The practice of hardening rotary cutting dies to provide a hard cutting edge whilst leaving the body of the tool soft.

A generic term covering several processes applicable to a suitable ferrous alloy that produces, by quench hardening only, a surface layer that is harder or more wear resistant than the core. There is no significant alteration of the chemical composition of the surface layer. The processes commonly used are carbonitriding, carburizing, induction hardening, flame hardening, nitriding, and nitrocarburizing. Use of the applicable specific process name is preferred.

A method of hardening the surface of steel to increase its wear resistance. Depending on the analysis of the steel, the following treatments can be employed: Case-hardening, Nitriding, induction hardening, Flame hardening.