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A 3.2 inspection certificate is a critical part of the procurement of steel


What is a 3.1 Certificate?

When one purchases steel, the manufacturer will release the MTC (Mill Test Certificate) to the buyer. All specifications of the steel are detailed in the MTC. This includes the mass, dimensions, chemical composition, mechanical strength, heat treatment status, etc. This information is especially important as it ensures that the stipulated quality of the steel has been reached.

This Mill Test Certificate is what we call a 3.1 Inspection Certificate. – i.e a 3.1 Inspection Certificate details the actual test results from the material in the lot from which the steel products have been supplied. The steel manufacturer’s own representative, independent from the manufacturing process, endorses this certificate. An example of this person would be the quality department or quality manager or supervisor.


What is a 3.2 Inspection Certificate?

The set of metallurgical tests to verify the key properties of the steel is essentially what a 3.2 Inspection Certificate entails.

A 3.2 Inspection Certificate verifies the 3.1 or Mill Test Certificate and the verified testing and issuing of the certificate is carried out by a certified independent third-party. In other words, 3.2 Inspection certificates provide independent assurance of the steel’s properties. It confirms that the steel supplied by a manufacturer meets the requirements of the buyer’s order.

3.2 inspection certificates therefore provide independent assurance of a material’s properties. It declares the products or material supplied by a manufacturer meet the requirements of the buyer’s order. They provide a higher level of certification. Manufacturers can be confident about the integrity of the steel material that they have purchased.

It is critical to use an ISO 17025:2017 and industry accredited metallurgy or materials testing laboratory to carry out 3.2 Inspection in order to protect the manufacture and mitigate the risk of failure.


3.2 Inspection for steel plate is relevant for steel sections and bars, and the tests required are:

  • Alloy Chemistry
  • Tensile Tests
  • Impact Tests
  • Microstructural Investigation (High Strength Materials)


3.2 inspection for steel pipe is relevant for tubes and fittings, and the tests required are:

  • Alloy Chemistry
  • Tensile Tests
  • Impact Tests
  • Flattening Test
  • Flaring Test
  • Hardness Traverse


A 3.2 Inspection Certificate is required in Marine and Offshore Manufacturing for the vessel or marine structure to remain in class.

3.2 inspection is required according to marine manufacture rules/law and is intended for risk mitigation.

Failures in marine vessels and structures result in excessively big costs, and often in lawsuits. In this eventuality, the owner of the vessel in question will be protected by 3.2 inspection by an ISO and industry-accredited materials testing laboratory, and further by the necessary weld procedure qualification.

The explosion of BP’s Deepwater Horizon oil rig in 2010 took 11 lives, resulted in the biggest oil spill in history and an indescribable environmental disaster, and ultimately cost BP $65 billion. In other words, one cannot put a price on compliance and risk mitigation.


One Eighty is Bureau Veritas marine and offshore approved. What does this mean?

The big advantage of this to clients is that Bureau Veritas inspection is now no longer required if testing is done by One Eighty’s accredited laboratory.  Our Bureau Veritas approval means that the inspection is built into our service.

Bureau Veritas approval means that One Eighty is an extremely cost-effective solution for metallurgical and mechanical testing.  A 3.2 recertification of steel can be achieved through One Eighty Materials testing at a fraction of the price.


For more information on One Eighty’s 3.2 Inspection offering or any other metallurgical services, contact Dr Janet Cotton on

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