Heat number

A heat number is a unique identification coupon number that is stamped on a material plate after it is removed from the ladle and rolled at a steel mill.

It serves as a traceable identifier that links the metal product to its specific batch or "heat," allowing access to detailed records about the material's composition, manufacturing process, and quality assurance.

[1] Industry quality standards require materials to be tested at the manufacturer and the results of these tests be submitted through a report, also called a mill sheet, mill certificate or mill test certificate (MTC).

The only way to trace a steel plate back to its mill sheet is the heat number.

A heat number is similar to a lot number, which is used to identify production runs of any other product for quality control purposes.