| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite roll for hot roiling made by centrifugal casting having excellent wear resistance and surface roughening resistance, moreover excellent in accident resistance and stably applicable to a final stand in hot finish rolling. SOLUTION: This is a composite roll for hot rolling produced by centrifugal casting and having an external layer and an internal layer, in which the external layer has a compsn. contg., by weight, 1.5 to 2.6% C, 0.1 to 2.0% Si, 0.1 to 2.0% Mn, 7 to 15% Cr, 2.5 to 10% Mo, 3 to 10% V and 0.5 to 5% Nb and simultaneously satisfying 0.27 <=Mo(%)/Cr(%)<=0.8 and Cr(%)/C(%)>=3.3, the internal layer has a compsn. contg. 2.5 to 4.0% C, 1.5 to 3.5% Si, 0.3 to 2.0% Mn, 0.1 to 0.8% Cr, 0.1 to 4.0% Mo, 0.1 to 1.0% V, <=0.5% Nb, >1.5 to 6.0% Ni and 0.02 to 0.08% Mg, and it has a structure contg. a bainitic phase of >=20% by area ratio.
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