| 摘要 |
PURPOSE:To improve resistances to seizure and surface roughening by combining the composition of components and distribution of hardness of an outer layer with the specific conditions of a core material and joining metallurgically the outer layer to the core material. CONSTITUTION:A composite roll for hot rolling is formed by joining metallurgically an outer layer of high Cr cast iron to a core material of cast, forged steel having a >=55kg/mm.<2> tensile strength and a >=1 elongation. Said high Cr cast iron contains by wt%, 2-3.5% C, 0.5-1.5% Si, 0.4-1.5% Mn, 8-25% Cr, 0.5- 3% Mo, <=10% V, and <=1.5% Ni. The molten metal of this cast iron is poured onto the outer circumference of the core material and is metallurgically joined to the core material, to form the outer layer. The joining strength of a boundary part between the outer layer and the core material is >= the lower strength of either of the outer layer or the core material. Further, the layer has a >=70 hardness (Shore hardness) and a <=3 (Shore hardness) hardness lowering, till the depth of 100mm. from the surface. |
