How to read an aluminium MTC
A line-by-line walkthrough of an EN 10204 3.1 mill test certificate — the fields to check before you sign for the goods.
| Line | Field | What it tells you | What to check |
|---|---|---|---|
| 1 | Certificate number | Unique ID for this specific MTC. Use it for traceability. | Format and stamp consistent with the issuing mill. |
| 2 | Order / contract number | Your PO number or the mill’s internal order ref. | Matches your PO file. |
| 3 | Product form | Rolled plate / sheet / coil / bar / tube. | Matches the order spec. |
| 4 | Alloy designation | Numeric alloy (e.g. 5083) + temper (e.g. H116). | Number matches your spec. Temper matches the spec. |
| 5 | Standard reference | EN 485 / ASTM B928 / GB/T 3880 etc. | Standard version is current. Marine plate should cite ASTM B928 or EN 485 specifically. |
| 6 | Heat / cast number | Batch identifier for the chemistry. | All plates in the same heat should share this number. |
| 7 | Plate / piece numbers | Each individual plate or coil in the shipment. | All shipped pieces are listed. Cross-check with the packing list. |
| 8 | Dimensions | Thickness × width × length, in mm. | Within tolerance per the standard. Width and length match your cutting spec. |
| 9 | Quantity / mass | Number of pieces and total mass (kg or t). | Matches your invoice and weighbridge receipt. |
| 10 | Mechanical properties | Tensile strength (Rm), yield strength (Rp0.2), elongation (A%). | Within the spec range for the alloy and temper (e.g. 5083 H116: Rm ≥ 305 MPa, Rp0.2 ≥ 215 MPa, A ≥ 10%). |
| 11 | Chemical composition | Element-by-element content (Mg, Mn, Fe, Si, Cu, Zn, Cr, Ti, others). | All values within the spec range. Mg content matches the alloy designation. |
| 12 | Class society stamp (if any) | DNV, ABS, BV, LR, CCS mark if the order called for class approval. | Stamp is present if you ordered it. Stamp format matches the society’s published layout. |
| 13 | Inspector signature | Name, qualification, date, stamp. | Wet stamp or qualified electronic signature. Date is on or before the shipping date. |
- Standard not specified. Every MTC must cite the standard (EN 485, ASTM B928, etc.). If the field is blank or only says “per mill standard”, ask for the standard number.
- Temper not specified or not in the published temper list. Marine 5xxx plate is typically H116, H321, H111, or O. Anything else (H32, H34, etc.) may still be valid but should be confirmed.
- Mechanical properties outside the spec. If Rm or Rp0.2 is below the minimum for the cited standard, the plate does not meet your order and should be rejected or downgraded.
- Heat number mismatch. Different heats in the same shipment may indicate plate from multiple batches joined together — usually fine but worth checking against your order terms.
- Inspector signature missing. EN 10204 3.1 is invalid without a qualified inspector signature. The certificate is just a draft until that signature is present.
- Class society stamp missing when ordered. If you ordered DNV approval and the MTC has no DNV stamp, the goods may have shipped without witnessing. Push back before accepting.
People also ask
What’s the difference between EN 10204 3.1 and 3.2?
3.1 is signed by the mill’s qualified inspector. 3.2 adds independent third-party validation (typically the classification society or an accredited inspection agency). Most marine orders are 3.1; high-value or first-batch orders with class society witnesses are usually 3.2.
Can the MTC be issued in English?
Yes, English is the standard language for international plate shipments. If your MTC arrives in a different language, ask for a translated copy — the original must still be retained for the class society’s audit trail.
What if the dimensions on the MTC don’t match the actual plate?
Stop. Measure 3–5 random pieces from the shipment with calipers or a tape. If the variance exceeds the tolerance (typically ±0.2 mm on thickness for plate, ±2 mm on width and length), photograph the discrepancy and notify the mill before unloading the rest.
Why is “producing mill” sometimes blank on the certificate?
Traders and stockists often omit the producing-mill name for commercial reasons. EN 10204 does not require it; the heat number and standard reference are sufficient for traceability. For class-society work, the producing mill name will appear on the society’s own approval document.
How long should I keep MTCs?
As long as the vessel is in service — typically 20–30 years for commercial marine work. Class society rules require MTC retention for the life of the classed asset. File both paper and electronic copies.
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