Abstract: A method for manufacturing a forged steel roll comprises: casting, by the ESR method, a steel ingot which contains, by mass %, C: 0.3% or more, Si: 0.2% or more, Cr: 2.0-13.0% and Mo: 0.2% or more, and further contains Bi at 10-100 ppm by mass; and forging the steel ingot to manufacture the roll. According to this method, since freckle defects can be sealed near the center of the steel ingot, the roll can be stably used over a long period of time.

Abstract: A method for manufacturing a forged steel roll comprises: casting, by the ESR method, a steel ingot which contains, by mass %, C: 0.3% or more, Si: 0.2% or more, Cr: 2.0-13.0% and Mo: 0.2% or more, and further contains Bi at 10-100 ppm by mass; and forging the steel ingot to manufacture the roll. According to this method, since freckle defects can be sealed near the center of the steel ingot, the roll can be stably used over a long period of time.

Abstract: A method of producing a tool steel comprises quenching a steel containing, by mass percent, C: 0.25 to 0.60%, Si: 0.10 to 1.20%, Mn: 0.20 to 1.50%, Ni: 0.50 to 2.00%, Cr: 1.00 to 4.20%, Mo: 0.30 to 2.00%, V: 0.10 to 1.00% and Al: 0.005 to 0.10%, in order to obtain a hardness H such that the hardness index defined below by the formula (1) becomes between 0.20 to 0.95; and then tempering the steel; K=(H−H2)/(H1−H2)  (1) Where H1: Vickers hardness of the steel with 10 mm thickness after heating to a temperature of the Ac3 transformation point plus 50° C., and quenching into water; H2: Vickers hardness of the steel with 10 mm thickness after heating to the same temperature as defined above, and cooling to room temperature over 20 hours.

Abstract: A method of casting non-ferrous metals such as aluminum, magnesium, or zinc alloys uses casting components made from a tool steel comprising effective amounts of carbon, silicon, manganese, chromium, molybdenum, and vanadium, optional amounts of cobalt and increased level of molybdenum. Using the tool steel as a casting component, particularly as a mold, provides improvements in corrosion resistance, oxidation resistance, softening resistance, degradation resistance and deformation resistance. The tool steel casting component has a chromium oxide layer which is formed, in one mode, during the casting operation, to enhance the life and durability of the casting component and improve its casting performance.