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 816 / 843 °C and cool very slowly in the furnace at a rate of not more than minus 6 °  C per hour to a temperature below 538 °C, then allow to cool naturally. This will produce a maximum hardness of 223 BHN.

Hardening : Heat the furnace to 927 / 954 °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 quench.

Control of decarburization can be accomplished by using any one of the modern heat-treating furnaces designed for this purpose. If endothermic atmospheres are used, a dew point between + 4 / 10 °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 S-7 at 204 °C. This tempering temperature is therefore suggested for cold-work applications. Tempering at 482 / 538 °C is usually desirable for hot-work applications.