| 摘要 |
PURPOSE:To improve repetitive bending characteristics by subjecting a cold-rolled directional silicon steel plate to decarburization annealing and final anealing then performing flattening annealing accompanying cooling owing to specific conditions. CONSTITUTION:A silicon steel slab is hot-rolled to a steel plate which is then subjected to intermediate annealing for 5min at 900 deg.C, after which it is cold-rolled to final plate thickness. This silicon steel plate is decarburization-annealed in wet hydrogen for 3min at 820 deg.C, after which an annealing separating agent of MgO+ 1.5% TiO2 is coated and the plate is subjected to final annealing. Next, a phosphate base insulation film is formed, after which the plate is subjected to flattening annealing. The flattening annealing is accomplished by soaking the steel plate for 5sec-3min at 780-850 deg.C in a neutral atmosphere then slow cooling the same at cooling rates of average 2-20 deg.C/sec for 780 deg.C-300 deg.C. Otherwise, the plate is cooled at 7-50 deg.C/sec in a temp. range of 700-500 deg.C, and is slow cooled at cooling rates of 2-15 deg.C/sec between 500-300 deg.C, whereby it is subjected to flattening annealing. The repetitive bending characteristics of the silicon steel plate improve. |
