Positive material identification: what does PMI prove?

PMI quickly checks composition to confirm or distinguish materials. XRF, OES and other methods have different capabilities and limitations, particularly for light elements and carbon. Evaluate technical specifications, the price basis, delivery terms and quality evidence together. A lower number is not a comparable offer if it covers a different grade, weight, coating or delivery scope.[1][2]

When importing steel from Iran, price differences often reflect weight basis, local tax treatment, delivery location, cutting, packing, freight, quote validity and documentation. Keep one order, lot and acceptance reference from RFQ through discharge and any claim. Specify settlement currency, the named port or final delivery place, inspection language and destination project requirements. Ask the responsible parties to confirm applicable border charges and documents for the actual shipment rather than assuming that an Iranian domestic quote represents the importer's landed cost.

Surface condition, coatings, rust, curvature, calibration alloy and operator practice affect results. Matching chemistry cannot establish heat treatment, properties or microstructure.[2][3][4]

Specify grades and distinguishing elements, method, calibration, surface preparation, test count and locations, acceptance logic, marking and reporting. Compare offers only after aligning units, the weight basis, taxes, packaging, loading, freight and quote validity. An omitted cost can outweigh the apparent saving per kilogram. Keep the supplier’s currency and payment date visible before converting to your purchasing currency.

Ask every supplier to answer the same written specification. This prevents an apparently cheaper offer from silently changing the product or scope. Confirm the following before comparing prices:

Use this table to structure the decision. It does not replace engineering calculations or the contract. The final column identifies the evidence to review before accepting an offer.

Errors often begin when a trade name replaces a technical specification, one photograph stands for an entire shipment, or the delivery scope is missing from the quote. Address these specific risks: Method unsuitable for carbon; Testing through a coating; Automatic library-match acceptance; Insufficient sampling. Turn each risk into a written acceptance criterion, sampling requirement or traceable document.

A standard number alone does not demonstrate conformity. Specify the edition, grade, dimensions, tolerances, test method, heat or batch number and acceptance authority. For an import project, confirm the destination’s requirements and the project’s approved specification; an Iranian market designation is not automatic evidence of an equivalent local grade.

PMI is a powerful mix-up screen within a traceability plan. It is not a complete material qualification on its own.[4][5]

Before ordering, prepare a single comparison sheet covering the product, quantity, unit, theoretical and actual weight, base price, taxes, freight, delivery window, documents and acceptance criteria. Identify who pays each cost and who records discrepancies at receipt. This makes the negotiation clearer and gives the receiving team an agreed basis for checking the shipment.