Non-oriented electrical steel sheet and manufacturing method therefor
A method of manufacturing a non-oriented electrical steel sheet is disclosed. A method of manufacturing a non-oriented electrical steel sheet according to the present invention includes reheating slab consisting of Si: 2.0-4.0%, acid-soluble Al: 0.01-0.04%, Mn: 0.20% or less, Sb: 0.005-0.10%, N: 0.005% or less, S:0.005% or less, C: 0.005-0.015%, Fe in a balance amount, and other inevitable impurities in weight percent (wt %); hot rolling the slab to prepare a hot rolled steel sheet; cold rolling the hot rolled steel sheet to prepare a cold rolled steel sheet; primarily recrystallization-annealing the cold rolled steel sheet; and high-temperature annealing the cold rolled steel sheet subjected to the primarily recrystallization-annealing.
1. A non-oriented electrical steel sheet, consisting of
Si: 2.5-3.5%, Al: 0.3% or more and less than 1.5%, Mn: 0.3% or more and less than 1.5%, N: 0.001-0.005%, S: 0.001-0.005% in weight %, Sb: 0.02-0.25% and Sn: 0.02-0.25%, Fe in a balance amount, and other inevitable impurities,
wherein contents of the Al, Mn, Sb, and Sn satisfy Equations 1 to 3:
0.9<([ Al ]+[ Mn ])<1.5 [Equation 1]
0.05<([ Sb ]+[ Sn ])<0.25 [Equation 2]
0.07<([ Sb ]+[ Sn ])/([ Al ]+[ Mn ])<0.17 [Equation 3]
wherein, in Equations 1 to 3, [Al], [Mn], [Sb], and [Sn] refer to weight percent (%) of each Al, Mn, Sb, and Sn, and
wherein the non-oriented electrical steel sheet has an iron loss (W10/400) of less than 13.8.
2. The non-oriented electrical steel sheet of claim 1 , wherein a thickness of the electrical steel sheet is 0.15 to 0.35 mm.
3. The non-oriented electrical steel sheet of claim 2 , wherein the non-oriented electrical steel sheet includes composite inclusions comprising one or two selected from AlN and MnS, and the composite inclusions having a size of greater than or equal to 10 nm has a distribution density of less than or equal to 0.02 unit/mm 2 .
4. The non-oriented electrical steel sheet of claim 3 , wherein the electrical steel sheet has an average grain size of 50 to 150 μm.
5. The non-oriented electrical steel sheet of claim 1 , wherein the non-oriented electrical steel sheet has greater than or equal to 2.9% of a texture fraction in which a {001} plane is parallel to the plate surface of the electrical steel sheet within an error range of 15°.
6. A method of manufacturing a non-oriented electrical steel sheet, comprising
preparing a slab consisting of Si: 2.5-3.5%, Al: 0.3% or more and less than 1.5%, Mn: 0.3% or more and less than 1.5%, N: 0.001-0.005%, S: 0.001-0.005% in weight %, Sb: 0.02-0.25% and Sn: 0.02-0.25%, Fe in a balance amount, and other inevitable impurities, wherein contents of the Al, Mn, Sb, and Sn satisfy Equations 1 to 3;
reheating the slab and hot rolling the same to prepare a hot rolled steel sheet;
cold-rolling the hot rolled steel sheet to prepare a cold rolled steel sheet; and
finish-annealing the cold rolled steel sheet:
0.9<([ Al ]+[ Mn ])<1.5 [Equation 1]
0.05<([ Sb ]+[ Sn ])<0.25 [Equation 2]
0.07<([ Sb ]+[ Sn ])/([ Al ]+[ Mn ])<0.17 [Equation 3]
wherein, in Equations 1 to 3, [Al], [Mn], [Sb], and [Sn] refer to weight percent (%) of each Al, Mn, Sb, and Sn, and
wherein the non-oriented electrical steel sheet has an iron loss (W10/400) of less than 13.8.
7. The method of claim 6 , wherein the electrical steel sheet subjected to the finish-annealing step comprises composite inclusions including one or two selected from AlN and MnS, and the composite inclusions having a size of greater than or equal to 10 nm has a distribution density of less than or equal to 0.02 unit/mm 2 .
8. The method of claim 6 , wherein the slab is reheated at 1,100° C. to 1,200° C.
9. The method of claim 8 , wherein the hot rolling is finished at greater than or equal to 800° C.
10. The method of claim 9 , which comprises hot rolled plate-annealing the hot rolled steel sheet at 850 to 1150° C.
11. The method of claim 10 , wherein the cold rolled steel sheet is 0.15 to 0.35 mm thick by applying a reduction ratio of 70 to 95%.
12. The method of claim 9 , wherein the electrical steel sheet subjected to the finish-annealing step has greater than or equal to 29% of a texture fraction in which a {001} plane is parallel to the plate surface of the electrical steel sheet within an error range of 15°.