| 摘要 |
PROBLEM TO BE SOLVED: To provide an external layer material of a roll for hot rolling and a composite roll for hot rolling, excellent in abrasion resistance, thermal shock resistance and surface roughening resistance.SOLUTION: A composition of an external layer material contains, by mass%, C:2.4 to 3.5%, Si:1.2 to 2.4%, Mn:0.2 to 2.0%, Cr:0.8 to 2.1%, Mo:0.3 to 1.1%, Ni:3.0 to 6.0%, V:1.0 to 2.2%, Nb:0.1 to 0.5%, REM:0.0005 to 0.1%, Al:0.003 to 0.05% and the remainder Fe with inevitable impurities, and contents of C, Cr, V, Nb, REM and Al satisfy Cr+0.2≤C-(0.24×V+0.13×Nb)≤3.0 and 0.01≤REM/Al≤3.2, where C, Cr, V, Nb, REM and Al: contents of each elements (mass%). |
