| 摘要 |
PURPOSE: To provide a hot rolling method for enabling the pressurized contact of materials having different widths of sheet bars and reducing breaking at the time of rolling the materials after preriminary joining. CONSTITUTION: In the continuous hot rolling for joining bars of different width materials having the difference of >=10mm in the width of slab before continuous finish rolling, assuming a preceding hot rolled stock is a wide material and the succeeding stock is a narrow material, mating the middle parts in the width of both materials so that the max. gap between the end parts to be joined is <=5mm and, taking this as reference, >=5% of the cross-sectional area of the narrow material is preliminarily joined in the direction of both edge parts in the width. In the hot rolling method in which rolling just after joining is executed and the bars are joined using concave rolls for hot rolling having the relationship of Et-Mt>=100μm between the max. roll diameter Et and the min. roll diameter Mt in a steel sheet rolling parts, rolling just after joining the sheet bars is performed at 35-60% draft within 60sec after preriminary joining.
|
