| 摘要 |
<p>PURPOSE: A non-oriented electrical steel sheet with low core loss and high strength and a manufacturing method thereof are provided to perform the final annealing in a temperature range ensuring small variations of yield strength to keep the elongation ratio of the steel sheet over a certain level, thereby stably obtaining the properties of low core-loss and high strength. CONSTITUTION: A manufacturing method of a non-oriented electrical steel sheet with low core loss and high strength comprises a step of hot-rolling and cold- rolling of a slab, and a step of final annealing the slab to obtain 1-50% of area fraction of an un-recrystallized structure at the cross section of a steel sheet. The slab consists of C of 0.005 wt.% or less, Si of 4.0 wt.% or less, P of 0.1 wt.% or less, S of 0.03 wt.% or less, Mn of 0.1-2.0 wt.%, Al of 0.3-2.0 wt.%, N of 0.003 wt.% or less, Cu of 0.02 wt. %, and Cr: 10 wt. % or less, and Fe and inevitable impurities of the remaining amount. The average size of recrystallized grain after final annealing is controlled to be less than 10micrometers. The final annealing is performed in a temperature range ensuring that the variations of yield strength are 3.0MPa or less. The elongation ratio of the steel sheet by performing the final annealing is controlled to be more than 20%. The yield strength of the steel sheet by performing the final annealing is controlled to be more than 500MPa. A annealing of hot-rolled steel sheet is performed after the hot-rolling before the cold rolling.</p> |
