Non-oriented electrical steel sheet and method for producing the same

Patent metadata

Field	Value
Publication number	US-10822678-B2
Application number	US-201515541964-A
Country	US
Kind code	B2
Filing date	Nov 17, 2015
Priority date	Jan 7, 2015
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

When a non-oriented electrical steel sheet is produced by hot rolling a slab containing, by mass %, C: not more than 0.0050%, Si: 1.5-5.0%, Mn: 0.20-3.0%, sol. Al: not more than 0.0050%, P: not more than 0.2%, S: not more than 0.0050% and N: not more than 0.0040% to form a hot rolled sheet, cold rolling the hot rolled sheet without conducting a hot band annealing and then subjecting to a finish annealing, a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by CaO/(SiO2+Al2O3+CaO) is set to not less than 0.4 and/or a compositional ratio of Al2O3 defined by Al2O3/(SiO2+Al2O3+CaO) is set to not less than 0.3, and a coiling temperature in the hot rolling is set to not lower than 650° C.

First claim

The invention claimed is:

1. A non-oriented electrical steel sheet having a chemical composition comprising C: not more than 0.0050 mass %, Si: 1.5-5.0 mass %, Mn: 0.20-3.0 mass %, sol. Al: not more than 0.0050 mass %, P: not more than 0.2 mass %, 5: not more than 0.0050 mass %, N: not more than 0.0040 mass %, and the remainder being Fe and inevitable impurities, wherein a compositional ratio of CaO in oxide-based inclusions existing in a steel sheet defined by the following equation (1):
CaO/(SiO 2 +Al 2 O 3 +CaO)  (1)

is not less than 0.4 and/or a compositional ratio of Al 2 O 3 defined by the following equation (2):
Al 2 O 3 /(SiO 2 +Al 2 O 3 +CaO)  (2)

is not less than 0.3.

2. The non-oriented electrical steel sheet according to claim 1 , characterized by including at least one element group of the following groups A-D:
Group A: Ca: 0.0005-0.0100 mass %,
Group B: one or two selected from Sn: 0.01-0.1 mass % and Sb: 0.01-0.1 mass %,
Group C: one or two selected from Mg: 0.001-0.05 mass % and REM: 0.001-0.05 mass %, and
Group D: one or more selected from Cu: 0.01-0.5 mass %, Ni: 0.01-0.5 mass % and Cr: 0.01-0.5 mass %,
in addition to the above chemical composition.

3. A method for producing a non-oriented electrical steel sheet by hot rolling a slab having a chemical composition as claimed in claim 2 to form a hot rolled sheet, cold rolling the hot rolled sheet without conducting a hot band annealing and subjecting to a finish annealing, characterized in that a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by the following equation (1):
CaO/(SiO 2 +Al 2 O 3 +CaO)  (1)

is not less than 0.4 and/or a compositional ratio of Al 2 O 3 defined by the following equation (2):
Al 2 O 3 /(SiO 2 +Al 2 O 3 +CaO)  (2)

is not less than 0.3, and a coiling temperature in the hot rolling is not lower than 650° C.

4. A method for producing a non-oriented electrical steel sheet by hot rolling a slab having a chemical composition as claimed in claim 2 to form a hot rolled sheet, cold rolling the hot rolled sheet after a hot band annealing and subjecting to a finish annealing, characterized in that a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by the following equation (1);
CaO/(SiO 2 +Al 2 O 3 +CaO)  (1)

is not less than 0.4 and/or a compositional ratio of Al 2 O 3 defined by the following equation (2):
Al 2 O 3 /(SiO 2 +Al 2 O 3 +CaO)  (2)

is not less than 0.3, and the hot band annealing is conducted at a temperature of 900-1150° C.

5. A method for producing a non-oriented electrical steel sheet by hot rolling a slab having a chemical composition as claimed in claim 1 to form a hot rolled sheet, cold rolling the hot rolled sheet without conducting a hot band annealing and subjecting to a finish annealing, characterized in that a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by the following equation (1):
CaO/(SiO 2 +Al 2 O 3 +CaO)  (1)

is not less than 0.4, and/or a compositional ratio of Al 2 O 3 defined by the following equation (2):
Al 2 O 3 /(SiO 2 +Al 2 O 3 +CaO)  (2)

is not less than 0.3, and a coiling temperature in the hot rolling is not lower than 650° C.

6. A method for producing a non-oriented electrical steel sheet by hot rolling a slab having a chemical composition as claimed in claim 1 to form a hot rolled sheet, cold rolling the hot rolled sheet after a hot band annealing and subjecting to a finish annealing, characterized in that a compositional ratio of CaO in oxide-based inclusions existing in the slab defined by the following equation (1):
CaO/(SiO 2 +Al 2 O 3 +CaO)  (1)

is not less than 0.4 and/or a compositional ratio of Al 2 O 3 defined by the following equation (2):
Al 2 O 3 /(SiO 2 +Al 2 O 3 +CaO)  (2)

is not less than 0.3, and the hot band annealing is conducted at a temperature of 900-1150° C.

7. The non-oriented electrical steel sheet according to claim 1 , wherein the steel sheet has an iron loss (W 15/50 ) of not more than 3.28 W/Kg and a magnetic flux density (B 50 ) of not less than 1.722 T.

8. The non-oriented electrical steel sheet according to claim 1 , wherein the steel sheet has an iron loss (W 15/50 ) of not more than 3.05 W/Kg and a magnetic flux density (B 50 ) of not less than 1.726 T.

9. The non-oriented electrical steel sheet according to claim 1 , wherein the steel sheet has an iron loss (W 15/50 ) of not more than 3.13 W/Kg and a magnetic flux density (B 50 ) of not less than 1.725 T.

Assignees

• Jfe Steel Corp

Inventors

• Nakanishi Tadashi
• Nakajima Hiroaki
• Okubo Tomoyuki
• Oda Yoshihiko

Classifications

• Y02P10/20

  Recycling · CPC title

• H01F1/16

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

• C21D8/12

  during manufacturing of articles with special electromagnetic properties · CPC title

• C22C38/06 Primary

  containing aluminium · CPC title

• C22C38/18

  containing chromium · CPC title