| 摘要 |
PURPOSE:To develop a compound cast iron roll having excellent resistance to wear, thermal crack and surface roughening by forming on an outside shell layer of the compound cast iron for rolling and subjecting the same together with the outside shell layer to a heating treatment to a specific temp., then removing the coating layer therefrom. CONSTITUTION:The inside shell layer 3 of the work roll to be used at the time of hot rolling of steel material is formed of a cast iron such as high-toughness cast iron or ductile cast iron having excellent toughness and the inside shell layer 2 made of the high-hardness cast iron contg. network eutectic carbide such as high-chromium cast iron or high-alloy grain cast iron is integrated by welding to the inside shell layer 3 to form the compound cast iron roll. The coating layer 4 is formed to the outside of the outside shell, layer 2 of such roll by thermally spraying a high-melting point metal, boron compd., carbide, cermet, etc., having the solidus line temp. higher than the solidus line temp. +80 deg.C of the cast iron of the outside shell layer to 100mum-2mm thickness. The outside shell layer 2 and the coating layer 4 are formed. The outside shell layer 2 and the coating layer 4 are heated and held for 5-20hr to and at the solidus line temp. +80 deg.C of the cast iron of the outside shell layer in an induction heating furnace 5 and thereafter, the coating layer 4 is removed. The network eutectic carbide is aggregated and powdered, by which the heat resistance, etc., of the outside shell layer 2 are improved. |
