| 摘要 |
PURPOSE:To obtain a high-speed tool steel excellent in wear resistance, chipping resistance, machinability, etc., by specifying a composition consisting of C, Si, Mn, Cr, W, Mo, V, Al, and Fe and also by controlling respective contents of N, S, and O as impurities. CONSTITUTION:The high-speed tool steel has a composition which consists of, by weight, 0.5-1.5% C, 0.1-1% Si, 0.1-1% Mn, 3-7% Cr, 5-25% (W+2Mo) (where W is <=12% or unadded and Mo is 2-12%), 0.6-5% V, 0.02-0.2% Al, and the balance Fe with usual impurities and further contains, if necessary, 0.02-0.2% of one or more elements among La, Ce, Y, and Nb and/or 1-20% Co and in which N, S, and O are limited to <=0.01%, <=0.04%, and <=40ppm. In this steel, large amounts of high-hardness carbide are finely crystallized out and the fineness of the cast structure in the outside peripheral part is improved. In this way, machining property and wear resistance are improved and the occurrence of chipping in tips of cutting tools is inhibited.
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