Tool steel contains various amounts of tungsten, molybdenum, cobalt and vanadium to increase the heat resistance and durability of the metal. This makes them ideal when used for cutting and drilling.
Tool Steel is divided into these Four groups: water-hardening, cold-work, shock-resisting, high-speed. The determination of a choice from the group will depend on; the cost effectiveness, working temperature, required surface hardness, strength, shock resistance, and toughness requirement.
If there is a more severe demand requirement such as extreme temperature, increased abrasiveness, high corrosion, or excessive loading – higher alloy content (and carbides) may be required.
Water-hardening class - Named from its essential property of having to be water quenched. This grade of tool steel is essentially plain high carbon steel. It is commonly used because of its low cost.
Cold-work classes -Is a group of three tool steels: oil-hardening, air-hardening, and high carbon-chromium. The steels in the group have high hardenability and wear resistance, with average toughness. Typically they are in the production of larger parts or parts that have a minimum distortion requirement when being hardened.
Shock-resisting class - This class has high shock resistance and good hardenability. It is designed to resist shock at both low and high temperatures. It also has a very high impact toughness and relatively low abrasion resistance.
High Speed Steel - As we know it is special type of tool steel made by its special heat treatment process making it hard, tough and can be used at high speed for cutting other metals.