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 A steel mill or steelworks is an industrial plant for the manufacture of steel. It may be an integrated steel works carrying out all steps of steelmaking from smelting iron ore to rolled product, but may also be a plant where steel semi-fini ...

. 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.{{Cite web , title=What Is a Heat Number? , url=https://www.wermac.org/documents/heat_number.html , access-date=2024-11-19 , website=www.wermac.org 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 A lot number is an identification number assigned to a particular quantity or lot of material from a single manufacturer. Lot numbers can typically be found on the outside of packaging. For cars, a lot number is combined with a serial number to fo ...

, which is used to identify production runs of any other product for

quality control Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach plac ...

purposes.

Numerical significance

Usually, but not universally, the numbers indicate: * the first digit corresponds to the furnace number * the second digit indicates the year in which the material was melted * the last three (and sometimes four) indicate the melt number.

References

Steelmaking Metallurgical processes Quality control