| 摘要 |
PROBLEM TO BE SOLVED: To provide a continuously cast slab surface cracking determination method capable of appropriately determining the probability of the generation of surface cracking in continuously cast slabs from a downstream malfunction of a flow regulating valve for secondary cooling water.SOLUTION: A downstream water pressure and a downstream quantity of water of a flow regulating valve at a time of continuous casting at which no surface cracking occurs to continuously cast slabs S are detected per secondary cooling zone to set a water pressure-water quantity reference line L representing a relation between the downstream water pressure and the downstream quantity of water of the flow regulating valve, and a water pressure-water quantity reference area A is set by adding or subtracting a double value &sgr; of a standard deviation &sgr; of a pressure difference for the water pressure-water quantity reference line L downstream of the flow regulating valve to or from the water pressure-water quantity reference line L. If the downstream water pressure and the downstream quantity of water of the flow regulating valve detected at the time of the continuous casting deviate from the water pressure-water quantity reference area A, it is pointed out that surface cracking may occur to the continuously cast slabs S at the time of the continuous casting. If the surface cracking does not occur to the continuously cast slabs to which it is pointed out that the surface cracking may occur, the water pressure-water quantity reference area A is updated and set.SELECTED DRAWING: Figure 3 |
