Non-oriented electrical steel sheet and manufacturing method therefor

• US 10,643,771 B2
• Filed: 12/05/2014
• Issued: 05/05/2020
• Est. Priority Date: 12/23/2013
• Status: Active Grant

• Current Assignee: POSCO Co. Ltd. (Posco Holdings Incorporated)
• Original Assignee: Posco Holdings Incorporated
• Inventors: Lee, Hunju, Lee, Sang-Woo, Sin, Su-Yong
• Primary Examiner(s): Slifka, Colin W.
• Application Number:
  US15/107,900
• Publication Number:
  US 20160322137A1
• Time in Patent Office: 1,978 Days
• Field of Search: None
• CPC Class Codes: C21D 8/1222 Hot rolling
• CPC Class Codes: C21D 8/1233 Cold rolling
• CPC Class Codes: C21D 8/1261 following hot rolling
• CPC Class Codes: C21D 8/1272 Final recrystallisation annealing
• CPC Class Codes: C21D 9/46 for sheet metals
• CPC Class Codes: C22C 38/001 containing N
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/004 Very low carbon steels, i.e. having a carbon content of less than 0,01%
• CPC Class Codes: C22C 38/008 containing tin
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/14 containing titanium or zirconium
• CPC Class Codes: C22C 38/60 containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
• CPC Class Codes: H01F 1/14775 in the form of sheets
• CPC Class Codes: H01F 1/16 in the form of sheets H01F1/147 takes precedence

Abstract

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.

Claims

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/mm².

4. The non-oriented electrical steel sheet of claim 3, wherein the electrical steel sheet has an average grain size of 50 to 150 μ

m.

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/mm².

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°

.