| 摘要 |
PURPOSE:To prevent the casting defect to be generated at the boundary between inside and outside layers and to improve the accident resistance of a roll by providing an intermediate layer consisting of a graphite steel between an outside layer material consisting of a high-Cr steel and core material consisting of a ductile cast iron and metallurgically binding the respective layers. CONSTITUTION:The steel of the high-Cr material contg. 10-25wt% Cr is used for the outside layer material 1 and the ductile cast iron material is used for the shaft core material 3. The graphite steel layer consisting of 1.0-2.0% C, 2.0-2.5% Si, 0.4-1.0% Mn, <=1.5% Ni, <=3.0% Cr, <=0.8% Mo, and the balance Fe and unavoidable impurities are sinterposed as the intermedaite layer 2 between the outside layer material 1 and the shaft ocre material 3. this roll is formed by first casting the molten metal of the outside layer 1 into a rotary metallic mold on a centrifugal casting machine, casting the molten metal of the intermediate layer 2 therein before the inside surface thereof is not solidified yet and casting the molten metal of the inside layer 3 into the mold thereafter. The generation of the delamination accident of the outside layer and the breakage accident of the body part is prevented by the high-Cr roll constituted in the above-mentioned manner. |
