Certified Welding Inspector (CWI) Prep

Exam blueprint

Sourced from AWS QC1 (Standard for AWS Certification of Welding Inspectors) + AWS B5.1 (Specification for the Qualification of Welding Inspectors)

• Part A — AWS A2.4 welding symbols10%
• Part A — AWS A3.0 terminology5%
• Part A — Weld discontinuities + causes15%
• Part A — NDT methods (RT, UT, MT, PT, VT)15%
• Part A — Welding processes (SMAW, GMAW, FCAW, GTAW, SAW)10%
• Part A — Metallurgy + heat-affected zones5%
• Part B — Practical visual inspection (replicas + Book of Specs)20%
• Part C — Code-book navigation (typically D1.1)20%

1. 01Part A — Fundamentals (closed book)

   ~240min

   The make-or-break section. 150 multiple-choice questions in 2 hours, ~48 seconds per question, no books allowed. Symbols, terms, discontinuities, NDT, processes, metallurgy.

   • The eight common weld discontinuities

     Memorize these and the conditions that cause them: (1) POROSITY — gas pockets from contamination, lost shielding, or wet electrodes. (2) SLAG INCLUSIONS — flux trapped between passes; from poor inter-pass cleaning, especially in SMAW/SAW. (3) INCOMPLETE FUSION — weld metal did not melt to base metal; from low heat input, wrong angle, or surface contamination. (4) INCOMPLETE PENETRATION — root not fully filled in groove welds; from too-large root face, too-small root opening, or low current. (5) UNDERCUT — base-metal groove at weld toe from excessive current/voltage or wrong angle. (6) OVERLAP — weld metal flows over base without fusing; opposite-side problem from undercut. (7) CRACKS — most serious; hot cracks (during solidification, sulfur/segregation), cold/hydrogen cracks (after cooling, in HAZ, from H₂ + restraint + susceptible microstructure). (8) LAMINATIONS — base-metal defects (mill flaws), not from welding. The CWI exam tests both APPEARANCE on a sample/photo AND likely CAUSE.

     Reference: AWS A3.0 Standard Welding Terms and Definitions

   • When to choose RT, UT, MT, PT, or VT

     VT (Visual): always first; finds surface defects only. Free, fast, requires good lighting + gauges. RT (Radiography): X-ray or gamma-ray film/digital; finds VOLUMETRIC defects (porosity, slag, incomplete penetration) most reliably. Weak on tight cracks because of orientation sensitivity. Requires radiation safety. UT (Ultrasonic): sound-wave reflection; finds CRACKS and lack of fusion better than RT, plus works on thick sections where RT fails. Operator-skill dependent; phased-array UT is now common on bridges. MT (Magnetic Particle): iron particles attracted to surface/near-surface flaws on FERROMAGNETIC materials only — not on austenitic stainless or aluminum. PT (Penetrant): dye-penetrant; finds surface-breaking flaws on any non-porous material. Slow because of dwell + developer time. The CWI exam loves "which method would best detect [defect type] in [material/condition]" questions — make a 5x5 grid in your notes.

   • AWS A2.4 symbol reading — beyond the basics

     You already know the basics from D1.1 prep. CWI Part A pushes deeper into less-common items: TAIL information (process, specification, NDT method, special instructions); finishing-method letters (C = chipping, G = grinding, M = machining, R = rolling); the contour symbol (flush, convex, concave) versus finish symbol (a separate letter ABOVE the contour); arrow-side vs other-side ambiguity rules when the joint is symmetric; and how to interpret a BACKING WELD vs a BACK WELD vs a MELT-THROUGH (different symbols, different meanings, all small variants of a similar shape). The exam will test you on a complex symbol with 5+ elements — break it down systematically: arrow → reference line → above/below → tail → finishing.

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

   • Recognizing welding processes from features

     You should be able to identify SMAW (stick), GMAW (MIG/wire-fed solid wire with shielding gas), FCAW (flux-cored — gas-shielded or self-shielded), GTAW (TIG, tungsten + filler rod, very clean welds), and SAW (submerged arc, granular flux blanket, used for thick plate and pipe seams). The exam asks process-specific defect questions: "lack of side-wall fusion in spray-mode GMAW is most often caused by..." (low travel angle / heat input). Also know typical applications: SMAW for field repair, GMAW for production indoor work, FCAW for outdoor structural, GTAW for stainless/aluminum/root passes, SAW for shop fabrication.

   Practice questions (3)

   1. 1. A weld in carbon steel cracks 24 hours AFTER welding, in the heat-affected zone. Most likely classification?

      • A.Hot crack from sulfur segregation
      • B.Cold crack (hydrogen-induced cracking)✓ correct
      • C.Lamellar tearing
      • D.Crater crack from arc termination

      Cracking that appears HOURS to DAYS after welding, in the HAZ, in carbon or low-alloy steel, is classic hydrogen-induced cracking (HIC), also called cold cracking. It requires hydrogen + susceptible microstructure (martensite from rapid cooling) + restraint stress. Hot cracking happens DURING solidification (minutes, not hours). Lamellar tearing is a base-metal layered defect (parallel to plate surface), not HAZ-specific. Crater cracks occur AT WELD TERMINATIONS during cooling, also typically immediate.

   2. 2. An inspector must identify a tight, transverse crack in a 2-inch-thick low-alloy structural steel CJP weld. Which NDT method is the BEST primary choice?

      • A.Radiographic Testing (RT)
      • B.Ultrasonic Testing (UT)✓ correct
      • C.Magnetic Particle (MT) only
      • D.Penetrant Testing (PT)

      UT is the best primary choice for detecting tight cracks in thick sections. RT is orientation-sensitive: a tight crack perpendicular to the radiation beam can be missed entirely. MT only finds surface and near-surface flaws — a buried crack in 2-inch plate is past MT range. PT only finds surface-breaking flaws. UT can detect cracks throughout the thickness regardless of orientation when the angle and frequency are properly chosen.

   3. 3. A welding symbol shows a fillet weld on the arrow side with the letter G in the contour position (immediately above the fillet symbol). What does the G specify?

      • A.Gas-metal arc welding (GMAW) is required
      • B.The weld must be ground to a flat or specified contour after welding✓ correct
      • C.A general inspection is required
      • D.Galvanizing required after welding

      In AWS A2.4, the letter G in the finishing-method position means GROUND. Other valid finishing letters: C = chipping, M = machining, R = rolling, P = peening. G does NOT denote a process (GMAW); processes appear in the TAIL, not on the symbol itself. "General inspection" and "galvanizing" are not AWS A2.4 conventions.

2. 02Part B — Practical (open Book of Specifications)

   ~150min

   AWS provides a fictional "Book of Specifications" (BOS) for Part B — original acceptance criteria, gauges, and procedures unique to the test. Part B is a hands-on visual-inspection exam: replicas, photographs, charts. Reasoning beats memorization.

   • How the Book of Specifications differs from real codes

     The BOS is INTENTIONALLY different from D1.1 or any real code. AWS does this so candidates cannot rote-memorize answers — every Part B candidate works from the same fictional spec, applying real inspection methodology. Acceptance limits in the BOS may be tighter or looser than D1.1 in any specific dimension. Strategy: in the first 5 minutes, FLIP THROUGH THE BOS to learn its layout — table of contents, where the acceptance criteria tables live, where the discontinuity definitions live. Then mark up your BOS with sticky tabs as you work — you can write in it.

   • Reading weld replicas + photographs

     Part B replicas are physical resin/plastic copies of welds with built-in defects, plus 2D photographs. You will use a CWI-issued visual gauge kit (fillet gauges, undercut gauges, weld profile templates). Apply the BOS acceptance criteria — measure, compare, decide. Common traps: (1) measuring at the WRONG LOCATION (BOS may say "max undercut at the weld toe in the throat region"); (2) misreading a fillet leg as the throat (the throat is shorter — leg × 0.707 for equal-leg fillets); (3) accepting a discontinuity that the BOS specifies as REJECTABLE regardless of size (cracks, for example, are usually any-size-rejectable in the BOS just like D1.1).

   • Part B time discipline

     46 questions in 120 minutes = ~2.6 minutes per question. Replicas take longer than photos. Strategy: (1) Take inventory at minute 0 — count the replica stations and photo stations. (2) Do photos FIRST (faster, build confidence, free up replica stations for later candidates if shared). (3) Spend no more than 5 minutes on any single question — if stuck, mark it, move on, return at minute 100. (4) Always answer EVERY question — no penalty for guessing. (5) When in doubt between accept/reject, lean toward the BOS literal text rather than your own field-judgment habit. The BOS is the law here.

   Practice questions (1)

   1. 1. On a Part B replica, an inspector measures a fillet weld leg of 5/16 inch and a throat of 0.20 inch. The Book of Specifications requires a minimum 0.22-inch throat. Inspector's call?

      • A.Accept — the leg is adequate
      • B.Reject — measured throat 0.20 in is below the BOS-specified minimum 0.22 in✓ correct
      • C.Accept — throat is calculated as leg × 0.707, not measured
      • D.Reject only if the leg is also undersized

      When the BOS specifies a minimum THROAT, you measure the throat (or measure the leg and apply the conversion ONLY when the BOS instructs that). Here the throat is below minimum — reject. A is wrong because leg adequacy does not guarantee throat adequacy on a concave fillet. C confuses a calculation shortcut with the actual measured value — the test will say which to use. D over-conditions the rejection — undersized throat alone is sufficient cause.

3. 03Part C — Code book (typically D1.1)

   ~150min

   Open-book navigation under time pressure. Most candidates pick D1.1 because they prepped on it. Speed comes from KNOWING WHERE THE ANSWER LIVES — not rereading the section.

   • Tab your code book + master the index

     Buy a fresh copy of the chosen code (you must bring an UNANNOTATED clean copy on test day; pre-test annotations are forbidden, but TABS and HIGHLIGHTING are allowed). Tab the major clauses: Definitions, Design, Prequalification, Qualification, Fabrication, Inspection, Symbols, plus the most-frequently-tested tables (welding-symbol chart, prequalified-joint geometries, acceptance-criteria tables, essential variable tables). Do NOT over-tab — 30 tabs is the sweet spot. Practice using the INDEX — most CWI candidates leave 4-5 questions on the table because they searched the wrong section.

   • Three question types and how to attack each

     Type 1 — DIRECT LOOKUP ("What is the maximum X per Table Y?"): go straight to the table. Type 2 — APPLICATION ("Given these conditions, is the weld acceptable?"): identify which clause governs, then check the criteria. The clause may be in Inspection (Clause 8 in D1.1) but the dimensional limit may be in a referenced table. Type 3 — INTERPRETATION ("Which of these statements is TRUE per D1.1?"): read every option, eliminate those that contradict the code's explicit text. Beware "almost-right" distractors that change a single word ("must" vs "may", "all" vs "most"). Always double-check by finding the exact source sentence.

   • Part C time budget

     46 questions in 120 minutes = same ~2.6 minutes per question as Part B. Open-book DOES NOT mean look up everything — that path runs out of time. Aim to answer 50% of questions from MEMORY (you should have read D1.1 cover-to-cover before test day) and look up only the 50% requiring a specific number. Mark every "I think I know but want to verify" question and circle back at minute 90. The biggest Part C failure mode is candidates who never finish — leave the last 5 minutes for guessing on unanswered questions.

   Practice questions (2)

   1. 1. A CWI candidate is taking Part C using AWS D1.1 as the chosen code. Allowed in the exam room?

      • A.A heavily-annotated D1.1 with handwritten notes
      • B.A clean D1.1 with tabs and highlighting only — no handwriting✓ correct
      • C.A laptop with a digital D1.1 PDF
      • D.A photocopied D1.1 made by the candidate

      AWS allows tabs and highlighting in the code book but PROHIBITS handwritten notes, post-it notes with notes, or marginal annotations. Laptops/PDFs are not allowed (paper only). Photocopies are not allowed (must be the original AWS-published book). A candidate caught with annotations can be disqualified on the spot.

   2. 2. A Part C question asks the maximum allowable undercut for a cyclically loaded structural steel weld with material thickness over 1 inch. Where in D1.1 do you look first?

      • A.Clause 4 (Design)
      • B.Clause 5 (Prequalification)
      • C.Clause 8 (Inspection) + Table 8.1✓ correct
      • D.Clause 9 (Tubular)

      D1.1 acceptance criteria for visual inspection — including undercut limits — live in Clause 8 (Inspection), with the actual numerical limits typically in Table 8.1 (or its equivalent in the edition you carry). Clause 4 is design, not acceptance. Clause 5 is prequalification of WPSs. Clause 9 covers tubular structures specifically — a different acceptance table applies. Knowing that "acceptance criteria → Clause 8" saves 60-90 seconds on every related question.

4. 04Eligibility, exam day, and recertification

   ~30min

   You cannot show up cold — AWS QC1 requires an experience-and-education prerequisite. Plan eligibility BEFORE you study, schedule the exam early (seats fill 4-6 months out), and budget for the 9-year recertification cycle.

   • Eligibility under AWS QC1

     AWS QC1 sets the experience requirement on a sliding scale: a candidate with a 4-year engineering degree typically needs 1 year of relevant welding experience; a 2-year associate or trade school typically needs 2-3 years; high-school grads need 5+ years of relevant experience. "Relevant experience" means welding, supervising welding, inspecting welding, or teaching welding — documented on the AWS application by employers. Vision exam: at least 20/40 corrected near-vision (Jaeger 2 at 12 inches), color discrimination required. Apply with documented experience BEFORE you book the exam — AWS reviews and approves applications before you pay.

     Reference: AWS QC1 Section 6 — Qualification Requirements

   • The 9-year recertification cycle

     CWI certification expires after 9 years. To recertify before expiration: pay a fee, document continuous welding-inspection experience, pass a closed-book endorsement renewal exam (or multiple endorsements if applicable). The 9-year mark is the LATEST you can renew without retaking the full 3-part exam. There is also a 3-year vision-recheck and many candidates carry endorsements (D1.1, D1.5, D15.1, ASME, API) that may renew on shorter cycles. Maintain a logbook from day 1 — AWS will ask for documented inspection time at renewal.

   Practice questions (1)

   1. 1. A high-school graduate with 3 years of structural welding experience applies for the CWI exam. Eligible under AWS QC1?

      • A.Yes — high-school graduates need only 2 years
      • B.No — high-school graduates typically need 5 or more years of relevant experience✓ correct
      • C.Yes — any welding experience qualifies
      • D.Only if a CWI sponsor signs the application

      AWS QC1 sets the experience requirement on a sliding scale tied to education: 4-year engineering degree → ~1 year, 2-year associate → ~2-3 years, high-school graduate → 5 or more years. A 3-year candidate without further education is short of the QC1 minimum. There is no "CWI sponsor signature" workaround — AWS requires documented experience, not a sponsor. Always apply BEFORE booking the exam.

External resources

• Official
  AWS CWI Certification Program ↗

  Official AWS page for the CWI program. Application forms, fee schedule, exam scheduling, body-of-knowledge document, sample questions, and the experience/education calculator are all here.

• Official
  AWS QC1 Standard for AWS Certification of Welding Inspectors ↗

  The actual standard governing CWI qualification, examination, and recertification. Not strictly required to study, but reading Section 6 (Qualification Requirements) and Section 9 (Examination Procedures) helps you understand the rules of the game.

• Official
  AWS CWI Pre-Seminar / Seminar ↗

  AWS's own week-long pre-exam seminar plus the optional 1-week pre-seminar. Pricey, but the pass-rate boost is real, and the seminar instructors are AWS-approved CWIs who teach to the actual exam style. Most candidates who attend pass on the first attempt.