A shipment of pipes or flanges can be perfect, yet still be rejected because of one missing line on the certificate. Inspectors, EPC contractors and overseas buyers check certificates line by line. This MTC format checklist lists everything a professional mill test certificate should include, so your documents pass first time.

What is an MTC?

A mill test certificate (MTC), also called a material test certificate or inspection certificate, confirms that material meets the ordered specification. It records chemical composition, mechanical properties, heat treatment and test results for specific heats or lots. Most international buyers require certificates to EN 10204 3.1, and some to 3.2 — see EN 10204 3.1 vs 3.2.

Section 1: Header details

  • Manufacturer's name, logo, address and contact details
  • Certificate title and EN 10204 type (for example "Inspection Certificate EN 10204 3.1")
  • Certificate number and date of issue
  • Customer name and address
  • Customer PO number and date
  • Your sales order or invoice number

Section 2: Product description

  • Product type (seamless pipe, WNRF flange, 90° LR elbow, stud bolt)
  • Material specification and grade (ASTM A312 TP316L, ASTM A182 F51, ASTM A105)
  • Dimensional standard (ASME B36.19M, B16.5, B16.9, B16.11)
  • Size, schedule or class, facing, ends
  • Quantity per line and unit
  • Heat number / lot number for each line — see heat number traceability
  • Manufacturing route (seamless, welded, forged) and condition (annealed, normalised)

Section 3: Chemical composition

A table listing each element required by the specification, with:

  • specified minimum and maximum limits,
  • actual heat analysis values,
  • product analysis values if required.

For stainless and duplex grades, buyers may also ask for calculated PREN — see PREN explained.

Section 4: Mechanical properties

  • Tensile strength (specified and actual)
  • Yield strength (0.2% proof)
  • Elongation and, where required, reduction of area
  • Hardness (HB, HRC, HV) with limits — important for sour service
  • Impact test values with test temperature and specimen size, where required
  • Test specimen orientation and location if specified

Section 5: Heat treatment

  • Heat treatment type (solution annealing, normalising, quench and temper)
  • Temperature and holding time
  • Cooling method (water quench, air cool)

Missing heat treatment information is a very common reason for rejection, especially for A182 and A234 grades.

Section 6: Other tests and examinations

Include results for every test the specification or order requires:

  • Hydrostatic test with pressure and duration — see hydrostatic test for pipes
  • NDT — ultrasonic, eddy current, radiography, DPT — see NDT methods for steel
  • PMI results — see PMI testing explained
  • Intergranular corrosion test (ASTM A262) for stainless where required
  • Ferrite content and phase testing (ASTM A923) for duplex
  • Flattening, flaring and bend tests for pipes and tubes
  • Visual and dimensional inspection

Section 7: Statements and compliance

  • Statement that the material complies with the specification and order
  • Statements for supplementary requirements (NACE MR0175/ISO 15156, mercury-free, radioactivity-free) where requested
  • Country of origin and mill (for traders)
  • PED or other regulatory statements where applicable

Section 8: Signatures and stamps

  • Name, designation and signature of the authorised inspection representative (independent of production)
  • Company stamp
  • For EN 10204 3.2, the third-party or purchaser inspector's signature and stamp

Common reasons certificates are rejected

  • Heat numbers on certificate don't match material marking.
  • Missing grade, standard or dimensional standard.
  • Chemistry or mechanical values outside limits — or typed wrongly.
  • Heat treatment not stated.
  • Required tests (impact, IGC, hydro) missing.
  • "Various" sizes or heats without item-wise breakdown.
  • Unsigned or 2.2 report presented as 3.1.
  • Trader's certificate without the original mill certificate attached.

Paper, Word or software?

Many companies still create certificates by editing old Word or Excel files. That's where copy-paste errors — the wrong heat number, an old PO number — creep in. Dedicated certificate software stores heat data once and generates certificates accurately for every order.

MTCMitra is built for exactly this. It creates EN 10204 3.1 certificates from ready templates, so heat numbers, chemistry, mechanical values and test results are entered once and printed correctly in a professional, branded format every time. Read MTCMitra: mill test certificate software for metal companies or buy MTCMitra.

Frequently asked questions

Is a mill test certificate the same as EN 10204 3.1?

In trade, "MTC" usually refers to an EN 10204 3.1 inspection certificate, though the term is sometimes used loosely for other test reports.

Can a trader issue an MTC?

A trader should provide the original manufacturer's certificate. If the trader processes material further, it can issue its own certificate for that work while maintaining traceability.

Should actual values or just "OK" be shown?

Actual test values should be shown against specified limits. "OK" alone is not acceptable to most buyers.

How long should certificates be kept?

As long as your quality system and customer contracts require — often many years for pressure equipment materials.

Key takeaways

  • Include header, product, chemistry, mechanical, heat treatment, tests, statements and signatures.
  • Match heat numbers exactly between certificate and material.
  • Show actual values against limits for every required test.
  • Use software to eliminate copy-paste errors.

A clean, complete certificate is often the final step between dispatch and payment — make it flawless every time.