Paper is the cheapest steel test you will ever run.
What a certificate does and does not say
A mill test report lists heat number, chemical composition and mechanical results from the producing mill. It ties a plate to a melt, which is the foundation of traceability.
It does not certify your machining, heat treatment or final hardness. Treat the certificate as the starting point of the quality chain, not the end.
FAQ
What should match between certificate and plate?
The heat number stamped or marked on the plate must match the paperwork exactly. Any gap in that chain is a traceability break worth resolving before machining.
Are third-party retests ever needed?
When a certificate cannot be produced, or the application is critical, sampling and retesting is the standard fallback. Cost is small against the risk of an unknown steel.
How long should certificates be kept?
Retention typically follows the mold's service life plus a margin. Many shops archive by mold serial so any future question can be answered from one folder.
All figures above refer to standard product data sheets; final confirmation is subject to written quotation.