Technically, the Hardened and Tempered Steel Strip produced by the Company is that in the martensitic condition where high levels of hardness are achieved which are then accompanied by the appropriate ductility and shock resistance properties the user industries require. The heat treatments involved are carried out on continuous production lines, each line containing 2 furnaces, the first of which heats the steel to temperatures from which, after rapid cooling, the steel is fully hardened. At this stage the steel, whilst very hard, is also very brittle and it is the second furnace in the production line, the tempering furnace, that reheats the steel to temperatures at which the steel is softened slightly and develops some ductility and impact resistance. Typically, steel is hardened from temperatures of 880/920°C whereas the tempering process uses temperatures of 400 - 580°C and the selection of temperatures in this range is critical as it determines the final hardness (and tensile strength) of the steel. With the range of steel grades involved hardness levels of between 380 VPN to 650 VPN are possible, the steels with the highest carbon levels being most suitable for hardening to the upper ranges of hardness. With accurate tempering temperature control the range of hardness achieved on any one item can be restricted to 30 - 40 VPN. Thus, across the whole range of high carbon steels, a large number of very specifically-tailored strip products can be engineered for particular end-use applications.