HOT ROLLED STEEL PLATE EXCELLENT IN SCALE ADHESION BY CONTINUOUS HOT ROLLING PROCESS AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a steel plate reduced in the amount of formed scale, uniformized in the thickness of scale in a coil, and excellent in scale adhesion by treating a steel slab of specific composition under specific rolling conditions. SOLUTION: A steel, having a composition containing the essential elements used for the ordinary hot rolled steel plate, that is, prescribed amounts of C, Si, Mn, P, S, Al, Cr, and Fe, is used. A steel slab of this composition is introduced into a heating furnace or reheated after temporarily formed into cold slab, and prescribed strain is applied to the surface by means of coiling and uncoiling of a stock bar in a coil box, followed by rolling at proper temp. and draft by means of a finish rolling mill. Then, channel cooling is performed to lower the temp. to a value in a proper range, followed by coiling. By this method, the steel plate, in which the thickness of scale on the surface of the steel plate and the fluctuations in the thickness of scale on the surface of the steel plate are regulated to =5m and =1m, respectively, can be obtained.