Structural-weld quality: from WPS to NDT

Weld quality depends on base metal, joint design, consumables, heat input, skill, sequence and acceptance criteria as well as final appearance. 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.

Hydrogen, restraint, thickness and metal temperature change cracking risk. Root, fusion and internal discontinuities may escape visual inspection; NDT requirements depend on joint classification.[2][3][4]

Record code edition, joint detail, base metal, WPS and PQR, welder qualification, consumables, preheat and interpass temperatures, inspection stages and acceptance criteria. 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: Welding without a WPS; Poor fit-up; Damp consumables; Late NDT. 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.

Final inspection cannot reconstruct an uncontrolled process. Establish hold points before joints become inaccessible.[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.