To reduce the scale thickness of a steel plate in hot-rolling and the developing ratio of a scale fault.
In a descaling in a hot-rolling process, the high pressure water is injected on the surface of the steel plate at one or more times and the super high pressure water is injected on the surface of the steel plate within about 10sec after removing the scale on the surface layer to remove the scale which can not remove in the descaling with the high pressure water. The super pressure water is injected within about 10sec after injecting the high pressure water on the surface of the steel plate 3 at the outlet side of a rough-rolling mill 1 and a finish-rolling is executed within about 10sec after this descaling. In such a case, the pressure of the high pressure water is made to 120-180kgf/cm2 and the pressure of the super high pressure water is made to ≥250kgf/cm2.
ARIGA TAKASHI
KIHARA SHIGERU
Next Patent: DESCALING METHOD IN OUTER SURFACE OF SEAMLESS STEEL TUBE