EN 10204 at a glance
EN 10204, Metallic products, Types of inspection documents, is the full title. The current edition, EN 10204:2004, replaced the 1991 version.
The standard sorts documents, not test methods. What it fixes is the kind of certificate that comes with the delivery and who signs off on it. The actual test values still come from the referenced product standard (ASTM A240, A516, B424) and the relevant test methods: PMI, tensile, Charpy, ASTM A262.
- Applies to all metallic products, stainless, nickel alloy, carbon and alloy steel, in every form.
Non-specific inspection and specific inspection, four document types split across two families: 2.1 and 2.2 on one side, 3.1 and 3.2 on the other. What buyers mean when they ask for a "mill test certificate" is nearly always a 3.1. Move up to 3.2 and you add an independent countersignature.
There's shorthand for all this on the order line. Writing "EN 10204 3.1" on the purchase order is what binds the delivered heat to its test results, it's the traceability contract itself.
What is EN 10204?
EN 10204 is a short, document-only standard. It doesn't say how to test steel or what the metal must contain. Instead, it defines the types of inspection documents a supplier issues, and the level of validation behind each one. Chemistry and mechanical requirements come from the referenced material standard, for example ASTM A240 for stainless flat product, or ASTM A516 for pressure-vessel plate. The paperwork proving the delivered product met those requirements is what EN 10204 governs. Because it's a European norm adopted worldwide, "EN 10204 3.1" has become the common language of material certification, even on ASTM- and ASME-referenced orders.
EN 10204:2004 lays out exactly four document types. Which one lands in your hands comes down to a single question: was the inspection specific to the batch you're buying, or non-specific?
Specific vs non-specific inspection
The split between the 2.x and 3.x documents comes down to one distinction the standard defines: whether testing happened on the actual products being supplied or just on general production. That's why a 3.1 or 3.2 outranks a 2.1 or 2.2 whenever grade conformity has to be proven against the delivered heat.
Non-specific inspection (types 2.1, 2.2)
Non-specific inspection covers tests the manufacturer ran on material made to the same specification, but not necessarily on the items delivered to you. These results show the production process turns out conforming material; they don't trace back to your specific heat or piece. A 2.1 declaration of compliance carries no test results at all. A 2.2 test report carries results, but from general production, not your lot. Non-specific documents work fine for non-critical, commodity material, where batch traceability isn't required.
Specific inspection (types 3.1, 3.2)
Specific inspection means tests carried out on the products actually supplied, or on test units from the same cast, so the certificate's results belong to your material. The chemical analysis and mechanical values tie back to the heat / cast number printed on the certificate and stamped on the product itself. Both 3.1 and 3.2 certificates come from specific inspection; that's the reason corrosion-resistant and pressure-vessel steel gets ordered to a 3.x document in the first place. Who validates the result is where the two part ways.
The four EN 10204 document types
Each type states the inspection basis, confirms whether results reflect the delivered product, and names who signs off. The table works as a quick reference; the notes below fill in the detail for each one.
| Type | Document | Inspection basis | Results on your actual product? | Validated / signed by | Typical use |
|---|---|---|---|---|---|
| 2.1 | Declaration of compliance with the order | Non-specific | No, no test results | The supplier (statement only) | Non-critical commodity material |
| 2.2 | Test report | Non-specific | General production, not the batch | The supplier's own department | Low-criticality material needing indicative data |
| 3.1 | Inspection certificate 3.1 | Specific | Yes, the delivered heat | The manufacturer's authorized inspection representative, independent of the manufacturing department | Default for corrosion-resistant & pressure-vessel steel |
| 3.2 | Inspection certificate 3.2 | Specific | Yes, the delivered heat | The authorized inspection representative and the purchaser's representative or an inspector named in official regulation | PED, sour service, classed/critical equipment |
2.1: Declaration of compliance with the order
A 2.1 is nothing more than a flat statement that the material meets the order's requirements, with no test results attached. It's the weakest document in the stack, and it won't do where proof of grade actually matters.
2.2: Test report
A 2.2 reports results from general production of the same grade, checked off by the supplier's own department. The figures are genuine, but they can't be traced back to the specific items you actually receive.
3.1: Inspection certificate 3.1
A 3.1 covers tests run on the actual delivered material, and it's validated and signed by the manufacturer's authorized inspection representative, someone independent of the manufacturing department. It carries the heat or cast number, measured chemistry and mechanical properties, and a statement of conformity. This is the industry-standard mill test certificate, or MTC.
3.2: Inspection certificate 3.2
A 3.2 is a 3.1 with an added countersignature, either from the purchaser's authorized representative or from an inspector designated by official regulation: a notified body, a class surveyor, or a third-party agency. Contracts that require an independent witness to the testing call for this level.
EN 10204 3.1 vs 3.2: the decision
Both are specific-inspection certificates covering tests on your heat. The real difference comes down to who signs off on the result. A 3.1 gets validated inside the mill by someone independent of production. A 3.2 needs that, plus a second signature from an outside party. Want a line-by-line breakdown of either document? Check out how to read a mill test certificate.
| Dimension | EN 10204 3.1 | EN 10204 3.2 |
|---|---|---|
| Inspection basis | Specific (tests on the delivered product) | Specific (tests on the delivered product) |
| Who validates | Manufacturer's authorized inspection representative, independent of the manufacturing department | The same representative plus the purchaser's representative or an inspector per official regulation |
| Independent third party? | No external countersignature required | Yes, notified body, class surveyor or agency (e.g. TÜV SÜD, Bureau Veritas, DNV, SGS, ABS) |
| Typical driver | Standard corrosion-resistant / pressure-vessel order | PED critical equipment, sour service, classed/marine, customer-witnessed inspection |
| Cost / lead-time | Issued with the material, no added wait | Added cost and lead-time for witnessing / countersignature |
In practice, a 3.1 covers the great majority of stainless, nickel-alloy and PVQ orders adequately. Demand a 3.2 when a third party must countersign the inspection. That typically applies to PED pressure equipment judged to need it, classed marine work, or a contract calling for witnessed testing.
What's on an EN 10204 3.1 certificate
A compliant 3.1 stands on its own: it links measured results to a traceable heat and closes with a signed conformity statement. The checklist below spells out what a QA reviewer confirms is present before accepting the material. Every line traces back to the heat / cast traceability chain.
| Field | What it records |
|---|---|
| Order / standard & edition | The product standard and edition the material is certified to (e.g. ASTM A240, ASME SA-516) |
| Grade / UNS | Grade designation and UNS number (e.g. 904L / N08904) |
| Heat / cast number | The melt identifier linking results to the batch, the traceability anchor |
| Chemical analysis | Measured wt% for each specified element against the standard's limits |
| Mechanical results | Tensile, yield (0.2% proof), elongation, hardness and, where required, Charpy impact |
| Dimensions / quantity | Product form, size and quantity certified |
| Heat-treatment condition | Delivery condition, e.g. solution-annealed or normalized |
| Supplementary tests | IGC per ASTM A262, hydrostatic, UT, RT or PMI when ordered |
| Marking | How the material is marked to match the certificate |
| Conformity statement & signatory | Declaration of compliance signed by the authorized inspection representative |
MTC vs mill test report (MTR) and legacy 3.1A / 3.1B / 3.1C
Two terminology bridges cause most of the confusion during receiving inspection. First, MTC vs MTR: "mill test certificate (MTC)" is the EN 10204 term, while "mill test report (MTR)" is what ASTM calls the same kind of document, the certificate furnished under general-requirements specs like ASTM A480 for stainless or ASTM A20 for pressure-vessel plate. For a specific-inspection document, an ASTM A240 MTR and an EN 10204 "3.1" MTC carry the same heat-traceable data. Use whichever name the contract calls for, and you'll avoid an argument at inspection.
Second, there's the 1991 → 2004 designations. The 2004 edition folded the older codes together, most often, the old 3.1.B became today's 3.1, while the old 3.1.C and 3.1.A both map to 3.2. So if a legacy drawing calls for "3.1B," a current 3.1 does the job.
| EN 10204:1991 | EN 10204:2004 equivalent | Note |
|---|---|---|
| 2.1 | 2.1 | Declaration of compliance |
| 2.2 | 2.2 | Test report |
| 2.3 | , (withdrawn) | Content now served by 3.1 |
| 3.1.A | 3.2 | Inspection by official / regulatory inspector |
| 3.1.B | 3.1 | Most common legacy → current mapping |
| 3.1.C | 3.2 | Inspection by the purchaser's representative |
| 3.2 | 3.2 | Designation retained |
Grades & forms covered: the MTC you get at Nandini
EN 10204 classifies the document itself; it's the grade standard that dictates what the actual numbers need to be. Every grade Nandini supplies comes with a mill test certificate traceable back to the heat. That's what proves the material conforms to its own grade standard.
Material comes from genuine mills, producers like Aperam, Outokumpu, Jindal, POSCO, Nippon Steel and JFE. Nandini hands over the original mill MTC along with its own EN 10204 3.1 certificate. Together, they form a chain from mill MTC to delivered certificate, keeping the heat traceable all the way from melt to dispatch.
Stainless & super-austenitic (304 / 316 / 904L)
Austenitic and super-austenitic stainless flat product meets ASTM A240 / ASME SA-240 requirements. Each heat ships with a 3.1 MTC reporting the solution-annealed chemistry and mechanicals against the standard. For aggressive sulfuric-acid and high-chloride duty, 904L (UNS N08904, PREN ~34) is the workhorse. A classic spec error is reaching for Alloy 20 or 625 when 904L already covers the service with its copper-bearing, ~4.5% Mo chemistry. Nandini's a certified specialist in 904L. Order it as 904L coil or 904L plate with a 3.1 MTC.
Nickel alloys (Incoloy 825)
Nickel-alloy flat product has to conform to ASTM B424 / ASME SB-424, not A240. Incoloy 825 (UNS N08825, often mis-ordered as "Inconel 825") gets picked for its combined resistance to reducing and oxidizing acids, and for sour service. In that case, the heat needs to be supplied in the condition qualified to NACE MR0175 / ISO 15156 sour service. A 3.1 MTC comes standard. A 3.2 is furnished only where the contract calls for witnessed inspection. You can order Incoloy 825 coil or Incoloy 825 plate directly.
PVQ / pressure-vessel plate (A516)
Pressure-vessel plate conforms to ASTM A516 / SA-516 read with ASTM A20 general requirements, and is routinely certified 3.1 (3.2 where PED or the fabricator requires it). Two things buyers under-specify: normalized plate with Charpy impact tested at the design temperature for low-temperature vessels, and the HIC-tested (NACE TM0284) variant for sour service, both appear on the certificate only if ordered. See A516 Gr 70 pressure-vessel plate, the normalized plate and the NACE-HIC plate.
Which certificate your standard or service demands
The document type is usually driven by the governing code or service, not by preference. The map below pairs common drivers with the EN 10204 type and the traceability they imply. For the sour-service rules specifically, see sour-service certification.
| Standard / service | Typical EN 10204 type | What it needs on the certificate |
|---|---|---|
| General stocked corrosion-resistant material | 3.1 | Heat-traceable chemistry & mechanicals |
| PED 2014/68/EU pressure equipment | 3.1 (3.2 for critical / specific safety) | Specific inspection; 3.2 or material appraisal where the category demands independent endorsement |
| Sour service (NACE MR0175 / ISO 15156) | 3.1 + traceability | Heat qualified to the sour-service condition; HIC per NACE TM0284 for HIC-resistant plate |
| Classed / marine (ABS, DNV, LR) | 3.2 witnessed | Class surveyor countersignature |
| ASTM A240 / A516 / B424 material | 3.1 MTC (ASTM "MTR") | Results per the grade standard and its general-requirements spec (A480 / A20 / B906) |
How to order material with the right MTC
The certificate you get depends entirely on what the purchase order calls for. To make sure the right document ships with the heat, spell out, in this order:
- EN 10204 type, 3.1 (standard) or 3.2 (independent countersignature required).
- Product standard & edition, e.g. ASTM A240, ASME SA-516, ASTM B424.
- Grade + UNS, remove designation ambiguity (e.g. 904L / N08904); cross-check with the UNS / Werkstoff cross-reference.
- Tests required, chemistry, tensile, Charpy at temperature, IGC per ASTM A262, hydrostatic, UT or RT, depending on what the service actually demands.
- Third-party inspection, name the notified body, class society or agency if a 3.2 is required. Build in lead-time for witnessing, too.
- Copy format, stamped physical certificate and/or electronic copy with dispatch.
Send the specification to the Nandini Steel Engineering Team, and they'll confirm ex-stock availability and issue a firm offer. See the MTC we supply, and feel free to request a sample MTC.
Testing behind the certificate
A 3.1 or 3.2 certificate draws its numbers from a fixed set of tests; EN 10204 just notes which ones were run and what they showed. Spectrometry checks chemistry, and PMI (positive material identification) confirms it again once the material arrives. Yield, ultimate strength and elongation come from tensile testing. Low-temperature toughness is checked with Charpy impact. Resistance to intergranular attack gets tested through intergranular corrosion testing per ASTM A262. Plate and welds are checked for soundness by hydrostatic, ultrasonic (UT) and radiographic (RT) examination. All of this sits under material testing, PMI, NDT and MTC. Nandini runs PMI on receipt too, to confirm grade, so the heat in hand matches what's on the certificate.
FAQ
What is EN 10204 3.1 vs 3.2?
What is a 2.2 test report versus a 3.1 certificate?
Is a 3.1 certificate enough for a pressure vessel?
Is EN 10204 3.1 the same as a mill test report (MTR)?
Does old EN 10204 3.1B equal the current 3.1?
Does Nandini supply material with an EN 10204 mill test certificate?
Request material with a 3.1 or 3.2 MTC
Send your grade and UNS, product standard, form, dimensions, the tests required and the EN 10204 type, and the Nandini Steel Engineering Team will confirm ex-stock availability and issue a firm offer with full mill test certificate documentation. All catalog products sit ex-stock, ready for immediate dispatch; live pricing comes through on RFQ. For the wider trust picture, have a look at our certifications, quality assurance and about Nandini Steel. EN 10204 documentation gates pressure-vessel fabrication just as it does oil & gas (sour) service.
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