alloys

High-speed steel is a high-alloy tool steel that is mainly used as a cutting material, i.e. for milling tools, drills, turning tools and broaching tools. The designation refers to the three to four times higher cutting speeds compared to ordinary tool steel. While ordinary tool steel loses its hardness from around 200 °C, high-speed steel retains its hardness up to around 600 °C. The common abbreviations begin with HSS or HS, derived from the English High Speed Steel. German designations are high-speed steel, (high-performance) high-speed steel, high-speed high-speed steel and high-performance cutting steel.

The terms AHSS and HSS are not directly related, although both are tool steels. AHSS stands for Advanced High Strength Steel and refers to modern, high-strength unalloyed cold work steels. After its development in 1906, high-speed steel very quickly replaced conventional tool steel (cold-work steel) in cutting tools and has now almost completely replaced it.

Of all the cutting materials used in modern, industrial machining technology, such as carbide, cermets or boron nitride, high-speed steel has the highest breaking strength and the best grindability, but the lowest hot hardness and wear resistance, so that even higher cutting speeds are possible with other cutting materials.