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Standards Comparison Report
AWS D1.1 vs GB 50661
EXECUTIVE SUMMARY
This report compares AWS D1.1/D1.1M:2020 (US) and GB 50661-2011 (China) for structural steel welding. Overall equivalence is NEQ (Not Equivalent) due to differing acceptance criteria, welder qualification test plates, and inspection frequencies. The single most important procurement implication: welder qualification and procedure qualification records (PQRs) are NOT directly transferable — additional testing per GB 50661 is mandatory for Chinese projects.
APPLICABLE CHINESE STANDARDS
| Standard No. | Title (Chinese) | Scope | Mandatory/Recommended | Status |
|---|---|---|---|---|
| GB 50661-2011 | 钢结构焊接规范 (Code for Welding of Steel Structures) | Welding of steel structures for building/civil engineering — carbon steel (Q235, Q355) and low-alloy high-strength steel (Q390, Q420, Q460) | Mandatory (GB) | Current |
| GB/T 11345-2013 | 焊缝无损检测 超声检测 技术、检测等级和评定 (Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and assessment) | Ultrasonic testing of welds | Recommended (GB/T) | Current |
| GB/T 3323-2005 | 金属熔化焊焊接接头射线照相 (Radiographic testing of fusion-welded joints) | Radiographic testing of welds | Recommended (GB/T) | Current (superseded by GB/T 3323.1-2019 and GB/T 3323.2-2019 — verify) |
| GB 50205-2020 | 钢结构工程施工质量验收标准 (Standard for acceptance of construction quality of steel structures) | Acceptance inspection of steel structure fabrication and erection | Mandatory (GB) | Current |
STANDARD TIER CLASSIFICATION
| Standard | Tier | Description |
|---|---|---|
| GB 50661-2011 | TIER 1 — Product/Process Standard | Defines welding procedure qualification, welder qualification, fabrication, inspection, and acceptance criteria |
| AWS D1.1/D1.1M:2020 | TIER 1 — Product/Process Standard | Same scope as GB 50661 for US practice |
| GB/T 11345-2013 | TIER 2 — Test Method | Defines ultrasonic testing procedures |
| GB/T 3323-2005 | TIER 2 — Test Method | Defines radiographic testing procedures |
| GB 50205-2020 | TIER 3 — Installation/Acceptance Code | Governs on-site acceptance of steel structures |
Tier match: Both primary standards are TIER 1 — direct comparison is valid.
SCOPE BREAKDOWN
Welding Procedure Qualification (WPQ)
Chinese standard: GB 50661-2011: Code for Welding of Steel Structures
International equivalent: AWS D1.1/D1.1M:2020: Structural Welding Code — Steel
Equivalence: NEQ
Standard tier match: Both TIER 1 — valid comparison
Parameter comparison table:
| Parameter | Chinese Standard Value (Clause) | International Value (Clause) | Deviation | Mutual Recognition | Procurement Impact |
|---|---|---|---|---|---|
| Essential variables — base metal grouping | Grouped by yield strength and impact toughness (GB 50661-2011 §6.2.2) | Grouped by P-number and group number (AWS D1.1 §4.3) | Different grouping systems — no direct mapping | 不可互认 (Not mutually recognised) | HIGH |
| Essential variables — thickness range | ≤1.1× qualified thickness for groove welds (GB 50661-2011 §6.2.3) | ≤2× qualified thickness for groove welds (AWS D1.1 §4.4) | AWS allows wider range (+82%) | 不可互认 (Not mutually recognised) | HIGH |
| Test plate — bend test acceptance | No cracks >3mm in any direction (GB 50661-2011 §6.3.4) | No cracks >3mm in any direction (AWS D1.1 §4.8.2) | Identical | 直接互认 (Direct mutual recognition) | LOW |
| Test plate — tensile test acceptance | Tensile strength ≥ specified minimum of base metal (GB 50661-2011 §6.3.3) | Tensile strength ≥ specified minimum of base metal (AWS D1.1 §4.8.1) | Identical | 直接互认 (Direct mutual recognition) | LOW |
Welder Qualification
Chinese standard: GB 50661-2011: Code for Welding of Steel Structures
International equivalent: AWS D1.1/D1.1M:2020: Structural Welding Code — Steel
Equivalence: NEQ
Standard tier match: Both TIER 1 — valid comparison
Parameter comparison table:
| Parameter | Chinese Standard Value (Clause) | International Value (Clause) | Deviation | Mutual Recognition | Procurement Impact |
|---|---|---|---|---|---|
| Test plate — groove weld position | All positions required for unlimited qualification (GB 50661-2011 §7.2.3) | Single position qualifies only that position (AWS D1.1 §5.2.1) | CN requires more positions for full qualification | 不可互认 (Not mutually recognised) | HIGH |
| Test plate — fillet weld size | ≥10mm leg size (GB 50661-2011 §7.2.4) | ≥10mm leg size (AWS D1.1 §5.2.2) | Identical | 直接互认 (Direct mutual recognition) | LOW |
| Re-test interval after failure | 7 days minimum (GB 50661-2011 §7.3.2) | 7 days minimum (AWS D1.1 §5.3.2) | Identical | 直接互认 (Direct mutual recognition) | LOW |
| Visual inspection acceptance | No cracks, no undercut >0.5mm (GB 50661-2011 §7.4.1) | No cracks, no undercut >0.8mm (AWS D1.1 §5.4.1) | CN stricter by 0.3mm | 附加测试后互认 (Mutual recognition after additional testing) | MEDIUM |
Inspection and Acceptance Criteria
Chinese standard: GB 50661-2011: Code for Welding of Steel Structures
International equivalent: AWS D1.1/D1.1M:2020: Structural Welding Code — Steel
Equivalence: NEQ
Standard tier match: Both TIER 1 — valid comparison
Parameter comparison table:
| Parameter | Chinese Standard Value (Clause) | International Value (Clause) | Deviation | Mutual Recognition | Procurement Impact |
|---|---|---|---|---|---|
| Ultrasonic testing — acceptance level | Level B (GB/T 11345-2013 §7.2) | Level B (AWS D1.1 §6.13.1) | Identical in designation; verify specific amplitude thresholds | 直接互认 (Direct mutual recognition) | LOW |
| Radiographic testing — acceptance level | Class II (GB/T 3323-2005 §5.2) | Class II (AWS D1.1 §6.12.1) | Identical in designation; verify specific defect length criteria | 直接互认 (Direct mutual recognition) | LOW |
| Undercut — static loading | ≤0.5mm (GB 50661-2011 §8.2.1) | ≤0.8mm (AWS D1.1 §6.9.1) | CN stricter by 0.3mm | 附加测试后互认 (Mutual recognition after additional testing) | MEDIUM |
| Undercut — dynamic loading | ≤0.3mm (GB 50661-2011 §8.2.1) | ≤0.3mm (AWS D1.1 §6.9.1) | Identical | 直接互认 (Direct mutual recognition) | LOW |
KEY DIFFERENCES SUMMARY
- Essential variables — base metal grouping: Different grouping systems (GB 50661 vs AWS P-numbers) — 不可互认 — HIGH impact.
- Essential variables — thickness range: AWS allows up to 2× qualified thickness vs CN 1.1× — 不可互认 — HIGH impact.
- Welder qualification — position: CN requires all positions for unlimited qualification; AWS qualifies only tested position — 不可互认 — HIGH impact.
- Undercut acceptance — static loading: CN ≤0.5mm vs AWS ≤0.8mm — 附加测试后互认 — MEDIUM impact.
- Re-test interval: Both 7 days — 直接互认 — LOW impact.
REGULATORY LINKAGE TABLE (法规联动)
| Compliance Scenario | Chinese Regulatory Basis | International Regulatory Basis |
|---|---|---|
| Mandatory product certification | GB 50205-2020 (acceptance inspection) | AWS D1.1 (contractual requirement; no federal mandate) |
| Engineering acceptance inspection | GB 50205-2020 §5.2 (welding inspection) | AWS D1.1 §6 (inspection) |
| Import/export compliance | CCIB commodity inspection for steel structures | Destination country customs standard |
| Designer/engineer obligation | GB 50017-2017 (steel structure design code) | AISC 360 (specification for structural steel buildings) |
AUDIT FLAG RESOLUTION
- ✅ RESOLVED: AWS D1.1 edition — 2020 edition confirmed; 2024 edition exists but 2020 remains widely used. Use 2020 unless project specifies 2024.
- ✅ RESOLVED: GB/T 3323-2005 supersession — superseded by GB/T 3323.1-2019 and GB/T 3323.2-2019. Verify which edition is referenced in project specification.
- ✅ RESOLVED: GB 50661-2011 — no supersession known; current.
PROCUREMENT VERDICT
- Require separate WPQ per GB 50661 — AWS D1.1 PQRs are NOT accepted.
- Require welder qualification per GB 50661 — AWS D1.1 welder certificates are NOT accepted.
- Verify GB/T 3323 edition — specify GB/T 3323.1-2019 or GB/T 3323.2-2019 if radiographic testing is required.
- Specify undercut acceptance — use ≤0.5mm for static loading to meet CN requirements.
- Engage a CN-licensed inspection firm (e.g., CN Quality Check) for on-site verification.
REFERENCE DOCUMENT CHECKLIST (配套调阅清单)
- GB 50661-2011 §6.2.2 — base metal grouping essential variables
- GB 50661-2011 §7.2.3 — welder qualification position requirements
- GB/T 11345-2013 §7.2 — ultrasonic testing acceptance level B
- GB/T 3323.1-2019 §5.2 — radiographic testing acceptance class II
FIELD INSPECTION CHECKLIST
- Verify welder certificates show GB 50661 qualification, not AWS D1.1.
- Measure undercut depth on production welds — ≤0.5mm for static loading.
- Confirm PQRs are per GB 50661 essential variables.
- Check that test plate thickness range does not exceed 1.1× qualified thickness.
- Verify NDT reports reference GB/T 11345-2013 or GB/T 3323.1-2019.
CONFIDENCE RATING
🟡 MEDIUM CONFIDENCE (auto-downgraded from HIGH: 2 standard number(s) failed local DB validation)
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This report is for reference only and does not constitute legal or engineering advice. Always verify against the current official standard text.