Free sample · CWI Part C D1.1

Try a full lesson: How D1.1 is organized, and its design and materials rules

This is a complete lesson from the course (module 1 of 9, Body of knowledge topic C.5.1, C.5.2), followed by 3 practice questions with full explanations. Nothing to sign up for.

Like the way it teaches?The course has a lesson like this for every task in AWS's content outline.

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What this module covers

Materials and Design carries at least 5% of the Part C questions under AWS B5.1:2025 Table 8.1. That is a small slice, but this module does a second job: it teaches you the layout of AWS D1.1/D1.1M:2025, which every other module depends on.

Part C is open book. The exam is 55 questions (50 scored and 5 unscored pretest items) in 135 minutes at a Prometric center. The code is on screen as a PDF with bookmarks, but word search is disabled. The D1.1 endorsement description (Rev. 10.14.2025) also permits a bound printed copy. Either way, you win on this exam by knowing where things are, not by remembering numbers.

By the end you will be able to:

  • name the clause for any topic in under ten seconds,
  • tell the Engineer's, Contractor's and Inspector's jobs apart,
  • find the design rules for a connection, and the base metal and filler metal rules for a WPS.

We cite clauses, parts and tables by number only. Keep your own copy open while you read.

The clause map

Learn this list cold. It is the single most useful thing in the course.

ClauseWhat lives thereAsk yourself
1 General RequirementsScope, limitations, who is responsible for what"Who has to do this?"
2 Normative ReferencesOther standards D1.1 calls up"Which outside document applies?"
3 Terms and DefinitionsCode meanings of words"What does this word mean here?"
4 Design of Welded ConnectionsEffective areas, weld sizes for design, connection details"Is this connection designed right?"
5 Prequalification of WPSsThe conditions that let a WPS skip testing"Can this WPS be used without a PQR?"
6 QualificationTesting WPSs, welders, operators, tack welders, CVN"What test, what range?"
7 FabricationShop and field work: preparation, preheat, consumables, workmanship, repairs"Was the work done right?"
8 InspectionInspector duties, acceptance criteria, NDT procedures"Is the weld acceptable?"
9 Stud WeldingStuds, start to finish"Is it a stud?"
10 Tubular StructuresTubular design, qualification and inspection"Is it a tube or pipe member?"
11 Strengthening and Repairing Existing StructuresWork on structures already in service"Is it an existing structure?"
AnnexesNormative (binding) and informative (guidance), plus sample forms"Is there a form, guideline or method for this?"

Use the bookmarks like a table of contents

With no word search, the bookmark panel is your index. Expand a clause, then its parts, then its subclauses. Practice opening the panel, collapsing everything, and drilling down. Speed here saves minutes per question.

A good habit: before you read the question options, say the clause number out loud in your head. Then go there.

Read a clause in three passes

  1. Scope sentence. The first subclause tells you what the clause or part applies to, and often what it does not.
  2. The rule. Find the subclause that answers the question.
  3. The exceptions. Look for "unless", "except", "when specified in the contract documents" and notes under tables. Many exam questions hinge on the exception.

Look it up drill

Question typeWhere to goWhat to check
Who is responsible for XClause 1Engineer, Contractor or Inspector, and whether the contract documents can change it
What does a term meanClause 3The code definition, not your shop usage
Is the job tubularClause 10 firstWhether Clause 10 adds to or replaces the general rule
Is it a studClause 9Stud welding has its own qualification and inspection
Is it an existing buildingClause 11Base metal evaluation and repair rules

What the exam tests here. Many questions are really "which clause?" questions in disguise. If you can name the clause, you are halfway done.

Where design and connection rules sit

Clause 4 is for the designer, but the inspector reads it too

Clause 4 covers how welded connections are designed: the effective area of groove, fillet, plug and slot welds, the effective throat, minimum and maximum sizes the design may call for, and details such as lap joints, transitions in thickness and width, and fillet weld terminations. It separates rules common to all connections from added rules for cyclically loaded (fatigue) connections.

As an inspector you rarely design anything. You read Clause 4 to check that what the drawings show, and what the welder made, is consistent with the code, and to understand terms like effective length and effective throat that appear in acceptance questions later.

Statically or cyclically loaded

The Engineer states in the contract documents whether a connection is statically or cyclically loaded. That one choice changes which design rules, which acceptance criteria and sometimes which workmanship rules apply. When a question mentions fatigue, repeated loading, cranes or bridges, think "cyclically loaded" and look for the cyclic part or column.

Tubular connections

Do not look for tubular design rules in Clause 4. Clause 10 holds them, along with tubular prequalification, qualification and inspection additions.

If the question asks about...Go to...
Effective throat or effective area of a weldClause 4, the common requirements
A fatigue detail or stress range categoryClause 4, the cyclically loaded requirements
A T, Y or K tubular connectionClause 10
Who decides static vs cyclicClause 1 and the contract documents

Base metals and filler metals in the code

Base metals

D1.1 applies to carbon and low-alloy structural steels within the limits its scope sets. Clause 5 lists the base metals that may be used with prequalified WPSs, grouped so that steels with similar strength and weldability are treated together. A steel that is not in that list is not automatically forbidden, but a WPS for it must be qualified by test under Clause 6.

For existing structures, Clause 11 asks for the base metal to be evaluated before welding, because old steel may not match a current specification.

Filler metals

Clause 5 also holds a filler metal matching table. It pairs each base metal group with the filler metal classifications that match its strength. When you check a WPS against that table, you are checking strength: will the weld metal hold up about as well as the steel around it? Clause 4 says when the design calls for matching filler and when undermatching is allowed.

Clause 7 then controls how filler metals are handled in the shop: storage, drying and exposure limits, especially for low-hydrogen electrodes. Module 5 covers that.

Worked navigation (invented example)

A question says: "Steel X (invented) is joined to steel Y (invented). Which filler metal group is matched?" Your path:

  1. Clause 5 bookmark.
  2. Find the base metal table and locate both steels. Note their groups.
  3. When groups differ, read the table notes. The code tells you how to pick filler for a mixed joint.
  4. Read across to the filler metal matching table.

What the exam tests here. Knowing that base metal and filler metal lists live with prequalification (Clause 5), handling lives in fabrication (Clause 7), and the strength logic lives in design (Clause 4).

Check yourself

The three questions below cover finding who holds a responsibility, where tubular design rules live, and where the filler metal matching rules sit.

Where to look in your own books

  • AWS D1.1/D1.1M:2025 Clause 1: scope, limitations, responsibilities of the Engineer, Contractor and Inspector
  • AWS D1.1/D1.1M:2025 Clause 3: terms and definitions
  • AWS D1.1/D1.1M:2025 Clause 4: design of welded connections, common and cyclically loaded requirements
  • AWS D1.1/D1.1M:2025 Clause 5: base metal list and filler metal matching table for prequalified WPSs (confirm table numbers)
  • AWS D1.1/D1.1M:2025 Clause 10: tubular structures
  • AWS D1.1/D1.1M:2025 Clause 11: strengthening and repairing existing structures
  • AWS B5.1:2025 Table 8.1: Code Applications subjects and minimum weights
  • AWS D1.1 endorsement description (Rev. 10.14.2025): exam format and code reference policy

Practice set

Pick an answer in your head, then open the explanation. Every wrong option is explained too.

1. Materials and Design

A new inspector wants to read the code's own statement of what the Engineer, the Contractor and the Inspector are each responsible for. Which clause should they open first?

  1. Clause 3, Terms and Definitions
  2. Clause 8, Inspection
  3. Clause 1, General Requirements
  4. Clause 2, Normative References
Show answer and explanation

Answer: C. Clause 1, General Requirements

Clause 1 (General Requirements) sets the scope and the responsibilities of the Engineer, Contractor and Inspector. Clause 3 defines terms but does not assign duties. Clause 8 expands on inspection duties in detail but is not where the three parties' responsibilities are first set out side by side. Clause 2 only lists other standards the code calls up.

Reference: AWS D1.1/D1.1M:2025 Clause 1 (responsibilities)
2. Materials and Design

The drawings show a T-connection between two round hollow structural sections. Which clause holds the requirements D1.1 writes specifically for tubular connections like this one?

  1. Clause 10, Tubular Structures
  2. Clause 4, Design of Welded Connections, common requirements
  3. Clause 5, Prequalification of WPSs
  4. Clause 11, Strengthening and Repairing Existing Structures
Show answer and explanation

Answer: A. Clause 10, Tubular Structures

Clause 10 holds the requirements written for tubular structures, including the design of T, Y and K connections between hollow sections and the tubular additions to prequalification, qualification and inspection. Clause 4 sets design rules for welded connections in general, but its common requirements are not the tubular-specific ones. Clause 5 covers WPS prequalification, not connection design. Clause 11 is for strengthening and repairing structures already in service.

Reference: AWS D1.1/D1.1M:2025 Clause 10 (tubular structures)
3. Materials and Design

A fabricator wants to confirm that the electrode classification on a prequalified WPS matches the strength of the base metal. In which clause is the filler metal matching table found?

  1. Clause 7, Fabrication
  2. Clause 4, Design of Welded Connections
  3. Clause 6, Qualification, Part B
  4. Clause 5, Prequalification of WPSs
Show answer and explanation

Answer: D. Clause 5, Prequalification of WPSs

The base metal list and the filler metal matching table that a prequalified WPS must meet are in Clause 5. Clause 7 controls storage and handling of filler metals, not their matching. Clause 4 explains when matching filler is required by design but does not hold the matching table. Clause 6 Part B covers qualifying a WPS by test, which is the route used when Clause 5 is not met.

Reference: AWS D1.1/D1.1M:2025 Clause 5 (base metal and filler metal requirements)

The CWI Part C D1.1 course

Available now · instant access

Ready for the rest? The full course

  • 9modules of lessonsEvery task on the outline
  • 2full-length timed exams55 questions in 135 minutes each
  • 160practice questionsEach one explained
  • 35code-navigation drillsFind it fast in AWS D1.1
  • 1week-by-week study planSet to your exam date
See all 9 modules
  1. How D1.1 is organized, and its design and materials rules
  2. Prequalified WPSs
  3. Qualifying a WPS by test
  4. Welder, operator and tack welder qualification
  5. Fabrication: preparation, preheat and fit-up
  6. Workmanship, repairs and distortion
  7. Visual inspection acceptance
  8. NDT and its acceptance criteria
  9. Reports and records

Question bank and timed exams: Expert-reviewed: every question was checked by a CWI with 15 years in structural welding (2026-10-19). Every answer key is confirmed by a separate blind solve, and reported errors are fixed within 2 business days.

Questions are original and written to AWS's published content outline. Code is cited by section number so you can look it up in your own copy. Think something is wrong? Report it.