Mill Test Certificate (EN 10204 3.1) Explained for Rebar Buyers
A Mill Test Certificate to EN 10204 3.1 is the document that proves your steel rebar meets its specification. It records the actual chemical and mechanical test results for your material and is validated by the manufacturer’s independent quality department.
A Mill Test Certificate (MTC), also called a mill certificate or material test certificate, is the inspection document that travels with a batch of steel rebar and proves it meets the ordered specification. For German and EU-standard reinforcing steel, buyers almost always require a Mill Test Certificate to EN 10204 type 3.1. Understanding what a 3.1 certificate contains — and how it differs from 2.1, 2.2 and 3.2 documents — protects you against substandard material and keeps your project compliant with DIN 488 and EN 10080.
What a Mill Test Certificate (3.1) contains
An EN 10204 3.1 certificate reports the actual test results measured on the specific heat or batch you are buying, not generic typical values. For reinforcing steel a 3.1 MTC typically lists:
- Heat / cast number — links the certificate to the traceable batch of steel.
- Grade and standard — e.g. B500B to DIN 488 / EN 10080.
- Chemical composition — carbon, manganese, sulphur, phosphorus, nitrogen and the carbon equivalent value (CEV) for weldability.
- Mechanical properties — yield strength (Re), tensile strength (Rm), the Rm/Re ratio (k), and elongation (Agt) that defines the ductility class.
- Dimensions and mass — nominal diameter, rib geometry and mass per metre.
- Validation — signed by an authorised representative of the manufacturer’s quality department, independent of the production line.
These values let you confirm the bar truly meets, for example, the 500 MPa minimum yield and the ductility thresholds for B500B. The figures should match the property limits in our B500A vs B500B vs B500C comparison.
EN 10204 certificate types: 2.1, 2.2, 3.1 and 3.2
EN 10204 defines several inspection document types. The key difference is who tests the material and how independent the validation is.
| Type | Name | What it confirms | Validated by |
|---|---|---|---|
| 2.1 | Declaration of compliance | Material meets the order — no test results given | Manufacturer (statement only) |
| 2.2 | Test report | Compliance plus non-specific (typical) test results | Manufacturer |
| 3.1 | Inspection certificate 3.1 | Specific test results on the actual batch | Manufacturer’s independent QA department |
| 3.2 | Inspection certificate 3.2 | Specific test results, jointly endorsed | Manufacturer + buyer’s agent or notified body |
For structural rebar, the 3.1 certificate is the practical industry standard because it ties real, batch-specific test data to traceable material under independent QA sign-off. A 3.2 certificate adds third-party endorsement, often required for critical infrastructure or where a contract or inspection authority mandates it.
Why the Mill Test Certificate matters to buyers
The MTC is your evidence of conformity. It supports structural design assumptions under Eurocode 2, satisfies engineers and building-control checks, and underpins your import documentation. Without a valid 3.1 certificate you cannot prove the steel’s grade, ductility or weldability — which can stall a project or fail an inspection.
How the MTC fits the export documentation pack
For export shipments the Mill Test Certificate is one part of a wider pack that typically also includes a Certificate of Origin, a CE marking / Declaration of Performance where applicable, a commercial invoice and a packing list. See how to order rebar from Germany and our export and delivery page for how these documents are prepared and issued together.
Frequently asked questions
Common questions about Mill Test Certificates for rebar.
What is a Mill Test Certificate 3.1?
What is the difference between EN 10204 3.1 and 3.2?
Do I always need a 3.1 certificate for rebar?
What properties does the certificate confirm?
Is the Mill Test Certificate the same as a Certificate of Origin?
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