AWS D1.1 (Structural Welding Code – Steel) is the code published by the American Welding Society (AWS) for the welding of steel structures. It is one of the most widely used welding codes in the world for bridges, buildings, platforms and heavy steel construction. Companies working for the US, the Middle East or projects run to American specifications meet D1.1 often.
What is a prequalified WPS?
This is D1.1's best-known feature. If all of the material, welding process, joint detail, consumable and parameter limits defined in the code are met, the WPS can be written without welding and testing a test piece. If even one of the limits is exceeded, the WPS must be qualified by testing.
Related reading: AWS D17.1 explained · Weld records on Gulf oil & gas projects · What is a WPS?
Differences from the ISO system
| Topic | AWS D1.1 | ISO system |
|---|---|---|
| Procedure qualification | Prequalified WPS or qualification by testing | Usually qualification by testing to ISO 15614 (WPQR) |
| Welder qualification | Defined within the code | ISO 9606 |
| Acceptance criteria | The code's own inspection section | Mostly ISO 5817 quality levels (our article) |
| Quality system | Inspection responsibilities within the code | ISO 3834 (our article) |
The customer specification decides which system applies on a project. The two systems must not be mixed, and a document from one system must not be used in place of the other's.
Common mistakes
- Exceeding one of the prequalification limits and still treating the WPS as "prequalified"
- Not reading the preheat table correctly for the material thickness
- Treating an ISO welder qualification as valid on a D1.1 project
- Working to an old edition of the code
Which of these is in your records?
Most of these mistakes slip past when records are read one by one by eye, and auditors look for them first. The real question is which one sits in your own records. Upload your WPS to NTB SpecPro and quickly see which points may carry risk, the likely reason and a suggestion.
The NTB SpecPro welding module offers AWS D1.1 and D17.1 support alongside the ISO system for WPS and inspection evaluation, as a trial feature. Final evaluation stays with the authorized welding engineer.
Free tool: Carbon equivalent calculator (CE, CET, Pcm) · Welding heat input calculator
Prepared by NTB SpecPro process quality engineering; reviewed by an engineer holding the International Welding Engineer (IWE) qualification. Questions: info@ntbspecpro.com
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