| 摘要 |
A centrifugally cast composite rolling mill roll obtained by metal junction of: an outer layer obtained from a cast iron having a chemical composition containing, on a mass basis, 2.7-3.5% C, 1.5-2.5% Si, 0.4-1.0% Mn, 3.7-5.1% Ni, 0.8-2.2% Cr, 1.5-4.5% Mo, 2.0-4.5% V, and 0.5-2.0% Nb, the remainder being obtained from Fe and unavoidable impurities, the Nb/V mass ratio being 0.18-0.65 and the Mo/V mass ratio being 0.7-2.5, and a structure having, on an area basis, 15-45% cementite phase and 1-10% graphite phase; and an inner layer obtained from a cast iron of excellent mechanical strength. Practically no dendrite speckle segregation of bainite and/or martensite of 1.5 mm diameter or more is present in the usable region of the outer layer at depths of 10 mm or more from the surface. |
