Forged Mill Test Certificates (MTC / EN 10204 3.1)
A supplier sends a polished PDF certificate that does not match the steel actually shipped — wrong grade, invented chemistry, or a copied mill stamp.
How the scam works
- 1.Buyer requests an EN 10204 3.1 certificate to confirm grade and chemistry.
- 2.Seller returns a clean PDF with a recognizable mill letterhead and heat numbers.
- 3.The heat numbers are recycled from an unrelated batch, or the document is fully fabricated.
- 4.Delivered material is a lower grade (e.g. Q235 sold as S355) that fails on site.
Red flags to watch for
- Certificate arrives only as a flattened PDF image, never the original mill file.
- Mill named on the certificate has no record of the heat number.
- Chemistry values are suspiciously rounded or identical across batches.
- Seller resists third-party PMI (Positive Material Identification) testing.
How to protect yourself
- Verify heat numbers directly with the named steel mill, not the trader.
- Commission an independent PMI test and dimensional check before shipment.
- Require the native certificate file and cross-check the issuing signature.
In depth
The reason forged certificates are so effective is that the format itself is almost always genuine — only the link between the paper and the metal is broken. A fraudster either recycles a real certificate from an unrelated batch (so the heat numbers exist but describe different steel) or fabricates the chemistry outright on an authentic-looking template. Because the document passes a casual glance, the deception only surfaces when the steel is independently tested or fails in service, by which point the supplier has been paid and moved on.
Defeating it does not require metallurgical expertise, only a refusal to treat the certificate as self-proving. Contact the named mill through a channel you found yourself — never a number printed on the certificate or forwarded by the trader — and ask them to confirm the heat numbers, grade, and chemistry on record. Insist on the native file rather than a flattened image so you can inspect the stamp and signature, and for anything grade-sensitive, plan a positive material identification (PMI) test on the steel that actually arrives.
Related reading
Frequently asked questions
- How do I verify a mill test certificate from China?
- Contact the named steel mill directly through an official channel — never through the trader — and ask them to confirm the heat numbers, grade, and chemistry on the certificate. Request the original native file rather than a flattened PDF, and plan an independent PMI test on arrival.
- What is an EN 10204 3.1 certificate?
- EN 10204 3.1 is an inspection certificate issued by the manufacturer confirming the supplied steel meets the ordered specification, validated by the mill's own authorised inspector. Fraudsters fake the document or recycle heat numbers from unrelated batches.
- How can I tell if a mill test certificate is fake?
- Red flags include a certificate that only arrives as a flattened image, a mill with no record of the heat number, suspiciously rounded or identical chemistry across batches, and a seller who resists third-party PMI testing.
Real cases
Stainless that wasn't stainless
A buyer ordered 304 stainless against a clean 3.1 certificate. On-site PMI after delivery showed 201-series steel with high manganese and almost no nickel.
Worried this is happening to you?
Run your supplier through the structured verification checklist.