AWS D1.1/D1.1M:2025 Structural Welding Code – Steel Explained

A fabricator wins a bridge-adjacent building package in March, welds the first shop splice under the 2020 edition of D1.1, and then the owner’s inspector flags the WPS library because contract documents cite the 2025 edition. Nothing about the steel changed, but the paperwork suddenly did. That gap between ‘we always did it this way’ and ‘the code now says otherwise’ is exactly why understanding AWS D1.1/D1.1M:2025 matters for anyone who designs, fabricates, inspects, or erects welded steel.

Introduction: Why D1.1 Is the Backbone of Structural Steel Welding

A fabricator wins a bridge-adjacent building package in March, welds the first shop splice under the 2020 edition of D1.1, and then the owner’s inspector flags the WPS library because the contract documents cite the 2025 edition. Nothing about the steel changed, but the paperwork suddenly did. That gap between “we always did it this way” and “the code now says otherwise” is exactly why understanding AWS D1.1/D1.1M:2025 matters for anyone who designs, fabricates, inspects, or erects welded steel.

Welding is one of the few disciplines where a hidden defect can sit inside a load path for thirty years without a single visible sign. Because the consequences of getting it wrong fall on the public rather than on the shop floor, the structural welding industry runs on written, auditable rules. At the center of those rules sits a single document.

What AWS D1.1/D1.1M:2025 Actually Is

In plain language, AWS D1.1 is the structural welding code for steel: a comprehensive rulebook covering the design, fabrication, qualification, inspection, and repair of welded connections made from carbon and low-alloy constructional steels under static or cyclic (fatigue) loading. The full title of the current document is the Structural Welding Code – Steel, published by the American Welding Society (AWS).

The 2025 document is the 25th edition of the code, prepared by the AWS D1 Committee on Structural Welding and approved by ANSI on March 19, 2025, as confirmed in ANSI’s own announcement of the approval. That ANSI approval matters commercially as well as technically: it signals that the consensus development process met the openness and balance requirements U.S. regulators and contract attorneys expect when a standard is referenced in law or specification.

Who Needs This Code

The short answer: nearly everyone touching a welded steel structure. The longer answer breaks down by role:

• Designers and engineers of record (EORs) use D1.1 to determine what welded joint details are acceptable and how available strength and fatigue interact with the connection.
• Fabricators and welding engineers use it to write and qualify welding procedure specifications (WPS), manage preheat, and control distortion.
• Welders and welding operators qualify under it and work within its essential variables.
• Inspectors and NDT personnel apply its visual acceptance criteria and nondestructive testing requirements.
• Owners, general contractors, and plan reviewers cite it in specifications and in building-permit review.

Consider the scale this code quietly supports. Global crude steel production reached roughly 1,884 million tonnes in 2024, and a meaningful share of it ends up in welded buildings, towers, and industrial structures. When fabrication spans continents, a shared reference document like D1.1 is what allows a detail designed in one country to be welded and inspected in another against the same expectations.

How the Code Reaches Your Shop Floor

Very few welders read D1.1 cover to cover voluntarily. Instead, the code reaches them through three channels:

1. Contracts and specifications. Project documents almost always name a governing code edition by year. This is precisely the mechanism that created the problem in the opening story. If the specification says D1.1/D1.1M:2025, the 2020 WPS library becomes a compliance question, not a technical one.
2. Building-code adoption. The International Building Code references the AISC family of standards, and AISC’s steel construction specifications in turn point back to D1.1 for welding execution. That chain means the code effectively becomes law in adopting jurisdictions.
3. Inspection and quality systems. Since visual inspection is the baseline requirement for every weld under the code, and OSHA’s steel erection standard 1926.760 requires welds to be inspected by a qualified person, the acceptance criteria flow directly into daily field practice.

The D1 Committee has described the 2025 release as a substantial technical update rather than a light editorial pass, and AWS has published supporting material to help users understand the scope of the revisions. If your contract documents cite 2025, the practical work of adopting it is the subject of this entire guide, beginning with what the code actually covers in the next section.

Scope and Structure: What the 2025 Edition Actually Covers

Before anyone can apply AWS D1.1/D1.1M:2025, they have to know where its authority starts and stops. The scope clause is short, but it decides everything that follows: which welds, which metals, which processes, and which clauses an inspector can cite on a report. Skim it and you will eventually weld stainless to the wrong rulebook or reject a perfectly legal detail because it belongs to another standard.

In plain language, the code governs the design and fabrication of welded connections in carbon and low-alloy structural steel, using arc welding processes, for structures covered by the American Institute of Steel Construction. It addresses groove welds, fillet welds, and plug and slot welds, along with fatigue stress design parameters and prequalified welding procedure specifications. The published copy carries the dual inch-pound and metric designation (D1.1/D1.1M), is approved as an American National Standard, and is issued by the American Welding Society, which published the 2025 edition as the current revision superseding 2020. A readable preview is available directly from AWS Publications.

The Clause Map: Where Each Requirement Lives

The 2025 edition keeps the familiar clause architecture, so a shop that already navigated the 2020 edition will recognize the map. The value of learning it is speed: when a question arises on the floor, you know exactly which clause to open.

Clause	What it covers
Clause 1–2	Scope, terms and definitions (expanded in 2025)
Clause 3	Design of welded connections, including fatigue
Clause 4	Prequalification of welding procedure specifications
Clause 5	Welding procedure qualification, filler metals and shielding gases
Clause 6	Welder and welding operator qualification
Clause 7	Fabrication, preheat, fit-up and workmanship
Clause 8	Inspection, NDT and weld acceptance criteria
Clauses 9–11	Stud welding, tubular connections, and强化 provisions

Clause 3 covers design of connections, where available strength tables, joint details and fatigue categories live. Clause 4 hands shops a set of prequalified procedure specifications, which is the code’s way of saying these combinations have been proven enough that a supporting procedure qualification record is not required. Clause 5 and Clause 6 split procedure qualification from personnel qualification, an easy point of confusion for new quality managers. Clause 7 is the shop-floor clause: preheat, fit-up, tack welding, distortion and repair. Clause 8 sets inspection responsibilities and acceptance criteria, and it is where the 2025 edition adds provisions for Magnetic Particle Testing and Penetrant Testing while clarifying NDT personnel certification, as summarized in ANSI’s coverage of the 2025 release.

Processes Covered

The core arc processes are shielded metal arc welding (SMAW), submerged arc welding (SAW), gas metal arc welding (GMAW) and flux-cored arc welding (FCAW). Beyond those, the code addresses gas tungsten arc welding (GTAW), electroslag welding, and arc stud welding in dedicated clauses, so a fabricator running a stud welding line or an electroslag heavy-plate operation does not need a second structural standard for routine work. Process selection drives everything downstream: preheat tables, shielding gas choices, essential variables and the qualification ranges in Clause 5. If you are still building fundamentals on stick welding, our Advantages of Stick Welding guide explains why SMAW remains the default on structural sites.

What Is NOT Covered

This is where most compliance errors begin. D1.1 does not cover:

• Stainless steel structural welding — that falls under AWS D1.6.
• Aluminum structural welding — AWS D1.2 governs it; for practical aluminum process reading, see Aluminum MIG Welding: The Complete Practical Guide.
• Sheet steel 3/16 in. (4.8 mm) and thinner — AWS D1.3, which is why thin-plate and body work often cites a different code entirely.
• Pressure piping and tubing — ASME B31 series, with procedure qualification under ASME Section IX.
• Bridges, seismic energy dissipation, and cryogenic vessels — AWS D1.5, D1.8 and D1.14 respectively.

For alloyed and high-strength steels, also confirm that the base metal is one the code actually permits, since anything unusual routes through the added-material provisions of Annex S. Keeping steel, stainless, aluminum and sheet-metal work separated by code is the cheapest insurance a shop can buy, and it is the first thing a competent audit checks.

What’s New in D1.1/D1.1M:2025 vs the 2020 Edition

The jump from the 2020 to the 2025 edition of AWS D1.1/D1.1M isn’t cosmetic. Based on the AWS summary of changes and industry reporting from Fabtech, the technical updates will directly affect a shop’s paperwork, qualifications, and day-to-day fabrication. The biggest thing to know: compliance is judged by the edition called out in contract documents, so assuming your existing library is still valid is not a safe bet.

Design, Definitions, and Material Expansion

For designers, one of the most impactful changes sits in Clause 4. The 2025 edition adds a new Table 4.3 for the available strength of welded joints, refining how strength values are referenced for connection design without overgeneralizing weld capacity. AWS also expanded its terms and definitions to cut down on ambiguity between fabricator, inspector, and engineer interpretations.

Material coverage grew with Annex S: Added Base Materials. Previously unlisted structural steels can now be addressed within the code’s scope with applicable limitations, rather than sitting in a grey area. With that expansion came updated toughness provisions for projects requiring notch toughness. These are more explicit for applicable base metals and service conditions, so users must pay closer attention to a material’s designated toughness requirements before assigning prequalified or qualified WPSs. Every revision can be cross-checked against the official AWS D1.1/D1.1M code listing for project applicability.

Filler Metals, Shielding Gas, and Stud Welding

Clause 5 saw some of the largest housekeeping changes for filler metals. After heavy U.S. industry feedback, all references to the AWS A5.36/A5.36M flux-cored and metal-cored electrode specifications have been removed from D1.1. Shops can no longer lean on A5.36 listings within this code, so any WPS that referenced it must be evaluated for a D1.1-approved electrode classification.

For strength matching, Clause 5.6.2 now limits overmatching filler metals to no more than 10 ksi greater than the strength requirements of Table 5.7. That hard cap stops excessive overmatching from becoming a blanket fix for lower-strength base metals, pushing users to justify filler selection against the code rather than convenience. Shielding gas allowances were also clarified in Clause 5, preventing the assumption that any approved gas is interchangeable without checking the specific process and electrode limitations.

In Clause 9, Stud Welding, new provisions for type D studs have been added. These studs now carry their own qualification and application requirements, so any shop fabricating with type D headed studs needs to verify that its stud welding procedures and operator qualifications meet the added provisions.

Inspection Updates and WPS Documentation

Inspection received targeted updates in Clause 8. Visual inspection remains the baseline for all welds, but the 2025 edition clarifies inspection responsibility and documentation, tightening traceability between the WPS, the weld performed, and its accepted or rejected disposition.

On the documentation side, a change enforced on the shop floor is preheat accountability. Preheat and interpass temperatures must be documented on every WPS, with a maximum interpass temperature recorded when impact or material limits apply. That turns a previously expected practice for many low-hydrogen and toughness-governed welds into an explicit requirement for the procedure document itself, as highlighted by The Welder’s breakdown of D1.1 certification and documentation.

Auditing Your Existing WPS Library

With these updates combined, the audit should be methodical, not rushed. Start by sorting every active WPS by process and electrode classification, flagging any that reference A5.36 for replacement or re-support. Then verify any procedure using an overmatching filler against Clause 5.6.2‘s 10 ksi cap and confirm its justification against Table 5.7. Check every active procedure for preheat and interpass fields, ensuring a maximum interpass is filled in for any WPS tied to toughness-governed materials.

Next, cross-reference your base metals against Annex S and your connection designs against the new Table 4.3 if strength-governed. Finally, if your scope includes headed studs, pull your Clause 9 stud qualifications and verify that any type D studs you use are covered by a qualified procedure per the 2025 provisions. Resources such as CEI’s 2025 update breakdown and the official D1.1/D1.1M:2025 PDF will help validate changes against the exact text. A clause-by-clause audit is tedious, but it is the most effective way to prevent an inspector from rejecting an entire WPS library the moment the 2025 edition is enforced on your job.

Prequalified WPS Under Clause 5: When You Can Skip the PQR

For many structural steel shops, prequalification is the difference between getting to work and getting buried in procedure qualification paperwork. Under AWS D1.1/D1.1M:2025, a prequalified WPS requires no test coupon or PQR because the code prescribes base metals, fillers, joint geometries, and process parameters that have already been validated by experience. If every one of those prescribed conditions is met to the letter, the procedure is considered acceptable without performing a separate qualification test.

The Ingredients For Prequalification

Prequalification is not a blanket approval for “whatever you usually run”. For a procedure to qualify under Clause 5, it must fall within the strict boundaries set by the code. First, it must use approved base metals listed for prequalification. Second, the filler metal must match an applicable AWS A5 classification allowed for the chosen process. Third, the joint details must conform to the prequalified joint geometries, and fourth, the process parameters must stay within the ranges the code allows for that exact combination.

With filler metal selection being such a vital part of this equation, shops should be familiar with the options for alloy steel welding electrodes to ensure the classification they reach for is actually an allowed prequalified match, not just one that “looks right”.

What’s Changed In The 2025 Edition

The biggest organizational change for Clause 5 is readability. For the 2025 edition, Table 5.1 was reorganized by welding process, allowing welders and procedure writers to find prequalified conditions for their exact process without scanning across unrelated methods. Alongside this reorganization, minimum current requirements were added for non-short-circuit and pulsed gas-shielded processes, and maximum layer width limits were introduced. These additions are designed to prevent procedures that technically fit a joint geometry, yet fall outside of stable, proven deposition conditions.

Shielding gas options remain process-dependent under the prequalified tables as well. Not every gas that is used for production welding is permitted for prequalification, so the gas type, mixture, and flow must remain within what Table 5.1 allows for that process.

Perhaps the most notable expansion to the base metal list comes from industry reporting on the D1.1:2025 changes: A913 Grade 80 was added to the prequalified base metal list, making it the highest-strength grade ever prequalified under D1.1. This is a significant development for projects utilizing high-strength structural shapes, however, this allowance is strictly limited to the prequalified conditions prescribed by the code, and cannot be extrapolated to unlisted combinations.

Preheat, Interpass, and Where Flexibility Exists

Preheat is one of the most commonly misapplied aspects of prequalification. Prequalified minimum preheat and interpass temperatures are governed by the code’s preheat table (Table 5.11 in the 2025 edition). The code allows these minimums to be established by table, Annex B calculation, or qualification testing. Even if a WPS is prequalified for the joint and filler, the required preheat for the specific base metal thickness and grade must still be satisfied. Colder ambient conditions, tight restraints, or higher restraint details can still demand more than the absolute minimum, and the code’s intent is to prevent hydrogen-assisted cracking, not just satisfy paperwork.

Common Mistakes To Avoid

• Extrapolating parameters: Increasing voltage, amperage, or travel speed outside of the prequalified range for a process immediately disqualifies prequalification, even if the weld still “looks good”.
• Ignoring the reorganized table: Relying on memory of the 2020 layout can cause shops to miss process-specific restrictions that were clarified under Table 5.1 in the 2025 edition.
• Overstating base metal coverage: Just because a grade is similar does not mean it is prequalified. With the addition of A913 Grade 80, coverage is explicit, not implied.
• Forgetting current and layer width limits: The newly added minimum current requirements for non-short-circuit and pulsed gas-shielded processes, as well as maximum layer width limits, are mandatory for prequalification and cannot be ignored.

Ultimately, prequalification under Clause 5 is a privilege granted by strict compliance, not a shortcut around the code. When used within its prescribed boundaries, it can be incredibly efficient. When stretched beyond them, the WPS is no longer prequalified, and a supporting PQR will be required to be code compliant under AWS D1.1/D1.1M:2025.

Procedure and Welder Qualification: Essential Variables and Continuity

Clause 6 of AWS D1.1/D1.1M is where a welding procedure stops being a shop habit and becomes a documented, defensible qualification. Two different things get qualified here, and shops confuse them constantly: the procedure (the recipe, backed by a Procedure Qualification Record) and the person or machine (the welder or welding operator, backed by a performance test). A qualified welder working to an unqualified WPS is just as noncompliant as a perfect WPS run by someone who never demonstrated they can make the weld.

Essential Variables: The Lines You Cannot Cross

An essential variable is any change that the code considers significant enough to affect the strength, toughness, or soundness of the joint. If it changes beyond the range qualified, the WPS or the welder’s qualification is no longer valid and requalification is required. Typical essential variables include:

• Process changes (for example, moving from SMAW to FCAW on a qualified joint)
• Position changes (flat to vertical, or plate to pipe in fixed position)
• Filler metal classification changes, including strength level
• Preheat and interpass temperature changes outside the qualified range
• Base metal thickness and, for pipe, diameter ranges
• Current type and polarity, heat input where the code specifies it, and shielding gas composition or flow for gas-shielded processes

Nonessential variables can be adjusted within the WPS without requalification, provided the procedure still produces acceptable welds. The practical discipline is knowing which list a given parameter falls on before someone “tweaks” it on the floor. A filler metal swap is a frequent offender: a shop that swaps an E7018 for a higher-strength or different-classification electrode has quietly invalidated the procedure, no matter how well the weld looks. When you evaluate consumables for these decisions, guides such as Alloy Steel Welding Electrodes: Selection, Use & Safety help you understand what a classification actually promises before you put it on a qualified joint.

How a PQR Supports a Qualified WPS

The Procedure Qualification Record is the evidence. It documents a test weld made under controlled conditions, the supporting tensile and bend test results, toughness testing where required, and every variable recorded during the run. The WPS is then written from that PQR, covering the range of thicknesses, diameters, positions, and parameters the test actually demonstrated. Welding to a WPS whose supporting PQR does not cover the production condition is one of the most common audit findings in structural fabrication.

Test positions follow the familiar plate and pipe scheme: 1G, 2G, 3G, and 4G for groove welds in flat, horizontal, vertical, and overhead, and 1F through 4F for fillet welds. Pipe adds 2G, 5G, and 6G positions, with 6G giving the broadest range because it includes an inclined fixed position. Remember that qualification in one position does not automatically carry to another unless the code’s position range provisions explicitly allow it. Position work is also where technique matters most, which is why a solid All Position Welding Rod Guide is useful background reading for anyone preparing for 3G and 4G tests.

Thickness and diameter coverage work the same way: the qualified range runs from the minimum thickness tested up to a multiple of the coupon thickness, subject to the upper limits in Clause 6. A single thin-groove test does not qualify a shop for a 3-inch butt weld.

Continuity: The Six-Month Rule in Practice

Continuity documentation typically takes the form of a continuity log or report showing production welding in each qualified process at least once every six months. The log should identify the welder, the process, the dates, and enough detail (work order, WPS number, weld location) that an auditor can trace the entry back to real work. AWS D1.1 welding certification documentation expectations are stricter than many shops assume, so monthly review beats an annual scramble.

Welding Operators, Robots, and Records

Welding operators of automated and robotic systems qualify under the welding operator provisions rather than the manual welder qualification provisions, and their continuity is tracked separately. Machine variables, fixturing, and programmed parameters replace hand skill as the qualification focus. Keep WPS, PQR, WPQR, continuity logs, and visual inspection records in one controlled file set per person and per procedure; as AWS Welding Digest has noted, the documentation is the qualification an owner’s inspector actually reviews. Employers also carry recordkeeping duties under rules such as OSHA 1926.760 for welding on steel erection projects.

Design of Welded Connections: Strength, Fatigue, and Joint Types

On most structural steel jobs, two documents share the workload. The ANSI/AISC 360, Specification for Structural Steel Buildings, tells the engineer how strong a weld has to be. The AWS D1.1/D1.1M:2025 Structural Welding Code tells the fabricator how to make it, qualify it, and prove it is sound. Clause 4 is where D1.1 speaks the designer’s language, and understanding it keeps drawings, WPSs, and inspections pointed in the same direction.

CJP, PJP, and Fillet Welds: Three Different Bargains

The three weld types a structural drawing can call for carry very different obligations, and the distinction is the first thing to get right:

Weld type	What it delivers	Design basis	Inspection expectation
Complete joint penetration (CJP) groove	Full-thickness fusion; base metal carries the load across the joint	Joint is treated as strong as the parent material	Typically RT or UT plus visual, per the engineer’s requirements
Partial joint penetration (PJP) groove	Specified penetration only; unused part of the groove acts as a built-in flaw	Effective throat of the fused zone	Visual and groove dimensions; NDT only if specified
Fillet weld	Triangular fusion along edges or laps	Effective throat area times allowable stress	Visual, size checked against specified minimum

A CJP detail with a backing bar and a visually identical detail without one are not interchangeable, and a PJP groove sized for a 10 mm effective throat does not become a CJP because the arc happened to punch through. Designers, detailers, and welders need to read the joint the same way.

What Changed in 2025: Table 4.3 and Figure 4.7

The 2025 edition introduced a new Table 4.3 giving available strength values for welded joints, replacing the way strengths were previously presented. Alongside it, a new Figure 4.7 clarifies the maximum specified fillet weld size along edges of adjacent parts, a point shops have debated for years when plate thickness changes at a lap or T-joint. If your shop has crib sheets or CAD notes derived from the old tables, they need a side-by-side check against the new ones before the next detail goes out. AWS summarised these Clause 4 revisions in its Fabtech summary of what’s new in D1.1:2025.

Matching, Undermatching, and Overmatching Filler Metal

Clauses 4.4.1 and 4.2 refined the definitions of matching, undermatching, and overmatching filler metal strength, which matters because it determines how a joint is evaluated when the electrode is not the same grade as the plate:

• Matching: the filler metal’s specified minimum tensile strength meets the base metal’s specified minimum tensile strength.
• Undermatching: the filler is weaker than the base metal, so the weld throat governs the joint capacity.
• Overmatching: the filler is stronger than the base metal, which can concentrate strain in the heat-affected zone and can be restricted by the engineer.

The refinements tighten how these conditions are documented on the WPS, particularly for high-strength low-alloy base metals where an Alloy Steel Welding Electrodes: Selection, Use & Safety choice has real consequences for joint behaviour. Note that filler strength classification is a structural concept, not a licence to weld aluminium or stainless to a steel rulebook; those processes and base metals follow their own guides, such as Aluminum MIG Welding: The Complete Practical Guide.

Fatigue Categories in Plain Language

D1.1’s fatigue provisions do not ask how heavy the load is once; they ask how often it repeats and what the joint geometry does to it. Each welded detail is assigned a fatigue category, roughly from the most forgiving (smooth, ground transitions, transverse splices) down to the harshest (cover plates and longitudinal fillet-welded attachments). Two identical loads on two different details can produce vastly different allowable stress ranges, which is why grinding or removing weld toes is sometimes specified as an upgrade. Because as-welded profile, weld undersize, and arc strikes all degrade fatigue performance, operator technique counts as much here as it does in All Position Welding Rod Guide type work where profile control in every position determines the finished bead.

The practical takeaway: D1.1 Clause 4 does not replace AISC 360 Chapter J. The engineer sizes the weld and assigns the fatigue category; D1.1 confirms the joint can be produced, qualified, and inspected to deliver it. The 2025 revision cycle was deliberately aligned with AISC 360 and IBC publication schedules so the two documents stay in step, and the fabricator’s job is to make sure nothing is lost in the handoff between them.

Fabrication, Preheat, and Workmanship in the Shop and Field

Clause 7 is where the code stops being a document and starts being a torch in someone’s hand. Everything covered so far, from prequalified procedures to welder qualification, only produces a sound structure if the person striking the arc follows the fabrication rules. The 2025 edition of the AWS D1.1/D1.1M structural welding code for steel keeps this clause practical: base metal preparation, fit-up, preheat, tack welding, distortion control, and repair. For shops auditing their habits against the current edition, this is the clause that reveals the most day-to-day drift.

Preheat: Temperature, Extent, and Documentation

Preheat is the most scrutinized item in Clause 7, and for good reason. Hydrogen-induced cracking needs three things working together: a susceptible microstructure, tensile stress, and hydrogen in the weld. Preheat slows cooling, lets hydrogen diffuse out, and softens the hard zone that forms in the heat-affected zone. The 2025 edition specifies how far preheat must extend from the weld based on material thickness, so heating a two-inch band around a heavy fillet on thick plate no longer cuts it. The heat has to reach beyond the joint, proportional to the thicker member being joined.

In practice this creates two questions: what temperature, and how is it proven? Temperature is driven by the preheat and interpass table, which depends on thickness, steel grade, filler hydrogen level, and joint restraint. Proof is where shops fail. Contact pyrometers, thermal sticks, and infrared guns all have limits, and infrared readings on shiny ground steel are notoriously optimistic. Measure the base metal, not the surface oxide, at a defined distance from the joint, and record it before welding starts.

Low-Hydrogen Electrode Storage and Rebaking

Low-hydrogen consumables such as E7018 are only low-hydrogen while they stay dry. Their flux coating is hygroscopic: leave a rod exposed to shop humidity and it picks up moisture, the moisture drives hydrogen into the arc, and the weld inherits the risk. Clause 7 addresses this with storage, exposure limits, and rebaking requirements that vary by electrode classification, with the relevant AWS filler metal specification setting the baking temperature and holding ovens keeping electrodes at temperature between uses.

• Sealed containers stay sealed until the electrodes are needed.
• Once opened, electrodes are tracked against an exposure clock and returned to a holding oven or discarded when that clock runs out.
• Rebaking is permitted only for classifications that allow it, at the temperature and time the filler metal specification calls for, and an electrode may still fail if it absorbed too much moisture for too long.

Shops running SMAW heavily should treat this as a labeling job, not a memory job: date the boxes, log the oven, audit the rods. For a broader look at selecting and handling consumables, our alloy steel welding electrodes guide covers selection, use, and safety practices that apply equally to structural work.

Fit-Up, Tack Welds, and Base Metal Preparation

Clause 7 sets fit-up tolerances for root openings, land, and mismatch, and it treats tack welds as real welds: same qualified WPS, same welder qualification, same preheat, same visual acceptance. Chipping tacks off with a hammer and welding over contaminated ones is one of the fastest ways to introduce a rejected start. Tacks also act as restraint, so on heavy joints they contribute to the locking stresses that cause cracking.

The clause also covers surface condition and the unglamorous details that cause failures later: mill scale, paint, moisture, and cutting residue at the joint. Arc strikes outside the weld zone are prohibited and must be ground smooth and, where required, checked by magnetic particle inspection, because an arc strike on quenched-and-tempered steel is a microcrack waiting to be found by NDT.

Distortion, Repair, and Restored Surfaces

Distortion control is largely sequence: balanced welds, back-step and skip techniques, proper restraint, and alternating sides of a joint rather than running one long bead. The code does not hand you a distortion recipe, but it does require that corrective heating or straightening not damage the base metal. Repair provisions are more specific: mislocated holes may be filled by welding under defined conditions, and restored surfaces must meet the same acceptance criteria as any other weld. Reaming a hole, welding a plug, then reaming again is a controlled sequence, not an improvisation. Shops doing structural repair work will find the same discipline in our alloy wheel welding guide, where the tolerance for a bad repair is equally unforgiving.

Weather, Wind, and Gas-Shielded Processes

FCAW and GMAW lose shielding the moment wind reaches the arc. Clause 7 requires protection of gas-shielded welds from wind, rain, and snow, and requires preheat to be maintained through the pass. Field erection is where this bites hardest, since a tarp and a windbreak often matter more than machine settings. According to OSHA’s construction welding standards, shielding the arc and surrounding area is a compliance obligation, not a preference.

The intent behind Clause 7 is consistent: control the variables a qualified procedure cannot control for you. Temperature, moisture, fit-up, and weather are field conditions, and the fabricator owns them. The 2025 edition simply makes clearer what “owned” means in measurable terms.

Inspection, NDT, and Weld Acceptance Criteria

Clause 8 is where everything upstream of it—prequalification, procedure qualification, welder continuity, preheat—stops being a promise and starts being proof. It sets out who inspects, how deeply, to what criteria, and what happens when a weld fails. If you fabricate or erect structural steel, this is the clause most likely to end up in a dispute letter, which is exactly why it deserves a careful read in the 2025 edition.

Visual Inspection: The Universal Baseline

The single most important principle in Clause 8 is that visual inspection is not optional and not one option among many. It is the examination method every weld on a D1.1 project receives. Supplementary nondestructive testing (NDT) is layered on only when the design documents or the Engineer of Record call for it.

A common misconception is that a project with 100% ultrasonic testing on CJP groove welds somehow exempts the remaining fillet welds from visual work. It does not. NDT supplements visual inspection; it never replaces it. A weld that passes a radiograph still has to satisfy the visual acceptance criteria for profile, undercut, and reinforcement.

The code also recognizes two inspection tiers: ordinary visual inspection, and the deeper “detailed” examination that includes inspection for complete joint penetration and NDT interpretation. Personnel performing these roles must be qualified under Clause 6. A foreman eyeballing welds without documented qualification is building a compliance problem that surfaces at the worst possible time.

Nondestructive Testing Methods and Personnel Certification

D1.1 leans on four NDT methods, each with a different job:

• Radiographic Testing (RT) — reveals internal volumetric defects such as porosity, slag inclusions, and lack of fusion, with well-understood acceptance reference radiographs.
• Ultrasonic Testing (UT) — the preferred volumetric method for thick CJP groove welds, offering deeper penetration detection and no radiation handling requirements. Phased-array UT provisions have expanded in recent editions.
• Magnetic Particle Testing (MT) — detects surface and near-surface discontinuities in ferromagnetic materials such as the carbon and low-alloy steels welded with alloy steel welding electrodes.
• Penetrant Testing (PT) — the surface examination of choice where magnetism is impractical or the material is non-magnetic.

Two changes in the 2025 edition are worth flagging. First, AWS added provisions for Magnetic Particle Testing and Penetrant Testing, bringing surface examination methods more fully into the code’s structure instead of leaving them as loose cross-references. Second, AWS clarified the language around NDT personnel certification, tightening ambiguity about what “certified” means and whose written practice governs. Under D1.1’s traditional framework, certification is an employer function: the employer’s written practice defines training, examination, and qualification levels, aligned with recognized schemes such as ASNT SNT-TC-1A.

Who Is Responsible for What

A recurring source of project conflict is scope ambiguity between three parties. The 2025 edition continues AWS’s effort to define distinct responsibilities so nothing falls through a gap:

Party	Primary Responsibilities
Engineer of Record (EOR)	Specifies which welds require NDT, the method, extent, and acceptance criteria; approves repairs and reexamination; adjudicates departures from the code.
Welding contractor	Executes the work, performs required visual inspection with qualified personnel, provides qualified NDT personnel and equipment, maintains records, and notifies the inspector of repairs.
Inspector	Verifies the WPS in use, welder qualification and continuity, preheat, visual acceptability, and NDT results; documents findings and conformance.

On federally funded or construction-site work, OSHA 1926.760 imposes its own weld inspection requirements for steel erection, independent of contract language. When the specification, the code, and OSHA all apply, the strictest requirement governs.

Acceptance Criteria, Repairs, and Records

The 2025 edition also updated the visual inspection acceptance criteria—the tables welders love to argue about. Expect revisions in how undercut limits, crack prohibition, weld profile, porosity, and reinforcement are described and applied. The discipline this demands is simple: the acceptance criteria used on the shop floor must match the edition cited in the contract. Applying criteria from a superseded edition is the fastest route to rejected work, as reflected in AWS’s own reporting on the Fabtech coverage of what’s new in D1.1:2025.

Build an inspection and test plan before the first arc is struck. It should identify every weld type, its required examination, hold points, and the records generated. Keep a traceability package for each assembly: the WPS and revision used, welder identification and continuity verification, preheat and interpass logs, consumable control records, NDT reports with personnel certification references, and repair records with reexamination results. When a question arises three years later, that package—not memory—is the answer.

Clause 8 rewards shops that treat inspection as a planned production activity rather than an end-of-job scramble. Consult the official AWS D1.1 code page and the current preview PDF for the exact clause text as you update procedures and train inspection staff.

D1.1 vs D1.5, D1.6, ASME Section IX, and AISC 360: Choosing the Right Code

Picking a welding code is not a matter of which rulebook the shop knows best. It is a matter of which one the contract invokes. A fabricator that runs every job through its familiar AWS D1.1 procedures can still get rejected on a highway bridge, a stainless support frame, or a pair of seismic moment connections, because those projects arrive with their own requirements bolted on. The 2025 edition of D1.1 remains the default structural steel welding code in the United States, but default does not mean universal. Here is how the main codes divide the work, and where shops get into trouble by assuming qualifications carry over.

A quick side-by-side of the common codes

Code	What it governs	Typical trigger
AWS D1.1/D1.1M:2025	Carbon and low-alloy steel structural welding	Default for buildings and general steel structures
AASHTO/AWS D1.5	Bridge welding	Highway bridge work, specified by the owner
AWS D1.6	Stainless steel structural welding	Stainless frames, brackets, architectural support
AWS D1.3	Sheet steel (roughly 3/16 in / 4.8 mm and thinner)	Sheet framing, shear studs, light gauge members
AWS D1.8	Seismic energy-dissipating elements	High-seismic regions, demand-critical connections
ASME Section IX	Welding qualifications for boilers, vessels and piping	Pressure-retaining work
AISC 360	Structural design, including connection design	Engineer’s design calculations and drawings

D1.1’s lane: carbon and low-alloy steel

D1.1/D1.1M:2025, published by the American Welding Society and approved by ANSI, is written for carbon and low-alloy steels in static and cyclically loaded structures, from alloy steel welding electrodes selection through groove, fillet, and plug and slot welds, qualification, fabrication, and inspection. What it does not do is follow you into other materials or other service. Welding a stainless stair stringer? That is D1.6 territory. Welding an aluminum handrail or boat hull? Different code entirely, and a different body of technique, which is why resources like this aluminum MIG welding guide matter more than any D1.1 clause. Special alloys such as Alloy 20 fall outside D1.1’s base metal lists and need their own qualified procedures. Applying D1.1 outside its scope does not make the weld wrong in the abstract; it makes it undocumented against the standard the inspector will actually check.

Bridge work: AASHTO/AWS D1.5

Highway bridge welding is governed by AASHTO/AWS D1.5, commonly specified separately from D1.1 even when the same shop does the work. D1.5 brings its own fracture control philosophy: toughness testing requirements, fatigue consideration, and restrictions on fracture-critical members that D1.1 does not impose in the same form. A shop whose bridge experience consists of building a bridge-adjacent warehouse under D1.1 has not met D1.5’s requirements. If a project specification says “weld in accordance with D1.5,” no amount of D1.1 paperwork will substitute.

Seismic work: AWS D1.8 as a supplement

AWS D1.8/D1.8M addresses seismic energy-dissipating elements and demand-critical welds. In practice it is often invoked as a supplement to D1.1 rather than a replacement: the fabricator still works to D1.1 for general members, then adds D1.8 requirements for the specific connections that must absorb earthquake energy. Expect additional oversight, preproduction test coupons, and stricter inspection assignment on those joints. In high-seismic regions, confirm early whether the structural documents call for D1.8, because the added qualification and testing work cannot be retrofitted cheaply after steel has been cut.

Pressure work: ASME Section IX

Boilers, pressure vessels, and pressure piping fall under ASME Section IX, which qualifies procedures and welders through its own QW variables, position rules, and six-month continuity provisions. The ranges and variable boundaries are not the same as D1.1’s, so a Section IX performance qualification does not transfer, and vice versa. Shops that do both structural and pressure work keep two qualification files, deliberately, because merging them is how audits fail.

AISC 360 designs it; D1.1 builds it

One boundary confuses people constantly: AISC 360, the ANSI/AISC structural steel design specification, tells the engineer how strong a weld must be, which joint type to use, and how fatigue category affects the connection. Chapter J covers the design of connections. D1.1 does not replace those decisions; it tells the fabricator how to make the weld that satisfies them, covering preheat, qualification, workmanship, and acceptance criteria. The design drawing and calculation set come from AISC 360. The WPS, PQR, and inspection records come from D1.1. An engineer can specify a weld size; only a qualified procedure and welder can deliver it.

Contract language decides everything

Read the specification before the code. Division 05 structural specifications, addenda, and owner supplements typically name the governing code and its edition, and that language overrides shop habit. Mixing codes is the expensive path: applying D1.1 preheat and documentation to welds that also carry D1.5 toughness testing, or reporting Section IX continuity as D1.1 continuity, creates gaps that surface at inspection rather than at bid. Construction projects carry an extra layer of regulatory expectation around welder qualification, as outlined in OSHA’s steel erection welding requirements.

When the contract is ambiguous, ask the engineer of record in writing, confirm the edition year, and qualify to the most demanding code in play. Choosing the right rulebook costs an afternoon of reading. Choosing the wrong one costs requalification, rework, and reputation.

Adopting D1.1:2025: A Practical Compliance Roadmap and Common Mistakes

Codes rarely announce themselves on the shop floor. The 2025 edition shows up later: in a contract attachment, an inspector’s checklist, or an engineer’s transmittal asking which edition your WPS library was written to. Shops that treat the transition as paperwork get burned; shops that treat it as a controlled project come out cleaner. Adopting AWS D1.1/D1.1M:2025 is a repeatable process, and it starts with seven steps.

Seven Steps to a Controlled Transition

1. Put the current text in the right hands. Buy the 2025 edition and, where available, the change-marked version, in which additions are underlined so the delta from the 2020 edition stays traceable for quality teams. The AWS preview of D1.1/D1.1M:2025 is a useful first look before the full purchase lands.
2. Run a gap analysis on the WPS and PQR library. Most fabricators upgrading from the 2020 edition need to re-review prequalified procedures rather than rewrite them: compare each one against the reorganized Clause 5 tables, the updated toughness provisions, and the new available-strength table for welded joints.
3. Update preheat and interpass documentation. Reconcile your preheat charts, heat-input records, and preheat attestation forms with the ranges that changed for certain thicknesses and process combinations.
4. Review continuity logs. Six-month continuity is the rule that quietly fails audits. Pull every record, confirm current continuity dates, and schedule requalification before anything lapses rather than after an inspector finds it.
5. Train the people who apply the code. Welders, fitters, QC inspectors, and shop supervisors each need the sections they touch, plus new definitions and acceptance criteria. Include scope discipline: D1.1 governs carbon and low-alloy structural steel, while projects like aluminum MIG fabrication follow an entirely different rule set.
6. Update the quality manual and its forms. Revision numbers, WPS and PQR templates, inspection report headers, traveler footers, and document-control language should all name the current edition.
7. Communicate outward. Tell engineers of record, general contractors, and customers which projects will be welded to the 2025 edition and when the switch happens, and confirm in writing which edition the contract documents require.

The WPS Library Audit: Re-Review, Don’t Rewrite

Use the change-marked text as your working document and walk each WPS line by line with a three-tag system: unchanged (still complies as written), revised (parameters, preheat, or documentation need edits), and withdrawn (prequalified basis no longer exists). Most shops find the majority of procedures land in the first two categories, which is exactly why rewriting everything is wasted effort. Give the closest attention to the changes summarized in Fabtech’s overview of what’s new in D1.1:2025 and in The Fabricator’s clause-by-clause breakdown.

Most Frequent Adoption Mistakes

• Treating the new edition as “mostly the same.” Even small definition changes ripple into acceptance criteria. Prevention: a documented delta review signed off by your QC lead.
• Lapsed continuity records. The most common audit finding, and entirely avoidable. Prevention: a continuity calendar with alerts at 30, 60, and 90 days before expiry.
• Missing preheat documentation. The weld may have been preheated correctly with no record proving it. Prevention: preheat readings captured on the traveler at the time of welding, not reconstructed later.
• Superseded editions in project paperwork. Prevention: a single controlled list of approved codes, referenced by every quote, submittal, and work instruction.
• Assuming prequalification covers everything. Non-prequalified base metals, out-of-range thicknesses, and unlisted joint details still require a PQR. Prevention: flag exceptions during estimation, not during fabrication.
• Mixing code scopes. Stainless, sheet, and aluminum work each sit under their own standards, so crews should not carry practices from aluminum wheel repair into structural groove welds. Prevention: scope training alongside procedure training.
• Skipping the engineer of record. Prevention: joint review of the transition plan before the first production weld.

Why the Code Matters Beyond the Paperwork

There is a reason D1.1 has appeared in contracts and project specifications for close to a century, as AWS standards staff have noted in Welding Digest. It is the shared language that lets a designer, a fabricator, and an inspector agree on what a sound weld looks like without arguing. Regulators lean on that same language: steel erection rules such as OSHA 1926.760 expect welding and cutting to follow accepted practices for the process and the material. And as ANSI’s overview of the 2025 release makes clear, each edition reflects accumulated field experience rather than arbitrary revision.

That is the real argument for doing this work properly. A fabricator’s reputation is built on welds that pass inspection the first time, documentation that survives an audit, and the quiet reliability of knowing the shop welded to the edition the contract called for. Run the gap analysis, close the continuity gaps, fix the paperwork, and communicate early. The steel was never the hard part; proving it was welded correctly is where codes earn their keep.

Frequently Asked Questions

What is AWS D1.1/D1.1M:2025?

It is the 25th edition of the American Welding Society’s Structural Welding Code – Steel, approved by ANSI in March 2025. It sets requirements for the design, fabrication, qualification, inspection, and repair of welded carbon and low-alloy steel structures under static or cyclic loading.

Who needs to comply with D1.1:2025?

Structural engineers, detailers, welding fabricators, erectors, and inspectors working on welded steel buildings, platforms, frames, and similar structures. Compliance is typically invoked through contract documents, project specifications, or building code references rather than by law alone.

What changed in the 2025 edition compared with D1.2020?

Key changes include a new Table 4.3 for available strength of welded joints, new toughness provisions, a new Annex S covering added base materials, reorganized process-specific prequalification tables, limits on overmatching filler metal strength, removal of A5.36 references, new type D stud provisions, and updated inspection and NDT requirements.

Does a welder’s D1.1 qualification expire?

A qualification remains effective indefinitely as long as the welder uses that welding process at least once in any consecutive six-month period. If the welder lapses past six months without using the process, requalification is required.

What is a prequalified WPS and when do I need a PQR?

A prequalified WPS uses base metals, filler metals, joint details, and process parameters already accepted by the code, so no test coupon or PQR is needed. If your materials, joint design, or process conditions fall outside the prequalified ranges, you must qualify the procedure by testing and document a PQR.

Does D1.1 apply to stainless steel or aluminum welding?

No. Stainless structural welding falls under AWS D1.6 and aluminum structural welding under AWS D1.2. D1.1 is limited to carbon and low-alloy constructional steels, with other standards covering sheet steel, bridges, and seismic components.

How do D1.1 and AISC 360 work together?

AISC 360, the Specification for Structural Steel Buildings, governs structural design, while D1.1 governs how welded connections are produced, qualified, and inspected. The 2025 revision cycle for D1.1 was deliberately aligned with AISC 360 and the International Building Code cycles.

How should a shop transition from D1.1:2020 to D1.1:2025?

Buy the current edition, use AWS’s change-marked text to identify differences, audit your WPS and PQR library against new tables and filler metal rules, verify preheat and interpass documentation on every WPS, review welder continuity logs, and update your quality manual and training records before bidding work that cites the 2025 edition.