Verbundwalze und Verfahren zur Herstellung derselben

摘要

A 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: m2