Abstract: A wear- and seizing-resistant roll for hot rolling has a composition consisting essentially, by weight, of 2.0-4.0% of C, 0.5-4.0% of Si, 0.1-1.5% of Mn, 1.0-7.0% of Cr, 2.0-10.0% of Mo, 2.0-8.0% of V and balance of Fe and inevitable impurities; and has a metal structure comprising a matrix substantially comprising martensite, bainite or pearlite, 0.5-5% in area ratio of graphite, 0.2-10% in area ratio of MC carbides and 40% or less in area ratio of cementite. The roll of the present invention is suitable for work roll in the latter stand of a finishing train of a hot strip mill.

Abstract: The compound roll having a shell portion made of a hard, high-alloy cast steel or iron having excellent wear resistance and resistance to surface roughening and a core portion made of a tough cast iron or cast steel, the cast iron of the shell portion having a composition consisting essentially, by weight ratio, of 1.0-3.0% of C, 2.0% or less of Si, 2.0% or less of Mn, 2.0-15.0% of Cr, 10.0% or less of Mo, 2.0-8.0% of V, the balance being substantially Fe and inevitable impurities, an average diameter of crystal grains constituting a matrix of the metal structure of the shell portion being 100 .mu.m or less in a range from a surface to a depth of 50 mm when determined by an image analysis method on the crystal grains having diameters exceeding 30 .mu.m, and the crystal grains satisfying the formula: m.sub.2 .ltoreq.1.2 m.sub.1, wherein m.sub.1 is an average diameter of the crystal grains at the surface of the shell portion, and m.sub.

Abstract: The compound roll having a shell portion made of a hard, high-alloy cast steel or iron having excellent wear resistance and resistance to surface roughening and a core portion made of a tough cast iron or cast steel, the cast iron of the shell portion having a composition consisting essentially, by weight ratio, of 1.0-3.0% of C, 2.0% or less of Si, 2.0% or less of Mn, 2.0-15.0% of Cr, 10.0% or less of Mo, 2.0-8.0% of V, the balance being substantially Fe and inevitable impurities, an average diameter of crystal grains constituting a matrix of the metal structure of the shell portion being 100 .mu.m or less in a range from a surface to a depth of 50 mm when determined by an image analysis method on the crystal grains having diameters exceeding 30 .mu.m, and the crystal grains satisfying the formula: m.sub.2 .ltoreq.1.2 m.sub.1, wherein m.sub.1 is an average diameter of the crystal grains at the surface of the shell portion, and m.sub.

Abstract: The compound roll comprising a shell portion made of a hard cast iron having excellent wear resistance and resistance to surface roughening and a core portion made of a tough cast iron or cast steel, the cast iron of the shell portion having a composition consisting essentially, by weight ratio, of 2.5-3.5% of C, 0.5-1.5% of Si, 0.5-1.5% of Mn, 0.1% or less of P, 0.05% or less of S, 3.0-5.0% of Ni, 1.0-2.5% of Cr, 0.1-1.5% of Mo and balance Fe and inevitable impurities, an average diameter of primary precipitated particles constituting a matrix of the metal structure of the shell portion being 80 .mu.m or less in a range from a surface to a depth of 50 mm when determined by an image analysis method on the primary precipitated particles having diameters exceeding 30 .mu.m, and the primary precipitated particles satisfying the formula: m.sub.2 .ltoreq.1.2 m.sub.1, wherein m.sub.1 is an average diameter of the primary precipitated particles at the surface of the shell portion, and m.sub.