HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME

• Main Authors: SHIRASAKI Sonomi, GOTO Hiroto, KIMURA Yukio, NISHIURA Nobuo, UEOKA Satoshi
• Format: Patent
• Language: English; French; German
• Published: 08.01.2020
• Subjects: AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING

Provided is a hot-rolled steel sheet which does not exceed the allowable load of a coil opener during unwinding, even with a coil of a thick, wide, high-strength hot-rolled steel sheet. The hot-rolled steel sheet includes a steel sheet (S) cut in unsteady portions at its longitudinal head and tail ends in a cutting step after a rough rolling step, having a width of 1,200 mm to 2,300 mm, a thickness of 13 mm to 25.4 mm, and at least an API standard X65-grade strength, and used in a state of being unwound after having been wound around a coil (C). At least a longitudinal end corresponding to the start of unwinding includes a portion at its widthwise center recessed inwards in the longitudinal direction with respect to its two widthwise ends, the projection sizes of the two widthwise ends with respect to the recessed portion at the widthwise center are 20 mm to 295 mm, and the sum of the widths W1 and W2 of projecting portions at the two widthwise ends is set to 1/4 to 1/2 of the sheet width.