NNP

Quenching.  The rapid cooling with water (oil, or other fluid) to harden and temper heated metal. Dies are heat treated by heating in molten salt, then rapidly cooled by dousing into water or oil.  See heat treating.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor