Introduction:
Understanding 3.1 and 3.2 Material Certificates is very important for anyone working with industrial materials, quality control, or procurement.
These certificates may look similar at first glance, but they provide very different levels of traceability, testing, and compliance.
In many industries especially oil & gas, manufacturing, and instrumentation choosing the right certificate can make the difference between meeting a customer’s specification and facing costly rejections.
In this article, we will learn what 3.1 and 3.2 Material Certificates really mean, how they differ, and when each one is required.
What is a 3.1 Material Certificate?
When purchasing industrial components, you may come across 3.1 and 3.2 Material Certificates — both part of the EN 10204 standard.
Understanding the difference between 3.1 and 3.2 certificates is important for industries where safety, compliance, and documentation play a critical role
First let us understand what is a 3.1 material certificate. Then we will understand what is the difference between 3.1 and 3.2 material certificates.
A 3.1 Material Certificate is an official document that confirms a metal product meets specific quality and test requirements. It is issued under the European Standard EN 10204:2004. This certificate is signed by the manufacturer’s authorized inspection representative, who is independent of the production process.
The 3.1 certificate provides important details such as:
1) Material composition
2) Mechanical properties
3) Test results
4) Traceability information
Manufacturers do not release materials for production until they receive a satisfactory 3.1 certificate.
What is a Mill Test Certificate (MTC)?
A Mill Test Certificate (MTC) is a document provided by steel manufacturers to buyers. It includes essential details about the metal product, such as:
1) Weight and dimensions
2) Chemical composition
3) Mechanical strength
4) Heat treatment status
5) Test results
6) Traceability records
The MTC ensures that the steel product meets required quality standards and specifications.
Evolution of Material Certification Standards
Originally, material testing and certification were defined under the German standard DIN 50049. Over time, these definitions were incorporated into the European Standard EN 10204. The first version of EN 10204 was published in 1991 and included several certification types: 2.1, 2.2, 2.3, 3.1A, 3.1B, 3.1C, and 3.2.
In 2004, the standard was revised and renamed BS EN 10204:2004. The certificate types were simplified, leaving only:
- Type 2.1
- Type 2.2
- Type 3.1 (replacing 3.1B)
- Type 3.2 (replacing 3.1A, 3.1C, and 3.2)
Ensuring Material Traceability
Material traceability is crucial to identify potential issues if a problem arises. Here is how companies ensure proper traceability:
- Assign a unique material number when materials are received.
- Cross-reference this number with a job number.
- Verify the material certificate against the received material.
- Store the certificate in a digital format (PDF) for easy access.
- Maintain records that allow tracking from the end-user back to the original supplier.
By following these steps, manufacturers ensure compliance with ISO 9001 and maintain high-quality standards.
Difference Between 3.1 and 3.2 Material Certificates
3.1 Material Certificate
1) Issued by the manufacturer’s authorized representative.
2) Confirms that the material meets order specifications.
3) The representative is independent of the manufacturing process.
4) Includes actual test results for the specific batch of material.
3.2 Material Certificate
1) Includes all information from a 3.1 certificate.
2) Additionally verified by an independent inspection authority or the buyer’s authorized inspector.
3) Provides an extra layer of assurance through third-party validation.
4) More expensive due to additional verification costs.
Practical Application of 3.2 Certificates
For example, if a company orders a pump with a 3.2 certificate, the certification applies to individual components (e.g., casing, impeller, shaft), not the entire pump.
Customers should specify which components require 3.2 certification to avoid unexpected costs.
Key Takeaways for 3.1 and 3.2 material certificates
A 3.1 certificate is signed by the manufacturer’s inspection representative.
A 3.2 certificate is verified by an independent third party for added assurance.
Material traceability ensures quality and compliance with standards.
Customers should clearly specify their certification requirements to avoid additional costs.
Proper documentation helps in quality assurance and troubleshooting issues if they arise.
A 3.2 certificate provides an additional layer of assurance regarding material quality and traceability. Understanding the difference between 3.1 and 3.2 material certificates helps manufacturers and buyers ensure product quality, maintain compliance, and reduce risks in industrial applications.
Frequently Asked Questions (FAQs)
1. What are 3.1 and 3.2 Material Certificates?
3.1 and 3.2 Material Certificates are quality documents defined under EN 10204. They provide details about the chemical, mechanical, and testing properties of a material, along with varying levels of validation and oversight.
2. What is the main difference between 3.1 and 3.2 Material Certificates?
The key difference is the level of verification:
- 3.1 Certificate – Verified and signed by the manufacturer’s authorized inspection representative.
- 3.2 Certificate – Verified by both the manufacturer and an independent third-party inspector (for example, TPI or customer-appointed authority).
3. Why is a 3.2 certificate considered more stringent?
Because it includes third-party involvement. The external inspector independently validates the tests, results, and compliance, ensuring a higher level of traceability and assurance.
4. When is a 3.1 Material Certificate sufficient?
A 3.1 certificate is usually adequate for standard industrial applications where compliance with material specifications is required but no external verification is mandated.
5. When do industries require a 3.2 Material Certificate?
3.2 certificates are often required for:
- Critical applications (high pressure, high temperature, safety-critical parts)
- Oil & gas, petrochemical, and power plant equipment
- Customer-specific requirements that demand third-party verification
6. Do 3.1 and 3.2 certificates contain the same information?
Yes, the technical content is usually similar chemical composition, mechanical properties, heat treatment details, test reports, etc. The difference lies in who verifies and signs the certificate.
7. Are 3.2 certificates more expensive?
Yes. Because third-party inspection is involved, 3.2 certificates cost more and take longer to process.
8. Can a 3.1 certificate be upgraded to a 3.2 certificate?
Generally no. A 3.2 certificate requires the inspector to witness or verify tests during manufacturing, so it cannot be issued retrospectively.
9. Who issues 3.1 and 3.2 Material Certificates?
- 3.1 – Manufacturer’s quality department or authorized inspection representative.
- 3.2 – Manufacturer + Third-party inspector (such as Lloyd’s, TUV, SGS, DNV, BV, or customer inspector).
10. Are 3.1 and 3.2 certificates required for all materials?
No. They are typically required only when specified in:
- Customer purchase order
- Project specifications
- Industry standards
- Regulatory requirements
11. Which certificate is better: 3.1 or 3.2?
Neither is “better”; the choice depends on the required level of assurance.
- Use 3.1 for standard assurance.
- Use 3.2 when high-criticality and independent verification are required.
12. How can I know which certificate I need?
Check:
- Customer requirements
- Material class/certification level
- Project/industry standards
- Risk or criticality of the application
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