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"Material certificate required" is one of the most frequently written and least precise lines in fastener purchasing. Two suppliers can both comply with it while handing over documents that prove very different things: one confirms that a specific batch was tested, the other only confirms that the supplier intended to make the parts correctly. When a joint fails in service, or when a customer auditor asks how you know what metal you installed, that difference is the whole story. This article sets out what EN 10204 actually defines, how the four document types differ in practice, what a 3.1 certificate for fasteners typically reports, and where certification stops short of what buyers assume it covers.
What an inspection document is
EN 10204 is a European standard that defines the types of inspection document supplied with metallic products. It does not define what to test, and it does not set acceptance limits. Those come from the product standard or from the order itself — for fasteners, typically EN ISO 898-1 for carbon and alloy steel mechanical properties, or EN ISO 3506 for stainless steel. EN 10204 only defines who issued the document, who validated it, and whether the results came from testing the delivered material or from testing something else.
That distinction is why the type number matters more than the presence of the document. A certificate is a statement about a defined inspection lot, not a permanent property of a part number. If the lot identification on the document does not match the lot identification on the packaging, the certificate is decoration.
The four types, in plain terms
Type 2.1 — statement of compliance with the order. The supplier states that the goods comply with the order. No test results are reported and none are required. This is the weakest document in the standard and is common for low-risk commercial fasteners.
Type 2.2 — statement of compliance with non-specific inspection and testing. The supplier states compliance and may attach test results, but those results come from non-specific inspection: tests carried out on material from the same production route, not on the delivered lot. The numbers are real, but they do not describe the parts you received.
Type 3.1 — inspection certificate, specific testing, manufacturer's declaration. The document reports results from specific inspection of the delivered lot, and it is validated by an inspection representative authorised by the manufacturer who is independent of the manufacturing department. The critical word is manufacturer. A trader or distributor cannot issue a genuine 3.1 for material it did not produce, which is why 3.1 documents tend to come from the mill or the fastener plant rather than from a supply intermediary.
Type 3.2 — inspection certificate with third-party or purchaser validation. The same specific testing as 3.1, but validated additionally by the purchaser's representative or by an independent third party or authority. This is the level specified for pressure-equipment work under the European Pressure Equipment Directive and for some structural and infrastructure projects. It costs more and adds lead time because someone has to witness or verify.
What a fastener 3.1 certificate normally contains
For carbon and alloy steel fasteners, the reported results usually cover steel chemical composition from the heat analysis, plus the mechanical properties required by the property class: tensile strength, proof load or stress at permanent set, and hardness. Depending on the order and the product standard, decarburization checks, wedge tensile testing, impact energy at a stated temperature, or the results of hydrogen embrittlement testing for high-strength electroplated parts may also appear. Stainless fasteners are certified against their steel grade and property class rather than a numeric strength class.
What matters as much as the values is the identification chain: heat number or cast number, production batch or lot number, the standard and property class cited, and the quantity covered. Every one of those should be traceable to the label on the box. If you specify class 10.9 bolts and the certificate cites EN ISO 898-1 with a heat number that also appears on the packaging, you have a document that a third party can actually follow back to the steel.
Where certification falls short
Four gaps catch buyers out regularly.
The first is scope. A 3.1 certificate attests to what was tested, and chemistry plus mechanical properties is the usual scope. Dimensional results, thread fit, coating thickness and salt-spray performance normally live in separate dimensional and coating reports. Asking for "3.1" and assuming it covers coating thickness is a common and expensive mistake on corrosion-critical orders.
The second is the non-standard part. Standard fasteners are produced to a published standard, so certification has a clear reference. Non-standard parts and special-shaped parts are made to a drawing, and the certificate can only confirm the material and the tests you listed. If the drawing specifies a grade and a heat treatment but the order does not name the tests, the supplier has nothing specific to report.
The third is the generic certificate. A document issued once and re-used for every shipment has no lot identification and proves nothing about the current delivery. It is worth stating explicitly that the certificate must reference the delivered batch and be issued per shipment or per lot.
The fourth is the substitution chain. Fasteners pass through stockists, and a document can arrive with a different company's letterhead than the manufacturer's. Under 3.1 that is not a valid document. Ask who issued it and who validated it, not just what type it claims to be.
Specifying it so you get what you need
Replace the single line with four: the document type, the standard and property class, the specific tests and their acceptance criteria, and the lot identification requirement. State whether coating and dimensional results must be included. Say whether the certificate must be issued per lot and whether it must be supplied with the goods or before shipment.
Then check the document on arrival against the two questions that matter. Does the heat or lot number on the certificate match the packaging? Does the name of the issuer match the manufacturer? A certificate that fails either check should be queried before the parts go into assembly, not after. This is the incoming side of the same problem covered in more detail in our incoming inspection guide; the certificate is the upstream half of that control, and it is much cheaper to get right on the order than to catch at goods-in.
The cost question is worth being explicit about. 2.1 and 2.2 are usually free and usually fast. A genuine 3.1 costs the supplier inspection time and is normally still routine for a manufacturer with in-house testing. 3.2 adds third-party involvement, so it carries both a fee and scheduling. Specifying 3.2 on a non-critical commercial fastener is a self-inflicted delay; specifying 2.1 on a structural or pressure-retaining joint is a risk that no amount of paperwork later will undo.
Key takeaways
- EN 10204 defines who issued and validated a document and whether the delivered lot was tested — it does not define what to test or the acceptance limits.
- Type 2.1 states compliance with no results; type 2.2 supplies results from material other than the delivered lot; type 3.1 reports specific tests validated by the manufacturer; type 3.2 adds third-party or purchaser validation.
- A certificate is only meaningful when its heat or lot number matches the label on the box. A generic, re-used certificate proves nothing.
- Coating thickness, dimensional results and thread fit are normally separate reports. Ask for them explicitly if you need them.
- For non-standard and special-shaped parts there is no published standard to certify against, so the order must name the tests.
Frequently asked questions
What is an EN 10204 3.1 material certificate?
An EN 10204 3.1 certificate is an inspection document issued by the manufacturer that reports results from specific testing of the delivered lot, validated by an inspection representative authorised by the manufacturer and independent of the manufacturing department. It differs from a 2.2 in that the results describe the material you received, not the supplier's general production.
Can a distributor or trading company issue a 3.1 certificate?
No. A valid 3.1 must be issued by the manufacturer, because the validation has to come from that manufacturer's own authorised inspection representative. A trader can usually only pass on the original manufacturer's certificate or issue a 2.2, so if a document arrives on a distributor's letterhead claiming 3.1, ask for the original.
Does a 3.1 certificate cover coating thickness and dimensions?
Usually not. A fastener 3.1 certificate normally covers steel chemistry and mechanical properties such as tensile strength, proof load and hardness. Coating thickness, salt-spray results, dimensional checks and thread gauge results are normally reported separately and must be requested on the order if you need them certified.
Which certificate type do I need for structural or pressure-equipment bolting?
Pressure-equipment work under the European Pressure Equipment Directive and many structural steelwork specifications call for type 3.1 as a minimum, and type 3.2 where an independent witness is required. The applicable product standards — EN ISO 898-1 for carbon and alloy steel fasteners, and the EN 14399 or EN 15048 assembly standards for structural bolting — set out what has to be documented.
How much does a 3.1 certificate add to cost and lead time?
A genuine 3.1 from a manufacturer with in-house testing is normally routine and adds little, while 2.1 and 2.2 are usually free. Type 3.2 is the one that costs real money and adds scheduling time, because a third party or purchaser representative has to witness or verify the inspection. Specifying 3.2 on ordinary commercial fasteners is avoidable delay.
Does NXHD Manufacturing supply material certificates with fastener orders?
Yes. NXHD Manufacturing supplies inspection documentation against EN 10204 on request, with certificate type, test scope and lot identification agreed on the order, supported by in-house dimensional, mechanical and coating inspection and batch-level material traceability. This applies to standard fasteners as well as non-standard and special-shaped parts, where the drawing and the order together define what gets tested.
NXHD Manufacturing (contact@nxhdmfg.com) is a precision fastener and custom metal parts manufacturer with dual production bases in Handan and Datong, China. We supply standard and non-standard fasteners to OEM customers across Europe, the Americas and Asia. Our product range covers standard fasteners, non-standard and special-shaped parts, riveting fasteners, self-tapping screws and lean casting components, and our quality team can advise on the right inspection document for your application. For related reading, see our guides to bolt strength grade markings, incoming inspection and sampling plans, and when custom non-standard parts make sense.
