15.3 WPS, WPQR & ISO 15614

15.3 WPS, WPQR & ISO 15614

Quick Answer: A WPS (Welding Procedure Specification) is the production instruction welders follow (process, joint, consumables, parameters, preheat/PWHT, technique). A WPQR (Welding Procedure Qualification Record—also called PQR in some regions) is the proof file that a test weld made under recorded conditions passed the required tests. ISO 15614 (series) is a principal route to qualify arc welding procedures by testing. Essential variables define the qualified range; outside the range you need requalification or a different qualified procedure. IWI-S verifies WPS/WPQR compliance and witnesses procedure tests for conventional applications.

Module WI1.5 (with related technology modules) expects you to read a procedure pack, spot missing essential-variable control, and know what “qualified” means on a stamp. This is core Standard-level work: IWI-S is expected to witness procedure qualification and verify WPS/WPQR—beyond Basic-level observation.

WPS Versus WPQR — Never Swap the Labels

Logic chain:

1. Weld a test piece under recorded conditions (often witnessed).
2. Examine and test it (VT, NDT as required, bend, tensile, impact, hardness, macro, etc. per standard and application).
3. Compile the WPQR with actual values and test results.
4. Write one or more WPS documents that stay inside the qualified ranges for production.
5. Issue WPS to the shop; inspectors verify production against WPS, and that the WPS is supported by a valid WPQR.

A beautiful WPS with no supporting WPQR (when qualification is required) is not a qualified procedure. A WPQR without a usable WPS leaves welders improvising—also unacceptable.

Regional naming note: some industries say PQR (Procedure Qualification Record) for what ISO training often calls WPQR. Functionally the same idea: the qualification record, not the shop instruction.

ISO 15614 Series Overview (Arc Welding Qualification)

ISO 15614 is a multi-part series specifying how to qualify welding procedures by testing for various processes and material groups. Part numbering addresses different process families (arc welding of steels and other materials appears in dedicated parts). Training emphasis for IWI-S:

• Procedure qualification by test welding + testing is the mainstream path for structural and pressure work
• Other ISO routes exist in the broader procedure-qualification family (e.g. previous experience, standard welding procedure, consumable testing—depending on product standard permission). Know that 15614-type testing is the default story for “we ran a procedure test”
• The standard defines test piece, welding conditions, examination and testing, and how results translate into a range of qualification

You do not need to recite every clause number in an oral exam, but you must know what a complete qualification pack looks like and when production has left the qualified envelope.

Essential Variables — The Inspector’s Tripwires

An essential variable is a parameter whose change beyond allowed limits affects the properties of the welded joint enough that the procedure must be requalified (or another already-qualified procedure used). Non-essential variables may be adjusted within good practice without new mechanical testing, though they still appear on the WPS for process control.

Typical essential-variable families (examples—always read the governing qualification standard and product code):

• Welding process (ISO 4063 number)—changing process is not a trivial edit
• Material group / thickness / diameter ranges (e.g. ISO/TR 15608 grouping concepts used in qualification)
• Filler metal classification / A-number style grouping as applicable
• Preheat / interpass minimums; PWHT requirements
• Heat input / arc energy ranges where toughness or HAZ properties matter
• Joint type and welding positions covering production
• Shielding gas type for gas-shielded processes
• Progression (uphill/downhill) where specified as essential

Inspector field checks against the WPS/WPQR:

• Parent material group and thickness within range?
• Consumable classification matching qualified filler?
• Position of production weld covered by qualification?
• Recorded amperage, voltage, travel speed (or heat input) inside limits?
• Preheat achieved and documented when required?
• PWHT performed as qualified when required?
• Process number on the booth matching the WPS?

If production is outside the range, stop and call welding coordination. Do not “stretch” a WPQR because the schedule is tight.

What IWI-S Does on Procedure Tests

For conventional applications, IWI-S competence includes witnessing procedure qualification tests. Practical meaning:

Before welding the test piece

• Confirm test piece material, dimensions, joint preparation match the qualification plan
• Confirm WPS draft / preliminary WPS parameters are understood
• Verify equipment, consumables, and welder identity for the test
• Agree hold points for fit-up, root, fill, cap, and any heat treatment

During welding

• Record actual parameters (not only nominal WPS values)
• Note interruptions, repairs on the test piece, position, and technique
• Ensure traceability of consumable batches if required

After welding

• Confirm marking/identification of the test piece before cutting specimens
• Verify NDT and destructive testing are performed to the correct standard and laboratory scope
• Review results against acceptance criteria for the qualification standard and application
• Ensure the WPQR records actual values and that derived WPS ranges are justified

Witnessing is not passive tourism. Incomplete parameter logs produce worthless WPQRs and future production nonconformities.

Production Verification (Daily IWI-S Work)

Most inspector hours are not spent on brand-new procedure tests. They are spent on:

1. Document review — Is there a WPS for this joint? Is it approved/released? Is the WPQR reference real and in-date for the project’s document control rules?
2. Booth audit — Is the welder using the issued WPS? Are parameters monitored?
3. Fit-up and sequence — Root gap, misalignment, cleaning, and pass sequence as specified
4. Special process controls — Hydrogen control, back purge for stainless, buttering sequences, etc.
5. Change control — Material substitution, consumable brand change, or position change triggering essential-variable review

IWI-S may develop/review QC plans that list which joints require which WPS and which procedure tests are still open before production release.

Links to Acceptance and Personnel

• A qualified procedure does not make an imperfect weld acceptable under ISO 5817—it only authorises the method within a range
• A qualified procedure does not replace welder qualification (ISO 9606)—both gates are required
• Product codes may impose extra testing (e.g. impact sets, hardness maps) beyond a minimum 15614 menu—read the project specification

Exam Anchors

Memorise the directional statements:

• WPS = how to weld in production
• WPQR = evidence the procedure was tested and qualified
• ISO 15614 = major series for procedure qualification by testing (arc welding focus in IWI training)
• Essential variable change out of range = stop / requalify
• IWI-S witnesses procedure tests and verifies WPS/WPQR compliance for conventional work

Bridge to Welder Qualification

Even a perfect WPS fails if the person holding the torch is not approved for that process, position, material, and joint type. Section 15.4 covers ISO 9606 welder qualification—test pieces, validity, prolongation, and the inspector’s stop points when stamps expire or ranges do not cover production.