Heat number
From Wikipedia, the free encyclopedia
A heat number is an identification number that is stamped on a material plate after it is removed from the ladle and rolled at a steel mill.
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 or Mill Certificate. 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.
[edit] 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.
