How to Interpret a Stainless Steel Mill Test Certificate (MTC)

DLSS - Pipe&Tube - How to Interpret a Stainless Steel Mill Test Certificate (MTC)

Introduction

A Mill Test Certificate (MTC), also known as a Material Test Report (MTR), is a quality assurance document provided by the manufacturer. It ensures the delivered stainless steel material—such as tubes, pipes, plates, or fittings—complies with the specified standards and purchase order.

Understanding how to read an MTC is essential for engineers, QA/QC personnel, and buyers to ensure traceability and material compliance.


What Is a Mill Test Certificate (MTC)?

An MTC certifies:

  • Chemical composition (from ladle or product analysis)
  • Mechanical properties (yield strength, tensile strength, elongation, hardness)
  • Heat treatment condition
  • Test results (e.g., PMI, pressure, NDT)
  • Manufacturing and dimensional compliance

It serves as the material passport—linking the product to the production batch and quality tests performed.


Types of MTC (per EN 10204)

TypeDescriptionWitnessed by Third Party
2.1Declaration of compliance onlyNo
2.2Declaration + non-specific test resultsNo
3.1Manufacturer’s certificate with test dataNo
3.2Certificate validated by third-party agencyYes

For stainless steel tubes in industrial use, EN 10204 3.1 or 3.2 is commonly required.


Typical MTC Structure

1. Header Information

  • Manufacturer name and address
  • Customer name and PO number
  • Product description (e.g., ASTM A213 TP316L Seamless Tube)
  • Quantity and delivery date
  • Certificate number and date issued

2. Material Identification

  • Standard: ASTM A213 / EN 10216-5
  • Grade: TP304L / TP316L / S32205
  • Heat number: Unique number assigned to the molten batch
  • Production method: Seamless or welded, hot or cold worked

3. Chemical Composition

Usually presented in a table format, showing:

ElementCMnSiCrNiMoN
Result

Values must fall within the specified range of the standard (e.g., ASTM A213).

4. Mechanical Properties

Also in table format:

TestResultRequirement
Yield Strength… MPa≥170 MPa
Tensile Strength… MPa≥485 MPa
Elongation… %≥35%
Hardness… HRB≤90 HRB

5. Non-Destructive Testing (if applicable)

  • Eddy Current Test
  • Hydrostatic Test
  • UT/RT/MT reports
  • Grain size / IGC / PMI results

6. Certification Block

  • Signature of QA/QC department
  • Stamp of the mill or certifying body
  • Inspector signature (for 3.2 MTC)

How to Verify an MTC

Before accepting delivery, verify:

  • Material grade and standard match your order
  • Heat number is stamped on the product or traceable through marking
  • Test values meet or exceed requirements
  • NDT results are present for pressure applications
  • Third-party witness signature is valid for 3.2 certificates
  • MTC is original, not photocopied or altered

Why MTCs Matter in Heat Exchanger Tube Procurement

In critical applications—like boilers, chemical reactors, or offshore platforms—wrong or fake materials can cause catastrophic failure.

A valid MTC ensures:

  • Legal traceability and warranty claims
  • Compliance with EPC/client specs
  • Safe performance under pressure and corrosion
  • Conformance to ASME/ASTM/EN standards

DLSS Tube MTC Example

DLSS provides fully traceable MTCs for every order, including:

  • EN 10204 3.1 / 3.2 certificates
  • Heat & batch correlation
  • NDT and mechanical test reports
  • Witnessed inspection summary (for 3.2)
  • Pressure test logs
  • Optional PMI reports

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Contact DLSS for Certified Tube Supply

DLSS ensures every stainless steel tube is supported by a valid MTC with full compliance to ASTM, EN, and ASME standards.

Email: info@dlsspipe.com
Website: www.dlsspipeline.com

We don’t just deliver tubes—we deliver trust backed by documents.

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