WPS and WPQR — What They Are and How to Read Them
Introduction
The WPS (Welding Procedure Specification) and the WPQR (Welding Procedure Qualification Record) are the two fundamental documents of qualified welding. Any project requiring quality per ISO 3834, EN 1090 or ASME needs qualified WPSs.
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WPS — Welding Procedure Specification
The WPS is the document the welder follows during execution. It contains all instructions needed to make a welded joint.
WPS Content
| Field | Description | Example |
|---|---|---|
| Number | Unique ID | WPS-001-Rev.0 |
| Standard | Qualification standard | ISO 15614-1 |
| Process(es) | Welding process | 141 (root) + 135 (fill) |
| Joint type | Butt, fillet, etc. | BW (butt weld) |
| Base material | Material group | Group 1.1 (S235JR) |
| Thickness | Qualified range | 6-12 mm |
| Filler material | Classification | ER70S-6 / G3Si1, Ø 1.0 mm |
| Shielding gas | Type and flow | Ar + 18% CO₂, 15 l/min |
| Position | Qualified position | PA, PB, PC, PD, PE, PF |
| Preheat | Minimum temperature | 100°C |
| Interpass temperature | Maximum | 250°C |
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WPQR — Welding Procedure Qualification Record
The WPQR is the certificate proving the WPS was tested and approved through testing.
Mandatory Tests (ISO 15614-1)
| Test | Mandatory | Standard |
|---|---|---|
| Visual examination | Yes | ISO 17637 |
| Radiography or UT | Yes (BW) | ISO 17636/17640 |
| Transverse bend | Yes (BW) | Former 4t |
| Transverse tensile | Yes (BW) | Joint strength |
| Impact (Charpy) | When required | Toughness |
| Macrosection | Yes | Cross-section |
| Hardness (HV10) | Yes | Hardness profile |
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WPS vs. WPQR
| WPS | WPQR | |
|---|---|---|
| What | Work instruction | Qualification certificate |
| Who uses it | Welder | Coordinator / inspector |
| Content | Parameter ranges to follow | Actual parameters + test results |
| Standard | ISO 15609-1 | ISO 15614-1 |
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*Article based on ISO 15609-1, ISO 15614-1 and AWS Welding Handbook materials. Published on WeldFC Academy.*