How can you tell a Super-Duplex Stainless Steel from an Austenitic Stainless Steel, or a Nickel Alloy from a Copper Alloy when they all largely look the same?
That’s the problem experienced by many of the organisations in the supply chain. Kathy Stubbs, Group Technical & Quality Manager, outlines Langley Alloys’ approach to Positive Material Identification (PMI) and ensuring traceability throughout the Langley Alloys supply chain.
To ensure material traceability, product conformance and to ultimately ensure the safety of people and equipment, Langley Alloys employs PMI on all incoming stock material. Our PMI analysers are pre-loaded with our alloy specifications, enabling us to determine the product grade and verify compliance to the product purchase requirements.
For example, another stockist had offered some Aluminium Silicon Bronze to the Defence Standard 02-879 Part 2 Annex D. Material was delivered with suitably-conforming test certification. However, during a routine PMI analysis it was identified that the material was NOT Aluminium Silicon Bronze but in fact Nickel Aluminium Bronze, a very different alloy.
A repeat test of mechanical properties i.e. tensile test would not have revealed non-conformance due to the very similar properties of two grades. Two possible ways to determine conformance would be either a chemical analysis or a Magnetic Permeability test – neither of which are routinely undertaken by many distributors.
Langley Alloys were challenged by the supplier as to the validity of the results, but the combination of both PMI and Magnetic Permeability testing provided robust evidence.
