10-

Etymology
From AISI and SAE standards nomenclature for iron and steel grades for carbon steels with a maximum of 1% carbon content.

Prefix

 * 1)  Identifying a steel grade with a maximum of 1% carbon.

Usage notes
It is used in forming a four digit term, with the remaining two digits attached to the prefix signifying the sub-1% fractional percentage value of the carbon content of the steel. For example, a steel with 0.95% carbon would be graded 1095. (10+95, from 0."95"%)