| 摘要 |
PURPOSE:To obtain a full-or semiprocessed steel strip with enhanced magnetic flux density and iron loss by finishing the hot rolling of a steel contg. restricted C, Si or Si+Al, Mn and P at a temp. above the Ar3 transformation point and carrying out short-time annealing at a temp. below the A3 transformation point. CONSTITUTION:A steel ingot or slab consisting of <=0.02% C, <=1.5% Si or Si+Al, <=1.0% Mn, <=0.20% P and the balance Fe with inevitable impurities is heated and hot rolled. At this time, the hot rolling finish tamp. is adjusted to above the temp. represented by the equation for holding a gamma structure. The hot rolled steel strip is then annealed at a temp. below the A3 transformation point for 30sec- 15min. Thus, the grains of the steel strip can be made coarse by the inexpensive continuous annealing without carrying out decarburization. When each of said components exceeds the upper limit, C makes the grain coarsening difficult and deteriorates the magnetic characteristics and suitability to magnetic aging. Si or Si+Al raises the gamma phase existing temp., Mn is magnetically harmful, and P makes the plate brittle. |
