AWS D1.1 Structural Welding Code certified fabrication for steel structures destined for North American markets. Our CWI-supervised welding program ensures full compliance with AWS requirements for prequalified and qualified welding procedures.
30,000 T/Year Capacity
Plate up to 200mm
AWS D1.1 / EN 1090
Full NDT Testing
AWS D1.1 structural welding code compliance is a non-negotiable requirement for steel-fabricated components in North American building and bridge construction. At Leading Top Union (领拓互联), the Suzhou facility operates under AWS D1.1:2020 with full WPS/PQR qualification for all primary processes including SMAW (E7018), FCAW (E71T-1C), SAW (F7A2-EM12K), and GMAW (ER70S-6). Welding procedures are qualified to meet Charpy V-notch impact requirements down to -20°F (-29°C) for fracture-critical members, with documented CVN values exceeding 25 ft-lbs at minimum service temperature per AISC 360-16 Section A3.1b. Each WPS includes preheat and interpass temperature controls ranging from 50°F to 350°F depending on base metal thickness and carbon equivalent values, verified by calibrated infrared pyrometers with ±5°F accuracy.
AWS Certified Welding Inspectors (CWI) oversee all production welding with a 100% visual inspection rate per AWS D1.1 Table 6.1, supplemented by NDT methods including ultrasonic testing (UT) per ASTM E164 for thicknesses above 5/8 inch, magnetic particle testing (MT) per ASTM E709 for surface discontinuity detection, and radiographic testing (RT) per ASTM E94 for critical butt joints. For demand-critical seismic applications under AISC 341-16, enhanced inspection protocols are implemented including 100% UT of CJP groove welds in moment connections, with acceptance criteria per AWS D1.8 Clause 6. The CWI team maintains current certifications through AWS and conducts daily welder performance qualification per AWS D1.1 Clause 6, including re-qualification every six months for welders working on fracture-critical members. All inspection records are documented with digital traceability including weld map references, heat numbers, and operator stamps, providing complete chain-of-custody documentation for EPC project submittals.
Material compatibility is engineered for ASTM A36, A572 Grade 50, A588 weathering steel, A992, and A514 quenched-and-tempered alloys up to 100 ksi yield strength. Prequalified joint configurations per AWS D1.1 Table 3.1 include complete joint penetration (CJP) groove welds with backing bars, partial joint penetration (PJP) groove welds, and fillet welds in sizes from 3/16 inch to 1-1/4 inch leg length. For complex geometries, qualified WPSs are developed using the essential variables approach per AWS D1.1 Clause 4, documenting base metal thickness ranges (3/16 to 2 inches), welding position (1G, 2G, 3G, 4G), and filler metal classification with corresponding tensile strength verification per AWS A5.1 or A5.20. SAW capability includes single and multiple pass procedures for plate thicknesses up to 4 inches, with weld metal deposit rates reaching 15 pounds per hour for high-productivity heavy fabrication projects in power generation and mining equipment.
For oil and gas sector structural components, AWS D1.1 compliance ensures reliable performance in pipe rack supports, module skids, and flare tower structures operating in corrosive environments. Fabrication of A572 Grade 50 steel for a recent Gulf Coast petrochemical expansion included 340 tons of welded structural steel with CJP groove welds in moment-resisting frames, all inspected to AWS D1.1 acceptance criteria with zero rejections on UT. These structures required Charpy V-notch testing at -20°F per project specifications, with the WPS qualified to deliver consistent CVN values averaging 35 ft-lbs across 12 production weld test plates. For offshore wind turbine foundation components, ASTM A709 Grade 50 steel is welded for transition pieces and monopile sections, with AWS D1.1 procedures adapted to accommodate thickness transitions from 1.5 to 3.0 inches. The CWI team coordinates with DNV-GL surveyors for third-party verification of weld quality, meeting both AWS D1.1 and EN 1090-2 EXC3 requirements simultaneously for dual-certified projects.
In mining and mineral processing, AWS D1.1 structural welding supports the fabrication of heavy-duty conveyor bridges, crusher support structures, and grinding mill foundations subject to dynamic loading and abrasion. A recent 200-ton structural steel package for a Chilean copper mine was completed, incorporating A588 weathering steel with fillet welds sized per AWS D1.1 Table 8.1 for fatigue-loaded connections. The project required 100% MT of all fillet weld toes per AWS D1.1 Clause 6.14.2, with the CWI team documenting 1,200 linear feet of weld inspection. For power generation facilities, including combined-cycle gas turbine plants and coal-fired boiler supports, A992 steel moment frames are fabricated with demand-critical welded connections per AISC 341. These structures undergo cyclic loading analysis with weld metal matching base metal tensile strength within 10 ksi per AWS D1.1 Clause 5.3. Seismic qualification includes prequalified WPS for RBS connections and welded unreinforced flange-welded web (WUF-W) configurations, with documented interpass temperature control maintaining 150°F minimum for 2-inch thick flanges.
Shipbuilding and offshore platform applications require AWS D1.1 compliance for deck structures, helidecks, and module support frames fabricated from ASTM A131 Grade AH36 and DH36 steel. Welding procedures for these materials include controlled heat input parameters between 25 and 45 kJ/inch to maintain HAZ toughness per ABS and DNV-GL rules. For a recent offshore topsides module weighing 1,500 tons, 8,500 linear feet of AWS D1.1 compliant fillet welds were executed with 100% visual and MT inspection, achieving a first-pass acceptance rate of 98.7%. The project required weld metal hardness testing per ASTM E92 with maximum 350 HV10 for hydrogen-induced cracking prevention in thicknesses above 1.5 inches. The facility maintains separate weld procedure qualification records for each base metal grade and thickness combination, with over 120 active WPSs covering SMAW, FCAW, SAW, and GMAW processes for structural steel applications from 1/8 inch to 4 inches thick.
AWS D1.1 structural welding is delivered with full traceability from raw material receipt to final inspection, supported by the ISO 3834-2 quality management system at Leading Top Union. Every production weld is assigned a unique weld map number linked to the corresponding WPS, welder qualification card, NDT report, and material test certificate. The CWI team performs real-time monitoring of essential variables including preheat temperature, interpass temperature, welding current, voltage, and travel speed, with deviations exceeding ±10% triggering immediate corrective action per the non-conformance procedure. For fracture-critical members per AISC 360 Section N5, enhanced documentation is implemented including 100% UT with automated data recording, providing digital files compatible with EPC project management systems. Facility capacity of 15,000 tons annually includes dedicated bays for heavy plate welding with overhead cranes rated to 50 tons, enabling efficient handling of large structural assemblies up to 120 feet in length.
Pre-production engineering support is provided by the technical team including weld joint design optimization, filler metal selection per AWS A5.1 or A5.20, and preheat calculation per AWS D1.1 Table 3.2 based on carbon equivalent values. For complex projects requiring both AWS D1.1 and EN 1090-2 EXC3 compliance, combined WPSs are developed that satisfy essential variables from both codes, reducing qualification costs by up to 30% compared to separate procedures. The welder performance qualification program maintains a pool of 45 certified welders qualified in all positions for SMAW, FCAW, and GMAW processes, with annual requalification per AWS D1.1 Clause 6.3. Expedited qualification services are offered for new WPSs within 5 business days, including coupon preparation, welding, NDT, and mechanical testing per ASTM A370 for tensile and bend specimens. All qualification records are maintained in the digital quality database with 10-year retention for project audit readiness.
For global EPC firms requiring consistent quality across multiple fabrication packages, AWS D1.1 structural welding is provided with documented process control and third-party certification at Leading Top Union. The quality manual includes detailed procedures for weld repair per AWS D1.1 Clause 6.15, with maximum repair length limited to 2 inches per defect and total repair area not exceeding 5% of weld length. Calibration certificates are maintained for all welding equipment including power sources (Miller and Lincoln models), wire feeders, and preheat induction systems, with calibration intervals per ISO 10012. Shipping documentation includes weld maps, NDT reports, material certificates, and CWI sign-off sheets in both English and Chinese, formatted per EPC project requirements. Contact the technical sales team at info@leadingtopunion.com or +86-512-8888-6666 to discuss your AWS D1.1 structural welding requirements, including custom WPS development and qualification testing for your specific base metal and thickness combinations.
| Capability | Specification |
|---|---|
| Welding Code | AWS D1.1 / D1.5 / D1.8 |
| Processes | SMAW, FCAW, SAW, GMAW |
| Inspector Qualification | AWS CWI |
| Welder Qualification | AWS D1.1 Clause 6 |
| Seismic | AISC 341 demand-critical |
| Documentation | Full CWI inspection records |
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