Method and apparatus for cooling steel sheet

In an apparatus for cooling a hot rolled steel sheet, which comprises means for ejecting cooling water onto a steel sheet laid horizontally, from above and from below said steel sheet, immediately after the completion of hot rolling to cool said steel sheet;

• the improvement comprising:
• shielding means for shielding each of the both side edge portions of the upper surface in the width direction of said steel sheet from said ejected cooling water, said shielding means being movable in the width direction of said steel sheet so that the temperature distribution in the width direction of said steel sheet becomes uniform at the completion of the ejection of cooling water;
• and,
• means for determining a shielding width of each of said both side edge portions of said steel sheet, which is shielded from said ejected cooling water, on the basis of the width and the thickness of said steel sheet, the temperature and the flow rate per unit area of cooling water ejected onto the upper and the lower surfaces of said steel sheet, the period of time from start to completion of the ejection of cooling water, and the temperature distribution in the width direction of said steel sheet immediately before the start of the ejection of cooling water.