clause5.io/ welding/ aws-d1-1

What D1.1 Governs

AWS D1.1/D1.1M:2025 governs welding of structural steel components in buildings, industrial structures, and other non-bridge, non-pipe applications. The 2025 edition covers 5 welding processes (SMAW, SAW, GMAW, FCAW, and GTAW) across more than 100 base metals listed in 表 5.6, on carbon and low-alloy steels with 最小 yield strengths up to 100 ksi (690 MPa). The 2025 edition is the 25th, superseding the 2020 (24th) edition.

AWS D1.1 is the primary 溶接コード for structural steel in the United States, governing an estimated 70% of 構造用鋼溶接 nationally. Clause 1.1 defines its scope: the requirements for fabricating and erecting welded steel structures. When D1.1 is stipulated in 契約図書, conformance with all provisions is required except where the Engineer specifically modifies or exempts them per Clause 1.5.1.

The code applies to carbon and low-alloy steels that are 1/8 in [3 mm] or thicker with a minimum specified yield 強度 of 100 ksi [690 MPa] or less. This covers the vast majority of structural steel used in buildings, bridges, and industrial structures.

Common steels include A36, A572 Gr.50, A992, A588 weathering steel, and A913 high-strength grades. 確認 your steel against Table 5.6 using your mill test report.

D1.1 covers both nontubular members (wide-flange beams, plates, angles, channels) and tubular structures (hollow structural sections, pipe columns used as structural members). Clause 10 provides additional requirements specific to tubular connections.

What D1.1 Does Not Cover

Clause 1.4 explicitly directs users to other AWS codes for applications outside its scope. Aluminum welding falls under D1.2. Sheet steel under 1/8 in thick is covered by D1.3.

Reinforcing steel uses D1.4. ステンレス鋼 is governed by D1.6. Highway bridge welding has its own code in AASHTO/AWS D1.5. Strengthening and 補修 of existing structures is addressed in D1.7 and D1.8. Titanium falls under D1.9.

Pressure vessels, boilers, and piping systems are entirely outside D1.1 scope. These are governed by the ASME Boiler and Pressure Vessel Code. Cross-country pipelines are governed by API 1104. The distinction is critical: a structural pipe column in a building uses D1.1, but a pressurized steam pipe in the same building uses ASME.

The 11 Clauses of D1.1:2025

D1.1 is organized into 11 clauses: General Requirements (1), Normative References (2), Terms (3), Design (4), Prequalification (5), Qualification (6), 製作 (7), 検査 (8), Stud Welding (9), Tubular (10), and Strengthening/Repair (11). Clauses 5 and 6 govern WPS paths. Clause 8 governs 検査員 受入基準.

D1.1:2025 is organized into 11 clauses that cover the full lifecycle of a welded steel structure, from design through inspection. Unlike ASME IX, which addresses only qualification, D1.1 is a single comprehensive document covering design, procedure development, fabrication, and quality control.

Clause 1 — General Requirements

Scope, limitations, responsibilities of the Engineer, 施工業者, and Inspector. Defines what the code covers (structural steel) and what it excludes. Establishes the authority hierarchy for contract documents.

Clause 2 — Normative References

Lists all reference documents required for implementation, including AWS, ASTM, and ANSI standards that D1.1 incorporates by reference.

Clause 3 — Terms and Definitions

Definitions for terms used throughout the code. Critical for interpreting requirements consistently, particularly distinctions like 不連続 versus 溶接欠陥, and 事前認定 versus qualified.

Clause 4 — Design of Welded Connections

Requirements for designing welded connections in nontubular and tubular members. Covers effective 溶接 areas, allowable stresses, fatigue design, and joint configuration details for both statically and cyclically 読み込み済み structures.

Clause 5 — Prequalification of WPSs

The prequalified path. 溶接施工法 Specifications that meet all requirements of Clause 5 are exempt from the 資格試験 required in Clause 6. Covers approved base metals (Table 5.6), 溶加材 matching (Table 5.7), 予熱 requirements (Table 5.11), prequalified joint details (Figure 5.1), and essential variables (Table 5.5).

Clause 6 — Qualification

WPS qualification by 試験 and welding personnel 作業者資格. When a procedure does not meet all prequalified requirements of Clause 5, it must be qualified by testing per Clause 6. Table 6.6 lists 35 essential variables for 手順資格. Also covers 溶接士 and welding operator performance tests.

Clause 7 — Fabrication

Requirements for production welding, including 母材 preparation, preheat and interpass temperatures (Clause 7.6), 入熱 control for quenched and tempered steels (Clause 7.7), minimum すみ肉溶接 sizes (Table 7.7), weld profiles, repairs, and dimensional tolerances.

Clause 8 — Inspection

Inspector qualifications, 合否基準 criteria for 外観検査 (Table 8.1), and procedures for nondestructive testing including 磁粉探傷試験, 放射線透過試験, and 超音波探傷試験. Clause 8.9 provides the 目視 inspection acceptance criteria that inspectors apply daily.

Clause 9 — Stud Welding

Requirements for welding studs to structural steel, including stud base qualification, technique, and inspection criteria. Covers headed studs used as shear connectors in composite construction.

Clause 10 — Tubular Structures

Requirements specific to tubular connections, including 継手設計, WPS qualification for tubular joints, and inspection of tubular welds. All other clauses also apply to tubulars unless specifically noted otherwise.

Clause 11 — Strengthening and Repair of Existing Structures

Requirements for welded modification or repair of existing steel structures. Addresses the unique challenges of welding on structures that may be under load, including heat effects on existing members and fatigue life considerations.

Prequalified vs. Qualified WPS

D1.1 Clause 5 allows prequalified WPSs for common joints and processes without testing — the 製作者 documents 適合 with Table 5.1, 5.3, 5.4, and Figure 5.1. Clause 6 requires qualification by testing (PQR) for any WPS that falls outside prequalified 限界値. Most structural steel fabrication uses prequalified WPSs.

D1.1 provides two distinct paths to a compliant 溶接施工要領書, and the distinction is one of the most important concepts in the code.

The Prequalified Path (Clause 5)

Clause 5 defines prequalified WPSs — procedures that the code has already validated through decades of industry experience. Prequalification of WPSs shall be defined as exempt from the WPS qualification testing required in Clause 6.

To be prequalified, a WPS must conform with all applicable requirements of Clause 5: approved 溶接工程 (SMAW, SAW, GMAW except short-circuit, or FCAW), base metal listed in Table 5.6, filler metal per Table 5.7, 継手詳細 from Figure 5.1, and preheat per Table 5.11.

This path eliminates the cost and time of qualification testing. Many 鉄骨製作 shops work exclusively with prequalified joints and never need a Procedure 資格記録 (PQR). A typical building frame using A992 steel with E71T-1 FCAW wire and 規格 CJP groove welds or fillet welds qualifies entirely under Clause 5.

The Non-Prequalified Path (Clause 6)

When any element of a procedure falls outside the prequalified limits of Clause 5, the WPS must be qualified by testing per Clause 6. This requires producing a 試験溶接, extracting specimens, performing destructive tests, and documenting the results on a PQR. Common triggers include using GMAW short-circuit transfer, welding joint geometries not in Figure 5.1, or working with base metals not listed in Table 5.6.

D1.1’s prequalified path has no equivalent in ASME IX. Under Section IX, every WPS requires procedure qualification — there is no prequalified exemption. This is one of the most significant structural differences between the two codes. For ASME IX or API 1104, separate requirements apply.

After fabrication, Clause 8 governs inspection. Table 8.1 defines 外観合格 criteria for eight discontinuity categories — from 割れ (zero tolerance) to 気孔 (measurable limits). See the weld defects overview for the complete Table 8.1 breakdown. Before welding begins, the mill test report (MTR) confirms the base metal meets Table 5.6 group requirements and feeds the preheat lookup.

D1.1:2025 Compliance Tools

Clause5 provides free D1.1 compliance calculators: 予熱温度 lookup (Table 5.11), heat input calculation, 炭素当量 (Annex B), minimum すみ肉溶接サイズ (Table 7.7), and 溶着速度. Each 計算機 returns the exact code reference and applicable clause.

Each tool below applies a specific D1.1:2025 requirement. Select a calculator to look up the value for your application.

How D1.1 Compares to Other Welding Codes

D1.1 is one of several welding codes engineers encounter. The primary differences are scope, preheat methodology, base metal grouping, and whether prequalified WPSs are available. D1.1 covers structural steel; ASME IX covers pressure equipment; D1.5 covers highway bridges; CSA W59 covers Canadian structural steel.

"D1.1 is the most widely referenced structural welding code in the world. When a contract document says 'weld per code,' nine times out of ten they mean D1.1."

— Widely cited in CWI exam preparation, reflecting D1.1:2025 Clause 1.1 Scope