| 摘要 |
PROBLEM TO BE SOLVED: To provide a low magnetostriction bidirectionary oriented silicon steel sheet excellent in magnetic properties, and its manufacturing method. SOLUTION: The bidirectionary oriented silicon steel sheet has the following characteristics: magnetostriction, when alternating field is applied to the direction of easy magnetization of the steel sheet having <=6.5% Si content and an average grain size 10 times the thickness of the sheet or below and being in a stress-free state to perform magnetization to 1.7 T, is <=10×10-6; magnetostriction, in a state where a tension ranging from 1 MPa to the elastic limit is applied to the direction of easy magnetization in the plane of the steel sheet, is <=3.0×10-6; 100} integration degree is >=70% and <001> integration degree is <=70%; and the average spacing between the 180 deg. domain walls under the state of thermal demagnetization free from stress is <=0.50 mm, and/or the area ratio of a magnetic domain having zigzag magnetic domain walls is <=30%. It is preferable that a tension film of silica phosphate type or alumina boron oxide type is provided on the surface. This steel sheet can be manufactured by subjecting a steel sheet containing 0.02-0.20% C, <=6.5% Si and 0.2-2.0% Mn and having >=3 integration degree in the 100} <001> orientation after primary recrystallization to final annealing while interposing a separation agent at annealing which contains a substance accelerating decarburization or decarburization and Mn removal. |
