WPS vs PQR vs WPQ, explained

The three jobs in one table

Some codes use different labels for the welder record, such as WPQR or a welder qualification record, but the job is the same. The questions to ask on any exam item are: is this about the method, the proof of the method, or the person?

Each document in detail

The PQR: proof the procedure works

A procedure qualification starts with a test. Someone welds a coupon following a planned set of conditions, and the coupon is examined and mechanically tested to see whether the weld has the strength and soundness the code requires. The PQR is the record of that test: what was actually used, what was tested and what the results were.

Think of the PQR as lab evidence. It doesn't tell a welder what to do on the floor, and it's not edited to suit a job. If the test passes, the record stands behind one or more WPSs. If conditions change in a way the code treats as important, a new test and a new PQR may be needed, which brings us to the WPS.

The WPS: the instructions on the floor

The WPS is the document the welder follows. It lists the process, the joint type, the base metals, the filler, the position, the preheat and other conditions, and it gives ranges where the code allows them. The ranges matter: a welder may work anywhere inside them without a new test.

A WPS gets its authority one of two ways. Either it's backed by a PQR, or the code lets you use it without testing because it stays within a set of conditions the code has already accepted (a prequalified procedure in structural work, for example). Which route applies depends on the code, so a candidate has to know both exist.

Changes to a WPS depend on what you change. Some changes stay inside the supported range, some need a revision, and some need new qualification testing. The code defines which is which, and Part C trains you to find it. The Part C navigation workflow shows a lookup routine for questions like that, and the WPS and PQR review drill lets you practice spotting the entry a PQR does not cover. Preheat is one of those WPS entries, and the carbon equivalent calculator shows how steel chemistry raises the cracking risk that preheat is there to control.

The WPQ: proof about the welder

A welder qualification is separate from the procedure. The welder makes a test weld under a WPS, the weld is tested, and a passing result is documented in the WPQ. That record covers a defined range of process, material, thickness and position, and it stays valid only while the welder keeps using the process often enough. When a welder stops welding with a process for long enough, qualification can lapse and needs renewing under the code's rules.

The key idea: a qualified welder on an unqualified procedure still produces unsupported work, and a qualified procedure in the hands of an unqualified welder does too. You need both.

Who writes, who checks

In a typical shop the welding engineer or a qualified person writes the WPS and arranges the procedure test. A testing lab or the inspector may witness and evaluate it. The shop welding supervisor keeps the records. A CWI's part in all of it is verification:

• Before welding, confirm a WPS applies to the joint, the materials and the process, and that the welder holds a current qualification for it.
• During welding, check that the actual variables sit inside the WPS ranges.
• After welding, make sure the records match the work.

That's a workflow, not a rulebook, and the exact steps depend on the contract and code. The Part A guide shows where duties and responsibilities sit in the exam outline.

Where it shows up on the exam

On Part A (closed book), expect definition and relationship questions: which document proves a procedure, which one a welder follows, what a WPQ covers. On Part C (open book), the questions become navigation: where the code sets the rules for qualification, for changes to a procedure or for a welder's period of effectiveness. The Part C D1.1 guide includes a clause-finding drill that touches these.

If you're unsure which code to prepare for, the D1.1 or API 1104 comparison walks through the choice.

Mistakes to avoid

• Treating the PQR as the thing a welder follows. The welder follows the WPS.
• Believing one PQR covers any welder. The welder's own qualification is separate.
• Assuming a WPS never needs a second look. Changes that fall outside its ranges can trigger revision or retesting.
• Mixing code labels. Learn the job of each record, then learn your code's name for it.
• Forgetting that qualification can lapse when a welder stops using a process.

Check how well you know them

Quick self-test: explain all three in your own words, without looking, then say which one proves the procedure, which one covers the person and which one goes on the work table. Then see how you handle the related domains. The free 10-question Part A check is scored by area and shows exactly which topics to study first. Take it here, and read the explanation on every miss.

FAQ

Does every weld need a WPS?

Under most codes, production welding follows a written procedure. Some codes allow a prequalified WPS without testing, but it's still a written WPS. The governing code sets the details.

Does a PQR expire?

A PQR is a record of a test that was done, so it doesn't expire like a welder's qualification can. It stays valid for the procedures it supports, unless the code or your company rules require a new test after changes.

Who qualifies the welder?

The welder passes a test under a WPS, and the result is documented in a WPQ. The employer or testing organization witnesses and records it, following the code. A CWI can verify the records but isn't the person who qualifies.

Does the code change the rules?

Yes. Terms, ranges, what counts as a change and how long qualification lasts all differ by code, so always read the rules for the code in front of you.