EN 10204 vs ASTM and ASME: How the Standards Fit Together
- Steph Locke
- Blog , Learning
- June 11, 2026
- Updated:
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Open a Mill Test Certificate (MTC) and you will often see “EN 10204 3.1” in one corner and “ASTM A516 / ASME SA516” in another. Buyers ask the same question every time: which standard is the material actually certified to?
It’s a trick question. EN 10204, ASTM, and ASME are not rival standards. They answer three different questions, and a single certificate often satisfies all three at once.
Here’s how they fit together.
Three Standards, Three Questions
The quickest way to keep them straight:
- EN 10204 — is an inspection document standard — it answers “what kind of certificate is this and who authorised it?
- ASTM — is a material specification — it answers “what are the chemical composition, tensile strength, and impact requirements this steel must meet?
- ASME — * it answers “is this material approved for use in ASME-coded pressure equipment?“How can this material be used safely?*
EN 10204 governs the document. ASTM governs the material specification. ASME governs the equipment built from it. They sit on different axes, so they don’t compete but they stack.
EN 10204: The Certificate Type
EN 10204 is the European standard that defines the type of inspection document a mill issues. It says nothing about what the steel is. It only says how the test results were produced and who signed them off.
There are four types:
| Type | What it means |
|---|---|
| 2.1 | Declaration of compliance. No test results. |
| 2.2 | Test report from non-specific inspection — tests on similar product, not your batch. |
| 3.1 | Inspection certificate signed by the manufacturer’s own authorised representative, tied to your specific heat. |
| 3.2 | Same as 3.1, but co-signed by an independent third-party inspector. |
When a customer asks for “3.1 certs,” this is the standard they mean. They are specifying the level of assurance, not the material grade. Supplying a 2.2 when the purchase order says 3.1 is a non-conformance, even if the steel itself is perfect.
ASTM: The Material Specification
ASTM (the American Society for Testing and Materials, now ASTM International) develops the specifications that define a material. An ASTM designation tells you the chemical composition, the mechanical properties, and the tests the metal must pass.
You will recognise a few:
- ASTM A36 — structural steel
- ASTM A516 — pressure vessel plate
- ASTM A312 — stainless steel pipe
So ASTM answers “what is this material?” Europe answers the same question with its own EN material specs: EN 10025 for structural steel, EN 10028 for pressure vessel plate. ASTM and EN 10025 sit on the same axis. EN 10204 sits on a different one.
ASME: The Design Code
The American Society of Mechanical Engineers (ASME) develops the codes that govern how equipment is designed, fabricated, inspected, and operated safely. The best known is the ASME Boiler and Pressure Vessel Code (BPVC).
ASME doesn’t define the steel. It defines the rules for building safe equipment from it. When a material is adopted into the BPVC for code work, it gets an “SA” prefix. ASME SA516 is the code-adopted version of ASTM A516. The chemistry and properties are virtually identical. The SA designation just means it’s cleared for use in code-compliant pressure equipment.
How They Stack on One Certificate
Here’s the part that confuses people. A single mill certificate can carry all three at once.
Picture a plate of pressure vessel steel:
- The material is certified to ASTM A516 Grade 70 (or its dual designation, ASME SA516 Grade 70).
- The certificate is issued as EN 10204 Type 3.1 — the manufacturer’s representative has signed off the test results for that specific heat number.
- The finished vessel is then fabricated to ASME Section VIII.
Nothing here is in conflict. EN 10204 describes the paperwork. ASTM/ASME describe the material and the equipment. One document, three boxes ticked.
What to Check on a Purchase Order
Because these are separate axes, a purchase order needs to pin down all of them. Vague specs cause rejected material and delayed shipments. Check:
- Certificate type — is it 3.1, 3.2, or will 2.2 do?
- Material specification — ASTM A516, EN 10028, or both (dual-certified)?
- Design code, where it applies — ASME Section VIII, EN 13445, or a client spec?
Get one wrong and you have a non-conformance, even when the other two are correct.
Why UK and EU Manufacturers See American Standards
If you fabricate in Britain, why are ASTM and ASME on your desk at all? Global supply chains. Plenty of UK and EU work is built to American codes. Export contracts, oil and gas projects, and multinational clients who standardise on ASME all drive that. Mills routinely dual-certify plate to both ASTM and the equivalent EN spec so it can be sold either way.
The upshot: your quality team has to read certificates against more than one framework, often on the same project.
Why This Matters for Traceability
For procurement, quality, and welding inspection, mixing up these standards is expensive. The risks are familiar:
- Wrong certificate type accepted against a 3.1 requirement
- Material that meets EN but not the specified ASTM grade
- Failed audits when the chain of evidence doesn’t line up
- Rejected material, rework, and slipped deadlines
When you review certificates, you need confidence on all three axes: the right document type, the right material spec, and any design-code requirements. That gets hard fast when you’re working across hundreds of certificates and dozens of suppliers.
Less Paper. More Metal.
Most teams still check this by hand, it’s often done by opening PDFs one by one, hunting for the cert type, the grade, the heat number, and matching each against the order. It’s slow and easy to get wrong.
GoSmarter’s MillCert Reader, built by Nightingale HQ, reads the certificate and pulls out the EN 10204 type, the ASTM or ASME grade, and the heat number. It checks the values and files everything so you can find it in seconds. The result is faster compliance, cleaner traceability, and far less admin.
EN 10204, ASTM, and ASME aren’t competing. They describe the document, the material, and the equipment. Once you see them as three questions rather than three rivals, the certificate stops being confusing.
Because every hour spent decoding a certificate is an hour not spent making metal.
Frequently Asked Questions
What is the difference between EN 10204 3.1 and 3.2?
Is ASME SA516 the same as ASTM A516?
Why do UK and EU manufacturers work to American standards?
What should a purchase order specify to avoid a non-conformance?
Go Deeper
About the Author
Co-founder & Head of Product
Steph Locke is Co-founder and Head of Product at GoSmarter AI — former Microsoft Data & AI MVP building practical tools to cut paperwork and automate compliance for metals manufacturers.
