METHOD FOR CONTROLLING COOLING OF HOT ROLLED STEEL STRIP

PURPOSE:To manufacture a hot coil having uniform characteristic in longitudinal direction by coiling a hot rolled steel strip after cooling it to the specific temp., respectively at rapid cooling zone, air coiling zone and control cooling zone at the time of cooling the hot rolled steel strip after cooling on a hot run table. CONSTITUTION:At the time of cooling the high temp. hot rolled steel strip 2 coming out from a finish rolling mill 1 on the hot run table, at first making the characteristic of strength, etc., of the hot rolled steel strip the desired value by rapidly cooling to the prescribed temp. with cooling water at the rapid cooling zone 3, thereafter, the cooling water is removed with drainage device 9. Successively, after completing transformation of structure in the hot-rolled steel plate 2 by air-cooling in the air cooling zone 4, the cooling is controlled so as to become the prescribed coiling temp. in the control cooling zone 5 and this is coiled to a coiler 6. The uniform quality hot coil having extremely small variation in the characteristic of micro structure and strength, etc,. in the longitudinal direction is manufactured with good productivity.