A PQR is the test record that proves a welding procedure actually works. You weld a test coupon following a preliminary WPS, cut it apart, run destructive tests (tensile, bend, sometimes impact), and record everything. If the tests pass, you have a qualified procedure. The PQR is the evidence. The WPS is the instruction.
What Is the Difference Between a PQR and a WPS?
A PQR records what actually happened during a test. A WPS tells the welder what to do in production. The PQR contains single actual values; the WPS contains allowable ranges derived from those values.
| WPS | PQR | |
|---|---|---|
| Purpose | Tells the welder what to do | Proves the procedure works |
| Values | Ranges (min-max) | Actual single values used in the test |
| Revisions | Can be revised | Never revised — it's a historical record |
| Relationship | References one or more PQRs | Supports one or more WPSs |
You can't have a valid WPS without a supporting PQR — unless you're using prequalified procedures under AWS D1.1.
What Goes in a PQR?
A PQR contains three categories of data: the actual welding variables used during the test, the destructive test results, and the administrative record of who did what and when.
What Welding Variables Are Recorded?
Everything on the PQR is what actually happened during the test — not ranges, not targets. The actual amps, volts, travel speed, preheat temperature, filler metal, and base metal thickness. For example, a typical FCAW PQR on 3/8" A36 might record: 260 amps, 27.5 volts, DCEP, 3/4" root opening, E71T-1C 0.045" wire, 75/25 Ar/CO2 at 45 CFH.
What Destructive Tests Are Required?
The PQR must include results from destructive testing of the test coupon. The specific tests depend on the code and joint type.
| Test | What It Checks | Acceptance Criteria |
|---|---|---|
| Tensile | Strength of the welded joint | Must meet or exceed base metal minimum tensile (e.g., 70 ksi for A36) |
| Guided bend | Ductility and soundness | No open defects exceeding 1/8" in any direction |
| Impact (CVN) | Toughness at temperature | Three specimens per location, tested at specified temp (e.g., -20 F) |
| Macro etch | Fusion profile (fillet welds) | Complete fusion, adequate leg size, acceptable profile |
Radiography (RT) can sometimes substitute for bend tests per the applicable code section. Side bends are required instead of root/face bends when the test coupon exceeds 3/8" thickness under ASME IX.
What Administrative Data Is Included?
Who welded the coupon, who witnessed the test, which lab ran the destructive testing, and the date. The welder who makes the test coupon also qualifies as a performance qualifier (WPQ) for that process and position — two birds, one coupon. The 6-month continuity rule starts from the date of this test.
How Does the PQR-to-WPS Relationship Work?
The relationship is many-to-many. One PQR can support multiple WPSs, and one WPS can reference multiple PQRs.
- One PQR can support multiple WPSs — if each WPS's parameters fall within the qualification range established by the PQR test data
- One WPS can reference multiple PQRs — for example, one PQR for thin material (3/16" test coupon qualifying down to 1/16") and another for thick (1" coupon qualifying up to 2" under ASME IX QW-451)
When an auditor reviews your WPS, they trace it back to the supporting PQR(s) and verify that every essential variable is covered by the test data. This is a core part of passing a welding audit.
When Do You Need a New PQR?
Not every change to a WPS requires a new qualification test. You need a new PQR only when an essential variable changes beyond the qualified range.
| Variable Type | New PQR Required? | Examples |
|---|---|---|
| Essential | Yes | Changing process (SMAW to FCAW), changing P-Number, exceeding qualified thickness range |
| Supplementary essential | Only when impact testing is required | Adding or changing impact test requirements |
| Nonessential | No | Changing joint design, electrode diameter within the same F-Number |
The distinction comes from the code tables — ASME IX QW-250 or AWS D1.1 Table 4.5. Getting this wrong is how shops fail audits: they change an essential variable and keep using the old PQR.
How Many PQRs Does a Shop Need?
It depends on the range of work. A structural steel shop doing mostly A36 and A572 with FCAW might get by with 3-5 PQRs. A pressure vessel shop working across multiple alloys (P-1 through P-8) and thickness ranges could need 20 or more.
The goal is coverage: every WPS you write must have a PQR behind it with test data that covers the parameter ranges you're claiming.
Frequently Asked Questions
Can you revise a PQR?
No. A PQR is a historical record of what actually happened during a qualification test. It is never revised, amended, or superseded. If you need different qualification data, you run a new test and create a new PQR. WPSs can be revised freely; PQRs cannot. This is a critical distinction that auditors check.
What happens if a PQR test fails?
If the destructive tests do not meet acceptance criteria, the procedure is not qualified. You must adjust your parameters (amps, preheat, filler metal, technique) and run a new test coupon. Each test attempt generates its own PQR — including failed ones, which some shops retain as records of what did not work.
Does a PQR expire?
No. PQRs do not expire. A PQR qualified in 1995 is still valid today as long as the code edition you're working to recognizes the test variables. However, the welder who ran the test coupon does have a qualification that can lapse under the 6-month continuity rule.
Can one PQR support WPSs under different codes?
Generally no. ASME IX PQRs support ASME WPSs, and AWS D1.1 PQRs support AWS WPSs. The qualification rules, essential variable definitions, and thickness ranges differ between codes. Some overlap exists, but you should not cross-reference without verifying the specific code requirements.
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