EN 10204 Material Certificate: 2.1, 2.2, 3.1, and 3.2 Explained for Buyers and Suppliers
EN 10204 is the European standard that defines four types of inspection documents (2.1, 2.2, 3.1, 3.2) for metallic products. The type you need depends on what you’re making, who your customer is, and whether the part carries regulatory pressure or safety risk. Most procurement and QA people know they need “a 3.1 cert” but cannot explain the difference between 3.1 and 3.2, or why a 2.1 is not enough for a pressure-bearing part.
What EN 10204 Is — and Why the Type Number Matters
EN 10204 is the European standard “Metallic products — Types of inspection documents.” The current version is EN 10204:2004 (with a 2017 amendment clarifying the relationship to PED). It replaced the older DIN 50049 in 2004, though the DIN 50049 nomenclature (Werkszeugnis, Abnahmeprüfzeugnis) is still used colloquially in German-speaking markets.
The standard defines four types of inspection documents, distinguished by who issues the document and how the test results are validated:
| Type | Document name | Who issues it | Validation | Typical use |
|---|---|---|---|---|
| 2.1 | Declaration of compliance | Manufacturer (mill) | Self-declaration — the mill states the product meets the order, but no test results are shown | Non-critical commercial parts; commodity bar stock for non-safety applications |
| 2.2 | Test report | Manufacturer (mill) | Non-specific test results from the mill’s standard production testing — not necessarily on the actual delivered batch | Non-critical parts where the buyer wants some indication of properties, but not specific batch evidence |
| 3.1 | Inspection certificate | Manufacturer (mill) — signed by the mill’s authorized inspector who is independent of the manufacturing department | Specific test results on the actual delivered batch (heat number, batch number) | Most machined parts, structural components, automotive, general mechanical, oil & gas |
| 3.2 | Inspection certificate | Manufacturer’s authorized inspector and the buyer’s authorized representative (or an independent third party named per EN 10204 3.2) | Specific test results, validated by both the mill and an independent party | Pressure equipment (PED), safety-critical parts, nuclear, some aerospace and offshore |
What Is an EN 10204 3.1 Certificate?
A 3.1 certificate is an inspection certificate issued by the mill and signed by an authorized inspector who is organizationally independent of the mill’s manufacturing department, showing the actual test results — chemistry and mechanical properties — for the specific heat of metal you received. It is one of the four inspection-document types (2.1, 2.2, 3.1, 3.2) defined by EN 10204:2004 (amended 2017), and it is the default requirement for most machined parts, automotive serial parts (AIAG PPAP Element 10), and the minimum for PED Category I–II pressure equipment.
A 3.1 certificate must contain all of the following — if any one is missing, it is not a valid 3.1:
- A statement of compliance with the order.
- The heat / batch number, traceable to the delivered product.
- The actual chemical composition — measured values for this heat, not just the spec limits.
- The actual mechanical test results for this heat/batch: yield, tensile strength, elongation, hardness (and impact where specified).
- The name and signature of the mill’s authorized inspector, who must be independent of the manufacturing department.
What a 3.1 does not include: an independent third-party signature. That is the line between 3.1 and 3.2. A cert signed by the mill’s salesperson, account manager, or production supervisor is technically not a valid 3.1 — the signatory must sit in the mill’s quality function, separate from production.
| 2.1 | 2.2 | 3.1 | 3.2 | |
|---|---|---|---|---|
| Document name | Declaration of compliance | Test report | Inspection certificate | Inspection certificate |
| DIN 50049 legacy name (still used colloquially) | Werkszeugnis 2.1 | Werkszeugnis 2.2 | Abnahmeprüfzeugnis 3.1.A / 3.1.B / 3.1.C | Abnahmeprüfzeugnis 3.2 |
| Signed by | Mill only, no named inspector | Mill only | Mill’s authorized inspector, independent of production | Mill’s authorized inspector plus the buyer’s representative or an independent third party named per EN 10204 3.2 |
| Test results specific to your heat? | No test results shown | Non-specific (not necessarily your batch) | Yes — required | Yes — required |
| Independent third-party signature? | No | No | No | Required |
| Typical minimum application | Commodity / non-critical parts | Non-critical parts where the buyer wants some property indication | Most machined parts; automotive PPAP; PED Cat I–II; EN 1090 structural steel | PED Cat III–IV; oil & gas / offshore (NACE MR0175 service); safety-critical parts |
2.1 vs 2.2 vs 3.1 vs 3.2 — What Each Document Actually Contains
Each document type has a defined minimum content. Knowing what the mill is required to put on the document (and what they often leave off) is the difference between accepting a useful certificate and accepting a piece of paper that will get you rejected at your customer’s incoming inspection.
| Content | 2.1 | 2.2 | 3.1 | 3.2 |
|---|---|---|---|---|
| Statement of compliance with the order | ✓ | ✓ | ✓ | ✓ |
| Heat / batch number traceability to the delivered product | ✗ | optional | ✓ required | ✓ required |
| Actual chemical composition (measured values, not just spec) | ✗ | non-specific | ✓ specific to this heat | ✓ specific to this heat |
| Actual mechanical test results (yield, UTS, elongation, hardness, impact) | ✗ | non-specific | ✓ specific to this heat/batch | ✓ specific to this heat/batch |
| Name and signature of the mill’s authorized inspector (independent of production) | ✗ | optional | ✓ required | ✓ required |
| Independently validated (buyer’s inspector or third party) | ✗ | ✗ | ✗ | ✓ required |
Which Type Does Your Application Need?
The application drives the cert type. Below is the typical mapping — confirm with your customer’s purchasing specification, since many OEMs have stricter internal rules than the regulation requires.
| Application | Typical minimum | Why |
|---|---|---|
| Commercial machined parts, no safety function (e.g. brackets, covers, mounting plates) | 2.1 or 2.2 | No regulatory pressure; cost is the driver |
| General mechanical parts, OEM-supplied, non-safety | 3.1 | Standard industrial practice; customer’s QMS expects batch evidence |
| Automotive serial parts (PPAP package) | 3.1 | AIAG PPAP Element 10; IATF 16949 Clause 8.5.2 |
| Pressure equipment under PED 2014/68/EU, Category I–IV | 3.1 (Cat I) to 3.2 (Cat III, IV) | PED requires specific validation; higher categories require independent third-party validation |
| Oil & gas, sour service (NACE MR0175) | 3.1 minimum; 3.2 common | End-user specs (Shell, BP, Equinor, Aramco) usually require 3.2 |
| Aerospace (AS9100, but typically not EN 10204) | Heat-traceable MTC per AMS 2774 or equivalent | Aerospace usually uses AS9100 / AMS standards, not EN 10204 |
| Medical implants (ISO 13485, ASTM F136 / F138) | Mill cert per ASTM A240 + heat traceability | Medical follows ISO 13485 / ASTM standards, not EN 10204 |
| Structural steel for construction (EN 1090) | 3.1 with CE marking per EN 1090-1 | CE marking under CPR (Construction Products Regulation) requires factory production control + 3.1 cert |
| Power generation (ASME Section I, IV, VIII) | ASME-style material traceability (not strictly EN 10204 but uses the same concept) | ASME uses its own data report forms; EN 10204 may be supplementary |
What the Authorized Inspector Signs For — and What They Don’t
A common misconception is that the authorized inspector (the person who signs the 3.1 cert) takes personal responsibility for the metallurgy. They do not. The 3.1 cert is a controlled document attesting that the mill’s authorized representative has reviewed the test results and they conform to the order. The signatory is attesting to a process, not to a metallurgical opinion.
| The signatory does attest | The signatory does NOT attest |
|---|---|
| The product was manufactured by the mill named on the cert | That the chemistry shown is optimal for the buyer’s end use |
| The heat number shown corresponds to the product shipped | That the part is suitable for a specific application |
| The test results shown were obtained from testing this heat / batch per the cited test methods | That the test results will be repeated on the next heat |
| The test results meet the order specification (or any deviation is noted) | That the part will perform in service |
| The signatory is authorized per the mill’s quality manual and is independent of the manufacturing department | That the part meets any regulatory requirement beyond the order |
The PED 2014/68/EU Link — When 3.2 Is Required
The Pressure Equipment Directive (PED) is EU regulation 2014/68/EU, applicable to any pressure equipment or assembly with a maximum allowable pressure greater than 0.5 bar. It categorizes equipment into Categories I–IV based on the fluid state, fluid group, and pressure / volume combination.
| PED category | Material certificate required (per harmonized standard EN 10204) | Third-party validation |
|---|---|---|
| Article 4.3 (low risk) | 2.1 or 2.2 acceptable; 3.1 recommended | No |
| Category I | 3.1 | No |
| Category II | 3.1 | No |
| Category III | 3.2 (or 3.1 + Notified Body involvement) | Yes — either buyer’s inspector or Notified Body |
| Category IV | 3.2 with Notified Body certification of the material | Yes — Notified Body involvement mandatory |
The link between PED and EN 10204 is made through the harmonized standard EN 764-5 (Pressure equipment — Inspection documentation). EN 764-5 explicitly references EN 10204 and adds PED-specific requirements for the inspection certificate (e.g. the CE marking reference, the PED category, the notified body number when applicable).
What Most Buyers Get Wrong — The Top 5 Mistakes
From rejected-cert incidents we have seen on our own incoming inspection and from peers in the procurement community, these are the cert errors that show up most often.
| # | Mistake | Why it happens | Fix |
|---|---|---|---|
| 1 | Buyer orders 2.1 for a PED Cat III part | Procurement doesn’t know the PED category, or the part isn’t flagged as pressure-bearing in the BOM | Flag pressure-bearing parts in the BOM; require the cert type on the PO; train procurement on PED |
| 2 | Mill issues a 3.1 but the signatory is the production supervisor, not the quality function | Small mill, no separate inspection department | Buy from named mills with an accredited inspection department; audit the mill’s cert process |
| 3 | Cert shows chemistry but no mechanical test results (or vice versa) | Mill omitted one section by mistake, or it isn’t a “full” 3.1 | PO must list every test required; incoming inspection checks every section before accepting |
| 4 | Heat number on the cert doesn’t match the bar / billet marking | Mill shipped from a different heat than the cert was issued for | Incoming inspection physically checks heat-number marking against the cert |
| 5 | Cert is a generic PDF with no order number, no batch quantity, no delivery date | Mill re-uses an old template and forgot to fill in the order-specific fields | PO must list every required field; reject any cert with empty or placeholder fields |
How to Order the Right Cert Type — A Practical Workflow
For procurement and engineering teams that need a clean repeatable process:
- Identify the regulatory regime. Is the part pressure-bearing (PED)? Safety-critical (machinery directive, EN ISO 13849)? Structural (EN 1090)? Automotive (IATF 16949)? Medical (ISO 13485)? Each regime has its own cert rule.
- Map the regime to the EN 10204 type. PED Cat III/IV → 3.2. General industrial → 3.1. Non-critical commercial → 2.2. Commodity → 2.1.
- List the cert on the PO with full requirements. “EN 10204 3.1 cert required. Must include: heat number, batch quantity, chemistry, yield, UTS, elongation, hardness (or impact where specified), test standards (ISO 6892-1, ISO 6506, etc.), authorized inspector signature. Cert must be in English or bilingual with English.”
- Train incoming inspection to verify. Heat number matches the material. Cert has all required fields. Test standards cited match the PO. Signatory is in the mill’s quality function, not production. Cert is dated within 12 months of delivery (older certs → ask why).
- Reject and follow up. If any check fails, reject the lot and ask the mill to re-issue or re-test. Do not “accept with a deviation” — the deviation propagates into your customer’s PPAP and eventually into a field action.
How Do You Verify a 3.1 Certificate When It Arrives?
The single most reliable check takes 30 seconds: compare the heat number stamped on the bar, plate, or forging with the heat number printed on the certificate. A mismatch means the certificate does not actually cover the material you received — reject the lot. Around that anchor check, run a five-point verification on every 3.1 cert:
- Heat number matches the material. Physical marking on the product vs. the cert — the most underrated step and the most reliable way to catch a mismatch.
- All required fields are present. Order number, batch quantity, delivery date, chemistry, yield / UTS / elongation / hardness (or impact where specified), test standards cited, and the authorized inspector’s signature. A generic PDF with empty or placeholder fields gets rejected.
- Cited test standards match the PO. E.g. tensile per ISO 6892-1, hardness per ISO 6506/6507/6508, chemistry per ASTM E415 / E1086.
- Signatory is in the mill’s quality function, not production. A 3.1 signed by a production supervisor is technically not a valid 3.1.
- Cert is dated within 12 months of delivery. Older certs → ask the mill why before accepting.
Standards & Sources
EN 10204:2004 / EN 10204:2004/AMD1:2017 Metallic products — Types of inspection documents. Defines types 2.1, 2.2, 3.1, 3.2 and the validation requirements for each.
EN 764-5:2014 Pressure equipment — Inspection documentation. Links EN 10204 to the PED.
PED 2014/68/EU EU Pressure Equipment Directive. Defines the categories (I–IV) and the material validation requirements.
EN 1090-1:2009+A1:2011 Execution of steel structures and aluminum structures — CE marking, factory production control, FPC cert (refers to EN 10204).
DIN 50049 (superseded) Older German standard — the Werkszeugnis / Abnahmeprüfzeugnis nomenclature maps to EN 10204 2.1 / 3.1 / 3.2.
ISO 10474:2013 Steel and steel products — Inspection documents. ISO equivalent of EN 10204 (with minor differences).
ASTM A480/A480M General requirements for flat-rolled stainless and heat-resisting steel (used for ASTM-side certs, not EN 10204).
ISO 6892-1:2019 Tensile testing at room temperature.
ISO 148-1:2016 Charpy impact test.
ISO 6506-1:2014 Brinell hardness.
ISO 6507-1:2018 Vickers hardness.
ISO 6508-1:2015 Rockwell hardness.
ASTM E415 / E1086 Optical emission / XRF spectroscopy for chemistry.
EN 10002-1 (withdrawn, replaced by ISO 6892-1) Older tensile testing standard.
What is the difference between EN 10204 3.1 and 3.2?
A 3.1 cert is issued by the mill and signed by the mill’s authorized inspector who is independent of production. It shows actual test results on the specific heat of material you received. A 3.2 cert has the same content, but is additionally signed by the buyer’s authorized representative or an independent third party named per EN 10204 3.2. The 3.2 is the higher level of validation and is required for high-risk pressure equipment under PED 2014/68/EU Categories III and IV, and for many oil & gas and offshore end-user specifications.
Is a 2.1 cert acceptable for an automotive part?
No — not for a part going into a PPAP package or any safety-related application. AIAG PPAP Element 10 (Material / Performance Test Results) requires batch-specific test results, which only a 3.1 cert provides. A 2.1 cert is a self-declaration with no test data, which is below the bar for automotive. For PPAP, the part must ship with a 3.1 cert showing chemistry, mechanical properties, and the heat number tied to the delivery.
Can a 2.1 cert be upgraded to 3.1 after the fact?
No. The 3.1 cert is a document that must be issued at the time of manufacture, signed by the mill’s authorized inspector. The mill cannot retroactively convert a 2.1 to a 3.1 — the test data was either captured at the time (in which case the cert should have been 3.1 from the start) or it wasn’t. The only options are to re-order the material with the correct cert type, or to have the material independently tested and re-certified (rare, expensive, and usually not accepted by the customer). Always order the correct cert type up front.
Who is the “authorized inspector” on a 3.1 cert?
The authorized inspector is a person in the mill’s quality function who is organizationally independent of production, has been formally delegated in writing by the mill’s general management, and is named in the mill’s quality manual. In a large mill, this is a person in a central Inspection or Quality Assurance department. In a small mill, it may be the same person who also handles other quality functions, but they must still be independent of the manufacturing department that made the product. The signatory’s name, title, and the mill’s stamp or electronic signature must appear on the cert.
Does EN 10204 apply to non-metallic materials?
No. EN 10204 applies only to metallic products (steel, stainless, aluminum, copper, titanium, nickel alloys). For plastics, elastomers, and composites, different standards apply — e.g. ISO 1043 for plastic marking, EN 10245 for wire coatings, or material-specific ISO/ASTM standards. For polymers used in food contact or medical, the relevant regulations (EU 10/2011, FDA 21 CFR, USP Class VI) are not based on EN 10204 at all.
What is the difference between EN 10204 and DIN 50049?
DIN 50049 was the German predecessor to EN 10204 and is now superseded. The DIN 50049 nomenclature (Werkszeugnis 2.1, Werkszeugnis 2.2, Abnahmeprüfzeugnis 3.1.A, 3.1.B, 3.1.C, 3.2) is still used colloquially in German-speaking markets but has been replaced by the EN 10204 type numbers. The mapping is: DIN 50049 2.1 = EN 10204 2.1; 2.2 = 2.2; 3.1.A/B/C = 3.1; 3.2 = 3.2. When you see a German mill cert referencing “Abnahmeprüfzeugnis 3.1”, it is a 3.1 cert per EN 10204.
What is an EN 10204 3.1 certificate, in one sentence?
A mill-issued inspection certificate signed by an authorized inspector who is independent of production, showing the actual chemical composition and mechanical test results for the specific heat of metal you received — the default requirement for machined parts, automotive PPAP (AIAG PPAP Element 10), and PED Category I–II pressure equipment.
How long is an EN 10204 certificate valid?
The standard itself defines no expiry date. Common incoming-inspection practice treats a certificate as stale when it is dated more than 12 months before the delivery it accompanies, and asks the mill to explain or re-issue. Date and heat-number checks together catch most cert problems.
Is ISO 10474 the same as EN 10204?
ISO 10474:2013 is the ISO equivalent covering the same types of inspection documents for steel and steel products, with minor differences. EN 10204 remains the reference cited on European mill certificates; when a buyer specifies “EN 10204 3.1”, an ISO 10474 equivalent certificate should be accepted only if it provides the same batch-specific results and independent signatory.
- EN 10204:2004 / EN 10204:2004/AMD1:2017: Metallic products — Types of inspection documents (2.1, 2.2, 3.1, 3.2)
- EN 764-5:2014: Pressure equipment — Inspection documentation (links EN 10204 to PED)
- PED 2014/68/EU: EU Pressure Equipment Directive (categories I–IV)
- EN 1090-1:2009+A1:2011: Execution of steel structures and aluminum structures — CE marking, FPC
- DIN 50049 (superseded): Older German standard, nomenclature now mapped to EN 10204
- ISO 10474:2013: Steel and steel products — Inspection documents (ISO equivalent of EN 10204)
- ISO 6892-1:2019: Tensile testing at room temperature (commonly cited on 3.1 certs)
- AIAG PPAP 4th edition, Element 10: Material / Performance Test Results (requires 3.1 cert for automotive parts)
Need a 3.1 or 3.2 mill certificate with your order?
We supply CNC machined parts with full EN 10204 3.1 mill certificates — chemistry, mechanical properties, heat-number traceability, and authorized-inspector sign-off. For PED Cat III / IV parts we can arrange 3.2 through third-party inspection agencies.
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