SCWI key terms

The documented demonstration, by testing a welder on a specific joint type and position, that the welder can produce welds meeting the applicable code while following an already qualified welding procedure.

A welding condition that affects a welder's ability to make a sound weld; if it changes, for example the process, position, backing or current type, the welder must normally be requalified.

The limits within which a qualified welder may work, usually expressed as metal thickness, pipe diameter, welding position, process and joint type covered by the passed test.

The requirement that a qualified welder keeps working with the qualified process within a stated period, often six months; if the period passes without such work, the qualification lapses.

The orientation of a qualification test weld relative to gravity and the joint axis, such as flat, horizontal, vertical or overhead, which sets the production positions the welder is qualified for.

A destructive test in which a specimen cut from a qualified weld is bent over a former to stretch the weld and heat-affected zone, exposing lack of fusion, incomplete penetration or similar flaws.

The form or certificate that records the welder's identity, the test conditions used, the test results and the resulting range of qualification, signed by the responsible inspection authority.

A person who runs machine-guided or automatic welding equipment, such as submerged arc or robotic systems, where the machine controls travel and the operator sets and monitors the parameters.

Additional qualification testing permitted by code after a welder's first test fails, usually on a fresh coupon and often limited in number of attempts before further training is required.

A written document listing the variables a welder must follow to make a production weld, including process, filler metal, current and polarity, position, preheat, joint design and technique.

The record of the test weld used to qualify a procedure; it lists the actual variables employed and the results of the destructive and nondestructive tests performed on the coupon.

A procedure a code accepts without mechanical testing, provided the base metal, filler metal, joint detail, thickness and technique all fall within the code's stated limits.

A variable in a welding procedure that, if changed beyond the range the code allows, requires a new procedure qualification test because it can alter the mechanical properties of the weld.

A procedure variable that may be changed without requalifying the procedure, provided the welding procedure specification is revised; examples include travel speed range and some pass sequences.

A variable that becomes essential only when the work requires notch toughness, such as heat input or pass thickness, and must be requalified if changed outside the permitted limits.

The energy introduced into the weld per unit length, calculated from current, voltage and travel speed; excessive heat input can reduce toughness and increase distortion.

The minimum temperature of the base metal before welding and the maximum temperature allowed between passes; both are controlled to prevent cracking and to preserve weld properties.

A welded assembly made under the candidate procedure from which specimens are cut for the tensile, bend, impact or other tests the code requires.

A mechanical test in which a specimen is pulled until it fractures, measuring the strength of the welded joint, which must meet or exceed the specified minimum of the base metal.

A test that measures the energy absorbed when a notched specimen is struck by a falling pendulum, showing whether the weld and heat-affected zone meet toughness requirements at a stated temperature.

A code classification that places similar base metals into groups or numbers, so that qualifying a procedure on one metal also qualifies it for others in the same group.

A grouping system for electrodes and filler metals based on composition, strength and usability, allowing one qualification test to cover a range of similar consumables.

The limits of base metal and weld thickness a qualified procedure covers, derived from the thickness of the test coupon and the rules of the applicable code.

The person assigned by a manufacturer to control welding production, covering procedure and welder qualification, consumables, equipment and inspection, as described in welding quality management standards.

A project document that lists the inspections and tests to be performed, who performs them, the specifications used, and the hold and witness points along the fabrication sequence.

A stage in production where work must stop until the designated inspector or client representative has carried out the required inspection and recorded formal approval to continue.

A notified inspection stage that the client or inspector may attend; if they choose not to attend after being notified, the work may still proceed.

A record describing a product or process that does not meet requirements, together with its disposition, such as repair, rework, regrade, accept by concession or rejection.

Steps taken to remove the cause of a detected nonconformity so that it does not recur, as distinct from rework, which only corrects the affected product.

The practice of recording and controlling consumable batch numbers, storage conditions, baking cycles and issue records so that any finished weld can be linked to the consumables used.

The system that ensures only current, approved drawings, procedures and specifications are available at the work site, and that superseded versions are withdrawn from use.

A maintained list of qualified welders showing each person's identification, qualified ranges, test dates and continuity status, used to confirm who may weld what.

Inspection methods such as visual, radiographic, ultrasonic, magnetic particle and penetrant testing that reveal discontinuities in a welded component without damaging it.

A written description of how an NDT method will be applied, including equipment, technique, calibration, coverage and recording, detailed enough to give consistent, repeatable results.

The amount of a welded structure that must be tested, usually stated as a percentage of weld length or as random sampling of designated welds.

The limits set by code or specification that define whether an indication found by examination is acceptable or must be repaired before the work is released.

A signal or response produced during an examination that may come from a real discontinuity, a geometric feature of the joint or an equipment artefact; not every indication is a defect.

A small device of known dimensions placed on the part during radiography to show whether the chosen technique achieves the required sensitivity and contrast in the resulting image.

The grade, such as Level I, II or III, that defines what an NDT technician is permitted to do, from performing tests to interpreting results and approving procedures.

The specified stage at which nondestructive testing is performed, for example after the weld has cooled, a set delay after completion, or before and after post-weld heat treatment.