| 摘要 |
PURPOSE:To prevent warping occurred on steel sheet under winding by preparing the diameters of an entrance roll to a quenching zone and a roll at the first turning part with the specific values in an annealing process of steel plate in continuous annealing furnace composed of a heating zone, soaking zone, and quenching zone. CONSTITUTION:Steel strip 10 is annealed in a continuous annealing furnace 16 composed of a heating zone, soaking zone 12, quenching zone 14. In this case, a diameter D1 of a hearth roll 24 positioned at the entrance of the quenching zone 14 is made to the value expressed by the formula [I] and at the same time D2 of a hearth roll 20 provided at the first turning part of the quenching zone 14 to the value expressed by the formula [II]. In the formula [I], Ts denotes the temperature of steel sheet at the entrance of quenching zone, (t) the winding time of steel sheet 10 around the hearth roll 24 and (d) the thickness of steel sheet. Also in the formula [II], Yr1 denotes the yield stress of steel sheet at the entrance of the quenching zone, and Yr2 the yield stress of steel sheet at the first turning part of the quenching zone 14. |
