GRAIN-ORIENTED ELECTRICAL STEEL SHEET AND MANUFACTURING METHOD THEREFOR

• US 20190323105A1
• Filed: 12/21/2017
• Published: 10/24/2019
• Est. Priority Date: 12/22/2016
• Status: Active Grant

• Current Assignee: POSCO Co. Ltd. (Posco Holdings Incorporated)
• Original Assignee: Posco Holdings Incorporated
• Inventors: Park, Chang Soo, Han, Kyu-Seok, Joo, Hyung Don, Kim, Jae Kyoum, Kim, Woo-Sin
• Granted Patent: US 11,608,540 B2
• Time in Patent Office: Days
• CPC Class Codes: C21D 1/74 Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
• CPC Class Codes: C21D 2201/05 Grain orientation
• CPC Class Codes: C21D 2211/004 Dispersions; Precipitations
• CPC Class Codes: C21D 6/005 containing Mn
• CPC Class Codes: C21D 6/008 containing Si
• CPC Class Codes: C21D 8/005 of ferrous alloys C21D8/02 - C21D8/12 take precedence
• CPC Class Codes: C21D 8/12 during manufacturing of articles with special electromagnetic properties
• 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 2202/02 Magnetic
• CPC Class Codes: C22C 38/00 Ferrous alloys, e.g. steel alloys cast-iron alloys C22C37/00
• 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 38/005 containing rare earths, i.e. Sc, Y, Lanthanides
• 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 38/16 : containing copper
• CPC Class Codes: C22C 38/18 : containing chromium
• CPC Class Codes: C22C 38/60 : containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Abstract

A grain-oriented electrical steel sheet of an embodiment of the present invention comprises Si: 1.0% to 7.0% and Y: 0.005% to 0.5% by wt %, and the remainder comprising Fe and other inevitable impurities, and 10 pieces or less of inclusions comprising Y and having a diameter of 30 nm to 5 μm per area of 1 mm².

Claims

1. A grain-oriented electrical steel sheet comprising:

Si;

1.0 to 7.0% and Y;

0.005 to 0.5% by wt %, and the remainder comprising Fe and other inevitable impurities, and

10 pieces or less of inclusions comprising Y and having a diameter of 30 nm to 5 μ

m per area of 1 mm².

2. The grain-oriented electrical steel sheet of claim 1, further comprising

Mn:

0.01% to 0.5%, C;

0.005% or less (excluding 0%), Al;

0.005% or less (excluding 0%), N;

0.006% or less (excluding 0%) and S;

0.006% or less (excluding 0%) by wt %.

3. The grain-oriented electrical steel sheet of claim 1, further comprising

0.01 to 0.2 wt % of at least one of P, Cu, Cr, Sb, Sn and Mo, respectively singly or in a total amount.

4. The grain-oriented electrical steel sheet of claim 1, wherein,

the inclusions comprise at least one of a carbide of Y, a nitride of Y, an oxide of Y, and an Fe—

Y compound.

5. The grain-oriented electrical steel sheet of claim 1, comprising

3 to 9 pieces of the inclusions per area of 1 mm².

6. A method for manufacturing a grain-oriented electrical steel sheet, the method comprising:

heating a slab comprising Si;

1.0 to 7.0%, Y;

0.005 to 0.5% by wt %, and the remainder comprising Fe and other inevitable impurities;

hot-rolling the slab to produce a hot-rolled sheet;

cold-rolling the hot-rolled sheet to produce a cold-rolled sheet;

primary recrystallization annealing the cold-rolled sheet; and

secondary recrystallization annealing the cold-rolled sheet which is the primary recrystallization annealed;

wherein the step of primary recrystallization annealing comprises a heating step and a soaking step,

the step of heating is performed in an atmosphere having an oxygen partial pressure (P_H2O/P_H2) of 0.20 to 0.40, and

the step of soaking is performed in an atmosphere having an oxygen partial pressure (P_H2O/P_H2) of 0.50 to 0.70.

7. The method of claim 6, wherein,

the secondary recrystallization annealed steel sheet comprises 10 pieces or less of inclusions comprising Y and having a diameter of 30 nm to 5 μ

m per area of 1 mm².

8. The method of claim 6, wherein,

the slab further comprises Mn:

0.01% to 0.5%, C;

0.02 to 0.1%, Al;

0.01% or less (excluding 0%), N;

0.006% or less (excluding 0%) and S;

0.006% or less (excluding 0%) by wt %.

9. The method of claim 6, wherein,

the slab further comprises 0.01 to 0.2 wt % of at least one of P, Cu, Cr, Sb, Sn and Mo, respectively singly or in a total amount.

10. The method of claim 6, wherein, in the step of heating the slab, heating is performed at 1000 to 1280 ␣

.

11. The method of claim 6, wherein,

the step of heating is heating at a rate of 10 □

/s or more.

12. The method of claim 6, wherein,

the step of soaking is performed at a temperature of 800 to 900 □

.

13. The method of claim 6, wherein,

the step of primary recrystallization annealing is performed in a mixed gas atmosphere of hydrogen and nitrogen.

14. The method of claim 6, wherein,

the step of secondary recrystallization annealing comprises a temperature-raising step and a soaking step, and the temperature of soaking step is 900 to 1250 □

.

15. The method of claim 14, wherein,

the temperature-raising step of the secondary recrystallization annealing is performed in a mixed gas atmosphere of hydrogen and nitrogen, and the soaking step of the secondary recrystallization annealing is performed in hydrogen atmosphere.