| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a compound roll for hot rolling, which compound roll is excellent in the breaking resistance. SOLUTION: An outer layer composed of a high-speed-alloy-based cast iron material having a composition containing 2.5 to 4.0% C, 6.0 to 20.0% Cr, 2.0 to 12.0% Mo, 3.0 to 10.0% V, and 5.0% or less Nb is formed by the centrifugal casting method. Alternatively, after an intermediate layer has been formed, an inner layer is formed through the stationary casting method by pouring the molten metal of the inner layer material to become spheroidal graphite cast iron after adjusting the degree of superheatΔT(°C) of the molten metal of the inner layer material so as to satisfy the following condition, 100<[ΔT-400×äR<SP>2</SP>-(R-x)<SP>2</SP>}/R<SP>2</SP>]/100<250, whereΔT shows the degree of superheatΔT(°C) of the molten metal of the inner layer material, R shows a radius (m) of the inner layer, and x shows the thickness (m) of the outer layer or the intermediate layer to be melted by the molten metal of the inner layer material. In this way, the two or three layered compound roll is manufactured. As a result, the amount of Cr plus Mo in the inner layer is 0.8% or less, the amount of eutectic carbide is less than 12 area%, and the generation of breakage accidents during rolling can be prevented. COPYRIGHT: (C)2007,JPO&INPIT
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