6.3 Welder Performance Qualification (WPQ)
Key Takeaways
- WPQ tests the welder's skill — not the procedure. It uses bend tests, macro etch, or RT
- PQR tests the procedure; WPQ tests the welder — both are required for quality assurance
- Essential variables for WPQ: process, position, electrode F-number, vertical progression, thickness
- Qualification is valid as long as the welder welds with the process within 6 months (AWS D1.1)
- Harder positions qualify easier ones (e.g., 6G qualifies all positions)
- CWI verifies welder holds current, valid qualification for process, position, thickness, and electrode
6.3 Welder Performance Qualification (WPQ)
Welder Performance Qualification (WPQ) tests verify that a welder has the skill and ability to produce sound welds following a specific WPS. Unlike procedure qualification (PQR), which tests the procedure itself, WPQ tests the welder's capability.
WPQ vs. PQR — Key Differences
| Feature | PQR (Procedure) | WPQ (Welder) |
|---|---|---|
| What is tested? | The welding procedure (variables) | The welder's skill |
| Tests required | Tensile + bend (+ impact if specified) | Bend and/or macro etch (+ RT if permitted) |
| Tested by | Qualified technician or engineer | Test supervised by CWI or qualified person |
| Frequency | Once per procedure (unless essential variable changes) | Per welder, per process, per position |
| Expiration | Does not expire (unless essential variable changes) | May expire if welder does not weld for extended period |
WPQ Test Methods
| Test Method | Application |
|---|---|
| Guided bend tests | Most common — root and face (or side) bends per D1.1 |
| Macro etch | For fillet weld qualification — cross-section of weld examined |
| Fillet weld break test | Fillet weld broken open; examined for soundness |
| Radiography (RT) | May be used in lieu of bend tests on groove welds (per some codes) |
| Visual inspection (VT) | Always required as a first step before any testing |
WPQ Essential Variables (AWS D1.1)
When any of these variables change beyond the qualified range, the welder must re-qualify:
| Essential Variable | Change Requiring Re-Qualification |
|---|---|
| Process | Change from SMAW to GMAW (or any process change) |
| Position | Adding a position not qualified (but harder positions qualify easier ones) |
| Electrode/wire | Change in F-number group |
| Base metal | Change to a different group (with limitations) |
| Vertical progression | Change from uphill to downhill (or vice versa) |
| Single side to both sides | If backing is removed, re-qualification may be needed |
| Thickness | Outside the qualified thickness range |
Maintaining Welder Qualification
Per AWS D1.1, a welder's qualification remains valid as long as:
- The welder has welded with the process within the previous 6 months (some codes specify 3 months)
- No reason to question the welder's ability (failed inspections, significant quality issues)
- Essential variables have not changed beyond the qualified range
If the 6-month activity requirement lapses, the welder must re-qualify by producing a new test weldment.
Welder Qualification Records
The CWI must verify:
- Welder qualification is current (not expired)
- Welder is qualified for the correct process being used
- Welder is qualified for the position being welded
- Welder is qualified for the thickness range of the production weld
- Welder is qualified for the electrode/wire type being used
For the Exam: The CWI's role in welder qualification is to verify that the welder holds current, valid qualification for the specific work being performed. Know the essential variables that require re-qualification and the 6-month activity requirement.
Per AWS D1.1, a welder's qualification expires if the welder has not used the qualified process within:
Which of the following is an essential variable for welder performance qualification?
What is the CWI's primary responsibility regarding welder qualification?