode strikes an arc, and the burning coating shields the molten pool from the atmosphere.

The current-carrying rod that strikes the arc. In stick welding it is consumable and coated with flux; in other processes it may be non-consumable tungsten.

The glassy non-metallic layer formed by melted flux that floats on the weld bead. It protects the cooling metal and must be chipped off before inspection or the next pass.

A material in the electrode coating, wire core or granular blanket that dissolves oxides, prevents atmospheric contamination and helps the weld metal flow and cool cleanly.

An inert or active gas fed around the arc to displace air and protect the molten weld pool from oxygen, nitrogen and moisture that cause porosity and brittleness.

The gap between the electrode tip and the surface of the molten pool. Too long a gap spatters and loses shielding; too short one risks sticking the electrode.

The amperage flowing through the arc, set on the machine to suit electrode diameter and metal thickness. It mainly controls penetration and deposition rate.

The direction of current flow in a DC welding circuit, described as straight (electrode negative) or reverse (electrode positive), which changes heat balance and penetration.

The depth to which the weld metal and fusion zone extend into the base metal. Adequate penetration is essential for a joint as strong as the parent metal.

The raised ridge of solidified weld metal left by one pass of the electrode along the joint. Its profile indicates travel speed, current and arc control.

The first run deposited at the bottom of a joint, which fuses the two root faces together. It is the foundation of the whole weld and must penetrate fully.

The small deliberate space left between the two prepared edges at the bottom of a joint, allowing the root pass to penetrate through the full thickness.

A joint in which two pieces lie in the same plane and are joined edge to edge. Edges may be square, single-V or double-V prepared depending on thickness.

A joint formed by placing one plate over another and welding along the overlapping edges. It is simple to fit but creates a stress concentration at the edge.

A joint between two members meeting at roughly right angles, one edge resting on the face of the other. It is normally completed with fillet welds on one or both sides.

A triangular weld deposited in the corner where two surfaces meet, as in tee, lap and corner joints. Its size is given by the leg length.

A weld made in a prepared channel between two members, such as a V, U or J groove, used for butt joints that must carry full-thickness load.

A weld defect consisting of small gas-filled cavities trapped in the solidified metal, usually caused by moisture, dirt, oil or poor shielding during welding.

A groove melted into the base metal along the edge of a weld and left unfilled. It thins the section and acts as a stress raiser, weakening the joint.

The band of base metal next to the weld that did not melt but had its properties changed by the heat of welding, sometimes becoming harder or more brittle.

Unwanted bending, twisting or shrinkage of a welded assembly caused by uneven heating and cooling of the metal around the joint.

A short temporary weld used to hold parts in correct alignment before the main runs are deposited. Tacks must be small enough to be fused into the final weld.

The orientation of the joint during welding, classified as flat, horizontal, vertical or overhead. Position changes the difficulty of controlling the pool and slag.

The shaping of joint edges by cutting, grinding or machining into a bevel, V, U or J form so the arc can reach the full thickness and fuse it properly.

The clothing and gear worn to protect the welder, including a helmet with filter lens, leather gloves, apron, safety boots and eye protection for chipping.

A head shield fitted with a dark filter lens that protects the face and eyes from arc radiation, spatter and hot slag while leaving both hands free to work.

Painful inflammation of the eye caused by exposure to ultraviolet radiation from an arc, producing a gritty feeling and light sensitivity hours after exposure.

A ventilation system that captures welding smoke and metal oxide particles at the source and removes them from the work area to protect the welder's lungs.

A person stationed to monitor sparks, slag and hot metal during and after hot work, ready to raise the alarm and extinguish any fire that starts.

A written authorisation issued before welding or cutting in a hazardous area, confirming that combustibles are removed, ventilation is adequate and fire precautions are in place.