| 摘要 |
PURPOSE:To obtain a compound roll of which the surface part is highly resistant to wear and thermal crack and the core part is highly tough by forming a core material of a steel compsn. and an outside layer part of a cast iron compsn. having the structure in which crystallized graphite is dispersed into the matrix then welding the core material and outside layer material. CONSTITUTION:A water-cooled casting mole 2 is installed on a water-cooled mold stool 1 and the roll core material 3 made of the steel compsn. is placed concentrically to the inside thereof. A consumable electrode 4 forming the outside layer material made of the cast iron compsn. is inserted into the space. The stool 1 is connected via a cable 5 to a power source 6. Electroslag refining is started in this state. Part of the electrode 4 is immersed in a slag bath 7 and the other end is connected via a cable 8 to the power source 6. The liquidus line temp. of the bath 7 is lower than the liquidus line temp. of the outside layer material and the slag bath is adjusted to the compsn. by which graphite spheroidization is attained. The electrode 4 is melted by the resistance heat of the bath 7 and forms a molten metal bath 10 which solidifies to form the outside layer material 9. The outside layer material is cooled by the core material 3 and the cooled mold 2 to form the fine structure. As a result, the spheroidal graphite in the matrix is finely distributed and the resistance to thermal cracking is improved. |
