High-speed steels  (HSS), are a particular category of tool steels with high hardness and heat resistance up to  500°C. HSS have a chemical composition that includes tungsten, chromium, vanadium, molybdenum as well as carbon content between 0.7-1.5%. High-speed steels are a widely used for making metalworking tools (milling and lathe tools, drill bits, discs for cutting metal pieces, etc.).

This group includes steels used for heavy-duty uses including the possibility of reaching locally high temperatures, such as cutting tools and for cold working. High speed steels are mainly used for tools for roughing tools with high cutting speeds and large removal sections, twist drills, cutters and high performance taps. The brands such as 3343, 3243 and 3247 belong to high speed steel family. These characteristics are obtained by controlling the carbon content and the various alloying elements used, in particular: chromium, tungsten, molybdenum, vanadium and cobalt. It is also important to properly control the heat treatment parameters in order to obtain the necessary characteristics.