| 摘要 |
PROBLEM TO BE SOLVED: To improve a collecting degree in the crystal orientation of a silicon steel sheet and the magnetic flux density of the silicon steel sheet in which BN is utilized as an inhibitor and suitable amounts of V and Nb are added, by promoting the conversion precipitation of VN and NbN in a hot rolled sheet annealing stage or an intermediate annealing stage and a final finish annealing stage. SOLUTION: A silicon steel having a compsn. contg., by weight, 0.03 to 0.10% C, 2.5 to 4.5% Si, 0.05 to 1.5% Mn and 0.010 to 0.040% S+Se and satisfying the condition of Mn/(S+Se)<=2.5 is added with 0.0010 to 0.0060% B, 0.0050 to 0.0100% N and 0.001 to 0.020% V and/or Nb and also the relation of N-(14/10.8)×B>=0.0020 is satisfied. A slab having this compsn. is worked by hot rolling and is applied to hot rolled sheet annealing or intermediate annealing at 950 to 1100 deg.C and the residence time of >=30 sec is given thereto in a cooling stage to 800 deg.C. Furthermore, the final draft in the subsequent cold rolling is regulated to 80 to 90% and is held for 5 to 60 hr in the temp. region of 800 to 900 deg.C in a temp. raising stage in final finish annealing. |
