EN 10204 3.1 vs 3.2 Certificate: When the 3.2 MTC Is Mandatory (and How to Avoid Documentation Rejections at Customs)

If you source steel from China for anything more demanding than a garden shed, the paperwork that travels with the load can make or break the deal — sometimes literally, when a container is sitting in customs and the destination’s inspector refuses to accept the certificate. The single most common documentation question we get from procurement teams is EN 10204 3.1 vs 3.2: what is the actual difference, when is the higher 3.2 certificate mandatory, and how do you avoid the painful situation of learning the answer only after the steel has already shipped?

This guide walks through the EN 10204 standard in practical terms, with the kind of detail a QA/QC manager or project engineer actually needs — not a paraphrased Wikipedia summary. We will cover who can issue each certificate, which industries legally require the 3.2, what it costs you in time and money, and how to word your RFQ so the mill and the inspection body both deliver what your end-user signed off on.

1. What EN 10204 Actually Is (and the 2004 vs 3.1 / 3.2 Update Most Buyers Miss)

EN 10204 is the European standard that defines the types of inspection documents that can accompany a delivery of metallic products — steel plate, pipe, bars, sections, forgings, fittings. In plain terms, it is the rulebook for the “Mill Test Certificate” (MTC) that proves the chemistry and mechanical test results of the specific heat and lot you received.

The version that matters today is EN 10204:2004, which replaced the 1991 edition (EN 10204:1991). This is the update most buyers miss, and it matters because the numbering changed:

• The 1991 edition had 3.1.A, 3.1.B and 3.1.C, plus 3.2. The difference between them was largely about who signed and whether the inspector was “independent” of the production department.
• The 2004 edition consolidated these into just two specific-inspection types: 3.1 and 3.2. The old internal-independence requirements were dropped — what now matters is simply whether a third party witnessed and co-signed.
• Any certificate still marked “3.1.B” or “3.1.C” is referencing an obsolete standard. Many end-users and customs authorities will flag this.

So when a buyer asks for “EN 10204 3.1.B,” they almost always mean the current 3.1. When they ask for “3.1.C” or “3.2,” they mean the current 3.2 — a third-party-witnessed certificate. Knowing this lets you translate legacy spec sheets into current language and avoid a documentation mismatch before production even starts.

2. The Certificate Types at a Glance — and Which Are Still Valid

EN 10204:2004 defines four document types. The first two (2.1 and 2.2) are “non-specific” — the test results are not necessarily tied to your exact delivery lot. The last two (3.1 and 3.2) are “specific” — the results are traceable to the material you actually receive, by heat number and batch.

Type	Inspection basis	Issued by	Traceable to your lot?	Includes test results?	Status
2.1	Non-specific	Manufacturer	No	No (compliance statement only)	Valid — low-risk, non-critical use only
2.2	Non-specific	Manufacturer	No	Yes (generic test results)	Valid — non-critical structural use
3.1	Specific	Manufacturer’s authorized inspection rep	Yes (heat & batch)	Yes (chemistry + mechanical)	Valid — the default for most structural & pressure-grade steel
3.2	Specific, third-party witnessed	Manufacturer and third-party inspector (LR / DNV / TÜV / SGS / BV / ABS, or purchaser’s rep)	Yes (heat & batch)	Yes (chemistry + mechanical, independently validated)	Valid — mandatory for PED Cat. III/IV, marine, oil & gas, nuclear
3.1.A / 3.1.B / 3.1.C	Specific	Varied (1991 definitions)	—	—	Obsolete — superseded by the 2004 3.1 / 3.2 types

As a rule of thumb: for anything load-bearing, pressure-retaining, or going into a regulated end-use, 3.1 is the floor, and 3.2 is what you upgrade to when a code, a client spec, or a class society demands independent verification.

3. EN 10204 3.1 — What It Is, Who Issues It, and What It Proves

A Type 3.1 inspection certificate is issued by the manufacturer’s authorized inspection representative — the mill’s own QA department, not the sales team. It declares that the steel supplied complies with the requirements of the order, and it reports the actual test results for the specific heat and delivery lot, traceable by heat number and batch/lot number.

A proper 3.1 MTC will typically show:

• Product description, dimensions, quantity and heat/lot numbers
• The standard and grade (for example, EN 10025-2 S355J2+N, or ASTM A516 Gr. 70)
• Chemical analysis (C, Si, Mn, P, S, and alloying elements where relevant), with the actual values and the spec limits side by side
• Mechanical test results: yield strength, tensile strength, elongation, and impact energy (KV/J) at the specified test temperature — e.g. 27J at -20°C for S355J2
• Any supplementary requirements you specified (e.g. NACE MR0175, Z25 through-thickness testing, ultrasonic testing per EN 10160)
• The signature, name, and date of the manufacturer’s authorized inspection representative, and the manufacturer’s stamp

What 3.1 does not provide is independent verification. The mill tested its own steel and reported its own results. For the vast majority of structural and general engineering applications, that is perfectly adequate — the mill’s quality system and its reputation are the assurance. For higher-risk applications, the buyer’s spec will explicitly override this with a 3.2 requirement.

4. EN 10204 3.2 — The Third-Party-Supervised Certificate, and Who Can Issue It

A Type 3.2 inspection certificate is co-signed by two parties: the manufacturer’s authorized inspection representative and an authorized third-party inspector who has witnessed the relevant testing (and, in many cases, the production stage itself). The third party confirms that the tests were carried out in their presence, on the correct material, and that the reported results are valid.

Under EN 10204:2004, the third-party inspector must be one of the following:

• The purchaser’s authorized inspection representative — the buyer sends its own (or a contracted) inspector to the mill.
• A third-party inspection body designated by the product standard or regulation — for example, a Notified Body under the Pressure Equipment Directive.
• An independent inspection organization designated by the purchaser — the most common route in practice.

The third-party bodies you will see stamping 3.2 certificates in the steel trade are the established classification and inspection societies:

• Lloyd’s Register (LR)
• DNV (Det Norske Veritas)
• TÜV (TÜV Rheinland / TÜV SÜD / TÜV NORD)
• SGS
• Bureau Veritas (BV)
• ABS (American Bureau of Shipping)

Which one you need is usually not your choice — it is dictated by the end-user’s approved-vendor list, the marine class society on the project, or the Notified Body assigned to the pressure equipment. Specifying the wrong body is a common reason a 3.2 certificate gets rejected downstream, so confirm the named body before you place the order.

5. When the 3.2 MTC Is Mandatory — Pressure Equipment, Oil & Gas, Marine, Infrastructure, Nuclear

These are the situations where 3.2 is not optional. In each case the requirement comes from a regulation, a code, or a client specification that your end-user has already committed to — and the steel certificate is the document that proves compliance.

Pressure Equipment (PED 2014/68/EU)

Under the European Pressure Equipment Directive, equipment falls into Categories I to IV based on fluid type (hazardous/non-hazardous), state (gas/liquid), volume or nominal size, and pressure. For Categories III and IV, the conformity assessment modules require the involvement of a Notified Body, and the material inspection documents must be 3.1 as a minimum, with 3.2 (or a specific material approval) typically required for the pressure-retaining parts. A 3.1 alone will not satisfy a PED Cat. III/IV audit.

Oil & gas and energy projects

Operator specifications almost universally require 3.2 for pressure-containing and critical structural steel. Shell DEP sections, Saudi Aramco material specifications, and similar operator standards call out 3.2 (often with a named third party) for items such as line pipe, pressure vessel plate, and wellhead-related forgings. If you are supplying into an EPC package for a refinery, an LNG train, or a pipeline, expect 3.2.

Marine classification

Steel going into a classed vessel — hull plate, bulkheads, deck machinery foundations — must be certified to the relevant class society (LR, DNV, ABS, BV, etc.). The class society’s stamp is the third-party signature, so a 3.2 with the society’s logo is the expected document. “Class-approved” material without the society’s actual stamp on the certificate is not the same thing.

Public infrastructure

Large government-funded projects — bridges, rail, ports, stadiums — frequently carry a contractual requirement for 3.2 on primary structural steel, especially when public money and independent verification go hand in hand. The requirement is usually in the project’s technical specifications rather than in a product standard.

Nuclear

Nuclear-grade steel is governed by codes such as RCC-M, ASME III, or national nuclear standards, all of which demand third-party (and often additional qualitqualified) inspection. A 3.2 is the baseline; additional heat-specific qualifications and traceability are layered on top.

6. EN 10204 3.1 vs 3.2 in Practice: Why a 3.1 From the Mill Is Not Enough for These Jobs (and Why Some Buyers Learn This at Customs)

Here is the scenario we see repeated every year: a buyer orders pressure-grade plate to save cost, accepts the mill’s standard 3.1 certificate, ships the container, and then — at the destination port — the customs broker or the receiving QA team refuses to release the material because the certificate does not carry a third-party stamp. The reason is straightforward but often discovered too late:

• A 3.1 is self-certified by the manufacturer. For a PED Cat. III vessel, a classed ship, or an Aramco-spec line pipe, self-certification is not an accepted basis of compliance — regardless of how good the mill actually is.
• The third-party witness must occur at the time of production and testing. You cannot “upgrade” a 3.1 to a 3.2 after the steel has cooled and left the mill. The inspector has to witness the actual test coupons being taken and tested. If that window has passed, the only remedy is re-testing under witness on retained samples — when retained samples even exist.
• Customs and end-user auditors compare the declared certificate type against the import documents and the project spec. A mismatch — “spec says 3.2, certificate says 3.1” — is a clean, automatic rejection.

The cost of getting this wrong is rarely just the steel. It is the demurrage on a held container, the expedited re-test or re-order, and the schedule slip on a project whose penalty clauses are far larger than the material value. The fix is almost always upstream: confirm the required certificate type before you place the PO, and book the third-party witness into the rolling schedule.

7. Cost & Lead-Time Impact of a 3.2 Certificate — Typical Adders and the 5–10 Day Witness Window

A 3.2 is not free, and it is not instant. Budget for two things.

Cost adders

• Third-party inspection fees. Charged per heat or per inspection visit, typically a few hundred USD per heat for a routine visit, plus travel and per-diem if the inspector must travel to the mill. For a multi-heat order these add up.
• Mill handling charges. Some mills apply a 3.2 surcharge per certificate, commonly in the range of 1–3% of material value for plate and pipe, sometimes expressed as a fixed fee per heat.
• Witness-test sample preparation. Extra test coupons, lab time, and the machine-hours to run the witnessed tensile, bend, and impact tests.

Lead-time impact

The real cost is often schedule, not money. The third-party inspector has to be present during production and testing, which means the mill must align the rolling and testing schedule with the inspector’s availability. In practice this introduces a 5–10 working-day witness window on top of the normal production lead time — sometimes longer during peak inspection seasons or if the named body has a backlog at that mill.

Practical implication: if your project has a fixed shipping date, lock in the third-party body and the witness dates at the same time you confirm the order. Treating the 3.2 as a “we’ll sort it out at the end” item is exactly how containers miss vessels.

8. How to Word the 3.2 Requirement in Your RFQ (Copy-Paste Clause)

Ambiguous wording is the root cause of most certificate disputes. “Provide MTC” or “3.1/3.2 as applicable” gives the mill room to ship a 3.1 and argue it met the order. Be explicit. Drop the following clause into your RFQ or PO and edit the bracketed fields:

“Mill Test Certificate to EN 10204:2004 Type 3.2 shall be supplied for each heat and delivery lot, signed and stamped by the manufacturer’s authorized inspection representative and by the authorized inspection representative of [insert third-party body — e.g. Lloyd’s Register / DNV / TÜV Rheinland / SGS / Bureau Veritas / ABS]. The third-party witness shall attend during test coupon extraction and mechanical testing (tensile, bend, and impact at [insert test temperature]). The certificate shall reference the applicable material standard and grade ([insert, e.g. EN 10025-2 S355J2+N / ASTM A516 Gr.70]), the heat number, the batch/lot number, and shall report actual chemistry and mechanical results against the specified limits. Chemical analysis shall be by spectrometry; results for C, Si, Mn, P, S [and additional elements as required] shall be within the stated ranges. No certificate referencing superseded types (3.1.A / 3.1.B / 3.1.C) shall be accepted. The witness inspection date shall be confirmed within [X] working days of order acknowledgment.”

This single paragraph removes the three most common escape routes — wrong type, wrong body, wrong test basis — before the mill ever rolls the steel.

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9. Common Documentation Rejections: Missing Stamp, Wrong Standard, Chemistry Out of Spec, Missing Third-Party Logo

Even when a 3.2 is produced, the certificate itself can still be rejected. These are the defects we see most often when buyers send us certificates that their end-user or customs authority has bounced:

• Missing third-party stamp or signature. The mill signed, but the inspector’s stamp is absent, smudged, or not legible. A 3.2 without a clear, identifiable third-party stamp is, for audit purposes, a 3.1.
• Wrong or obsolete standard reference. Certificates citing “EN 10204:1991 3.1.B” or a product standard that has been superseded. Auditors flag the year and the type; both must be current.
• Chemistry out of spec. An actual value that breaches the stated limit — for example, phosphorus reported at 0.038% against a 0.035% ceiling for S355J2 — and the certificate still marked “compliant.” This is an immediate fail and usually points to a mill lab or data-entry error, not a real nonconforming heat. It is fixable only by re-issue with corrected, witnessed data.
• Missing third-party logo. The body is named in the text but its registered logo/identifying mark is not on the certificate. Many auditors look for the logo, not just the name.
• Heat-number mismatch. The heat number on the certificate does not match the heat number stencilled on the material or on the packing list. Without traceability, the certificate does not cover the steel in front of you.
• Missing test temperature or impact values. For grades requiring toughness (S355J2, A516 Gr.70 for low-temperature service), an MTC without the impact test temperature and the actual KV/J values is incomplete.
• Unsigned or undated. Surprisingly common on electronically generated certificates — the digital signature block is blank or the date field shows the test date rather than the issue date.

Most of these are caught by a 60-second document check the moment the certificate arrives — not after loading. Build that check into your receiving inspection.

10. The 3.2 Workflow at Yihang Metal — From Rolling Schedule to Stamped Certificate to Loading

This is how we handle a 3.2 order at Yihang Metal, so you know what to expect and where the checkpoints are:

1. Order confirmation & rolling schedule. On PO acknowledgment, we fix the rolling schedule for your heats and reserve the test-lab slot. We confirm the named third-party body with you and contact the body to propose witness dates.
2. Third-party booking. We submit the rolling and testing plan to the inspection body and lock in the witness window — typically within the 5–10 day lead-time noted above. You receive the confirmed witness date.
3. Production under witness. The inspector attends during test-coupon extraction from the rolled material. Coupons are identified by heat and batch and transferred to the lab under the inspector’s control.
4. Witnessed testing. Tensile, yield, elongation, bend, and impact (at your specified temperature) are run with the inspector present. Spectrometric chemistry is verified against the heat analysis. The inspector records the results.
5. Certificate issuance & stamping. The MTC is drafted with actual results against spec limits, signed by our authorized inspection representative, and stamped and signed by the third-party inspector — including the body’s registered logo.
6. Document pre-check. Before loading, we send you the scanned 3.2 for review against the PO clause. You confirm heat-number match, chemistry compliance, and the presence of the third-party stamp.
7. Loading & dispatch. Original (or countersigned) certificates travel with the shipment, with electronic copies issued ahead of the vessel for your QA file and customs broker.

The point of this workflow is that the documentation is treated as a production deliverable, not an afterthought. The most expensive part of a 3.2 order is never the inspector’s fee — it is the schedule risk of getting the witness date wrong.

11. Quick Reference Table: Which Projects Need Which Certificate

Application / end-use	Typical certificate required	Driver	Notes
General structural steel (buildings, racks, non-critical)	3.1	EN 10204 default	2.2 acceptable only for lowest-risk, non-load-bearing items
Pressure equipment — PED Cat. I / II	3.1 (minimum)	PED 2014/68/EU	Confirm module-by-module; some Cat. II modules still accept 3.1
Pressure equipment — PED Cat. III / IV	3.2	PED + Notified Body	Notified Body involvement mandatory; 3.1 alone will not pass audit
Oil & gas — line pipe, pressure plate, forgings	3.2	Operator spec (Shell DEP, Aramco, etc.)	Named third party usually specified by operator
Marine — hull & classed structure	3.2 (class-stamped)	Class society (LR / DNV / ABS / BV)	Society’s stamp is the third-party signature
Public infrastructure — bridges, rail, ports	3.1, often 3.2 on primary members	Project technical specification	Check the project spec line by line
Nuclear	3.2 + code-specific qualification	RCC-M / ASME III / national nuclear code	Layered qualification beyond a standard 3.2
Non-critical consumables, brackets, misc.	2.1 or 2.2	Buyer discretion	Only where no load or pressure function exists

If you are unsure which row your project falls into, the safe move is to ask the end-user or the inspection authority before you RFQ the mill — the answer determines not just the paperwork but the production plan.

At Yihang Metal, we supply carbon and alloy steel plate, pipe, bars, and sections with full EN 10204 documentation — from a straightforward 3.1 MTC for structural grades through to third-party-witnessed 3.2 certificates stamped by Lloyd’s, DNV, TÜV, SGS, BV, or ABS for pressure, marine, and oil & gas applications. We manage the witness schedule inside the rolling plan so the certificate is ready when the steel is, not weeks after. Send us your specifications, the applicable standard and grade, and the named third-party body your project requires — we will come back with a documented quotation and a confirmed witness window.