Why this matters
The Mill Test Certificate (MTC) is the legal record that a heat of steel meets the chemistry and mechanical properties you ordered. EN 10204 defines four certificate types; the two that matter for pressure-piping procurement are 3.1 and 3.2. A clean MTC review takes 15 minutes per heat and prevents the costliest defect a buyer can ship: wrong-grade material installed in service. This MTC review checklist is built around the EN 10204 standard structure documented by Project Materials and Holland Applied Technologies.
Field-by-field MTC review
1. Identification block. PO number, line item, manufacturer name and works address. Cross-check the works address against the supplier's accreditation — material made at an unlisted works is a red flag.
2. Product description. Standard + edition (e.g., ASTM A403-2023), grade (WP316L), size, quantity, and shape must match the PO line. A common error is WP316 quoted but WP316L delivered — the L (low-carbon) is required for welded service.
3. Heat number traceability. Every piece must trace to a heat number, and every heat number must appear in the chemistry table. Mark each PO quantity against a heat: missing pieces mean partial-heat shipment without disclosure.
