High-speed steel is a high hardness, high wear resistance and high heat resistance of tool steel, also known as high-speed tool steel or steel front. High-speed steel is the United States FW Taylor and M. White in 1898 created the. High-speed steel process performance, strength and toughness with good, so is mainly used to manufacture complex Boren and impact resistance of the metal cutting tools, bearings can also create heat and cold extrusion dies and so on. In addition to using high-speed steel produced by melting method, the 1960s and later appeared in powder metallurgy high speed steel, it has the advantage of avoiding the production of melting caused by carbide segregation performance degradation caused by mechanical deformation and heat treatment. High-speed steel is a complex of steel, carbon content is generally between 0.70 ~ 1.65%. More with the amount of alloying elements, the total up to 10 ~ 25%. According to the different alloy elements contained in can be divided into: ① tungsten high speed steel (tungsten-9 ~ 18%); ② tungsten molybdenum high speed steel (5 to 12% tungsten, molybdenum 2 ~ 6%); ③ high molybdenum high-speed steel (0 to 2% tungsten, molybdenum 5 ~ 10%); ④ vanadium high speed steel, according to the different amount of vanadium vanadium content is generally divided into (1 to 2% vanadium) and high vanadium content (including 2.5 V ~ 5%) of high-speed steel; ⑤ cobalt high speed steel (5 to 10% cobalt). By use of different high-speed steel can be divided into general-purpose and special purpose two. ① general-purpose high-speed steel: mainly used in the manufacture of cutting hardness HB ≤ 300 of the metal cutting tools (such as drills, taps, saw blade) and precision tools (such as hobs, shaper cutters, broaches), a commonly used steel W18Cr4V, W6Mo5Cr4V2 and so on. ② special-purpose high-speed steel: including cobalt high speed steel and super-hard high-speed steel (hardness HRC68 ~ 70), mainly for the manufacture of cutting difficult to machine metals (such as high temperature alloys, titanium alloys and high strength steel, etc.) tool, commonly used steel There W12Cr4V5Co5, W2Mo9Cr4VCo8 and so on. China, mainly from Japan, Russia, Germany, Austria, France, Ukraine, Brazil and other countries imports.