Your FREE CWI Flashcards 2026 – 250+ Cards

A discontinuity is any interruption in the weld's structure; a defect is a discontinuity that exceeds the code's acceptance criteria (rejectable).

An interruption in the typical structure of a weld — a lack of homogeneity. Not automatically rejectable.

A discontinuity that exceeds the applicable acceptance criteria of the governing code; by definition rejectable.

Cavity-type discontinuities formed by gas trapped in the solidifying weld metal; caused by contamination, poor shielding, or long arc.

Scattered (uniform), cluster (localized), and piping/wormhole (elongated cavities reaching the surface).

Nonmetallic flux material trapped in the weld; caused by poor interpass cleaning or improper technique.

A groove melted into the base metal next to the weld toe or root and left unfilled by weld metal; reduces base-metal cross-section.

Excessive current, too long an arc, incorrect electrode angle, or too fast travel speed.

Weld metal that flows over the base metal at the toe or root without fusing to it; a stress riser.

Failure of weld metal to fuse with the base metal or with a preceding weld bead (also called lack of fusion).

Weld metal does not extend through the full required depth of the joint root.

Incomplete fusion = no bonding (anywhere); incomplete joint penetration = root not filled to the required depth.

A fracture-type discontinuity with a sharp tip; the most serious flaw and almost always rejectable.

Hot cracking occurs during solidification (high temperature); cold cracking is hydrogen-induced and appears after cooling.

Hydrogen + a hard microstructure + stress, acting together; common in the HAZ of hardenable steels.

Longitudinal runs parallel to the weld axis; transverse runs across (perpendicular to) the weld axis.

Weld metal in excess of the quantity required to fill the joint, on the face or root side.

A localized discontinuity from striking the arc on the base metal away from the joint; creates a hard spot.

Step-like cracking in the base metal beneath welds, caused by through-thickness strain on non-metallic inclusions.

Metal particles expelled during welding that land on the surrounding surface; usually cosmetic.

A depression on the weld face or root extending below the adjacent base-metal surface (joint not fully filled).

Visual (VT), liquid penetrant (PT), magnetic particle (MT), radiographic (RT), and ultrasonic (UT).

Visual (VT), liquid penetrant (PT), and magnetic particle (MT).

Radiographic (RT) and ultrasonic (UT) — they detect internal flaws.

Examination of a weld with the eye (aided by gauges and light) for surface flaws, profile, and size; always done first.

A dye is drawn into surface-breaking flaws and a developer reveals them; works on any clean, nonporous material.

Detects only surface-breaking flaws — it cannot find subsurface or internal flaws.

Uses a magnetic field and iron particles to reveal surface and near-surface flaws.

Works only on ferromagnetic (ferrous) materials — not on aluminum or austenitic stainless steel.

Uses X-rays or gamma rays to image internal volumetric flaws (porosity, slag); produces a permanent record.

Radiographic testing (RT) — it images volumetric flaws well and leaves a record.

Sends high-frequency sound into the weld to detect internal flaws, especially planar cracks and lack of fusion.

Ultrasonic testing (UT) — most sensitive to planar flaws and good in thick sections.

RT is best for volumetric flaws with a permanent image; UT is best for planar flaws (cracks) and has no radiation hazard.

Visual inspection (VT) — it is the most economical and catches many flaws before other NDE.

Measuring fillet weld leg size and throat to verify the weld meets the required dimensions.

Yes. Liquid penetrant works on any clean, nonporous material, including aluminum (MT does not).

A geometric discontinuity (e.g., undercut, sharp toe) that concentrates stress and can initiate cracking.

Cracks and lack of fusion are planar (two-dimensional); porosity is volumetric (three-dimensional).

The governing code or specification (e.g., AWS D1.1, API 1104) — they define when a discontinuity is a defect.

The boundary between weld metal and base metal where they fused together.

A localized group of pores caused by intermittent shielding loss or contamination.

Elongated gas voids (wormholes) that extend toward the weld surface.

A crack running down the middle of the weld, often a hot crack from solidification.

A crack in the weld crater formed when the arc is broken improperly at the end of a bead.

Use a crater-fill technique or back-step to fill the crater before breaking the arc.

Weld metal piled above the surface beyond code limits; creates a sharp toe and stress riser.

Excess weld metal bulging above a straight line across the fillet toes.

A fillet face that dishes inward, reducing the effective throat.

Excess heat melting through the joint, leaving a hole or excessive root penetration.

A buildup of iron particles at a flux leakage field, marking a surface or near-surface flaw.

A coating that draws penetrant back out of flaws to make indications visible.

Wet uses particles in a liquid carrier (finer flaws); dry uses powder (rough surfaces, subsurface).

A measure of film darkness used to confirm the radiograph has adequate exposure for interpretation.

A penetrameter placed in an RT shot to verify the radiograph's sensitivity.

The probe that sends and receives ultrasonic sound waves into the weld.

A liquid or gel between the transducer and part that transmits sound into the material.

Straight beam checks thickness/laminations; angle beam finds weld flaws at an angle to the surface.

An NDE signal that is not an actual flaw (e.g., surface dirt, geometry); must be distinguished from real flaws.

An NDE indication caused by an actual discontinuity that must be evaluated against acceptance criteria.

Shielded Metal Arc Welding (stick) — a flux-coated consumable electrode whose coating forms a shielding gas and slag.

Gas Metal Arc Welding (MIG) — a continuous consumable wire shielded by an externally supplied gas.

Flux-Cored Arc Welding — a continuous tubular wire with flux inside, used self-shielded or with added gas.

Gas Tungsten Arc Welding (TIG) — a non-consumable tungsten electrode with inert gas and separately added filler.

Submerged Arc Welding — a continuous wire under a granular flux blanket; the arc is not visible.

By the gas and slag produced when the electrode's flux coating burns.

By an externally supplied shielding gas such as argon or carbon dioxide.

By an inert shielding gas (argon or helium); the tungsten electrode is not consumed.

By a blanket of granular flux that covers the arc and weld pool.

GTAW (TIG) — precise, clean welds ideal for thin material, root passes, stainless, and aluminum.

SAW (Submerged Arc Welding) — automated, high deposition, used on thick sections.

SMAW (stick) — minimal equipment, no external gas, works outdoors.

GMAW feeds a consumable wire (becomes filler); GTAW uses a non-consumable tungsten with separate filler.

Joining sheet metal with heat from electrical resistance and pressure; no filler metal is added.

Minimum tensile strength of 70,000 psi (70 ksi).

Welding position — 1 means all positions.

Coating type and current — 8 indicates a low-hydrogen, iron-powder electrode.

Moisture introduces hydrogen into the weld, raising the risk of cold (hydrogen-induced) cracking.

A low-energy metal transfer mode where the wire repeatedly touches the pool; good for thin material and out-of-position welds.

A high-energy mode where fine droplets cross the arc; high deposition, used in the flat/horizontal positions.

A thermal cut that preheats steel then burns it in a stream of oxygen; relies on oxidation.

They form protective oxides and don't oxidize like carbon steel, so the oxygen stream cannot burn through.

Cutting with a high-temperature ionized gas jet; cuts any electrically conductive metal, including stainless and aluminum.

An arc melts the metal and compressed air blows it away; used for back-gouging and removing defects.

An electrode that melts and becomes part of the weld (SMAW, GMAW, FCAW, SAW).

An electrode that conducts the arc but is not melted into the weld — the tungsten in GTAW.

The percentage of a 10-minute period a machine can weld at a given output without overheating.

CC suits SMAW/GTAW (stable amperage); CV suits GMAW/FCAW/SAW (stable voltage with wire feed).

A mix such as argon with carbon dioxide (e.g., 75% Ar / 25% CO2), or straight CO2.

Flux-cored welding where the flux alone shields the weld — no external gas needed; good for field work.

Direct current electrode positive (reverse polarity) — deeper penetration; common for SMAW low-hydrogen.

Direct current electrode negative (straight polarity) — less penetration, higher deposition.

Alternating current — the polarity reverses; helps with arc blow and is used in some GTAW (aluminum).

Deflection of the arc by magnetic fields; mitigated with AC, ground placement, or technique.

The volume of gas per minute protecting the weld; too low loses shielding, too high causes turbulence.

Inert gas — argon (most common) or helium, or argon-helium mixes.

CO2 is reactive and would contaminate/oxidize the weld; GTAW requires an inert gas.

Large irregular droplets cross the arc; more spatter, used at lower energy than spray.

A controlled mode pulsing between background and spray current for out-of-position spray-like welding.

A high-deposition process using molten slag resistance heating for thick vertical joints.

Joining metals with a filler that melts above 840 F (450 C) without melting the base metal.

Joining metals with a filler that melts below 840 F (450 C) without melting the base metal.

Brazing does not melt the base metal and bonds via capillary action; welding melts and fuses the base metal.

Heating steel to ignition temperature so the oxygen jet can start the oxy-fuel cut.

The width of material removed by a cutting process.

Molten material that resolidifies on the bottom edge of an oxy-fuel or plasma cut.

A focused laser melts/vaporizes material for a narrow, precise kerf.

An arc melts metal and a stream of compressed air blows it away to gouge or back-gouge.

Removing weld/base metal from the root side to reach sound metal before welding the back.

Examples include electrode classification, polarity, position, and preheat.

Base metal next to the weld whose microstructure and properties changed from welding heat without melting.

It can become hard and brittle, making it a common site for cracking.

To slow cooling so the weld and HAZ stay softer and hydrogen can escape — preventing cold cracking.

The temperature of the metal between weld passes; controlled to maintain preheat's benefits.

Post-Weld Heat Treatment — controlled heating after welding to relieve residual stress or improve toughness.

A calculated value from carbon and alloy content used to estimate a steel's weldability and cracking risk.

Greater hardenability and higher cracking risk — usually requiring more preheat.

Hydrogen, a hard (susceptible) microstructure, and tensile stress — all present together.

Faster cooling produces a harder, more brittle, more crack-prone microstructure.

Internal stress left in a weldment after welding due to uneven heating and cooling; PWHT can relieve it.

Dimensional change from the heating and cooling of welding; controlled by sequence, fixturing, and heat input.

The energy delivered per unit length of weld; it rises with voltage and amperage and falls with faster travel speed.

Slower cooling rate, larger weld bead, and a wider HAZ.

A hard, brittle steel microstructure formed by rapid cooling; associated with HAZ cracking.

Loss of ductility and cracking caused by dissolved hydrogen in susceptible steel.

A heat treatment that softens metal and relieves stress by heating and slow cooling.

Heating steel then air-cooling to refine grain structure and improve uniformity.

Rapid cooling (quench) for hardness, then reheating (temper) to restore toughness.

A material's ability to deform plastically (stretch) before fracturing.

A material's ability to absorb energy and resist fracture, especially under impact.

The ability of a steel to form hard martensite on cooling; increases with carbon and alloy content.

It keeps the metal hot longer, giving dissolved hydrogen time to diffuse out before the weld cools.

Removing slag, spatter, and contamination between passes to prevent inclusions and ensure fusion.

Coarsening of grains from welding heat that can reduce toughness near the fusion line.

The region of a weld where base and filler metal melted and solidified together.

A high-temperature face-centered-cubic phase of steel; transforms on cooling.

A soft, ductile body-centered-cubic phase of iron present in many steels.

A layered structure of ferrite and cementite formed on moderate cooling of steel.

Iron carbide (Fe3C) — a hard, brittle compound in steel.

Reheating hardened steel below its critical temperature to reduce brittleness and restore toughness.

Heating to relax residual stresses without significantly changing the microstructure.

The cooling rate above which hard martensite forms in steel.

It slows the cooling rate, reducing hardness and cracking risk.

A tendency to crack at high temperature due to low-melting films (e.g., sulfur).

Hot cracking that occurs as the weld pool freezes, often along the centerline.

Cracking during PWHT or service in the HAZ of certain alloy steels.

The stress at which a material begins to deform permanently.

The maximum stress a material withstands before breaking.

The percent a specimen stretches before fracture; a measure of ductility.

An impact test measuring the energy absorbed by a notched specimen at a set temperature.

The temperature range where steel toughness drops sharply as it gets colder.

Producing smaller grains to improve strength and toughness.

Degradation of metal by chemical/electrochemical reaction with the environment.

Accelerated corrosion when two dissimilar metals contact in an electrolyte.

Steel with small additions of alloying elements for strength, toughness, or hardenability.

The arrow side of the joint — the side the symbol's arrow points to.

The other side of the joint — the side away from the arrow.

Reference line, arrow, and tail (plus the weld symbol and dimensions); per AWS A2.4.

The joint to be welded.

References such as the process, specification, or other supplementary information.

AWS A2.4 — Standard Symbols for Welding, Brazing, and Nondestructive Examination.

A right-triangle symbol; the vertical leg is always drawn on the left.

To the left of the weld symbol.

To the right of the weld symbol.

A flag at the junction of the reference line and arrow — meaning the weld is made in the field, not the shop.

A circle at the bend in the reference line — the weld goes completely around the joint.

Butt, lap, tee, corner, and edge joints.

Two members in the same plane joined edge to edge.

Two overlapping members joined together.

One member perpendicular to another, forming a T.

Two members meeting at a corner, forming an L.

The edges of two parallel or nearly parallel members joined together.

Square, V, bevel, U, and J grooves.

A fillet joins surfaces at roughly a right angle; a groove weld fills a prepared groove between members.

The required shape of the finished weld face — flush, convex, or concave.

Leg size (left), and length and pitch for intermittent welds (right).

The joint is the geometry of how parts meet; the weld is how they are joined (fillet, groove).

A weld made through a hole (plug) or slot in one member to join it to another.

A supplementary symbol indicating complete joint penetration with visible root reinforcement.

The leg size of the fillet weld (in inches or millimeters).

A weld symbol showing a V-shaped groove preparation between members.

A weld symbol showing one member beveled to form the groove.

A weld symbol for a U-shaped groove preparation, used on thicker material.

A weld symbol for a J-shaped groove preparation on one member.

A weld symbol for a groove with no edge preparation (square butt joint).

Above or below the weld symbol, near the groove symbol.

The gap dimension inside the groove symbol.

A fillet weld in short increments at a regular pitch rather than continuous.

Length and pitch (center-to-center spacing) to the right of the fillet symbol (e.g., 2-5).

Identical weld symbols above and below the reference line — weld on both sides.

Complete Joint Penetration — the weld extends fully through the joint thickness.

Partial Joint Penetration — the weld intentionally does not fully penetrate the joint.

CJP welds the full thickness; PJP welds only part of it by design.

A symbol indicating backing material is used at the root of a groove weld.

Indicates a spacer is used in the root of certain groove welds.

Welding Procedure Specification — a written document directing the welder how to make a code-compliant weld.

Procedure Qualification Record — documents the test weld and results that qualify (support) a WPS.

Welder Performance Qualification — a record showing a welder can deposit sound welds within a range of conditions.

The WPS directs production welding; the PQR is the test record proving the WPS produces sound welds.

The WPS qualifies the procedure; the WPQ qualifies the welder (the person).

A welding variable whose change beyond set limits requires requalification of the procedure or welder.

Before welding, during welding, and after welding.

Base metal, fit-up, joint preparation, cleanliness, and welder/WPS qualification.

Amperage, voltage, travel speed, preheat/interpass temperature, and adherence to the WPS.

Visual inspection first, then required NDE and measurements against acceptance criteria.

Verify that materials, procedures, welders, and welds conform to the code, and keep accurate, impartial records.

Honesty, objectivity, and freedom from conflicts of interest; report findings factually regardless of pressure.

AWS B5.1 — Specification for the Qualification of Welding Inspectors.

How well the parts are aligned and gapped before welding; poor fit-up causes defects.

Certified Associate Welding Inspector — an entry-level AWS certification below the CWI.

Senior Certified Welding Inspector — the highest AWS welding-inspector certification level.

It is the cheapest method and catches many surface defects, so it is done first.

A point in fabrication where work must stop for inspection before proceeding.

The documented, impartial record of what was inspected, measurements, and accept/reject decisions.

Verifying a gauge or instrument reads accurately against a known standard.

A document with mandatory requirements (e.g., AWS D1.1) governing how welds are made and accepted.

A code gives mandatory rules; a specification details requirements for a product or procedure, often referenced by a code.

Acceptance means the weld meets the code criteria; rejection means a defect exceeds them.

Removing a defect and re-welding to bring the joint into conformance with the code.

A document recording work that does not meet requirements and its disposition.

A WPS that meets all code conditions to be used without procedure qualification testing (per AWS D1.1).

A coupon cut from a test weld and tested to failure to qualify a procedure or welder.

Correct classification, condition, storage (especially low-hydrogen electrodes), and traceability.

The ability to trace a material back to its mill certification and heat number.

A certified document of a material's chemical and mechanical properties.

Code limits for surface flaws (undercut, porosity, profile) judged during VT.

Report findings honestly and refuse to certify nonconforming work, free of conflicts of interest.

Welding fundamentals: processes, metallurgy, symbols, NDE, terminology, math, and safety (closed-book).

Hands-on practical inspection of plastic weld replicas using the Book of Specifications (46 questions).

Open-book application of a chosen code (50-65 questions), most often AWS D1.1 or API 1104.

A fictitious specification AWS supplies for Part B so the test measures inspection skill, not code memorization.

72% on each of Part A, Part B, and Part C, separately.

The parent material being welded or cut, as opposed to the filler metal added by the weld.

The metal added during welding (from an electrode or rod) that becomes part of the weld.

The portion of a weld that melted during welding — a mix of melted base metal and filler metal.

The exposed surface of the weld on the side from which it was made.

The points where the weld metal meets the base metal at the back/root of the joint.

The junction of the weld face and the base metal — a frequent flaw site.

The distance from the joint root to the toe of the fillet weld.

The shortest distance from the weld root to the face; the load-bearing dimension.

The depth that weld metal extends into the joint from the surface.

A single progression of welding along a joint; multi-pass welds use several beads.

1 = flat, 2 = horizontal, 3 = vertical, 4 = overhead; G = groove, F = fillet.

A groove weld made in the vertical position.

Fixed-pipe positions where the pipe does not rotate (6G is at a 45-degree angle).

Material placed at the root of a joint to support molten weld metal and ensure full penetration.

The gap between the members at the root of the joint before welding.

An angled edge prepared on a member to form a groove for welding.

The first weld pass that fuses the root of the joint.

The final weld pass(es) that complete the weld face.

How readily a metal can be welded to produce sound, serviceable joints.

A small temporary weld used to hold parts in alignment before final welding.

A weld bead made with little or no side-to-side motion.

A weld bead made with side-to-side oscillation to widen the bead.

A welding filter lens of the proper shade number for the process and current — protecting eyes from UV and IR.

To remove hazardous welding fume and gases from the breathing zone.

An authorization controlling welding/cutting fire risk in areas with combustibles.

The localized volume of molten metal during welding before it solidifies.

The change in weld-metal composition from melting and mixing in base metal.

An assembly whose component parts are joined by welding.

The surface of a member within the groove that is to be welded.

The portion of the groove face within the joint root (the unbeveled land).

The total angle of the groove between the members.

An imaginary line through the length of the weld in the direction of travel.

The shortest distance from the root to the face of the actual fillet weld.

The minimum throat used in design strength calculations for a weld.

A weld completed in one pass along the joint.

A weld built up with two or more passes.

The rate at which the arc moves along the joint; affects heat input and bead size.

The angle of the electrode relative to the weld axis (push or drag).

The angle of the electrode relative to the joint surfaces.

The length of wire/electrode beyond the contact tip or holder.

The surfaces of members in contact or close proximity that are to be joined.

Welding in positions other than flat (horizontal, vertical, overhead).

A test weld made to qualify a procedure or welder.

The state of a weld after welding before any further processing or heat treatment.

A groove formed by beveling both members on one side into a V.

A groove beveled from both sides, used to balance distortion on thick material.