CWI Part C (D1.1) Exam Study Guide (2026)
Everything the AWS CWI Part C Code Book Exam: AWS D1.1 Structural Steel tests, topic by topic: what each section covers, the facts that come up most, and how to study it. Pair it with the free 15-question practice test.
The exam at a glance
| Questions | 50 to 60 scored multiple-choice questions; English forms add about 5 unscored pretest items (55 to 65 in total) |
|---|---|
| Time | 120 minutes (135 minutes on forms with pretest items) |
| Passing score | 72% on Part C (each of Parts A, B and C must be passed at 72%) |
| Format | Open book: bring AWS D1.1/D1.1M (check the edition on your confirmation letter); a digital copy is provided for most code exams |
| Certifying body | American Welding Society (AWS) |
| Test provider | Prometric test center (computer-based) |
Mind map: the whole exam on one screen
Read the complete CWI Part C (D1.1) study notes for “Code Organization and General Requirements”
Our first full set of comprehensive notes, about 15 minutes of reading: Which edition? · How the code is organized · Shall, should and may · Who is responsible for what · How Part C is weighted, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.
1. Code Organization and General Requirements
How AWS D1.1 is laid out and how to read it: the clause numbers, shall, should and may, and who is responsible for what. AWS's Part C weights are at least 25% each on qualification, fabrication and inspection, and at least 5% each on materials and design, and reports and records.
Key facts
- Clauses in the 2020 and 2025 editions: 1 General Requirements, 2 Normative References, 3 Terms and Definitions, 4 Design, 5 Prequalification of WPSs, 6 Qualification, 7 Fabrication, 8 Inspection, 9 Stud Welding, 10 Tubular Structures, 11 Strengthening and Repair of Existing Structures.
- 'Shall' is mandatory, 'should' is a nonmandatory recommendation, and 'may' means a choice of optional procedures.
- Fabrication and erection inspection and testing are the Contractor's responsibility. Verification inspection is the Owner's prerogative and must be specified in the contract documents.
- The Engineer's role is set out in the code and contract documents, and Engineer approval is required for certain alternatives.
- The code applies to carbon and low-alloy steel structures; other applications have their own codes.
- Part C is open book. For applicable code exams AWS provides the code on screen as a PDF, in English only, and printed copies aren't permitted for certain exams, so practice finding items on screen as well as in print.
Flashcards
Exam tip: Use the index for unusual topics. It points to subclause numbers and is usually faster than flipping through the book.
2. Design of Welded Connections
Clause 4 topics that appear on the exam: fillet weld size limits, effective throat and length, lap joints and terminations.
Key facts
- Effective throat of an equal-leg fillet is 0.707 times the leg size when the face is flat, excluding reinforcement.
- The maximum fillet size along an edge under 1/4 in. thick is the material thickness; on 1/4 in. or thicker it is thickness minus 1/16 in., unless detailed to be built out.
- A fillet weld must be at least four times its nominal size long, or its effective size is limited to one quarter of its effective length.
- Stress-carrying lap joints need an overlap of at least five times the thinner part, and not less than 1 in.
- Cyclically loaded connections have stricter rules than statically loaded ones, so check the part of Clause 4 that applies.
Flashcards
Exam tip: Design is only about 5% of the exam with materials. Don't spend your tabbing time here: know where to look, and move on.
3. Prequalified WPSs
Clause 5: what makes a WPS prequalified, which processes qualify, and how to find the preheat requirement for a given steel and thickness.
Key facts
- Prequalified processes are SMAW, SAW, GMAW (except GMAW-S) and FCAW. GMAW-S, GTAW, ESW and EGW may be used but must be qualified by test.
- A prequalified WPS must meet every Clause 5 requirement: approved base metal and filler combination, prequalified joint details, and the preheat table.
- Preheat depends on steel group, process category and thickness. Example: A572 Grade 50 with a low-hydrogen process needs 50°F over 3/4 in. through 1-1/2 in., and 150°F over 1-1/2 in. through 2-1/2 in.
- When the base metal is below 32°F, preheat it to at least 70°F and hold that during welding.
- A WPS still has to be written and available to the welders, even when prequalified.
- Preheat applies at a distance from the point of welding at least equal to the thickness of the thickest part, but not less than 3 in.
Flashcards
Exam tip: Tab the prequalified base metal, filler and preheat tables. Preheat lookups are quick marks if you know exactly where the table is.
Test yourself on these topics
Take the free 15-question CWI Part C (D1.1) test, then save your results to unlock your Readiness Score and the mistakes bank.
4. Qualification of WPSs and Welders
Clause 6: qualifying a WPS by testing, welder and welding-operator performance tests, their thickness and position limits, and how long a qualification lasts.
Key facts
- Part B of Clause 6 covers WPS qualification by test; Part C covers performance of welders, welding operators and tack welders.
- Welder plate thickness (CJP): a 3/8 in. test qualifies 1/8 to 3/4 in.; over 3/8 and under 1 in. qualifies 1/8 in. to 2T; 1 in. or more qualifies 1/8 in. to unlimited.
Flashcards
Exam tip: Tab the WPS and welder qualification tables in Clause 6. A qualification question that uses the wrong table is the easiest mark to lose.
5. Fabrication
Clause 7: electrode storage and exposure, fillet weld minimum sizes, preheat application and weld workmanship. At least 25% of Part C.
Key facts
- Low-hydrogen electrodes out of sealed containers go in ovens at a minimum of 250°F, and wet electrodes must not be used.
- Table 7.1 Column A exposure limits: E70XX 4 hours, E80XX 2 hours, E90XX 1 hour, E100XX and E110XX 1/2 hour.
Flashcards
Exam tip: Fabrication and inspection questions are the most table-driven. Know the exact name of each table so you can search for it.
6. Inspection and Acceptance Criteria
Clause 8: inspector qualification, visual inspection timing and Table 8.1 acceptance criteria for undercut, porosity and weld size. At least 25% of Part C.
Key facts
- Table 8.1 prohibits any crack, regardless of size or location, and requires thorough fusion and filled craters (except outside the effective length of intermittent fillets).
- Undercut, statically loaded nontubular: under 1 in. thick, 1/32 in., with 1/16 in. allowed for an accumulated 2 in. in any 12 in.; 1 in. or thicker, 1/16 in. for any length.
Flashcards
Exam tip: Table 8.1 has separate columns by connection type. Always read the column heading before you read the limit.
7. Stud Welding, Tubular and Existing Structures
The later clauses: stud welding production control (Clause 9), tubular structures (Clause 10) and strengthening and repair of existing structures (Clause 11).
Key facts
- Clause 9 covers stud welding of steel studs. Before production, the first two studs welded with a given setup are bend tested 30° from their original axis.
- Clause 10 covers tubular structures, including T-, Y- and K-connections, with their own qualification and acceptance requirements.
Flashcards
Exam tip: These clauses are short. Skim them once so you know what's in them, then rely on the index if a question lands here.
How to pass
- Tab the code before exam day: Clause 5 preheat table, Clause 6 qualification tables, Table 7.1 electrode exposure, the minimum fillet weld table and Table 8.1 visual acceptance criteria.
- Use the index. It points to subclause numbers, not pages, and it's faster than flipping when a question names an unusual topic.
- About 55 to 65 questions in 120 to 135 minutes is roughly 2 minutes each. If a lookup takes more than 3 minutes, flag it and come back.
- Confirm the edition. AWS's references guide (20 Oct 2026) lists D1.1/D1.1M:2025, while older pages list 2020. Table numbers moved between editions, so bring and practise with the edition on your confirmation letter.
Frequently asked questions
How long should I study for the CWI Part C (D1.1) exam?
Most working candidates need 4 to 8 weeks at 45 to 60 minutes a day. Book your exam once your Readiness Score has stayed at 80 or higher for about a week.
Can I take the CWI Part C (D1.1) exam online?
AWS delivers Parts A and C on computer at Prometric test centers and Part B on paper at AWS-authorized exam sites. Its current guides don't describe remote proctoring. Format: open book: bring aws d1.1/d1.1m (check the edition on your confirmation letter); a digital copy is provided for most code exams. Check aws.org for updates.
What score do I need to pass the CWI Part C (D1.1) exam?
72% on Part C (each of Parts A, B and C must be passed at 72%). The exam has 50 to 60 scored multiple-choice questions; english forms add about 5 unscored pretest items (55 to 65 in total) and a time limit of 120 minutes (135 minutes on forms with pretest items).
What are the most tested topics?
The outline covers code organization and general requirements, design of welded connections, prequalified wpss, qualification of wpss and welders, fabrication, inspection and acceptance criteria, stud welding, tubular and existing structures. Use the free practice test to see which ones you need most.
The premium CWI Part C (D1.1) study path
Premium CWI Part C (D1.1) prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.
Your step-by-step study path
- 1Code Organization and General Requirements9 key notes, 115 flashcards, then 450 practice questions in 18 sets of 25Notes free with an account
- 2Design of Welded Connections9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 3Prequalified WPSs9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 4Qualification of WPSs and Welders9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 5Fabrication8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 6Inspection and Acceptance Criteria8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 7Stud Welding, Tubular and Existing Structures8 key notes, 110 flashcards, then 425 practice questions in 17 sets of 25Premium
- Final step: 6 full mock exams50 questions each, timed like test day. Pass them, then book your exam.Premium
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Summarized from AWS's official candidate information and the rules cited, checked October 2026. Confirm current requirements with American Welding Society (AWS).