Method of producing grain-oriented electrical steel sheet

Patent metadata

Field	Value
Publication number	US-9290824-B2
Application number	US-201214235935-A
Country	US
Kind code	B2
Filing date	Aug 15, 2012
Priority date	Aug 18, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

In a method of producing a grain-oriented electrical steel sheet by hot-rolling a steel slab of a chemical composition containing C: 0.001˜0.10%, Si: 1.0˜5.0%, Mn: 0.01˜1.0%, at least one of S and Se: 0.01˜0.05% in total, sol. Al: 0.003˜0.050%, N: 0.001˜0.020% by mass, subjecting to cold rolling, a primary recrystallization annealing, application of an annealing separator mainly composed of MgO and a finish annealing, a temperature rising rate S1 between 500˜600° C. in the primary recrystallization annealing is made to not less than 100° C./s and a temperature rising rate S2 between 600˜700° C. is made to 30° C./s˜0.6×S1° C./s, while a total content W (mol %) of an element having an ionic radius of 0.6˜1.3 Å and an attracting force between the ion and oxygen of not more than 0.7 Å −2 included in the annealing separator to MgO is adjusted to satisfy 0.01S2−5.5≦Ln (W)≦0.01S2−4.3 to produce a grain-oriented electrical steel sheet having excellent iron loss properties and coating properties.

First claim

The invention claimed is:

1. A method of producing a grain-oriented electrical steel sheet by hot-rolling a steel slab of a chemical composition comprising C: 0.001 to 0.10 mass %, Si: 1.0 to 5.0 mass %, Mn: 0.01 to 1.0 mass %, at least one of S and Se: 0.01 to 0.05 mass % in total, sol. Al: 0.003 to 0.050 mass %, N: 0.001 to 0.020 mass % and the balance being Fe and inevitable impurities, subjecting to single cold rolling or two or more cold rollings including an intermediate annealing therebetween to a final thickness and further to a primary recrystallization annealing, application of an annealing separator composed mainly of MgO and a finish annealing, wherein the primary recrystallization annealing a temperature rising rate S1 between 500 to 600° C. is made to not less than 100° C./s and a temperature rising rate S2 between 600 to 700° C. is made to 30° C./s to 0.6×S1° C./s, while a total content W (mol %) of an element having an ionic radius of 0.6 to 1.3 Å and an attracting force between ion and oxygen of not more than 0.7 Å −2 included in the annealing separator to MgO is adjusted to satisfy the following equation (1) in relation to the S2:
0.01 S 2−5.5≦Ln( W )≦0.01 S 2−4.3  (1).

2. The method of producing a grain-oriented electrical steel sheet according to claim 1 , wherein decarburization annealing is carried out after the primary recrystallization annealing.

3. The method of producing a grain-oriented electrical steel sheet according to claim 1 , wherein the element having an ionic radius of 0.6 to 1.3 Å and an attracting force between the ion and oxygen of not more than 0.7 Å −2 is at least one of Ca, Sr, Li and Na.

4. The method of producing a grain-oriented electrical steel sheet according to claim 1 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from Cu: 0.01 to 0.2 mass %, Ni: 0.01 to 0.5 mass %, Cr: 0.01 to 0.5 mass %, Sb: 0.01 to 0.1 mass %, Sn: 0.01 to 0.5 mass %, Mo: 0.01 to 0.5 mass % and Bi: 0.001 to 0.1 mass %.

5. The method of producing a grain-oriented electrical steel sheet according to claim 1 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

6. The method of producing a grain-oriented electrical steel sheet according to claim 2 , wherein the element having an ionic radius of 0.6 to 1.3 Å and an attracting force between the ion and oxygen of not more than 0.7 Å −2 is at least one of Ca, Sr, Li and Na.

7. The method of producing a grain-oriented electrical steel sheet according to claim 2 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from Cu: 0.01 to 0.2 mass %, Ni: 0.01 to 0.5 mass %, Cr: 0.01 to 0.5 mass %, Sb: 0.01 to 0.1 mass %, Sn: 0.01 to 0.5 mass %, Mo: 0.01 to 0.5 mass % and Bi: 0.001 to 0.1 mass %.

8. The method of producing a grain-oriented electrical steel sheet according to claim 3 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from Cu: 0.01 to 0.2 mass %, Ni: 0.01 to 0.5 mass %, Cr: 0.01 to 0.5 mass %, Sb: 0.01 to 0.1 mass %, Sn: 0.01 to 0.5 mass %, Mo: 0.01 to 0.5 mass % and Bi: 0.001 to 0.1 mass %.

9. The method of producing a grain-oriented electrical steel sheet according to claim 2 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

10. The method of producing a grain-oriented electrical steel sheet according to claim 3 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

11. The method of producing a grain-oriented electrical steel sheet according to claim 4 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

12. The method of producing a grain-oriented electrical steel sheet according to claim 6 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from Cu: 0.01 to 0.2 mass %, Ni: 0.01 to 0.5 mass %, Cr: 0.01 to 0.5 mass %, Sb: 0.01 to 0.1 mass %, Sn: 0.01 to 0.5 mass %, Mo: 0.01 to 0.5 mass % and Bi: 0.001 to 0.1 mass %.

13. The method of producing a grain-oriented electrical steel sheet according to claim 6 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

14. The method of producing a grain-oriented electrical steel sheet according to claim 7 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

15. The method of producing a grain-oriented electrical steel sheet according to claim 8 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

16. The method of producing a grain-oriented electrical steel sheet according to claim 12 , wherein in addition to the above chemical composition, the steel slab contains at least one selected from B: 0.001 to 0.01 mass %, Ge: 0.001 to 0.1 mass %, As: 0.005 to 0.1 mass %, P: 0.005 to 0.1 mass %, Te: 0.005 to 0.1 mass %, Nb: 0.005 to 0.1 mass %, Ti: 0.005 to 0.1 mass % and V: 0.005 to 0.1 mass %.

Assignees

• Watanabe Makoto
• Shingaki Yukihiro
• Takamiya Toshito
• Okubo Tomoyuki
• Senda Kunihiro
• Jfe Steel Corp

Inventors

• Watanabe Makoto
• Shingaki Yukihiro
• Takamiya Toshito
• Okubo Tomoyuki
• Senda Kunihiro

Classifications

• C23C22/74

  for obtaining burned-in conversion coatings · CPC title

• C21D8/1272 Primary

  Final recrystallisation annealing · CPC title

• H01F1/16

  in the form of sheets (H01F1/147 takes precedence) · CPC title

• C23C22/33

  containing also phosphates · CPC title

• H01F1/14775

  in the form of sheets · CPC title