MTC and EN 10204 Certification Guide

The moment one examines the EN 10204 specification, there is a tendency to interpret the types as what they represent regarding the levels of quality. For example, many buyers consider that obtaining a 3.2 certificate actually means that there is a greater amount of testing involved than obtaining a 3.1 certificate. This is, however, not the case. The difference is who validates the document: a 3.1 is certified by the manufacturer's own inspection department, independent of the production department, while a 3.2 is countersigned by an independent inspector or the purchaser's representative. The tests can be identical. What changes is the witness, and that is why a 3.2 cannot be created after the fact. This MTC and EN 10204 certification guide explains the practical consequences for material supplied acrosspipes and tubes andpipe fittings and flanges.

The Document Types

Type	What it is	Who issues or validates it
2.1	Declaration of compliance with the order	The manufacturer, with no test results
2.2	Test report	The manufacturer, with results from non-specific inspection
3.1	Inspection certificate	The manufacturer's inspection department, independent of production, with results from specific inspection on the material supplied
3.2	Inspection certificate	As 3.1, but also validated by an independent inspector or the purchaser's representative

Two distinctions carry most of the practical weight:

Specific against non-specific inspection. A 2.2 reports tests that were not necessarily carried out on the material you received. A 3.1 reports tests on that material. That difference is larger than the one between 3.1 and 3.2.

Who signs. 3.1 and 3.2 differ on the witness. Same tests, different validation.

Why 3.2 Has to Be Ordered Before Production

A 3.2 requires a third party to witness testing, so it has to be arranged before the testing happens. The consequences on an order:

Specifying 3.2 after the material is made is not possible, and re-testing finished material does not reconstruct it
Third party attendance has to be scheduled, which affects lead time
The agency is usually nominated by the buyer, and the nomination belongs in the enquiry
Cost is affected by inspection visits, not only by material

So the certification level is a commercial and schedule decision as much as a quality one, and it belongs in the enquiry rather than in a later clarification. This is covered on theEPC and project supply page.

What an MTC Should Let You Do

A mill test certificate is useful to the extent that it connects a specific piece of metal to a specific set of results. Minimum content for that to work:

Item	Why it matters
Heat or cast number	The link between the certificate and the material
Material specification, grade, class or type	What was ordered
Chemical composition	Against the specification range
Mechanical properties	Tensile, yield, elongation, and hardness where required
Impact test results with test temperature	The only proof of low temperature capability
Heat treatment condition	Some specifications accept only certain conditions
Dimensions and quantity	Matching what was shipped
Non-destructive examination performed	Method and extent
Standard edition	Projects specify an edition, and these are revised
Marking	How the certificate is traced to the item

The Items a Certificate Cannot Prove

Low temperature capability. Chemistry does not show it and positive material identification cannot find it.A106 Gr B and A333 Gr 6 are close enough in chemistry that only the Charpy report separates them, and the same applies toWPB and WPL6.

Which of two lookalike alloys it is, in some cases.Grade 91 and Grade 92 cannot be separated by standard portable positive material identification, because the difference is tungsten. Marking and segregation have to do that work.

Sour service suitability on its own. That requires the hardness, heat treatment condition and, where specified, HIC and SSC testing, and HIC depends on steelmaking cleanliness so it cannot be added later. See theNACE guide.

Traceability Through Cutting and Trading

Certification fails most often not at the mill but afterwards, when material changes form or hands:

A piece cut from a longer length must carry its identification across the cut, by transfer marking recorded at the time
Partial supply against one certificate needs split certification handled properly at the point of sale
Material passing through several hands can arrive with a copy of a copy and no traceable origin
Repacking and part loads break the link between heat numbers and the certificate

Where the end user is an operator who will inspect on arrival, the documentation has to satisfy that party rather than the intermediate seller.

What to State on the Enquiry

The certification type required, by EN 10204 designation
For 3.2, the nominated inspection agency and the inspection scope
Any additional testing beyond the specification minimum, such as impact, hardness, HIC or corrosion testing
Whether positive material identification is required, and at what stage
Marking requirements, including transfer marking if material will be cut
The standard edition the project is qualified against

Certification: Buyer Questions

What is the difference between EN 10204 3.1 and 3.2?

Who validates the certificate. A 3.1 is certified by the manufacturer's inspection department independent of production; a 3.2 is also validated by an independent inspector or the purchaser's representative. The tests can be identical.

Can a 3.1 be upgraded to a 3.2 after the material is made?

No. A 3.2 requires third party witnessing of the testing, so it has to be arranged before the tests happen, and re-testing finished material does not reconstruct it.

What is the difference between 2.2 and 3.1?

A 2.2 reports non-specific inspection, so the tests were not necessarily carried out on the material supplied. A 3.1 reports specific inspection on that material.

What proves low temperature capability?

Only the impact test report with its test temperature. Chemistry does not show it and positive material identification cannot find it, because A106 Gr B and A333 Gr 6 are close in chemistry.

How is traceability kept when material is cut?

By transfer marking recorded at the time of the cut, so the piece carries its identification across the cut rather than losing it.

Why does the standard edition matter on a certificate?

Standards are revised and projects are qualified against a stated edition, so material certified to a different edition creates a documentation gap at handover.

Applying This to an Enquiry

State the EN 10204 type in the enquiry, and for 3.2 name the inspection agency and the scope. Certification level affects lead time and cost, and a 3.2 asked for after production cannot be supplied at any price.

Quotations are available in USD, OMR, AED, SAR, QAR, KWD and BHD, on EXW, FOB, CFR or CIF terms, with EN 10204 3.1 certificates as standard and 3.2 on request. Lead time is confirmed at quotation.

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MTC and EN 10204: What 3.1 and 3.2 Actually Mean