It consists of hardening the material in its whole cross-section (i.e. through the material) up to the temperature of austenitization (30 - 50°C above the temperaure of the AC3/ACm changes), warming it at this temperature and then slowly cooling it down at a speed not lower than the critical speed in order to obtain as a result the diffusionless structure.
After having been hardened, the steel is very hard and durable, yet less plastic and modellable.
Graph scale: 0-160 T
Graph scale: 0-1200 °C