Positive Material Identification or PMI for short is employed to quantify the elemental make up of a metal alloy. Why is the elemental make up of an alloy important in Oil Country Tubular Goods? For starters, being able to measure the elemental content of a metal assists in classification. Determining the steel grade is important for the following reasons:
- Assuring the proper material specified for the project is used
- Determining min and max yield strength
- Selecting the proper welding technique and filler material for the joint
Cr, Mo, Ni, and C are quantitative elements that users ask to identify the most among other elements. Carbon is particularly important in differentiating steel grades within the same family. Also, carbon is a necessary input factor in the Carbon Equivalent (CE) formula. The CE formula predicts the compatibility of different grades of steels being joined together with a weld joint. Carbon Equivalency helps in selecting a welding technique and filler alloy.
Due to a gas line explosion in 2010, The National Transportation Safety Board recommended that the Pipeline and Hazardous Materials Safety Administration (a division of the US Department of Transportation) remove the grandfather clause for pipelines constructed before 1970. It was also recommended to PHMSA that organizations keep traceable records which list the type of material used in a pipeline’s construction and how it was constructed. Traceable records refer to pipe mill records, purchase requisitions or documents that state minimum pipe yield strength, seam type, wall thickness, and diameter.
Regulatory change is mandating stricter quality standards and records management. Verichek can help you solve unknown metal content through Positive Material Identification. Contact us today and let’s craft a material quality plan together.
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