METHOD FOR MANUFACTURING STEEL PLATE

PROBLEM TO BE SOLVED: To provide a method of manufacturing a steel plate by which the temperature inhomogeneity of a thick steel plate, in particular temperature inhomogeneity in the width direction, is reduced and the steel plate having good flatness is obtained in a natural cooling stage after cooling by heating the plate by suppressing power consumption for induction heating. SOLUTION: In a line 100 of manufacturing the steel plate, a cooling system 10, a shape correction device 20 and an induction heating device 30 are installed in this order. Let a value f be given by the following formula 1, f=0.004×(W/t)2-1.8×(W/t)+22, wherein W is the width (mm) and t is the thickness (mm) of the steel plate 1, and the difference between the maximum temperature and the minimum temperature of the surface temperature of the steel plate after cooling the steel plate 1 with the cooling system 10 be ΔT (°C). Then (1) when ΔT>f, the steel plate 1 is heated with the induction heating device 30 so as to be ΔT≤f and then sent back to a stage before the shape correction device 20 and the shape of the steel plate 1 is corrected with the shape correcting device 20. On the other hand, (2) When ΔT≤f, the shape of the steel plate 1 is corrected with the shape correcting device 20 without heating the steel plate 1 with the induction heating device 30. COPYRIGHT: (C)2005,JPO&NCIPI