What is the difference between an EN 10204 3.1 and 3.2 certificate?
An EN 10204 3.1 certificate is issued by the manufacturer and validated by its own inspection department, which must be independent of production. A 3.2 certificate covers the same test results but is additionally countersigned by an independent inspector — either the purchaser’s representative or a third party such as SGS, BV, TUV or Lloyds.
Key Takeaways
- EN 10204 defines four inspection document types: 2.1, 2.2, 3.1 and 3.2.
- Type 3.1 is issued by the manufacturer and validated by its own inspection department, which must be independent of the production department.
- Type 3.2 carries the same results plus the countersignature of an independent inspector or the purchaser’s representative.
- Type 2.2 is a test report on non-specific inspection and does not trace to the actual delivered items — it is not a substitute for 3.1.
- The heat number is the field that ties the certificate to the physical part; without it the document proves nothing about what arrived.
- Kalp Alloys issues the certificate in its own name because it manufactures the material, rather than passing on a certificate from an unnamed mill.
The four EN 10204 document types
EN 10204 does not describe a quality level. It describes who inspected the material and how closely that inspection is tied to the specific items being delivered. That distinction is what the four type numbers encode.
| Type | Inspection basis | Issued and validated by | Ties to the delivered items |
|---|---|---|---|
| 2.1 — Declaration of compliance | Non-specific | Manufacturer | No test results at all |
| 2.2 — Test report | Non-specific | Manufacturer | Results from general production, not from your items |
| 3.1 — Inspection certificate | Specific | Manufacturer’s independent inspection department | Yes — results are from the delivered heat |
| 3.2 — Inspection certificate | Specific | Manufacturer plus an independent inspector or purchaser representative | Yes — with countersignature |
The practical line is between 2.2 and 3.1. A 2.2 report is generated on non-specific inspection: the results are genuine but they come from the manufacturer’s general production, not from testing carried out on the batch you received. A 3.1 certificate is specific — the results relate to the heat that produced your material. Where a specification says 3.1 and a 2.2 is supplied, the substitution is a non-conformance regardless of how good the numbers look.
How to read a mill test certificate, block by block
A certificate is checked, not filed. Six things are worth verifying before material is accepted onto site.
- Issuer and type. Whose name is on the document, and does it state 3.1 or 3.2? A certificate issued by a trading company describes material that trader bought, not material that trader made.
- Heat or cast number. This is the anchor. It must appear on the certificate and be physically stamped or marked on the item. If they do not match, the certificate belongs to different material.
- Material specification and grade. Check it against the purchase order in full, including any suffix. A105 and A105N are different requirements; F316 and F316L are different requirements.
- Chemical composition. Each element should fall inside the range the specification allows. Pay attention to carbon on L grades, and to chromium, nickel and molybdenum on stainless and duplex.
- Mechanical properties. Tensile strength, yield strength, elongation and, where required, hardness and Charpy impact values, each above the specified minimum.
- Heat treatment condition. Annealed, normalised, quenched and tempered, solution annealed — this must match what the specification calls for, and it is the field most often skipped.
On sour service, add the hardness survey. On alloy items, add the PMI report. On duplex, add the ferrite content.
Why the name on the certificate matters
A mill test certificate is a statement by whoever issued it. When the issuer is the company that melted, forged and tested the material, the document and the material have the same author, and a question about either goes to one place.
When material is bought through a marketplace or a stockist, the certificate that arrives is a copy of a document issued by a mill the buyer did not select and cannot query. If a project auditor challenges a value, the query travels back down the chain, and the trader in the middle can only forward it.
Kalp Alloys manufactures at 5, Jay Vijay Industrial Estate, B/h. Akash Vikas Estate, Keval Kanta Road, Rakhial, Ahmedabad. The heat number on our certificate traces to our own melt and forging record, the dimensional report comes from our own inspection bay, and the certificate is issued in the name of Kalp Alloys. For approved-vendor submissions, code-governed lines and validated facilities, that is not a marketing distinction — it is the difference between a package that clears and one that does not.
Additional documentation supplied on request
The 3.1 certificate is the base. Depending on the service, the following are added to the pack:
- EN 10204 3.2 with witnessing by SGS, BV, TUV or Lloyds, arranged at our plant before dispatch.
- NDT records — radiography, ultrasonic, magnetic particle or dye penetrant, as the specification requires.
- Hydrostatic test report where the item is pressure tested.
- PMI report confirming alloy identity at the finished part rather than at the billet. Worth requesting on every nickel alloy item, because Hastelloy C276, Inconel 625 and Incoloy 825 are visually indistinguishable once machined.
- NACE MR0175 / MR0103 compliance statement with supporting hardness survey results — see NACE MR0175.
- Ferrite content on duplex and super duplex, and ASTM A262 intergranular corrosion testing on austenitic grades.
- Charpy impact results on low-temperature grades such as ASTM A350 LF2.
Reference data for the grades we supply is published on our chemical composition and mechanical properties pages, so a certificate can be checked against the expected ranges before material leaves our floor.
Frequently Asked Questions
An inspection certificate issued by the manufacturer, based on specific inspection of the delivered material, and validated by the manufacturer’s own inspection department, which must be organisationally independent of the production department.
Both cover specific inspection of the delivered material. A 3.2 certificate is additionally countersigned by an independent inspector or the purchaser’s representative, typically SGS, BV, TUV or Lloyds, who witnesses the testing.
Not where the specification calls for 3.1. A 2.2 report is based on non-specific inspection, so the results come from general production rather than from the heat that produced your material. Substituting it is a non-conformance.
The heat or cast number identifies the batch of molten metal the part was made from. It appears on the certificate and is marked on the item, and it is the only link between the physical material and the document. Without a match, the certificate proves nothing.
Yes. Kalp Alloys manufactures the material at its own facility in Rakhial, Ahmedabad, so the EN 10204 certificate is issued in the name of Kalp Alloys rather than being a copy passed through from a third-party mill.
Yes. SGS, BV, TUV and Lloyds inspection can be witnessed at our Ahmedabad plant before dispatch, and the release note is issued together with the EN 10204 3.2 certificate.
Yes. An EN 10204 3.1 certificate is issued with every consignment regardless of order size, including trial quantities.
Positive material identification confirms the alloy composition of the finished component using a portable analyser. It is worth requesting on every nickel alloy and exotic grade item, because those materials are visually indistinguishable once machined.