ICC S2 Welding key terms

The application of heat to the base metal before welding so that moisture is driven off and the cooling rate is slowed, reducing the risk of cracking in thick or high-carbon steel.

The temperature of the weld and surrounding base metal measured immediately before the next pass is deposited; it must be kept within a maximum or minimum range specified by the procedure.

The portion of base metal that is not melted but whose microstructure and properties are altered by the heat of welding, and where cracking and toughness loss often originate.

The melted portion of a weld consisting of filler metal and fused base metal, whose composition and mechanical properties are governed by the welding procedure and consumable selection.

A written document that lists the essential and nonessential variables for producing a weld, such as process, filler, current, preheat, and position, and that has been supported by procedure qualification.

The documented record of the test weld made to qualify a welding procedure, including actual variables used and the results of mechanical tests performed on specimens taken from that weld.

A welding parameter, such as process, filler classification, or preheat level, that cannot be changed beyond the code's limits without requalifying the procedure because the change may affect weld properties.

A welding parameter that may be changed without requalifying the procedure because the code considers the change incapable of adversely affecting the mechanical properties of the completed weld.

A joint detail, such as those in the code's prequalified tables, that may be used without procedure qualification testing provided all specified conditions on base metal, process, and technique are met.

The shaping of member edges by cutting, machining, or grinding to produce the groove, bevel, or root opening required for the intended weld, including removal of contaminants before welding.

The separation between the two members at the root of a groove weld before welding, which controls penetration and must fall within the range permitted by the procedure.

The first pass deposited at the root of a groove weld, which establishes penetration and fusion into the joint and is the pass most prone to incomplete fusion and cracking defects.

Material placed at the root of a groove weld to support molten metal and help control penetration; it may be permanent steel, removable copper, or a consumable insert.

A test in which a welder makes a weld under controlled conditions to demonstrate the ability to produce sound welds in a given process, position, and thickness range.

The physical test assembly and examination, such as bend or radiographic testing, used to evaluate the welds made by a candidate during performance qualification.

The test plate or pipe welded by a candidate during qualification, from which specimens are cut and prepared for mechanical or nondestructive examination.

The orientation of the weld axis and face relative to the welder, such as flat, horizontal, vertical, or overhead, which determines the qualification range a welder earns.

A destructive test in which a specimen cut from a qualified weld is bent over a specified radius and the convex surface is examined for defects such as cracks or incomplete fusion.

A mechanical test in which a specimen is pulled to fracture to determine yield and ultimate strength, used to confirm that a procedure produces welds meeting specified strength requirements.

The requirement that a qualified welder use the process regularly within a defined period, or requalify, to keep the qualification valid and demonstrate maintained skill.

The filler metal, either bare or covered, that conducts current in arc welding and is deposited into the joint; its classification controls strength, toughness, and hydrogen content.

A covered electrode manufactured with a moisture-resistant coating and low hydrogen content, used to reduce the risk of hydrogen-assisted cracking in restrained or high-strength steel welds.

An arc welding process in which a flux-covered consumable electrode is manually fed, the coating decomposing to shield the molten pool and form slag over the finished weld.

An arc welding process using a continuous tubular electrode filled with flux that shields the arc, commonly used for structural steel with higher deposition rates than manual covered-electrode welding.

An arc welding process in which a continuous bare wire electrode is fed through a gun while an externally supplied shielding gas protects the molten weld pool from the atmosphere.

Gas supplied around the arc to exclude air and prevent porosity and contamination of the molten weld metal; its composition affects arc stability, penetration, and spatter.

A groove melted into the base metal along the toe or root of a weld that is left unfilled, reducing the effective throat and acting as a stress concentration.

Cavities in the weld metal formed by gas trapped during solidification, appearing as rounded voids that reduce the sound cross-section of the weld.

Solid nonmetallic material from the welding flux or coating that becomes entrapped in the weld metal, appearing as irregular elongated indications on a radiograph.

A condition in which weld metal does not fuse to the base metal or to a preceding pass, often caused by insufficient heat input, poor technique, or surface contamination.

A defect in which the weld does not extend through the full joint depth at the root, leaving an unfused gap that concentrates stress and can initiate fracture.

The examination of welds and connections by eye and with aids such as magnifiers and gauges, performed before, during, and after welding and required before other nondestructive methods.

Testing methods such as radiographic, ultrasonic, magnetic particle, and penetrant testing that reveal internal or surface discontinuities without damaging the welded component.

A nondestructive method in which penetrating radiation passes through a weld and exposes film or a detector, producing an image that reveals internal discontinuities such as porosity and slag.

A nondestructive method that sends high-frequency sound waves into a weld and analyzes reflected echoes to detect and locate internal discontinuities such as lack of fusion and cracks.

A surface and near-surface method in which a magnetic field is induced in ferromagnetic steel and iron particles reveal discontinuities where flux leakage occurs.

A surface method in which a liquid penetrant is applied to a cleaned weld and drawn into open discontinuities, then revealed by a developer for visual examination.

The shape and contour of the weld face and toes, including convexity and reinforcement, which must meet acceptance limits to avoid stress concentrations and inspection rejection.

A structural fastener such as an ASTM A325 or A490 bolt installed with controlled tension to clamp connected plies and transfer load by friction or bearing.

A bolt-tightening technique in which a specified additional rotation is applied to a nut already snugged tight, producing the required tension without measuring torque.

A tensioning method in which a torque wrench is calibrated against a verification device and used to tighten bolts to a torque that corresponds to the required installation tension.

A bolted joint designed so that the clamped plies do not slip under service load, requiring high bolt tension and specified faying-surface preparation to develop friction.

The contact surface between connected steel plies in a bolted joint, whose condition and cleanliness govern the friction developed in a slip-critical connection.

The condition in which plies of a bolted joint are brought into firm contact by a few impacts of an impact wrench or full effort of a spud wrench, the starting point for tensioning.

Unintended change in the shape or dimensions of a welded member caused by nonuniform heating and cooling, controlled by sequencing, restraint, and balanced welding techniques.

Internal stress locked into a weldment by restrained shrinkage and thermal gradients, which can promote cracking and reduce fatigue life even without external loading.