EN 10204 3.1 vs 3.2: What Is the Difference for Steel Buyers?
A buyer orders 200 tons of pressure vessel steel. The grade, thickness, and quantity are correct. But when the documents arrive, the certificate is EN 10204 3.1 instead of 3.2.
What does that mean? Is 3.2 actually better than 3.1? When does a project require 3.2? Who needs to sign the certificate?
This guide explains the difference between EN 10204 3.1 and 3.2 — and what buyers should confirm before placing an order.
1. What Is EN 10204?
EN 10204 defines the types of inspection documents used for metallic products. It covers several certificate types, including 2.1, 2.2, 3.1, and 3.2. For steel buyers, the most common are 3.1 and 3.2.
2. What Is an EN 10204 3.1 Certificate?
2.1 What Information Does a 3.1 Certificate Contain?
- ✔ Steel grade
- ✔ Heat number
- ✔ Chemical composition
- ✔ Mechanical properties
- ✔ Dimensions
- ✔ Heat treatment condition
- ✔ Test results
- ✔ Manufacturer identification
2.2 Who Issues the 3.1 Certificate?
A 3.1 certificate is issued by the manufacturer's authorized inspection department. The inspector must be independent of the production department.
2.3 Is EN 10204 3.1 Enough for Steel Purchasing?
It depends on the project specification, purchase order, applicable standard, end-user requirement, classification society, and third-party inspection requirement. For general applications, 3.1 is often sufficient. For critical projects, 3.2 may be required.
3. What Is an EN 10204 3.2 Certificate?
A 3.2 certificate involves both the manufacturer's authorized inspection representative and an independent inspector or purchaser's representative.
The independent inspection may be carried out by:
- ✔ SGS
- ✔ BV (Bureau Veritas)
- ✔ TÜV
- ✔ DNV
- ✔ Lloyd's Register
- ✔ RINA
4. EN 10204 3.1 vs 3.2: Key Differences
💡 Key point: EN 10204 3.2 is not simply a "higher grade" version of 3.1. The main difference is the involvement of an independent or purchaser-appointed inspection representative.
5. Does EN 10204 3.2 Mean Better Steel?
No. 3.2 does not automatically mean that the steel itself has better chemical or mechanical properties.
The same batch of SA516 Gr.70 can meet the same chemical composition, tensile strength, yield strength, elongation, and impact requirements under either 3.1 or 3.2. The difference is who participates in the inspection and document confirmation.
6. When Do Steel Buyers Need EN 10204 3.2?
6.1 Pressure Vessels and Boilers
- ✔ Pressure vessels, boilers, storage tanks, petrochemical equipment
6.2 Shipbuilding
- ✔ Classification society projects: DNV, ABS, LR, BV, RINA
6.3 Bridges and Critical Structures
- ✔ Bridge steel, structural steel, heavy-duty structures
6.4 Projects Requiring Third-Party Inspection
- ✔ If the purchase contract specifies EN 10204 3.2, the supplier must arrange it during production and inspection
7. What Should Steel Buyers Check on an EN 10204 Certificate?
- ✓ Grade — SA516 Grade 70 / SA516M Grade 70
- ✓ Heat Number — traceable to the physical plate
- ✓ Chemical Composition — C, Mn, Si, P, S, alloying elements
- ✓ Mechanical Properties — yield, tensile, elongation, impact
- ✓ Heat Treatment — N, TMCP, QT as applicable
- ✓ Thickness / Dimensions — matches the actual plates
- ✓ Inspection / Certification — manufacturer, inspector, signatures, certificate number
8. Common Mistakes When Ordering EN 10204 3.1 / 3.2 Steel
❌ Mistake 1: Asking for 3.2 after production
If 3.2 is not specified at the order stage, arranging third-party involvement after production may cause additional inspection, cost, and schedule delays.
❌ Mistake 2: Assuming 3.2 means better material
3.2 relates to the inspection and certification process, not the steel's chemical or mechanical properties.
❌ Mistake 3: Not specifying the inspection body
If a project requires third-party inspection, specify which body — SGS, BV, TÜV, or a classification society. Confirm at the PO stage.
❌ Mistake 4: Checking the certificate but not the heat number
Always verify that the heat number on the certificate matches the marking on the physical plate.
9. EN 10204 3.1 vs 3.2: Which One Should You Specify?
- ✔ Standard industrial steel procurement — 3.1 may be sufficient if the applicable specification and project requirements allow it.
- ✔ Projects requiring independent inspection — 3.2 may be specified.
- ✔ Pressure vessel / shipbuilding / critical projects — follow the project specification, purchaser's requirements, and applicable code/class requirements.
10. Frequently Asked Questions
❓ What is EN 10204 3.1?
EN 10204 3.1 is an inspection certificate issued by the manufacturer's authorized inspection department, confirming that the product meets the specified requirements.
❓ What is EN 10204 3.2?
EN 10204 3.2 is an inspection certificate that involves both the manufacturer's authorized inspection representative and an independent inspector or purchaser's representative.
❓ Is EN 10204 3.2 better than 3.1?
Not necessarily. 3.2 does not automatically mean the steel has better chemical or mechanical properties. The difference is the involvement of an independent inspection representative.
❓ What is the difference between EN 10204 3.1 and 3.2?
The main difference is the inspection and certification process. 3.1 is issued by the manufacturer's inspection department. 3.2 also involves an independent inspector or purchaser's representative.
❓ Who issues an EN 10204 3.1 certificate?
It is issued by the manufacturer's authorized inspection department, with the inspector independent of the production department.
❓ Who signs an EN 10204 3.2 certificate?
Both the manufacturer's authorized inspection representative and an independent inspector or purchaser's representative sign the certificate.
❓ Does EN 10204 3.2 require third-party inspection?
Yes. 3.2 involves an independent inspector or purchaser's representative, which may be a third-party inspection agency or classification society surveyor.
❓ Is EN 10204 3.1 acceptable for pressure vessel steel?
It depends on the project specification, purchase order, and applicable design code. Some pressure vessel projects accept 3.1; others require 3.2.
❓ Does an EN 10204 certificate guarantee steel quality?
A certificate confirms that the product, batch, and test results meet the agreed requirements. It is not a blanket guarantee of all possible properties.
11. Final Thoughts
Before placing a steel order, don't simply ask for "a material certificate." Check which EN 10204 certificate type is required by the project.
Three actions to confirm:
- ✔ Confirm the required certificate type (3.1 or 3.2)
- ✔ Confirm whether third-party inspection is required
- ✔ Make sure the heat number and test results are traceable to the physical plates
💡 Our view: For carbon steel plate orders, we can discuss the required EN 10204 certificate type, inspection requirements, and MTC details before production.
📚 Further Reading & Related Content
- 🔗 What Is a Heat Number on a Steel Mill Test Certificate?
- 🔗 Heat Analysis vs Product Analysis: What Is the Difference in Steel?
- 🔗 How to Read a Steel Plate Mill Test Certificate (MTC)
- 📄 EN 10204:2004, ASTM A20/A20M, ASME SA-516/SA-516M
Need Steel Plates with EN 10204 3.1 or 3.2 Certification?
CEHE STEEL supplies carbon steel plates with EN 10204 3.1 or 3.2 certification as required. Send us your specification and certificate requirements — we'll confirm the inspection scope and provide a quotation.