Learn about updates to the clauses in this important code
By Travis Green, Tom Schlafly, and Mike Gase
Reprinted with permission: The AWS Welding Journal
The D1 committees solicited input from users and other industry subject matter experts to significantly update AWS D1.1/D1.1M:2025, Structural Welding Code — Steel. The easy part, incorporating errata from the 2020 code, was completed, and then we implemented additional improvements. While there are changes in most clauses, this article focuses on what we believe to be the most significant ones in the 2025 code.
This edition added several new terms and definitions, and ambiguous terms were clarified. References to AWS A5.36/A5.36M, Specification for Carbon and Low-Alloy Steel Flux Cored Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding (Ref. 1), have been removed throughout the code since the specification has been withdrawn. Teresa Melfi’s 2020 Welding Journal article (Ref. 2) summarizes the reasons for creating AWS A5.36 and the challenges associated with its integration into the code. Electrodes addressed in A5.36 and complying with AWS A5.18, Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding (Ref. 3), A5.20, Specification for Carbon Steel Electrodes for Flux Cored Arc Welding (Ref. 4), A5.28, Specification for Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding (Ref. 5), and A5.29, Specification for Low-Alloy Steel Electrodes for Flux Cored Arc Welding (Ref. 6), are still referred to in AWS D1.1.
Clause 4 — Design of Welded Connections
A significant update to Clause 4 is in 4.7, titled “Strength.” This subclause includes both allowable stress design (ASD) and load and resistance factor design (LRFD). The inclusion of LRFD methodology is new to the code. Underlying assumptions related to dead-to-live load ratios and structural reliability are similar, if not the same, to what has been presented in American National Standards Institute (ANSI)/American Institute of Steel Construction (AISC) 360, Specification for Structural Steel Buildings, (Ref. 7) for many years. Note that AISC 360 refers to load and load combinations from the American Society of Civil Engineers (Ref. 8). The engineer should identify the loads and load combinations. Depending on the target reliability, modifications to the AISC 360 LRFD strength reduction factors may be necessary.
Definitions for allowable strength (nominal strength divided by an ASD safety factor), available strength (allowable strength in ASD or design strength in LRFD), and design strength (nominal strength times an LRFD strength reduction factor) have been incorporated into Clause 2, “Normative References.” ASD loads should still be used to assess fatigue performance. Table 4.3 summarizes various welded joint available strengths. It is imperative that LRFD design strengths only be used with LRFD loads.
Clause 4.3.2, titled “CVN Toughness Requirements,” has been clarified to allow specification of filler metal notch toughness by classification or by welding procedure specification (WPS) qualification by testing.
Clause 4.4.1, titled “Matching, Undermatching and Overmatching Conditions,” and Clause 2 enhance the definition of each term. Matching strength filler metals are defined as follows:
For base metals not listed in Tables 5.6 or 6.10 with a specified minimum yield strength equal to or greater than 60 ksi, the specified minimum tensile strength of the filler metal shall meet or exceed the specified minimum tensile strength of the lowest strength base metal in the joint but not by more than 10 ksi.
For base metals not listed in Tables 5.6 or 6.10 with a specified minimum yield strength of less than 60 ksi, the specified minimum tensile strength of the filler metal shall not exceed the specified minimum tensile strength of the lowest strength base metal in the joint by more than 20 ksi.
The filler metal/base metal combinations listed in Table 5.7 are matching strength filler metals for each base metal.
Overmatching strength filler metals are those that have tensile strengths greater than the matching definition. Similarly, undermatching strength filler metals are those that have tensile strengths less than the matching definition. Table 4.3 now states where undermatching and overmatching filler metals may be used. Where overmatching is used, often for weathering or toughness, the weld metal strength used to calculate the strength of the connection is the matching strength.
Clause 5 — Prequalification of WPSs
The most significant updates to Clause 5 are in Part E, “Filler Metals and Shielding Gases.” Clause 5.6.2, titled “Overmatching Filler Metal Strength,” now limits overmatching filler metals to no more than 10 ksi greater than the requirements of Table 5.7.
Previously, the code was unclear about what shielding gases could be used in prequalified procedures. Clause 5.6.4, titled “Shielding Gas,” now defines the term oxygen equivalent (OE) and requires that production shielding gas comply with electrode manufacturer OE limits or be the gas used to classify the filler metal. OE is the % oxygen in the shielding gas plus 0.5 times the % carbon dioxide in the shielding gases.
In the previous version of the code, Table 5.1, “Prequalified WPS Requirements,” summarized prequalified WPS requirements for shielded metal arc welding, submerged arc welding, and gas metal arc welding/flux cored arc welding. The table has been broken down by process to improve readability, and several electrode requirements have changed to be more conservative. Minimum current requirements were added for nonshort circuit and pulsed processes, and maximum layer width requirements have been added.
Table 5.6 presents approved base metals for prequalified WPSs. ASTM A913 Grade 80 base metal has been added to the new Group V (see Urtz, page 28).
Table 5.11 presents prequalified minimum preheat and interpass temperatures. That table now includes cast steels (ASTM A216, Ref. 10) in Categories A and B. In addition, ASTM A913 Grades 70 and 80 are included in new Categories F and G, respectively.
Figures 5.1 and 5.2 have been revised to make the proportions more realistic to avoid misrepresenting joint details. The required dimensions have not changed.
Clause 6 — Qualification
The primary updates to Clause 6 revolve around preheat and interpass temperature requirements; clarification of testing requirements for groove, fillet, and slot welds; the consumables verification test; and complete joint penetration (CJP) welder and welding operator test coupon requirements.
Clause 6.8.4, titled “Preheat and Interpass Temperature Qualification Requirements,” now defines preheat minimum requirements as well as interpass minimum and maximum temperatures.
Clauses 6.11 to 6.14 provide qualification extents and testing requirements for CJP groove welds, partial joint penetration (PJP) groove welds, fillet welds, and plug and slot welds, respectively. Most of this information is a clarification of the previous code. However, Table 6.5 and Figure 6.17 are new and relate to plug and slot weld qualification.
Clause 6.15, titled “Consumables Verification Test,” has been moved from the fillet weld qualification clause because it applies to other weld types using materials not complying with Clause 5 or when the WPS has not been qualified per 6.11 or 6.12.
Clause 6.17.5, titled “Extent of Qualification,” clarifies personnel qualifications based on the type of weld qualified, e.g., welders or welding operators who qualify using a CJP groove weld are qualified to weld PJP groove welds, fillet welds, plug and slot welds, and tack welds.
Figure 6.21, which is referenced in Clause 6.22.1 (“Welder and Welding Operator Test Coupons, Except for ESW, EGW, and Plug Welds”), consolidates several previous welder and welding operator figures. Figures 6.25 and 6.26 are new and only referenced in Table 6.12 for welder and welding operator qualification of fillet welds.
Clause 7 — Fabrication
Updates to Clause 7 include clarification of preheating and interpass temperatures, postweld heat treatment for stress relief, cast steel base metal discontinuities, fillet weld acceptance criteria, and weld tabs.
Clause 7.6.2 is titled “Extent of Preheat and Interpass.” In the previous code, preheat and interpass temperatures were required to extend the maximum base metal thickness in all directions from the joint but no less than 3 in. The new code reduces the required preheat and interpass distances for thinner materials as follows:
For base metal less than 11/2 in. thick, the distance heated shall be at least twice the base metal thickness.
For base metal 11/2 in. thick and greater, the distance heated shall be at least equal to the base metal thickness but not less than 3 in.
Clause 7.8, titled “Postweld Heat Treatment (PWHT) for Stress Relief,” states that when PWHT is performed, it shall be specified in the contract documents or approved by the engineer. PWHT shall be performed in conformance with a WPS that is qualified with PWHT or with a prequalified WPS meeting the PWHT requirements of Clause 5. In addition, it requires that PWHT be performed using written procedures that include information like heating rate, holding temperature, holding time, cooling rate, heating method, etc. The initial maximum furnace temperature was revised from 600° to 800°F.
Clause 7.23.1, titled “Fillet Welds,” clarifies that maximum convexity applies to the entire weld face and the face of individual weld beads.
Clause 7.30.2, titled “Weld Tab Exemptions,” replaces a previous provision that required weld tabs where practical. This list of exceptions eliminates the vague nature of the previous provision.
Clause 8 — Inspection
Updates to Clause 8 include edits to magnetic particle (MT) and liquid penetrant (PT) testing, time of testing, personnel certifications, and visual acceptance criteria.
Clause 8.10.1, titled “MT and PT Indications,” defines linear and rounded discontinuities. A linear discontinuity is one in which its length exceeds three times its width. A rounded discontinuity is defined as one in which its length is three times its width or less and is rounded or irregular. The weld must still meet Table 8.1 requirements.
Clause 8.14.6, titled “Personnel NDT Certification,” now includes subclauses addressing how nondestructive testing personnel can be certified. Clause 8.14.6.2, “Employer-Based Certification,” allows nondestructive testing personnel to be certified in accordance with the employer’s written practice by ASNT SNT-TC-1A (Ref. 11) or ANSI/ASNT CP-189 (Ref. 12). Clause 8.14.6.3, “Internationally Recognized Third-Party Certification,” allows nondestructive testing personnel to be certified by entities like ANSI/ASNT CP-9712 (Ref. 13), CAN/CGSB-48.9712 (Ref. 14), and ISO 9712 (Ref. 15).
Table 8.1, “Visual Inspection Acceptance Criteria,” Item 7, updates undercut requirements for welds under 12 in. long. The accumulated undercut length with depth greater than 1/16 in. shall not exceed the weld length multiplied by 0.16 for each weld length. In addition, Table 8.1, Item 8, now includes requirements for the amount of piping porosity that is acceptable based on whether the structure is statically or cyclically loaded, the direction of computed stress, the weld type, and the weld length. For example, given a fillet weld between a stiffener and web in a cyclically loaded structure, there are three piping porosity limits: (a) the sum of the diameters of visible piping porosity 1/32 in. or greater in diameter shall not exceed 3/8 in. in any linear inch of weld; (b) for welds greater than or equal to 12 in. in length, the sum of visible piping porosity 1/32 in. or greater in diameter shall not exceed 3/4 in. in any 12 in. length of weld; (c) and for welds less than 12 in. in length, the sum of visible piping porosity 1/32 in. in diameter or greater shall not exceed the weld length multiplied by 0.06 for each length of weld.
Clause 9 — Stud Welding
The most significant change in Clause 9 is the addition of Type D studs. These studs are made from deformed wire or bar conforming to ASTM A706/A706M (Ref. 16), Grade 60. The tension test requirements are 125% of the minimum specified yield strength. When fillet welding Type D studs, the welds shall comply with AWS D1.4/1.4M, Structural Welding Code — Steel Reinforcing Bars (Ref. 17).
Clause 10 — Tubular Structures
Clause 10 updates requirements for T-K-Y connections for dihedral angles, performance qualification, and ultrasonic testing (UT) of T-K-Y connections.
Clause 10.14.4.1, “WPSs without Prequalified Status,” requires a sample joint for the qualification of the WPS. This clause now permits the omission of overhead welding when it is not used in production.
Clause 10.14.4.2, titled “T-, Y-, or K-Connection WPS with Dihedral Angles Less than 30°,” provides rules for the qualification of joints with dihedral angles less than 30 degrees.
Clause 10.16.1, titled “Welders and Welding Operators,” provides clarification language.
Clause 10.29.1, titled “Procedure,” clarifies that UT shall be performed in accordance with a written procedure prepared by an NDT Level III. Level III certification can be obtained through ASNT SNT-TC-1A and ANSI/ASNT CP-189.
Clause 11 — Strengthening and Repair of Existing Structures
No substantive changes have been made to Clause 11, “Strengthening and Repair of Existing Structures.” The recently published AWS D1.7/D1.7M, Guide for Strengthening and Repairing Existing Structures (Ref. 18), provides additional information on this topic.
Annex S (Informative) — Guidelines for the Preparation of Proposals for Additions of Base Materials not Listed in D1.1
The new informative annex provides information about the procedure for adding new base metals to the code and information needed as part of this process. Recommended information includes material identification, producer(s), description, chemical composition, mechanical properties, welding parameters, historical use, etc.
In Closing
Thousands of volunteer and staff hours have been devoted to reviewing and modifying this important code. AWS codes and standards are available for purchase at pubs.aws.org. If you have a concern about the 2025 code or a revision you would like to propose, contact Jennifer Rosario at [email protected].
The D1Q Subcommittee on Steel Structures is always looking for volunteers willing to devote the time and effort needed to improve the code. In particular, the D1 Task Groups are looking for new members, and the D1 Committee on Structural Welding is seeking educators. Interested individuals can apply to the committees or task groups by completing the application at aws.org/about/get-involved/committees. WJ
In Memoriam
In 2023, Phil Torchio, the chair of the D1Q Subcommittee on Steel Structures that maintains AWS D1.1/D1.1M, passed away. He had a breadth of welding knowledge and experience. In addition, he worked diligently to improve the code through numerous proposals. The D1 members were privileged to have learned from and shared time with him. The Philip Torchio III Exemplary Committee Member Award was created to honor his contributions.
References
1. AWS A5.36/A5.36M, Specification for Carbon and Low-Alloy Steel Flux Cored Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding. Miami, Fla.: AWS.
2. Melfi, T. A. 2020. AWS A5.36 Specification Withdrawn from Publication. Welding Journal 99(9): 43, 44.
3. AWS A5.18/A5.18M, Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding. Miami, Fla.: AWS.
4. AWS A5.20/A5.20M, Specification for Carbon Steel Electrodes for Flux Cored Arc Welding. Miami, Fla.: AWS.
5. AWS A5.28/A5.28M, Specification for Low-Alloy Steel Electrodes and Rods For Gas Shielded Arc Welding. Miami, Fla.: AWS.
6. AWS A5.29/A5.29M, Specification for Low-Alloy Steel Electrodes for Flux Cored Arc Welding. Miami, Fla.: AWS.
7. ANSI/AISC 360, Specification for Structural Steel Buildings. Chicago, Ill.: ANSI.
8. ASCE/SEI 7-22, Minimum Design Loads and Associated Criteria for Buildings and Other Structures. Reston, Va.: ASCE.
9. ASTM A913/A913M-19, Standard Specification for High-Strength Allow-Alloy Steel Shapes of Structural Quality, Produced by Quenching and Self-Tempering Process (QST). West Conshohocken, Pa.: ASTM.
10. ASTM A216/A216M-21, Standard Specification for Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service. West Conshohocken, Pa.: ASTM.
11. ASNT SNT-TC-1A: Personnel Qualification and Certification in Nondestructive Testing. Columbus, Ohio: ASNT.
12. ANSI/ASNT CP-189: ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel. Washington, D.C.: ANSI.
13. ANSI/ASNT CP-9712:2023, Nondestructive Testing for Qualification and Certification of NDT Personnel. Washington, D.C.: ANSI.
14. CAN/CGSB-48.9712-2022: Non-destructive testing — Qualification and certification of NDT personnel. Ottawa, Ontario, Canada: CGSB.
15. ISO 9712:2021, Non-destructive testing — Qualification and certification of NDT personnel. Geneva, Switzerland: ISO.
16. ASTM A706/A706M-24, Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement. West Conshohocken, Pa.: ASTM.
17. AWS D1.4/D1.4M:2018-AMD1, Structural Welding Code — Steel Reinforcing Bars. Miami, Fla.: AWS.
18. AWS D1.7/D1.7M:2024, Guide for Strengthening and Repairing Existing Structures. Miami, Fla.: AWS.
TRAVIS GREEN ([email protected]), PE, SE, CWI, is chair of the AWS D1Q Subcommittee on Steel Structures and with WJE, Falls Church, Va. TOM SCHLAFLY ([email protected]) is co-chair of the AWS Task Group 1 on Design and with AISC, Chicago, Ill. MIKE GASE ([email protected]), SCWI, ASNT Level III, is chair of the AWS Task Group 3 on Fabrication and Task Group 4 on Inspection and with Midwest Steel Inc., Detroit, Mich.