With so many different ways of analyzing metals that various companies use, it can be difficult to understand exactly how your product or item is going to be tested. One of the most important decisions you will make is whether to use a destructive or a non-destructive method.

Much of this will depend on the item that you want the composition of to be identified and if you have any scrap that can be used instead of the actual product itself. In many instances, the best method to use will be a non-destructive analysis.

Positive material identification, or PMI, offers a non-destructive way of identifying a metal’s make up. PMI includes a number of methods, including Optical Emissions Spectroscopy, that can accurately determine the chemical make-up of an item without harming the item. This analysis is generally chemical in nature and can be performed either on site or under laboratory conditions.

While OES can be used to determine if something is made of a single metal, usually it is used to determine the chemical composition of an alloy.

What PMI Is Used For

  • To answer questions about a part which is part of an assembly or is just too large for shipping
  • When material identification or documentation can no longer be found
  • To test a sample which cannot be cut or altered for routine testing
  • When there are questions regarding samples, which are simply too costly to destroy
  • To test a mixed lot of materials that seems to not be what was purchased

Why is Positive Material Identification Testing Necessary?

The obvious purpose of PMI is to identify the metal or metals used to make a product. Typically, it is used to test alloys, providing important bits of information about the product beyond the composition: you can determine if a particular process has been successful in meeting set quality standards and compliance requirements (particularly for safety).

For wholesale suppliers and workers in manufacturing plants, it is vital to know the precise composition and grade of many commercially-used alloys because it allows all the parties in the supply chain to ensure alloy specifications, which are selected for their special properties, are perfectly matched. These include corrosion resistance, heat resistance, durability, and more.

Some industries have very strict alloy requirements, such as petroleum and power businesses. They must know exactly what the composition of a metal is before they can use a particular product. This is because the correct alloy with all the correct properties is necessary for a safe, efficient operation. When a composition is not as expected, it can cause destructive reactions and catastrophic events.

How is PMI Testing Done?

There are multiple methods and techniques to identify metals including hand-held XRF, Mobile ARC, visual spark and OES. These methods are fast and often take seconds to complete their analyses. They are also considered to be highly accurate.

Optical Emissions Spectroscopy is our main focus of PMI testing. This non-destructive form of testing leaves a 10-micrometer deep mark and provides. After the sample is prepped, such as grinding the surface, the spectrometer analyzes the spark during the shot to identify the components of the sample piece.

Understanding the PMI Standards

Like all other types of testing, there are specific standards set for each type of PMI test. The standards dictate almost every aspect of the procedure, from how the sample will be taken to the instrument that will be used to conduct the analysis. It also includes traceability so that you can review the results to fully understand the supply chain so that problems can be more easily identified and corrective action taken.

Due to these standards, it is important to have a fully trained professional or company performing PMI.

When is Positive Material Identification Testing Used?

PMI provides a quick and reliable way of getting the necessary information quickly.  If a company uses steels, metals, or alloys, positive material identification allows for confidence is the process and purchasing decisions. PMI also helps assure these choices are cost effective, too.

At the end of the day, PMI ensures that all safety requirements are met from research to the end product.

  • Research & Development – During research and development, positive material identification helps when choosing the right materials for an application from this complex and expanding selection.
  • Production – During production, PMI can help to confirm via certification that a customer has received the materials they have paid for.

Conclusion

PMI is useful to test the composition of metal alloys throughout all phases of the production process. By using one of the multiple non-destructive testing techniques, you can quickly and cost effectively test alloys to ensure they are what you ordered and are safe to use.

To ensure the results, PMI testing should be conducted by a professionally trained individual on your staff or by using a LAB certified company.

From 1 to 20,000 or more pieces, we have metal testing that will fit your need.