| 摘要 |
PROBLEM TO BE SOLVED: To provide a high hardness and high toughness cold work tool steel suitable for forging metallic mold, a forming roll, a rolling die and the like for use in cold work performed under especially severe use condition.SOLUTION: The high hardness and high toughness cold work tool steel hardenable at low temperature is provided which contains, by mass%, C:0.6 to 0.9%, Si:0.6 to 1.0%, Mn:0.1 to 0.6%, Cr:4.0 to 6.5%, Mo+W/2: over 2.0 to 5.0%, V:0.1 to 0.4%, N: over 100 to 500 ppm and satisfying H≥0.82, preferably H≥1.03, where H=2.10C+0.83Si-0.27Cr+0.19(Mo+1/2 W)+0.25 V, and the balance composed of Fe with inevitable impurities, and in which distribution density of MC type carbide and MC type carbide each having a particle diameter of 10 μm or less is 150/mm, and which is produced by a melting method and has a hardness of 63 HRC or more. |
