| 摘要 |
PURPOSE:To secure the toughness of an axial core part of body and neck parts of it by interposing an intermediate layer of high grade cast iron between an outer shell part of body and the axial core part, in a composite high alloy grain roll having slender, stepped shape. CONSTITUTION:A roll having a slender, stepped shape, is constituted of an outer shell part (a) of body, an axial core part (c) of body, and neck parts (d), the end parts 3 of which require especially toughness; the ratio of the neck length and the body length or the neck diameter, lN/lB or lN/DN are 0.8-1, 2, 3 or 8-13 respectively. The part (a) is formed with high alloy grain roll, and the (c), (d) parts are formed with ductile cast iron. Hereupon, the part (a) and the part (c) are welded to each other in one body by interposing an intermediate layer (b) consisting of a high grade cast iron containing 2.0-3.3% C, <=0.01% S, 0.01- 0.04% Mg. Thus, the generation of a graphite flake layer at the welded part, the toughness of which is remarkably deteriorated against a large surface pressure, is prevented. |
