Positive Material Identification (PMI)
Refers to the identification and analysis of various metal alloys based on their chemical composition in nondestructive testing (NDT). Measurement results are shown in the form of elemental concentration in percentage or by specific alloy name such as SS316L or Inconel 625. PMI is a field-testing method made possible by the portability of most PMI analyzers. These instruments also can be used in the laboratory. Our Company uses XL3T 800 handheld XRF handheld analyzer.
The Growing Importance of Positive Material Identification
Because specifications for materials used in industry are increasingly more specific, the need for PMI testing has been steadily increasing for the past several years. Periodic plant maintenance shutdowns are less frequent and consequently the materials used in the plant are in use longer. A wider variety of alloys that are indistinguishable to the eye are being used in individual plants. When facility staff replace components, they must be able to guarantee that the new part matches engineering specifications. Recent industrial accidents have cost the lives of workers and heightened the awareness of the need for accurate and comprehensive PMI inspections.
Examples of Where Positive Material Identification is Used
Today, many major oil companies require that every pipe, flange, connector, valve and welding seam in critical parts of the plant be measured to verify that materials match engineering specifications. Finally, global sourcing is another factor driving the need for PMI. Currently, metal buyers and suppliers are operating globally, and buyers need to verify the quality of the product they are receiving.