AWS CWI Exam: What to Expect on Each of the Three Parts
The AWS Certified Welding Inspector exam is three separate tests taken on the same day. Here's exactly what each part covers and how candidates fail.
The Three-Part CWI Exam Structure
The AWS CWI exam is actually three separate closed-book exams administered on the same day: Part A (Fundamentals), Part B (Practical), and Part C (Code Book). You must pass all three parts — you cannot substitute or skip any part. The total exam runs approximately 6 hours. Failing one part does not fail the others; you can retake individual parts within the allowed exam cycle. Part A and Part C are the most commonly failed parts. The exam is offered by AWS at testing centers nationwide, and the CWI credential is highly respected across structural, pipeline, pressure vessel, and manufacturing industries.
Part A — Fundamentals (150 Questions, 2 Hours)
Part A tests general welding knowledge across 10 topic areas: welding processes (SMAW, GMAW, GTAW, FCAW, SAW), welding symbols per AWS A2.4, metallurgy basics, weld discontinuities and their causes, nondestructive examination (VT, PT, MT, UT, RT) theory, mechanical testing (tensile, bend, hardness, impact), safety, qualification of welders and procedures, weld joint design, and welding codes overview. The questions are knowledge-based — no code book is needed. This is where strong general welding experience helps most. Candidates with field experience typically find Part A the most straightforward.
Part B — Practical (46 Questions, 2 Hours)
Part B tests your ability to measure and interpret real weld samples and drawings. You receive actual weld specimens, test plates, and drawings. Tasks include: measuring fillet weld leg and throat size with weld gauges, identifying discontinuities in macro-etch samples, reading and interpreting welding symbols from drawings, measuring groove weld dimensions, and identifying weld profiles (convexity, concavity, undercut depth). You are allowed to bring your own weld gauges and measuring tools — this is required. Candidates who have never used a bridge cam gauge or fillet weld gauge in the field consistently struggle here. Practice with real specimens before exam day.
Part C — Code Book (46 Questions, 2 Hours)
Part C is open-book, but it is still the most commonly failed part. You get one code book to reference — the code is assigned at registration (D1.1 Structural Steel is most common; D1.2 Aluminum, D1.5 Bridge, or API 1104 Pipeline are alternatives). The questions are highly specific and time-pressured — 46 questions in 2 hours means just over 2.5 minutes per question, and many require finding tables, figures, or provisions that are not where you expect them. You must know the code's index, table of contents, and key provision locations cold. Tabbing your code book in advance (ASNT, AWS, and many prep programs have tab kits) is not just allowed — it is essential.
How to Pass on the First Try
Candidates who pass on their first attempt share these habits: they use the official AWS Body of Knowledge (BOK) as their study outline, they practice code book navigation extensively before exam day, they bring calibrated weld gauges to Part B and have used them on real welds, and they take full-length timed practice exams. Minimum recommended study: 80-120 hours over 8-12 weeks. The CWI Prep app has 800+ questions mapped to the CWI Body of Knowledge with detailed explanations for every AWS standard reference.