Material Test Certificate vs MTC

A material test certificate and a mill test certificate (MTC) are terms often used interchangeably in the piping industry, but they carry subtle differences depending on context. A material test certificate is the broader term covering any document that certifies the chemical composition, mechanical properties, and compliance of a material with an applicable standard. A mill test certificate specifically refers to the test report issued by the producing mill at the point of manufacture. In practice, both terms refer to documents governed by EN 10204, the European standard that defines the types of inspection documents for metallic products.

Material Test Certificate vs Mill Test Certificate

Aspect	Material Test Certificate	Mill Test Certificate (MTC)
Definition	Any certificate confirming material properties and standard compliance	Test certificate issued by the producing steel mill
Issuing party	Mill, processor, or third-party lab	Steel mill or pipe/fitting manufacturer
EN 10204 types	2.1, 2.2, 3.1, 3.2	Typically 3.1 or 3.2
Scope	Raw material, semi-finished, or finished product	As-manufactured product from the mill
Data included	Chemistry, mechanicals, dimensions, heat treatment	Chemistry, mechanicals, heat number, dimensions
Third-party witness	Required for Type 3.2	Required for Type 3.2
Common usage	Formal procurement language	Day-to-day industry shorthand
Typical piping application	Purchase order specification	Pipe inspection and receiving

Key Differences in Practice

EN 10204 classification: The critical distinction lies in the EN 10204 type specified on the purchase order. A Type 3.1 certificate is issued by the manufacturer’s authorized inspection representative, while a Type 3.2 certificate requires validation by an independent inspection body or the purchaser’s designated representative. Both material test certificates and MTCs can be issued as Type 3.1 or 3.2.

Scope of testing: An MTC reports results from tests conducted during production at the mill, including chemical analysis from the ladle (heat analysis) and mechanical tests on samples taken from the production lot. A material test certificate may additionally cover tests performed by independent laboratories, especially when further processing (e.g., coating, heat treatment) occurs after the original mill production.

Traceability: Both documents must include the heat number to ensure full traceability from raw material to finished product. For critical piping applications in oil and gas, mill test certificates are required to trace every component back to its original steel heat.

Pro Tip

When writing purchase orders, always specify the EN 10204 certificate type (e.g., “3.1 per EN 10204”) rather than simply requesting an “MTC.” This avoids ambiguity and ensures the supplier delivers the correct level of certification, whether the document originates from the mill or a third-party laboratory.

every mill test certificate is a material test certificate, but not every material test certificate is an MTC. The EN 10204 type number is what truly defines the inspection and certification requirements for piping materials.

Read the full guide to mill test certificates