EN 10204 Mill Test Certificates: 2.1 vs 2.2 vs 3.1 vs 3.2 Explained

A mill test certificate (MTC) is the single most-asked-for document in metal procurement. It travels with the material from melt-shop to job site, gets photographed at goods-receipt, audited by the third-party inspector, archived for the project life. Get the type wrong and your shipment can sit at the dock for weeks while engineering issues a deviation. Get a forged one and you ship a product whose chemistry might not even be the right grade.

This guide explains the four types defined in EN 10204:2004, what each section of a 3.1 actually means, how to spot the most common falsifications, when 3.2 is mandatory, and provides a clean PO-language template. Skip to the type comparison if you only need the bottom line.

What is an MTC and why it matters

EN 10204 — first published in 1991 and revised in 2004 — is a European standard that codifies the four types of inspection documents a manufacturer can supply with metallic products. The closely aligned ISO 10474 makes the structure identical for non-EU markets. An MTC's job is to bind the physical product to a documented chain of evidence: which heat melted it, what its chemistry is, which mechanical tests it passed, who signed off, against which spec.

For pressure equipment under the EU Pressure Equipment Directive (PED 2014/68/EU) or ASME B&PV Code, an MTC is non-negotiable. For industrial fabrication — ductwork, tanks, structural — the MTC is what the QA department audits during IQA receiving. For end-customer warranty claims, the MTC is the primary traceability artefact.

The 4 EN 10204 types side-by-side

The legacy types 3.1.A, 3.1.B, 3.1.C and 3.2 from EN 10204:1991 were consolidated into 3.1 and 3.2 in the 2004 revision. You will still occasionally see "EN 10204 3.1.B" on older specifications — this is equivalent to the modern 3.1.

Anatomy of a 3.1 certificate

A compliant 3.1 lists the data points specified by EN 10168 (the companion information-list standard). At minimum, expect these blocks:

• Header: certificate number, date of issue, manufacturer name and address, customer PO number, delivery note number.
• Product description: standard (e.g. ASTM A240), grade (e.g. 304L), form (plate / sheet / bar), nominal dimensions, surface finish, heat number, batch / lot number.
• Chemistry: full elemental analysis from ladle and (where required) product analysis. Each value with its specification range.
• Mechanical properties: tensile, yield, elongation, hardness; sometimes Charpy impact, bend test.
• Heat treatment record: temperature, time, cooling medium.
• NDT results (when required): ultrasonic, radiographic, hydrostatic, eddy current.
• Specific tests: e.g. ASTM A262 for sensitisation, ASTM A923 for sigma, ASTM E45 for inclusion rating.
• Standards compliance statement: "We hereby certify that the material described above complies with…"
• Authorised signature + stamp: name, title, ID number of the manufacturer's inspection representative; manufacturer's official stamp.

How to spot a forged 3.1

Forged 3.1 certificates are unfortunately common in the global metals trade, especially for high-margin alloys. The forgery patterns are surprisingly consistent.

The single most effective verification step: ask the issuing mill directly. Most reputable mills have a certificate-verification email or web portal. Send them the cert number and they will confirm authenticity within 1-2 business days.

When to insist on a 3.2

A 3.2 typically costs 1-3% extra and adds 7-14 days lead time, so it's not appropriate for every order. Insist on 3.2 when any of the following apply:

• The end product is a pressure vessel under PED 2014/68/EU Category III/IV.
• ASME B&PV Section VIII Division 2 Class 2 or above.
• NACE MR0175 / ISO 15156 sour service in oil & gas.
• Lethal service per ASME B31.3.
• Offshore project class 1 — most operators (BP, Equinor, Total) require 3.2 by default.
• Nuclear class 1, 2 or 3 components.
• Ammonia plants, hydrogen service above 200 °C.
• Project-specific QA requirement — read the spec carefully.

Purchase-order language template

Drop this language into the PO body or a separate quality clause attached to the PO. It eliminates the most common source of certificate disputes: ambiguous ordering language.

Material shall be supplied with an EN 10204 type 3.1 inspection certificate as a minimum. The certificate shall include the manufacturer's heat number, full ladle and product chemical analysis per the applicable specification, all mechanical properties required by the specification (including but not limited to tensile, yield, elongation, hardness and Charpy impact where applicable), heat treatment record, surface and dimensional inspection records, NDT records where required, and any product-specific tests called out by the specification (e.g. ASTM A923, ASTM A262, NACE TM0177). The certificate shall be signed by the manufacturer's authorised inspection representative, independent from the production department, and shall reference each applicable governing standard. For type 3.2, witness shall be provided by [TÜV SÜD / SGS / Bureau Veritas / purchaser's representative] and a copy of the witness report attached to the certificate. The original signed certificate shall accompany each shipment; an electronic PDF copy shall be emailed to [QA contact] within 24 hours of despatch. Any non-conformance shall be reported to the purchaser within 24 hours of discovery.

For more on Mailong Metal's QA process, see our services page and about us. For the full text of the standard, see EN 10204:2004↗; for the data-list companion, EN 10168↗.