How to Read a Mill Test Certificate: EN 10204 2.2, 3.1, 3.2

A mill test certificate is one of the most important documents in a steel order, and one of the least carefully read. Many buyers file it after checking only the grade. A few minutes of checking can reveal a heat number that does not match or a test result outside the standard, before the steel reaches your project.

This guide explains the EN 10204 document types and shows how to read a certificate step by step.

EN 10204 Certificate Types Compared

Type	What it is	Test results	Who is involved
2.1	Declaration of compliance with the order	None	Manufacturer
2.2	Test report based on non-specific inspection	Yes, but not necessarily from your batch	Manufacturer
3.1	Inspection certificate based on specific inspection	Yes, from the delivered batch	Manufacturer's authorized inspection representative, independent of production
3.2	Inspection certificate with independent validation	Yes, from the delivered batch	As 3.1, plus the purchaser's representative or a designated inspector

For a practical overview, see this guide to EN 10204 certificate types. Your contract or project specification should state which type is required. Check the current standard for exact wording.

2.2 vs 3.1 vs 3.2: Which Do You Need?

• Type 2.2 can suit lower-risk general orders where batch-specific results are not required.
• Type 3.1 is a common requirement for structural and project work, because its results relate to the delivered material.
• Type 3.2 is used where the specification requires independent validation. It adds time and cost, so arrange it before production.

How to Read a Mill Test Certificate Step by Step

1. Check the issuer: confirm the manufacturer, certificate number and date.
2. Check the certificate type: the document should state which EN 10204 type it is, if that was ordered.
3. Match the product: compare the product, size, standard and grade with your purchase order.
4. Trace the heat number: find the heat or batch number and match it to the marking on the steel and the packing list. This is the most important step.
5. Check chemistry: compare each element with the limits in the named standard and edition.
6. Check mechanical results: compare yield, tensile, elongation and any impact results and test temperature with the standard.
7. Check extra requirements: look for any ordered tests, such as ultrasonic testing or coating mass.
8. Check the signature: confirm the certificate is signed or stamped as your order requires.

Warning Signs on a Steel Certificate

• Heat numbers that do not appear on the steel or packing list
• Results that look identical across different heats or orders
• A grade or standard that differs from your order
• Missing impact results when the grade requires them
• Different fonts or signs of editing in a scanned document
• Results printed exactly on a limit across many elements

None of these proves a problem on its own, but each is a reason to ask questions. If you are unsure, ask your supplier for a clearer copy and consider independent testing.

What a Certificate Cannot Prove

A certificate describes what was tested and reported. It does not prove that the steel in front of you is that heat unless the marking and traceability hold up. For critical orders, combine the paperwork with product testing and third-party inspection before loading. Portable alloy testing can also help check alloy steels, as we explain in our 304 vs 316 stainless steel guide.

What to Include in Your Inquiry

• The required document type, such as EN 10204 3.1
• The standard and edition, if your specification names one
• Any extra tests and their acceptance limits
• Marking and packing list requirements
• Any third-party inspection body, named before production

Frequently Asked Questions

Is a mill test certificate the same as EN 10204 3.1?

Not necessarily. "Mill test certificate" is a general trade term. Check which document type is actually stated on the certificate.

Can a stockist supply a 3.1 certificate?

Stock material often comes with the original mill certificate. Make sure it can be traced to your material, especially if it has been cut or processed.

Can a certificate type be upgraded after production?

It is usually difficult, especially for 3.2, which involves an independent party. State your requirement before production.

Ask for the Right Document First

The easiest way to avoid certificate problems is to agree the requirement before ordering. Send us your specification, including the certificate type and any inspection needs, and our sales team will confirm what can be provided with your order.