| 摘要 |
PROBLEM TO BE SOLVED: To provide a roll external layer material for hot rolling excellent in resistances to wear, surface roughening, sand burning, and thermal impact; and a composite roll for hot rolling using the same. SOLUTION: The external layer material comprises, in terms of mass%, 2.6-3.5% C, 1.0-2.5% Si, 0.2-1.5% Mn, 0.8-2.7% Cr, 1.0-3.0% Mo, 2.0-7.0% Ni, 1.3-2.5% V, 0.1-0.8% Nb, 0.020-0.2% B, at least either lower than 0.05% Ti or 0.1% or lower Al, and the balance being Fe and unavoidable impurities, provided that the contents of C, Cr, Nb, and V satisfy 2.0≤C-(0.24V+0.13Nb)≤3.0, Cr/C<1.0, and 3.0≤Cr+V≤4.5 [wherein C, V, Nb, and Cr respectively satisfy their contents (mass%) described above]. The material may further contain 0.1-4.0% Co. COPYRIGHT: (C)2004,JPO
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