EN 10204 3.1 vs 3.2 Certificates on a Fastener PO: What Each Attests, Who Validates It, and What to Write

A mill test report is not a certificate type

The document that arrives with a fastener lot is often called an MTR or MTC. Those are trade terms, not EN 10204 certificate types, and a report does not become a 3.1 because the supplier calls it one ²⁷. For the document to count as Type 3.1 it has to say so explicitly, carry specific inspection results, and show the manufacturer's validation ²⁷. This is where purchase orders go wrong. If your clause asks only for a "material certificate" or "mill test report", you have not specified a verification level. And the paperwork you receive may sit at a lower level than your own quality plan assumes ¹⁷. Write the type on the PO and check the delivered document against that wording, not against its title.

Who validates 3.1 and who validates 3.2

The difference between the two types is who signs off the inspection results, not what the certificate is printed on. Use this to decide which type your PO can actually obtain from the supplier you are quoting.

Check the supplier can support the type before you place the PO

A valid 3.1 rests on the manufacturer having an inspection function that sits outside production, which is the kind of control an ISO 9001 quality system is built to carry ²⁷²². Ask these before the PO, not after the first delivery.

• Confirm the supplier holds a certified quality system and can show the certificate ¹².
• Ask who signs inspection documents and whether that role reports outside manufacturing ²⁷.
• Ask how lot traceability is kept from steel heat number to finished part ²².
• Ask for the certificate type to be confirmed at quotation, so availability is settled before you commit ²⁷.

Data fields to require on the certificate

A certificate is only checkable if it carries the fields you will compare against the delivered lot. These are the fields the sources describe for a fastener material certificate; none of them is specific to 3.1 or 3.2, so require them whichever type you name ¹⁹²⁶.

• Steel grade, heat number, chemical composition and mechanical properties ¹⁹.
• Tensile, yield and elongation results, plus hardness where applicable ²⁶.
• Test standards applied and an authorized signature with title ²⁶.
• Heat number on the certificate matching the physical markings on the parts ¹⁷.

What choosing 3.2 commits you to

Type 3.2 cannot be assumed to follow from a 3.1 already issued. The additional representative or inspector has to validate the specific inspection documentation, so the type must be specified before production and the inspection plan agreed at that point ²⁷. If you raise 3.2 after the lot is made, you are asking for a validation step that was not planned into the run. The cost side is real but not quantified for EN 10204 in this evidence. A comparable case exists in hot-dip galvanizing: ASTM F2329, a specification with added inspection and documentation obligations, is reported to carry a 10-25% premium over the simpler ASTM A153 ⁴. Treat that as an analogous figure for what added inspection and documentation can cost, not as the 3.2-over-3.1 premium.

Confirm the requirement against your own product specification

Nothing in this evidence tells you which end uses or standards require 3.2 rather than 3.1 for fasteners. The verification hierarchy is clear — 3.2 carries independent inspection, while a manufacturer declaration such as 2.1 carries less weight ¹⁷ . But the trigger for stepping up to 3.2 comes from your customer specification or product standard, not from the certificate standard itself. So the sequence for your PO is: read what the applicable specification demands, name that type explicitly, and only then agree the inspection plan with the supplier. If the specification is silent, the choice is yours to justify internally, and the sources here do not make it for you.

FAQ

Related pages

• Manufacturer audits and verification service page
• Manufacturing capabilities service page
• Which EN 10204 Certificate Should Your Fastener PO Name — and What Does It Actually Prove?
• 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