| 摘要 |
PURPOSE:To attain to prevent the oxidation of a coil surface due to the poor cooling by a method wherein, even in case of not correctly measuring a coil temp. by a thermometer, is used a cooling cycle controlling method of an annealig furnace for maintaining a coil to a predetermined cooling temp. CONSTITUTION:In case of cooling the coil after annealed in a batch type annealing furnace after cold rolled by a natural cooling cycle or a forced cooling cycle, a necessary cooling time f(W) is obtained from a curved line formed by statistically computing the shortest necessary cooling time during normal cooling treatment against a total coil wt. W according to a steel kind. Subsequently, when a temp. of a thermometer is reached to a predetermined cooling completed temp. a practical cooling time is computed as a sum of a natural cooling time t1 and a forced cooling time t2 and the difference tD from a necessary cooling time is calculated by formula 2. In the case of tD>=0, because a practical cooling time is above a necessary cooling time, the cooling is carried out by the inducation of the thermometer and, in the case of tD<0, because the thermometer does not correctly measure the coil temp., a forced cooling cycle is succeeded until tD>0. |
