High Speed Steels are a high-performance subset of tool steels, that are able to machine materials at high cutting speeds, thus the name High Speed Steel. This subset of tool steels is characterized high hardness (above 60 Rockwell C) and high wear resistance. The primary alloying elements of high speed steels are a combination of carbon, chromium, vanadium, molybdenum or tungsten, and sometimes cobalt. The main reason cobalt is added in some grades of high speed steel is to increase the hot hardness which increases the cutting efficiency of tools when high temperatures are reached. There are three types of High Speed Steels: Tungsten-type grades, Molybdenum-type grades, and Cobalt-type grades.
日本高速鋼：SKH51，SKH52，SKH53，SKH54，YXM2，YXM3，YXM4，XVC3，XVC5，XVC11，SKH58，SKH10，SKH55，SKH56，SKH57，SKH59，SKH3，SKH4，SKH4A，SKH4B，SKH4C，SKH5，SKH2，HAP5R，HAP10，HAP40，HAP50，HAP72，SKH40，YXM1，YXMT，YXM7，YXM34，YXM42，YXM60，YHX2，YXH3，YXH4，YXR3，YXR3，YXR7等。
