The quality of a welded part depends as much on the skill of the welder applying the procedure as on the approved procedure (WPS) itself. A welder certificate is the record that independently confirms a welder can produce acceptable welds within a defined range of process, material group, thickness and position. For steel, the reference standard is EN ISO 9606-1.
For purchasing and quality teams selecting a subcontract welding supplier, this is one of the first documents requested during a supplier audit. In this article we summarise what the certificate covers, how it is obtained and how its validity is maintained.
Why Is Welder Certification Mandatory?
Many standards and directives require that only qualified welders work in production:
- EN 1090-2 — For structural steelwork in EXC2 and above, welders must be qualified to EN ISO 9606-1.
- EN ISO 3834-2 — Under comprehensive quality requirements, personnel competence must be documented.
- PED 2014/68/EU — Personnel making permanent joints on pressure equipment must be approved by a competent body.
- EN 15085-2 — For railway vehicles, welder qualification is a prerequisite for the certification level.
In short: The WPS defines "how to weld"; the welder certificate defines "who is allowed to weld it". Auditors ask for both together.
How Is the EN ISO 9606-1 Test Carried Out?
The test is performed on a test piece representative of actual production conditions and is witnessed by an inspection body or an authorised examiner. The typical sequence is:
- Defining the test piece: Plate or pipe, butt weld (BW) or fillet weld (FW), thickness and position are selected.
- Welding: The welder welds the test piece in accordance with an approved or preliminary (pWPS) procedure.
- Examination and testing: Visual testing is always carried out, followed by radiography (RT) or bend tests; for fillet welds, a fracture test or macro examination is used.
- Assessment: Acceptance criteria are generally based on EN ISO 5817 level B (level C for certain imperfection types).
- Issuing the certificate: A successful welder receives a certificate stating the range of qualification.
What Does the Certificate Cover? Essential Variables
Based on the variables used in the test piece, the certificate defines a specific range of qualification. Welds made outside this range are not covered by the certificate.
| Variable | Example | Effect on Range |
|---|---|---|
| Process | 135 MAG, 136 flux-cored wire, 141 TIG, 111 covered electrode | Each process is qualified separately |
| Product type | Plate (P) / Pipe (T) | A pipe test also covers plate under certain conditions |
| Weld type | Butt (BW) / Fillet (FW) | A butt weld test may cover fillet welds under suitable conditions |
| Material group | ISO/TR 15608 groups 1, 8, 10, etc. | Range extends on a group basis |
| Filler type | Solid wire (S), cored wire (M, B, R) | Limited by wire type |
| Thickness | Test thickness t | Qualifies a range based on t |
| Position | PA, PB, PC, PF, PE, H-L045 | Harder positions cover easier ones |
For more detail on welding positions, see our article on welding positions.
Validity Period and Prolongation
The certificate remains valid subject to two conditions:
- 6-month confirmation: Every 6 months, the welding coordinator or employer confirms that the welder has worked continuously within the scope of the certificate. If a welder has not worked with the relevant process for more than six months, the certificate lapses.
- Prolongation method: EN ISO 9606-1 recognises three options: a retest every 3 years; prolongation every 2 years by verifying two production welds made within the last 6 months through volumetric testing or destructive testing; or unlimited validity where production quality is documented (for EN ISO 3834-certified manufacturers).
Tip for buyers: During a supplier audit, don't just check a photocopy of the certificate — also check the latest 6-month confirmation signature and the prolongation method.
What Should Purchasing Teams Check?
- Do the process, material group and thickness range on the certificate cover your part?
- Does the position range match the positions the part will be in during welding?
- Are the 6-month confirmations up to date?
- Does the welder list match the WPS list?
- Is welding coordination carried out by a welding engineer (IWE/EWE)?
At ArmaWeld, welder qualifications, the WPS portfolio and the project documentation package are managed together; at the start of each project we define which welder will work to which WPS. For more on this topic, read our articles What is a WPS? and What is a WPQR?
Frequently Asked Questions
How long is a welder certificate valid?
Under EN ISO 9606-1 it is renewed every 2 or 3 years, depending on the prolongation method chosen; in both cases, employer confirmation is required every 6 months. For EN ISO 3834-certified manufacturers, unlimited validity based on documented production quality is also possible.
What is the difference between EN ISO 9606-1 and EN ISO 14732?
EN ISO 9606-1 qualifies welders performing manual and semi-automatic welding. For robotic and fully mechanised welding, operators are qualified to EN ISO 14732.
Which standard applies to aluminium welding?
Welder qualification for aluminium and its alloys is carried out to EN ISO 9606-2.
See Welder and WPS Documents Side by Side
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