Mill Test Report vs Mill Test Certificate: Understanding EN 10204 Types

MTR, MTC, CMTR: Different Names, Same Document?

The terms are used interchangeably in practice, but they have distinct meanings in standards terminology:

Mill Test Report (MTR): The most common term in North American practice. Refers to a document from a steel mill reporting the chemical and mechanical test results for a specific heat of material.

Mill Test Certificate (MTC): More common in European and international practice. Generally synonymous with MTR, but the term "certificate" implies a formal attestation — the mill is certifying compliance, not just reporting data.

Certified Material Test Report (CMTR): Emphasizes the certification aspect. Often used in nuclear and high-criticality applications where the certification chain is paramount.

In practical MTR review, the distinctions between these terms rarely matter. What matters is the type of inspection document as defined by EN 10204.

What Is EN 10204 and Why Does It Matter?

EN 10204 is the European standard that classifies metallic product inspection documents into types. While it is a European standard, EN 10204 types are referenced globally — you will see "3.1 certificate required" in purchase orders from Houston to Singapore.

The standard defines four types, grouped into two categories:

Non-specific inspection (Types 2.x): Test results are from routine production testing, not from the specific order. The tests were performed, but not necessarily on the exact material being shipped to you.

Specific inspection (Types 3.x): Test results are from the actual production lot/heat being shipped. The tests were performed on samples representative of your material.

What Is an EN 10204 Type 2.1 Declaration of Compliance?

A statement that the delivered products are in compliance with the requirements of the order, without inclusion of test results.

This is the minimum level of documentation. The manufacturer declares compliance but provides no chemical or mechanical test data. There is nothing to verify against specification limits because no test results are reported.

Type 2.1 is rarely acceptable for pressure equipment, structural, or pipeline applications. It may be used for non-critical commercial materials.

What Is an EN 10204 Type 2.2 Test Report?

A document in which the manufacturer declares that the delivered products are in compliance with the requirements of the order, and supplies test results based on non-specific inspection.

The test data is real, but it comes from routine testing — not necessarily from the specific heat being shipped. The mill runs standard quality checks on production batches and provides those results.

Type 2.2 is acceptable for some commercial applications but is generally insufficient for code construction, pipeline, or critical-service materials.

What Is an EN 10204 Type 3.1 Inspection Certificate?

A document issued by the manufacturer's authorized inspection representative, independent of the manufacturing department, in which they declare that the products are in compliance, with test results from specific inspection of the actual production lot.

This is the most commonly required certificate type for industrial applications. Key characteristics:

• •Test results are from the specific heat/lot being shipped
• •The inspector is authorized by the manufacturer but independent of production
• •The document traces to specific heat numbers
• •Chemical and mechanical test data is from the actual material

Type 3.1 is the standard requirement for API 5L, ASME code construction, and most pressure equipment and structural applications.

What Is an EN 10204 Type 3.2 Certificate?

Same as Type 3.1, but the inspection is witnessed and validated by both the manufacturer's authorized representative AND the purchaser's designated representative or an independent inspection body.

Type 3.2 requires dual sign-off — two independent inspectors verify the test results. This is the highest level of material certification.

Type 3.2 is required for: - Nuclear applications (NRC 10 CFR 50 Appendix B) - Some offshore pipeline projects - Military and defense applications - High-pressure, high-consequence applications where material failure risk must be minimized

The additional cost and logistics of third-party witnessed inspection make Type 3.2 significantly more expensive than Type 3.1.

What Should You Verify About the Certificate Type on an MTR?

When reviewing an MTR/MTC, first verify that the certificate type matches the purchase order requirement:

• •Check the certification statement — does it reference EN 10204 and specify the type?
• •For Type 3.1: verify the document is signed by an authorized representative identified as independent of manufacturing
• •For Type 3.2: verify both the manufacturer's and the third-party inspector's signatures
• •Confirm that test results reference the specific heat number matching your material

MTR.AI validates the certificate type as part of its compliance check, ensuring the level of certification matches what was specified in the procurement documents.