Mismatched Heat Numbers on Structural Bolts
A shipment of 2,000 ASTM A325 high-strength structural bolts arrives for a bridge project. The supplier provides an EN 10204 3.1 mill certificate listing heat number H2245 and mechanical properties. Your receiving inspection finds that 180 of the 2,000 bolt heads are stamped H2254, not H2245. The supplier's sales representative says the stamps are a 'typo at the heading station' and that all bolts came from the same Heat H2245. The project specification requires full traceability from mill heat to installed bolt, and the bolts are needed for a weekend erection. The certificate covers only H2245. The supplier offers to send a corrected certificate by email on Monday. Your receiving report is due today. No test certificates for H2254 are available.
1. What disposition is appropriate for the 180 mismatched bolts, and why?
Read the worked answer
Quarantine the 180 bolts. A heat-number stamp is a primary traceability identifier; it cannot be waived by a verbal assurance. If the bolts are actually H2254, the mechanical properties and chemical composition may differ, and the 3.1 certificate does not cover them. If the stamps are wrong, the supplier must correct them under a documented concession and provide objective evidence-such as remaking the marks, a revised certificate, or PMI/hardness testing-before release. The remaining 1,820 bolts can be accepted only if their H2245 stamps match the certificate and the certificate is valid for the specification. Do not mix suspect bolts into the erection lot.
2. What records must accompany the corrected certificate before the bolts are released?
Read the worked answer
Require a revised EN 10204 3.1 certificate for H2254, or a signed statement from the mill/heading station explaining the mis-marking with batch records; a nonconformance report; the receiving inspection record showing the 180 count and stamp numbers; and objective verification (PMI, hardness, or tensile test) if identity is not conclusively established. The release record must link each bolt lot to the heat number and certificate. If the supplier cannot provide traceability, reject the 180 bolts.
3. The site superintendent asks you to release the 180 bolts 'under deviation' because the bridge erection cannot slip. How do you respond?
Read the worked answer
Explain that a deviation can be considered only by the engineer of record and the quality authority, with a written technical justification. It is not the inspector's role to create a deviation to protect a schedule. I would document the request, keep the bolts quarantined, and escalate. If the engineer accepts a deviation, it must be recorded and the bolts must still be identifiable. Signing a release without traceability would misrepresent the material and is an ethical breach.