QUENCH - A quench refers to a rapid cooling.
Traditionally, hand engravers were required to harden their own gravers
and punches. Quench hardening is a mechanical process in which steel
and cast iron alloys are strengthened and hardened. These metals
consist of ferrous metals and alloys. This is done by heating the
material to a certain temperature, differing upon material, and then
rapidly cooling the material. This produces a harder material by either
surface hardening or through-hardening varying on the rate at which the
material is cooled. The material is then often tempered to reduce the
brittleness that may increase from the quench hardening process.