From High-Speed Tungsten Steel to High-Temperature Molybdenum Steel: A Century of High-Speed Steel

摘要

The evolution of high-speed steel of optimal composition is discussed from the perspective of the theory adopted in alloying thermostable tool steel. A century ago, in 1910, tools made from steel con-taining ～ 0.7% C and ～ 18% W were first demonstrated at the World Industrial Expo in Brussels. Such tools increased metal-cutting speeds from 5-8 to ～ 30-40 m/min and increased the productivity (the rate of chip removal) from 3-5 to 300 kg/h. Subsequently, these were characterized as high-speed steels, and their primary property—retention of hardness on heating to high tem-peratures—as red hardness or thermal stability. The appearance and wide use of high-speed steel called for major changes in machine-tool design—in particular, increase in power of the primary drive from 1-2 to 80-100 kW, followed by the installation of an individual drive (electric motor) and replacement of the V-belt drive by a gear transmission. On account of the rising cutting forces, the rigidity of the machine tool had to be increased. This entailed the use of massive compo-nents—in particular, a cast frame. Thus, the metal-cut-ting machine acquired its current form basically as a result of the appearance of high-speed steel.