The identification chain

The strongest traceability chain connects the physical marking to the packing list, báo cáo kiểm tra, heat-treatment batch and original material certificate. If any link uses a different heat number, grade or quantity, resolve the discrepancy before installation.

Transferred markings after cutting or machining should follow a controlled procedure authorized by the quality system.

Common marking elements

Marking methods and placement

Low-stress stamping, dot-peen, engraving or other approved methods may be used depending on material and project rules. Marking should remain legible without damaging pressure-boundary or sealing surfaces.

Coating and preservation teams should mask or reproduce identification under a documented system. Tags can supplement—but should not casually replace—durable product marking.

What to do when marking and MTC disagree

Quarantine the flange. Compare purchase order, packing list, supplier certificate and inspection records. Ask the manufacturer for a controlled correction or documented re-verification; do not grind and restamp the item based on assumption.

PMI may help confirm alloy family, but it cannot by itself reconstruct the original heat traceability or approve unauthorized re-marking.