Canada BWR key terms

A written, qualified document that lists the variables, ranges, and techniques a welder must follow to make a production weld that meets the required code and properties.

A record of the actual values used and the test results obtained when a weld test coupon was made to prove that a welding procedure produces acceptable joints.

Testing of an individual welder's skill by making a test weld under controlled conditions, to show the person can produce sound welds with a given process and position.

A welding condition, such as process, filler classification, or base metal group, that must fall within the qualified range or the procedure must be requalified before production use.

A welding condition that may be changed outside the values recorded in the procedure qualification without invalidating the qualification, though the change is usually still recorded on the WPS.

A specially prepared test assembly welded to the proposed procedure and then destructively tested or examined to establish the mechanical properties and soundness of the joint.

The test joint a welder makes for performance qualification; its type, thickness, and position set the limits of what that welder is later permitted to weld.

The orientation of the joint and the direction of welding progress, such as flat, horizontal, vertical, or overhead, which affects difficulty and the range of production work a welder may perform.

The specific method of joining metal by heat or pressure, for example shielded metal arc, gas tungsten arc, gas metal arc, or submerged arc welding, each with distinct variables and qualifications.

An arc process in which a flux-coated consumable electrode melts to form the weld and its coating generates shielding gas and slag that protect the molten metal.

An arc process using a non-consumable tungsten electrode and a separate shielding gas, with filler metal added by hand or fed automatically when required.

An arc process using a continuously fed consumable wire electrode and an externally supplied shielding gas, commonly run in short-circuit, globular, spray, or pulsed transfer.

An arc process in which the arc is buried under a blanket of granular flux, giving high deposition rates and deep penetration with little visible arc radiation.

The energy delivered per unit length of weld, usually calculated from arc voltage times current divided by travel speed, which strongly influences cooling rate and microstructure.

Heating the base metal to a specified temperature before welding to slow cooling, reduce hydrogen cracking risk, and improve fusion in thick or hardenable steels.

The temperature of the weld and surrounding base metal measured just before the next pass is deposited, kept within a qualified maximum to control toughness and properties.

The rate at which the arc moves along the joint; it affects bead shape, penetration, and heat input, and is a variable that must stay within qualified limits.

The electrical potential across the arc, controlled mainly by arc length; it influences bead width, penetration profile, and the heat input calculation.

The code system of letters and numbers printed on a consumable that identifies its strength, position capability, coating or flux type, and current requirements.

The consumable added to a joint to form the weld, chosen to match or exceed the required strength, toughness, corrosion resistance, and composition of the base metals.

A category used in qualification rules that groups steels or alloys with similar welding behavior, so a procedure qualified on one member may cover others in the group.

A calculated number combining carbon with other alloying elements to estimate how readily a steel hardens and cracks when welded, guiding preheat decisions.

Delayed cracking caused by hydrogen trapped in a hard weld or heat-affected zone, often appearing hours after welding; controlled by preheat, low-hydrogen consumables, and clean joints.

The region of base metal next to the fusion line that was heated but not melted, where microstructure and properties change and where many cracking failures begin.

How quickly a weld and its heat-affected zone lose heat after welding; it determines hardness, toughness, and cracking susceptibility and is governed largely by heat input and preheat.

The proportion of melted base metal that mixes into the weld deposit, altering the final composition and properties, especially in dissimilar or cladding welds.

The boundary between melted weld metal and unmelted base metal; incomplete fusion along this boundary is a common discontinuity found by inspection.

A discontinuity where weld metal fails to melt into the base metal or the previous pass, often from low heat input, poor angle, or travel speed that is too fast.

Gas pockets trapped in solidified weld metal, appearing as rounded voids on a radiograph; caused by moisture, contamination, poor shielding, or improper technique.

Nonmetallic flux or slag material trapped between passes or along the fusion line, usually from poor interpass cleaning or incorrect manipulation of the electrode.

Gas supplied around the arc to exclude air and prevent oxidation and nitrogen pickup in the molten weld pool; composition and flow rate are controlled variables.

Granular or coated mineral material that generates shielding gas and slag, stabilizes the arc, and protects the weld, as in submerged arc or stick electrode coatings.

Flushing the underside of a pipe or root gap with inert gas during welding to prevent oxidation of the root bead, commonly required for stainless and reactive alloys.

A destructive test pulling a specimen until it breaks, used to measure ultimate strength and yield and to confirm the weld meets the qualified minimum values.

A destructive test bending a welded specimen to a specified radius to reveal ductility problems, incomplete fusion, or other flaws near the root or face.

A volumetric examination using penetrating radiation to produce an image of internal weld soundness, revealing porosity, inclusions, and incomplete penetration.

A volumetric inspection method that sends high-frequency sound into the weld and reads returning echoes to locate and size internal planar flaws such as cracks or lack of fusion.

The first-line examination of a completed weld for bead profile, undercut, spatter, surface cracks, and dimensional compliance, done before other testing is planned.

Depositing weld metal while progressing upward on a vertical joint, a technique that improves penetration and is often required for qualification in the vertical position.