| 摘要 |
PURPOSE:To constitute a titled roll usable for all stands by oneself by unifying metallurgically the 1st and 2nd outer layers, consisting each of a steel having different composition, and the 2nd layer and a core part, respectively, and controlling the hardness of each layer by heat treating it at a temperature not less than an A1 transformation point. CONSTITUTION:A composite roll for hot strip mill is constituted of the 1st outer layer, formed by a graphite-crystallizing type high Cr material of specific composition for a rear stage, the 2nd layer, formed by an adamite material of specific composition for the front stage, and a core part formed by a nodular graphite cast iron consisting of a specific composition excellent in toughness. The 1st outer layer and the 2nd one of the composite roll, and the 2nd outer layer and the core part thereof, are unified respectively by melt-sticking, and the hardness of the 1st outer layer is regulated to >=Hs80, and that of the 2nd layer to 50-60Hs, by heat treating them at a high temperature not less than an A1 transformation point. This composite roll is used for a work roll of strip mill at a finishing stage, and can be incorporated into a stand having required characteristics different with the decrease of its diam., thus the roll can be used for all stands by oneself. |
