The Mill Test Certificate (MTC) is the most important document in pipe fitting procurement. This guide explains exactly what EN 10204 3.1 means, what it contains, and how to read and verify it.
EN 10204 is the European standard that defines the types of inspection documents issued by manufacturers of metallic products — including pipe fittings. It specifies what information must be included in each document type and who is responsible for issuing it.
For buttweld pipe fittings, EN 10204 is the universally referenced certificate standard — used in ASME, API, NORSOK, Shell DEP, and virtually all industrial project specifications worldwide, regardless of whether the fitting is manufactured in India, Europe, or anywhere else.
| Type | Name | Issued By | Test Basis | When Specified |
|---|---|---|---|---|
| 2.1 | Declaration of Compliance | Manufacturer | Non-specific inspection | Rarely — non-critical |
| 2.2 | Test Report | Manufacturer | Non-specific inspection | Low-pressure, general |
| 3.1 | Inspection Certificate 3.1 | Manufacturer's QC | Specific inspection | Standard for all industrial |
| 3.2 | Inspection Certificate 3.2 | Manufacturer + Third Party | Specific inspection | Nuclear, critical offshore |
Name and address of the fitting manufacturer. ISO certification details. The issuing authority — must be the manufacturer's own Quality Control department, independent from production.
Heat number (cast number) — the unique identifier linking the fitting to a specific melt of steel. Product form, dimensions, quantity. ASTM/ASME material standard and grade (e.g. ASTM A234 WPB).
Actual chemical analysis results for all specified elements — carbon, manganese, silicon, phosphorus, sulfur, and any alloying elements. Results must comply with the ASTM standard requirements.
Actual tensile test results — tensile strength, yield strength, elongation, reduction of area. Hardness results where specified. All must meet ASTM minimum requirements.
Heat treatment condition (normalized, quenched & tempered, solution annealed etc.). Temperature and time where required by the material standard. Critical for alloy grades like WP91.
Impact test results (for LTCS grades, NACE grades), hydrostatic test, NDE results (RT, UT, MT, PT), dimensional inspection, and any other project-specified additional testing.
Check the heat number on the MTC matches the heat number stamped or stencilled on the actual fitting. This is the critical traceability link.
Verify chemical composition values are within ASTM limits for the specified grade. Carbon, Mn, P, S are the key elements to check for WPB.
Confirm mechanical properties meet minimums — tensile strength ≥415 MPa and yield ≥240 MPa for WPB. Different limits apply for each grade.
Check the signatory — EN 10204 3.1 must be signed by the manufacturer's Quality Control department representative. A 3.2 additionally requires a third-party inspector's signature.
PMI verification — for specialty alloys (SS 316L, Duplex, Inconel), Positive Material Identification (PMI) using XRF analyser provides additional verification that the actual fitting composition matches the MTC.
EN 10204 3.1 MTC — Standard with Every Shree Impex Steel Supply
Every buttweld fitting supplied by Shree Impex Steel comes with EN 10204 3.1 Mill Test Certificate as standard — no extra charge. The MTC includes full chemical composition, mechanical properties, heat number, and dimensional compliance. PMI testing and EN 10204 3.2 (third-party witnessed) are available on request.
Included as standard with every supply. No extra charge. Request a quote today.