BUYING GUIDE
Mill test certificates
A mill test certificate (MTC) is the document a mill issues stating the chemical composition and mechanical test results of a specific heat of material. EN 10204 defines the certificate types — 3.1 is the common one for traceable structural and pressure work. On 2ndMetal, listings with a certificate carry an MTC badge, and the document is released with your order.
What an MTC actually says
An MTC ties a physical piece of metal to its production record: the heat number, the chemical analysis of that heat (carbon, manganese, chromium and the rest), and the mechanical results — yield strength, tensile strength, elongation, and impact values where the spec demands them.
It certifies the material as produced, not the piece as it sits in a yard today. That distinction matters for surplus: the certificate stays valid for the heat, and the buyer's job is matching the piece in hand to the heat on paper — usually via hard-stamped or painted heat numbers on the material.
EN 10204 types, in plain terms
Type 2.1 is a bare declaration of compliance — no test results. Type 2.2 adds test results, but from non-specific inspection: results typical of the production, not necessarily your heat.
Type 3.1 is the workhorse: specific test results for your actual heat, validated by the mill's own inspection department, independent of production. Most structural, piping and pressure-vessel specifications in the Gulf call for 3.1.
Type 3.2 adds a second signature — an independent third-party inspector or the purchaser's representative witnesses the testing. It appears on critical pressure and offshore work, and it makes the material noticeably more expensive.
When you genuinely need one
If the work is engineered — structural steel under a consultant, process piping, anything with a design code behind it — the specification will name the certificate type, and you should buy accordingly. An uncertified piece cannot be certified after the fact; re-testing at a lab produces a test report, not a mill certificate.
If the job is general fabrication — a bracket, a base plate, a machine guard — the certificate usually adds cost without adding anything the job needs. Being honest about which kind of job you have is the single biggest saving available in metal buying.
How MTCs work on 2ndMetal
Listings with a certificate on file show an MTC badge with the certificate type. The document itself is released to you with the order once it is confirmed — it stays available on your order page alongside the invoice and delivery note.
Certificates are supplied as issued by the mill. We do not retype, summarise or amend them, and we flag dual-certified material (one heat certified to two specifications, such as A53/A106 pipe or 304/304L stainless) where the paperwork shows it.
Common questions
Can I get the MTC before I buy?
The listing shows that a certificate exists and its type. The full document is released with a confirmed order — certificates carry mill and purchase details that are commercially sensitive before a sale.
Is a 3.1 certificate from surplus material still valid?
Yes. The certificate belongs to the heat, not to the first buyer. As long as the piece is traceable to the heat number on the certificate, a 3.1 MTC is as valid on surplus as on new mill supply.
What is dual certification?
One heat tested to satisfy two specifications at once — 304/304L stainless and A53/A106 pipe are the common cases. Dual-certified material can be used against either specification.