One of the documents most frequently requested by European buyers from Turkish CNC suppliers is the “Type 3.1 material certificate.” This certificate verifies which casting lot the part was produced from, along with its chemical composition and mechanical properties, and is mandatory especially for pressure equipment, offshore, defense, medical, and automotive parts. This guide explains the EN 10204 certificate types, the contents of the 3.1 certificate, and how to request it during the RFQ phase.
What Is EN 10204?
EN 10204 is the European standard that defines the “types of inspection certificates” for metallic products. The standard specifies who issued the certificate and to which batch the test results it contains apply. There are four types:
| Type | Name | Content | Who Approves |
|---|---|---|---|
| 2.1 | Declaration of Conformity | Declaration that the product conforms to the order; no test results available | Manufacturer |
| 2.2 | Test report | Non-specific inspection results (from the same product group, may not belong to the order batch) | Manufacturer |
| 3.1 | Inspection certificate | Chemical and mechanical test results specific to the order batch | The manufacturer’s independent authorized unit |
| 3.2 | Inspection certificate | Same content as 3.1 + approval by the buyer’s representative or an independent organization | Manufacturer + buyer/third party |
In practice, 2.2 is used for commercial-grade parts; 3.1 is used for the vast majority of parts with technical requirements; and 3.2 is used in regulated fields such as pressure equipment and nuclear applications.
What Is Included in a 3.1 Certificate?
- Manufacturer (steel mill/rolling mill) information and certificate number.
- Material description: Standard (e.g., EN 10088-3), grade (1.4404), form, and dimensions (Ø25 h9 bar).
- Cast/charge number (heat number): The key to traceability; stamped or labeled on the bar.
- Chemical composition: Percentage values and standard limits for C, Si, Mn, P, S, Cr, Ni, Mo, etc.
- Mechanical properties: Yield strength, tensile strength, elongation, and, when required, hardness and impact (Charpy) values.
- Heat treatment condition: Annealed, solution-treated, normalized, etc.
- Signature/stamp of the authorized unit.
Who Is Responsible for What in CNC Contract Manufacturing?
An important distinction: The 3.1 certificate is issued by the material manufacturer (steel mill or rolling mill); the machining contractor cannot issue this document. The machining contractor’s responsibilities are as follows:
- Purchasing the material with a 3.1 certificate (if purchased from a stockist, the stockist must have obtained the certificate from the original manufacturer).
- Matching the casting number with the work order, part lot, and shipping invoice (traceability).
- Attaching their own declaration of conformity (stating that the parts were manufactured in accordance with the drawing and order) and, upon request, the measurement report.
- Deliver a copy of the certificate with the batch shipment and archive it (for up to 10 years in the aerospace and medical sectors).
At Tornelle, for orders requiring a certificate, the casting number is recorded on the work order, the raw material scrap is labeled along with the batch, and a copy of the certificate is included in the shipping package along with the measurement report. We describe our general approach in our quality assurance document.
How to Request a Certificate?
The correct request must be made before placing the order; certificates requested afterward often cannot be provided because the material may have been taken from stock without a certificate. Include the following in your RFQ and order:
- “Material certificate EN 10204 3.1, with each batch” (or 2.2 / 3.2, as required).
- Specify the material standard and quality exactly (e.g., “1.4404 – EN 10088-3” or “6082 T6 – EN 755-2”).
- If additional tests are required, specify them: low-temperature impact test, hardness test, corrosion test, PMI (portable metallographic analysis).
- If the casting number must be marked on the part or label, specify the method (laser marking, label).
- Specify the format (PDF, paper copy) and language (certificates in English or German are common) for the certificate.
Impact on Price and Lead Time
Certified bar stock is generally 3–10% more expensive than uncertified commercial stock, and lead times may be longer for certain special grades. However, when the request is submitted with the order, this impact is manageable. A certificate requested after the fact may require the batch to be remanufactured; therefore, clarifying the requirement upfront is the most cost-effective approach. For other documentation items that affect pricing, please refer to our article on the 12 factors.
Common Mistakes
- Saying “We want a certificate” without specifying the type—there is a significant difference between 2.2 and 3.1.
- Assuming the certificate will be issued by the machining manufacturer.
- Requesting documentation without specifying traceability by casting number — the documentation exists, but it remains unclear which part it pertains to.
- Failing to check the standard listed on the certificate when accepting equivalent materials (AISI 316L and 1.4404 differ by small margins in their chemical composition).
Frequently Asked Questions
Is a 3.1 certificate required for every CNC part?
No. For commercial-grade parts, a 2.1 or 2.2 certificate is sufficient. A 3.1 certificate is required for pressure-bearing, load-bearing, corrosive environment, medical, defense, and automotive safety parts.
Can a 3.1 certificate be obtained in Turkey?
Yes. Turkish steel producers and major stockists offer EN 10204 3.1-certified material; imported special alloys are also supplied with certification.
In what language is the certificate issued?
Mostly in English or bilingual (English/Turkish); German certificates are also common for materials of European origin.
What is the difference between 3.1 and 3.2?
The content is the same; in 3.2, the results are also approved by a buyer’s representative or an independent organization. It involves higher costs and takes longer; it is required only where mandated by regulations.
Conclusion
An EN 10204 3.1 certificate serves as proof of your part’s material composition and can be provided without issue from Turkey when properly requested. The key is to specify the type, standard, and traceability requirements in writing before placing your order. For parts requiring certification, submit your technical drawings via the quote form; you will receive a quote that lists material and documentation costs as separate line items.
