Steel Mill Test Certificates (MTCs) play a critical role in verifying the quality, compliance, and traceability of steel products. For UK and international buyers, understanding the difference between EN 10204 Type 3.1 and Type 3.2 certificates is essential to avoid delays, rejections, and compliance issues.
This guide explains what steel mill test certificates are, how 3.1 and 3.2 certificates differ, and when each is required.
EN 10204 3.1 vs 3.2 – Quick Decision Guide
- Choose 3.1 → Standard construction, fabrication, most steel orders
- Choose 3.2 → Critical infrastructure, offshore, oil & gas, or when required by contract
Most steel projects only require EN 10204 3.1 certification. Type 3.2 should only be specified when independent third-party verification is contractually required.
What Is a Steel Mill Test Certificate?
A Steel Mill Test Certificate is an official document issued by the steel manufacturer confirming that the supplied material complies with the specified standard and grade.
An MTC typically includes:
- Steel grade and standard
- Chemical composition
- Mechanical properties
- Heat or batch number
- Traceability details
Mill test certificates provide assurance that the steel supplied matches the agreed specification.
What Is EN 10204?
EN 10204 is the European standard that defines the types of inspection documents supplied with metallic products.
It sets out:
- Who issues the certificate
- Level of verification
- Degree of independence in inspection
The most commonly used certificate types in steel procurement are Type 3.1 and Type 3.2.
EN 10204 Type 3.1 Certificate Explained
A 3.1 certificate is issued by the manufacturer’s authorised inspection representative and confirms that the steel complies with the order specification.
Key characteristics:
- Issued by the steel manufacturer
- Based on actual test results
- Includes full chemical and mechanical data
- Most commonly used certificate type
Typical use cases:
- Structural steel projects
- General fabrication
- Commercial and industrial construction
Type EN 10204 3.1 certificates are widely accepted for the majority of UK steel applications.
EN 10204 Type 3.2 Certificate Explained
A EN 10204 3.2 inspection certificate provides a higher level of assurance and includes independent verification.
Key characteristics:
- Verified by an independent inspector or purchaser’s representative
- Involves third-party validation
- Higher cost and longer lead time
Typical use cases:
- Critical infrastructure
- High-risk or regulated industries
- Client- or contract-specific requirements
Type 3.2 certificates are only required where explicitly specified.
EN 10204 3.1 vs 3.2 – Key Differences
| Feature | EN 10204 3.1 | EN 10204 3.2 |
|---|---|---|
| Issued by | Manufacturer | Manufacturer + Independent party |
| Verification | Internal | Third-party |
| Cost | Standard | Higher |
| Lead time | Faster | Longer |
| Typical use | Most projects | High-risk applications |
The key difference between EN 10204 3.1 and 3.2 is the level of verification. A 3.1 certificate is issued by the manufacturer and is sufficient for most structural and commercial applications. In contrast, a 3.2 certificate requires independent third-party validation, increasing both cost and lead time.
For most projects, specifying 3.1 ensures compliance without unnecessary delays or additional inspection costs.
Cost and Lead Time Impact of 3.1 vs 3.2
- 3.1 Certificate
- Included in standard pricing
- No impact on lead time
- Issued directly by mill
- 3.2 Certificate
- Additional inspection cost
- Requires third-party coordination (SGS, BV, etc.)
- May delay shipment by several days
In many international projects, unnecessary specification of 3.2 certification can increase total project cost without adding practical value.
When 3.1 vs 3.2 Is Typically Used
- 3.1 is used for:
- General construction
- Steel structures
- Fabrication projects
- Commercial buildings
- 3.2 is required for:
- Oil & gas projects
- Offshore structures
- Nuclear or high-risk environments
- Projects with strict regulatory oversight
When Should Buyers Specify a 3.1 or 3.2 Certificate?
Buyers should specify:
- 3.1 certificates for most structural and fabrication projects
- 3.2 certificates only when required by:
- Contract documents
- End-client specifications
- Regulatory bodies
Always confirm certificate requirements before placing an order.
Common Buyer Mistakes with Mill Test Certificates
Some of the most common issues include:
Not specifying certification type at order stage
- Assuming 3.2 is always “better”
- Receiving certificates that don’t match heat numbers
- Not checking traceability between certificate and material
- Over-specifying 3.2 and increasing unnecessary cost
These mistakes often result in project delays or rejected steel.
How CoreMet Steel Supports Buyers with Certification
CoreMet Steel ensures all supplied materials meet project certification requirements by:
- Confirming certification type before order placement
- Supplying EN 10204 3.1 as standard
- Arranging 3.2 certification when required
- Verifying full traceability (heat number matching)
- Coordinating with third-party inspectors when needed
Our focus is to ensure steel arrives fully compliant and ready for use.
How CoreMet Steel Supports Buyers
CoreMet Steel works as a steel sourcing partner, helping buyers:
- Evaluate UK and imported options
- Balance cost, lead time, and compliance
- Verify standards, grades, and certification
- Secure reliable supply chains
Our role is to help buyers make informed, project-specific decisions.
Industry Standards and Further Guidance
Guidance on inspection documents and certification standards is provided by organisations such as the British Standards Institution (BSI), which oversees the adoption of EN standards in the UK. For detailed global steel certification practices, buyers can also refer to the World Steel Association.
Speak to CoreMet Steel
Choosing the correct certification is critical for compliance, cost control, and project timelines.
Contact CoreMet Steel for:
EN 10204 3.1 certified steel (standard supply)
- 3.2 certification with third-party inspection
- UK & international project support
- Fast delivery from trusted mills
- Full traceability and documentation
get a free quote
Built for reliable steel supply.projects.trade.sourcing.partnerships.
From steel coils to fencing systems: sourcing quality materials for global buyers, projects, and distributors.
