| 摘要 |
PURPOSE:To obtain a grain oriented electrical steel sheet having a lower iron loss by forming a high magnetic flux density polycrystalline steel sheet of a specific sheet thickness which contains specific ratios of Si and Sn and is controlled in the content of C, N and S so as to have specific tension and specific crystal grain boundary shape. CONSTITUTION:A hot rolled sheet consisting of a steel stock having a prescribed compsn. is subjected adequately to annealing and cold rolling, then to an adequate heat treatment and cooling prior to the final cold rolling. The polycrystalline steel sheet which contains 2.3-4.3 Si and 0.04-0.4% Sn, is limited to <=0.0015% C and respectively <=0.0010% N and S as impurities and consists of the balance substantially Fe is thereby yielded. The sheet thickness of the resulted steel sheet is 0.15-0.23mm, B10>=1.90T and 0.2-1.0kg/mm<2> tension exists therein; in addition, the average value of the respective SF values as the steel sheet when SF=(area of crystal grains)X4pi/(length of crystal grains)<2> as the index to express the characteristic of the grain boundary shape relating to the respective crystal grains is <0.60. The grain oriented electrical steel sheet having the low iron loss of W17/50<=0.90W/kg is thus obtd. |
