Which EN 10204 Certificate Should Your Fastener PO Name — and What Does It Actually Prove?

Name the certificate type on the PO

"Send me a mill certificate" is not a specification. EN 10204 defines four different documents, and they are not interchangeable ¹⁶. If your purchase order does not name the type, you will usually receive the cheapest one that satisfies the word "certificate" ¹⁶. That is the whole reason the type has to be fixed before the order goes out: the supplier's default is the least expensive document that answers the request, and nothing in the wording stops it. So write the type — 2.1, 2.2, 3.1 or 3.2 — into the PO line, not into a covering email. A mill test report or MTC is a trade term, not automatically an EN 10204 3.1 certificate; the report must explicitly meet Type 3.1, use specific inspection results and carry the required manufacturer validation ¹⁷. If you leave the type open, you have no basis to reject what arrives.

What each EN 10204 type proves about the batch

The four types sit on a verification ladder, and the rung you buy decides what the document can prove. Type 2.1 carries no test data, so it tells you the manufacturer declares compliance and nothing more ^{16, 18}. Type 2.2 adds manufacturer test results but still no independent verification ¹⁸. Type 3.1 is the first type that carries actual results from the batch you received, certified by an inspection representative independent of production ^{16, 17, 18}. Type 3.2 adds a further designated validator on top of that ^{17, 18}. One point trips buyers up: 3.1 does not require third-party inspection — the independence is from production, not from the manufacturer ¹⁷. If your application genuinely needs third-party verification, 3.2 is the type that adds it. And you should specify it before production and agree the inspection plan, because an existing 3.1 cannot be assumed to become a 3.2 after the fact ¹⁷.

Is the mill test report offered actually a 3.1?

A supplier saying "yes, we provide mill certificates" tells you nothing about which document you will get. Two suppliers can both answer yes and send documents with completely different evidentiary value. One is a signed statement that the goods meet the order; the other carries measured chemistry and mechanical results traceable to the batch in your warehouse ¹⁶. MTR and MTC are trade terms; check that the report explicitly meets Type 3.1, uses specific inspection results and has the required manufacturer validation ¹⁷. If any of those three is missing, the document is not a 3.1 and you should reject it and re-specify rather than accept it as equivalent. Treating the two as synonyms is how a buyer ends up with a 2.1 in the file and a 3.1 on the PO ¹⁷.

Link the certificate to the fasteners you receive

The heat number is the field that links certified material to the delivered parts, so a certificate without one tied to your lot does not prove which material was used ^{16, 17}. Where the heat number is missing from the finished part, ask how the supplier preserved lot traceability through production.

• Confirm the heat number appears on the certificate ¹⁶
• Confirm the same heat number can be traced to the delivered fasteners ^{16, 17}
• Ask how markings, labels and controlled records connect the finished part to the certified material ¹⁷
• Ask how lot traceability was preserved through production if the heat number is not on the part ¹⁷

Which results the certificate must report, and at what testing basis

A 3.1 certificate is only as useful as the results printed on it, so agree the test content before production rather than after the first delivery. A minimum documentation package for susceptible fasteners includes a material certificate (EN 10204 3.1 or 3.2) carrying steel grade, heat number, chemical composition, mechanical properties and confirmation of compliance, plus heat treatment, surface preparation, coating, baking and verification testing records ¹. On the embrittlement side, sustained load testing is the production-suitable method: it is a post-production quality assurance step intended for testing large numbers of samples from a given lot, with methods described in ASTM F606 Section 7, ASTM F519 and ISO 15330 ⁴. Analytical methods (ASTM G129, ISO 7539-7, ASTM F1624) are not suitable for production-scale testing because of time and cost, and are often used for R&D instead ⁶. That distinction matters when you write the PO: if you ask for an analytical method, you are asking for something the supplier cannot run on a production lot. The sources do not state a per-heat, per-lot or per-part testing frequency for the results that appear on a 3.1 certificate, so agree the frequency with the supplier rather than assuming one.

When hardness or coating pushes the documentation beyond the material certificate

Two specification choices change what you should require alongside the certificate. The first is hardness. Susceptibility of steel fasteners to hydrogen embrittlement increases significantly when the specified hardness is above 39 HRC (380 HV); below that threshold, fasteners normally have no significant susceptibility ³. That threshold is not exact — second-order effects of chemistry, tempering temperature and sub-microstructure can vary it by as much as ±1.0 HRC (~±10 HV) ³. For fasteners above the threshold, the documentation package should extend beyond the material certificate to include baking and verification testing records ¹. The second is coating specification. Where ASTM F2329 is specified instead of A153, adhesion testing becomes mandatory on every batch lot, coating minimums rise, documentation gets heavier, and the buyer should expect a 10-25% cost premium ^{5, 9, 27}. A153, by contrast, performs adhesion testing only when a problem is already visible ⁹. One practical consequence: if you require dimensional inspection of parts on delivery under F2329, you must supply the galvanizer with the necessary inspection tools and gauges, because the standard does not assume the plant holds them ²⁷. Decide the coating specification before the RFQ, not after the first delivery.

Does the supplier's quality system support the certificate you are asking for?

Certificate issuance sits inside a quality system, so it is worth checking what the supplier's system actually covers before you rely on the document. ISO 9001:2015 and IATF 16949 are cited as quality-system elements supporting hydrogen embrittlement prevention, including supplier qualification and lot-level material traceability from steel heat number to finished product ³⁰. That is the framework that makes a heat number traceable through production rather than a number typed onto a certificate. Suppliers list a range of certificates they can provide — CE, ISO, REACH, RoHS and PPAP among them — and some state they can supply material test reports with goods delivery ^{15, 19}. Those are supplier claims about their own document lists, not evidence that any particular certificate type will be issued for your order. The sources do not establish which certificates a supplier is entitled to issue, so ask the supplier to confirm the specific type and scope in writing before the PO is placed.

Where the sources disagree on certification cost and testing frequency

The only quantified certification-related premium in these sources is the 10-25% F2329-over-A153 galvanizing premium, and it is a coating-specification premium rather than a certificate-type premium ^{5, 27}. The sources do not quantify a price premium for EN 10204 3.1 versus 2.2 versus no certificate, so do not carry the F2329 figure across to certificate types. What the table shows is that the specification choice is also a resourcing choice: the stricter coating standard adds testing cadence, documentation and tooling obligations that you have to plan for before the order, not after the first delivery ^{5, 27}.

FAQ

Related pages

• Manufacturer audits and verification service page
• Manufacturing capabilities service page
• EN 10204 3.1 vs 3.2 Certificates on a Fastener PO: What Each Attests, Who Validates It, and What to Write
• Manufacturer or Trader? What a Fastener Buyer Can Verify Before an Audit — and What Stays Unproven
• Fastener Import Contracts: Packaging, Quality Documents and Coating Clauses You Can Specify — and What to Verify Yourself