MTC EN 10204 3.1 vs 3.2: What Buyers Must Check Before Accepting Material

2026-06-28 · 6 min read · TrueGrade Metals engineering team

Every year, buyers accept container-loads of nickel alloy on certificates that wouldn't survive a 5-minute audit. The EN 10204 standard defines exactly what a mill test certificate (MTC) must contain — here's how to use it to protect yourself.

What EN 10204 actually defines

The standard ranks inspection documents by who validates them:

• 2.1 / 2.2 — the mill's own declaration. No independent test results. Not sufficient for pressure or safety service.
• 3.1 — validated by the mill's independent inspection department (independent of production). Actual test results for your specific heat. This is the industrial standard for pressure equipment and our default on every order.
• 3.2 — validated by an independent third party (BV, SGS, TÜV) or the buyer's own inspector, who witnesses the testing. Required for critical service: nuclear, subsea, many EPC specs.

The 5 checks that catch 95% of problems

• 1. Heat number match. The number stamped on the material must appear on the MTC. No match = no traceability.
• 2. Standard match. The MTC must cite the same standard revision as your PO (e.g. ASTM B444, not just "ASTM").
• 3. Chemistry in range. Every element's result must fall inside the standard's limits — not just "conform". For 625: Ni ≥ 58%, Cr 20–23%, Mo 8–10%, Nb+Ta 3.15–4.15%.
• 4. Mechanical results present. Tensile, yield and elongation must be actual measured values for your heat, not minimums copied from the standard.
• 5. Signature and independence. A 3.1 must be signed by the inspection department — and a 3.2 must name the third-party witness and their stamp.

Red flags

Certificates issued weeks after shipment, "typical values" instead of test results, missing heat numbers, or PDFs that look edited. Any of these and the material should be quarantined until resolved. We issue the MTC before shipment precisely so your incoming inspection can pre-verify.