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NDT - Positive Material Identification
The Objective
While engineers push the boundaries of material capacities to their limits in the design, traceability of proper material becomes ever more important. In addition to compatibility issues, several other reasons can exist for material specification including design, corrosion resistance, and compliance to codes and standards such as ASME Boiler and Pressure Vessel Code.
Quality procedures are put in place to document materials as they are received and as they move through the production process, but what happened to those raw materials before they arrived at the receiving dock? Each time raw material changes hands - from the mill to service centers, from processing plants (e.g., pipe, tube and fittings) to subcontractors – the opportunity for error increases, resulting in questionable material quality.
The Solution
With Positive Material Identification (PMI) the alloy composition, and thus, the identity of materials can be determined. If a material certificate is missing or/and you need to be certain about the type of material used, PMI as an NDT method is the best solution. Positive Material Identification is particularly used for high quality metals like stainless steel and high alloy metals.
There are two methods of Positive Material Identification:
- The XRF-principle
X-ray fluorescence is one of the methods for PMI. The equipment contains radioactive sources or a low voltage x-ray generator, which sends out radiation. The exposed material then sends temporarily element specific radiation back, generating energy. As every element has its own atomic structure, this reflection will generate a different energy level for every element.
This energy is measured and detected, thus identifying the alloy elements. The disengaged radiation is very low and extra safety means are not necessary. The important advantage of the XRF-method is that it in service can be executed without damaging the material. Directly after the inspection, you will receive the results.
- Spark emission spectrography
Spectrography is based on optical emission. The equipment consists of a probe which releases a spark that is used to vaporize the material being analyzed. The atoms and ions in this vapor produce a spectrum which can be optically measured and then recalculated to determine the components of the material.
Why SGS?
SGS Industrial Services has the knowledge, expertise and experience to perform conventional and advanced NDT inspections around the world using our unique network. We are pleased to inform you anywhere around the world about how SGS can help you in improving the reliability of your processes and assets.
Send us your inquiry on Positive Material Identification now.
Our Services for Positive Material Identification
With our portable equipment a measurement is possible almost everywhere. This measurement could be on heat exchangers, steel constructions or petrochemical installations. Also sorting of big bulk of metals is possible.
Material properties like structure difference and heat treatments have no influence on the results of the PMI measurements. However, it is important that the surface is identical to rest of the material.
In a very short time the plant or components and raw materials can be mapped into any Asset Integrity Management System in order to prevent unexpected failures or extension of maintenance periods.
SGS Industrial Services offers positive material identification (PMI) Service also combined with other advanced or standard NDT methods.
NDT Training
SGS not only provides Non-Destructive Testing Services for its clients but also provides NDT Training Courses and Certification Services in accordance with European (EN473) and American (ASNT) Standards, available at the SGS NDT Training Center in Shanghai.
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