Thin grain-oriented electrical steel sheet and manufacturing method therefor
AssigneePosco
InventorsKyung-Jun Ko, ll-Nam Yang, Jae-Hwa Song
Life of this patent
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Abstract
A thin grain-oriented electrical steel sheet and a manufacturing method therefor are provided. The grain-oriented electrical steel sheet manufacturing method of the present invention comprises the steps of: hot rolling a slab, thereby manufacturing a hot rolled sheet; annealing the hot rolled sheet; cold rolling the annealed hot-rolled sheet, thereby manufacturing a cold rolled sheet; primarily recrystallization-annealing the cold rolled sheet by decarburizing and nitriding same; and secondarily recrystallization-annealing the cold rolled sheet which has been primarily recrystallization-annealed.
Claims9
A manufacturing method for a thin grain-oriented electrical steel sheet, the method comprising:
- hot rolling a slab including, by weight:
- 2.5 to 4.0% of Si, 0.03 to 0.09% of C, 0.0150 to 0.0400% of Al, 0.04 to 0.15% of Mn, 0.010% of less (excluding 0%) of S, 0.0020 to 0.0120% of N, 0.010 to 0.050% of P, and 0.03 to 0.12% of a sum of one or more of Sn and Sb with a remainder of Fe and unavoidable impurities to manufacture a hot rolled sheet;
- annealing the hot rolled sheet;
- cold rolling the annealed hot-rolled sheet to manufacture a cold rolled sheet;
- performing primary recrystallization annealing by decarburizing and nitriding the cold rolled sheet;
- and performing secondary recrystallization annealing of the cold rolled sheet after completing the primary recrystallization annealing,
- wherein contents of Al and N in the slab satisfy the following Relations 1 and 2,
- when a temperature difference between a heating temperature T1 and a soaking annealing temperature T2 in the hot-rolled sheet annealing is ΔT, ΔT≥200° C. is satisfied, and when cooling from T1 to T2, a cooling rate is controlled to 30° C./sec or less, and
- a nitrogen amount ΔN increasing in the cold rolled sheet by the nitriding in the primary recrystallization annealing satisfies the following Relation 3:
- 0.039
- -
- 0.1
- Ht
- ≤
- [
- Al
- ]
- -
- 27
- /
- 14
- ×
- [
- N
- ]
- ≤
- 0.047
- -
- 0.01
- Ht
- [
- Relation
-
- 1
- ]
- 15.5
- -
- 5
-
- Ht
- ≤
- [
- Al
- ]
- /
- [
- N
- ]
- [
- Relation
-
- 2
- ]
- wherein [Al] and [N] denote contents (wt %) of Al and N in the slab, respectively, and Ht denotes a thickness (mm) of a final hot rolled sheet,
- [
- Al
- ]
- -
- 27
- /
- 14
- ×
- [
- N
- ]
- +
- (
- 0.23
- -
- Ct
- )
- *
- 0.125
- ≤
- (
- 27
- /
- 14
- )
-
- Δ
-
- N
- ≤
- 0.03
- [
- Relation
-
- 3
- ]
- wherein [Al] and [N] denote contents (wt %) of Al and N in the slab, respectively, and Ct denotes a thickness of a final cold rolled sheet.
A thin grain-oriented electrical steel sheet comprising, by weight:
- 2.5 to 4.0% of Si, 0.03 to 0.09% of C, 0.0150 to 0.0400% of Al, 0.04 to 0.15% of Mn, 0.010% of less (excluding 0%) of S, 0.0020 to 0.0120% of N, 0.010 to 0.050% of P, and 0.03 to 0.12% of a sum of one or more of Sn and Sb with a remainder of Fe and unavoidable impurities, wherein a nitrogen amount ΔN increasing in the steel sheet by nitriding satisfies the following Relation 3:
- [
- Al
- ]
- -
- 27
- /
- 14
- ×
- [
- N
- ]
- +
- (
- 0.23
- -
- Ct
- )
- *
- 0.125
- ≤
- (
- 27
- /
- 14
- )
-
- Δ
-
- N
- ≤
- 0.03
- [
- Relation
-
- 3
- ]
- wherein [Al] and [N] denote contents (wt %) of Al and N in the steel sheet, respectively, and Ct denotes a steel sheet thickness.
Dependencies are inferred from the claim text.