What is High Speed Steel? How to Selection of High Speed Tool Steels

Selection of high speed tool steels

High speed tool steel consists of a set of tool steel alloys that are named because of their quality to cut objects at a much faster rate compared to conventional high carbon steel that was earlier used in cutting tools. There are a number of reasons behind high speed steel being the best in the market for cutting tools. It has unique level of hardness, resistance against abrasion, resistance against melting or even softening at extremely high temperatures etc. This is mainly due to the alloying metals present in the composition of high speed steel as well as the heat treatment used in its making. The heat treatment used in producing high speed tool steel is the cause behind the material’s high hardness. Selection of high speed steel depends on a variety of aspects, such as – area of application, temperature etc. 


Classification of high speed steel: There are about forty or more types of high speed steel available in the market. While the first category is rich in tungsten, the second category is rich in molybdenum. Each of these grades are particularly marked with either T or M and then followed by a unique number to separate it from other high speed steel grades. Clients can select between tungsten based or molybdenum based high speed steel, depending on their application. Although the basic qualities of high speed steel remain intact, but, depending on the alloy content, few intricate characteristics of each of these high speed steel grade change. 


Special characteristics depending on the alloy content: As discussed earlier, chromium content in the high speed steel results in increased hardenability and reduction in oxidation damage while undergoing the heat treatment. Cobalt in high speed steel increases hot hardness. Tungsten or molybdenum are two of the defining metals in high speed steel that discerns the tool steel’s structure. Tungsten steel exhibits more hot hardness and molybdenum steel has more toughness. Vanadium leads to the formation of vanadium carbides that improves hot hardness as well as provides the steel with ample resistance against wears. Enduring heat capacity also increases due to the vanadium in the steel alloy. 


Application of high speed steel: High speed steel shows outstanding resistance against abrasion and hardness. Each of the grades differ in toughness, hot hardness, decreased brittleness or robustness. Thus, these alloys are leading materials for use in cutting tools in various industries. Taps, broaches, drills, saw blades, tool bits, milling cutters etc are few of the widely used application areas of high speed steel. Cutting tools made with leading quality high speed steel lasts much longer compared to carbon steel. In fact, the specialized treatments and a wide range of grades are available in the market that serve special purposes. High speed steel can be used even in the most common places, such as – woodworking or during the machining of high end alloys. Dies, punching etc are not conventionally considered within the group of cutting tools but, these can also be made with high speed steel. 


Surface treatments: High speed tool steel are sometimes coated with a black or other vibrant coloured oxide finish in order to be used with ferrous or non-ferrous metals. For other specialized application, different kinds of coating is available.


The selection of high speed steel is optimal for its application. It is one of the leading tool steel in the market.