| 摘要 |
<p>PROBLEM TO BE SOLVED: To stably manufacture an inexpensive hot rolled sheet excellent in magnetic properties by regulating the thickness of a hot rolled sheet, having a composition consisting of specific amounts of Si and Mn and the balance Fe with inevitable impurities to a specific value or below and also regulating magnetic flux density so that it is higher in specific directions with respect to rolling direction than in the directions other than the above. SOLUTION: The contents of Si and Mn are regulated, by weight, to 0.1-4.0% and 0.05-1.5%, respectively, and it is preferable that acid-soluble Al is contained. Further, sheet thickness is <=1.20 mm, preferably <=0.8 mm, and the magnetic flux densities in the directions at angles of 45 deg. and 135 deg. with respect to rolling direction are higher than those in the other directions. It is preferable to regulate the coefficient of friction between a hot roll and a steel sheet to <=0.25 at least one pass at finish hot rolling and also to use, as hot roll cooling water, an emulsion where 0.5 to 20% oil and fat are mixed. A sheet bar after roughing is joined to a preceding sheet bar and finish hot rolling is continuously performed, by which the occurrence of roll slip at the time of low friction rolling can be prevented and the steel sheet excellent in surface condition can be manufactured.</p> |
