| 摘要 |
PURPOSE:To obtain a titled steel plate which is easy to grow crystal grains in stress relief annealing and has an excellent blanking property in hot rolling of Al-contg. electrical steel by coiling the steel at specific temp. or passing through the same at specific temp. and under tensile force after cold rolling the strip at a specific B/N ratio. CONSTITUTION:The steel of <=0.10% C, <=0.3% Si, <0.30% Mn, <0.08% P, <=0.05% S, 0.005-0.10% Al, <=0.01% N is hot rolled and is coiled at >=650 deg.C or B is incorporated at 0.5-2.5 B/N. After such steel is cold rolled, the strip is heated to temp. above 400 deg.C and below temp. of recrystallization in a continuous annealing furnace and is subjected to recovery annealing under >=0.35kg/mm.<2> tension. Here, crystal grains are grown in stress relief annealing by the regulation of the coiling temp. or in the case of contg. B, without the regulation thereof. If the temp. during annealing is below the lower limit, there is no recovery effect, the softening of the strip is insufficient and the flatness is not improved. In excess of the upper limit, the hardness of the strip decreases considerably from optimum blanking hardness. If the tensile force during annealing is below the lower limit, the function of improving the flatness of the steel plate is low. |
