Annealing : For annealing, the steel should either be packed in a suitable container, using a neutral packing compound, or placed in a controlled atmosphere furnace. Heat uniformly to 843 / 871 °C and cool very slowly in the furnace at a rate of not more than minus 6 °C per hour until the furnace is black. The furnace may then be turned off and allowed to cool naturally. This will produce a maximum hardness of 228 BHN.

Hardening : Heat the furnace to 940 / 969 °C, then place the tool in the hot furnace near the thermocouple. Let the tool heat 'naturally' to the furnace temperature, soak for 20 minutes plus an additional 5 minutes per inch of thickness and air quench.

Control of decarburization can be accomplished by using any one of the modern heat-treating furnaces designed for this purpose. If endothermic atmosphere are used, a dew point between +4 / 10 degree C is suggested. In older type manually operated exothermic atmospheric  furnaces, an oxidizing atmosphere is required. Excess oxygen of about 4 to 6%is preferred. If no atmosphere is available, the tool should be pack hardened or wrapped in stainless steel foil to protect its surface.

Tempering : The best combination of hardness and toughness is obtained by tempering A-2 at 204 °C.