Glossary
Mill Test Reports and Material Certs
What a mill test report contains, the four EN 10204 certificate types, the specific versus non-specific distinction that matters, and what it does to receiving.
A mill test report, commonly shortened to MTR, is a quality document from the material producer recording what a piece of metal actually is. Material test certificate, or MTC, is the same thing under a different name, with MTR the common North American term and MTC the common European one.
What Is On One
| Section | What it records |
|---|---|
| Heat number | Also called a melt number. Identifies the batch of molten metal the product came from, working like a lot or batch number |
| Chemical composition | Percentages of elements including carbon, manganese, phosphorus, sulphur and silicon |
| Mechanical properties | Tensile strength, yield strength, elongation, and often hardness |
| Grade and specification | The standard the material was produced to, commonly an ASTM, ASME or EN designation |
| Dimensions and product form | Plate, section, pipe, with sizes |
| Additional testing | Where required, Charpy impact, ultrasonic or hardness results |
The heat number is the one that matters operationally. Everything else on the certificate describes the material. The heat number is what connects the certificate to a physical piece you can point at.
The Four EN 10204 Types
EN 10204:2004 defines four inspection document types for metallic products. The names get quoted constantly and the underlying distinction gets quoted rarely.
| Type | What it is | Inspection basis |
|---|---|---|
| 2.1 | Declaration of compliance with the order, with no test results included | Non-specific |
| 2.2 | Test report based on routine production testing | Non-specific |
| 3.1 | Inspection certificate with results from the batch supplied, signed by the manufacturer’s own independent quality representative | Specific |
| 3.2 | As 3.1, plus verification by an independent third party or buyer-appointed inspector | Specific |
The distinction that matters is specific against non-specific. Types 2.1 and 2.2 tell you about the producer’s process. The results, where there are any, come from routine testing that may not be from your material at all. Types 3.1 and 3.2 report tests on the actual heat or lot being delivered to you.
That is why a 3.1 is the working standard on oil and gas, chemical and power work, and why a 3.2 appears on safety-critical scope where an independent inspector witnesses the testing. A 3.1 is not acceptable where a 3.2 was specified, and the place to catch that is the purchase order instead of the delivery.
These summaries reflect how the standard is described across the supply chain. EN 10204 and the ASTM specifications are paid documents, so confirm the exact requirement against the standard itself and against your contract before relying on any of it.
What This Does to Your Receiving Process
Here is the part trade explanations leave out, and it is the whole systems consequence.
If your customers ask for certificates, heat numbers have to survive from receiving through to the finished job. That single requirement changes receiving from a quantity check into a quantity and identity check.
Concretely:
- Material is received against a heat number, alongside quantity and grade
- The heat number stays attached as the material is cut, issued, and consumed
- The finished item can be traced back to every heat that went into it
- The certificate is retrievable against that trace
Shops that skip this discover it during a client audit or a warranty claim, which is the expensive way to find out. The certificate is usually in a filing cabinet somewhere. What is missing is the defensible link between that paper and the unit that shipped.
In system terms this is lot tracking. Odoo implements it through lots and serial numbers with a traceability report, and the equivalent exists in any competent inventory system. What varies is whether receiving actually captures it, because the software cannot record what nobody typed in.
Why the Link Breaks
Certificates themselves do not expire. The material was what it was. What fails is the connection between the document and the physical piece, and it fails in predictable places:
- At receiving, when the heat number is never captured because the receiver was checking quantity
- At the saw, when a length is cut and the remnant goes back to the rack unmarked
- In the rack, when similar sizes from different heats end up in the same bay
- At issue, when material goes to a job with no record of which piece it was
- At the filing cabinet, when the certificate is stored by supplier and invoice instead of by heat
Most of those are process failures instead of software failures, which is worth saying plainly. A shop with disciplined marking and a paper log has better traceability than a shop with good software and an undisciplined yard.
Related
- Metal fabrication ERP for Alberta job shops covers where this sits alongside the other things a fab shop needs from a system
- Procurement readiness covers the wider documentation set large buyers ask for
- Procurement readiness checklist turns that into something actionable
Frequently Asked Questions
- What is a mill test report?
- A mill test report, usually shortened to MTR, is a quality document from the material producer recording the chemical composition, mechanical properties, grade, heat number, and applicable specification for a metal product. Material test certificate, or MTC, is the same document under a different name. MTR is the common North American term and MTC the common European one.
- What is a heat number?
- A heat number, sometimes called a melt number, identifies the batch of molten metal a product came from. It works like a lot or batch number and it is the link that ties a physical piece of steel back to its test results. Lose the heat number and the certificate becomes a piece of paper about some steel somewhere.
- What is the difference between EN 10204 3.1 and 3.2?
- Both report actual test results from the specific batch supplied. A 3.1 is signed by the manufacturer's own independent quality representative. A 3.2 adds verification by an independent third party or a buyer-appointed inspector, which is why it is routinely specified on oil and gas, offshore, and safety-critical work. A 3.1 is not acceptable where a 3.2 was specified, so the requirement has to be caught at order time.
- What is the difference between 2.1, 2.2 and the 3 series?
- It is specific versus non-specific inspection, and that is the distinction that actually matters. Types 2.1 and 2.2 are non-specific, meaning a declaration of compliance with no test results, or a report based on routine production testing that may not be from your material. Types 3.1 and 3.2 are specific, meaning the results come from the actual heat or lot being delivered to you.
- Do mill test reports expire?
- The document does not expire, because it records what the material was when it was made. What fails is the link between the certificate and the physical piece. Once material is cut, moved, or stored without its identity travelling with it, you hold a certificate and a piece of steel and no defensible way to say they belong together.