| 摘要 |
PROBLEM TO BE SOLVED: To uniformely form thin scale over the entire area of the surface of s steel strip by executing rough rolling a steel slab containing not less than a specified amount of P at the temp. not lower than a specified temp., at the time of finish-rolling the rough bar with a rolling mill having four or more stands after descaling, executing descaling with high-pressure water not lower than a specified pressure between the stands of a 1st-4th stand. SOLUTION: When the steel slab containing >=0.03 wt.% P is roughly rolled at >=1050 deg.C, descaling with the high-pressure water of >=20 kgf/cm2 is executed at least between the stands of the 1st-4th stand. When interstand descaling with the high-pressure water of >=20 kgf/cm2 is executed between the stands of the 1st-4th stand of the finishing mill consisting of seven stands and rough rolling is executed at >=1050 deg.C, the thin scale of <=3μm is obtained. When the interstand descaling is not executed or the treatment is executed with the high-pressure water lower than 20 kgf/cm2, the thin scale of <=3μm is not obtained.
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