Non-oriented electrical steel sheet and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-11142813-B2
Application number	US-201716463412-A
Country	US
Kind code	B2
Filing date	Nov 15, 2017
Priority date	Nov 25, 2016
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

Disclosed is a non-oriented electrical steel sheet low in iron loss that is substantially free of Al and contains large amounts of Si and Mn. The disclosed non-oriented electrical steel sheet has a chemical composition containing C: 0.0050% or less, Si: 2.0% to 6.0%, Mn: 1.0% to 3.0%, P: 0.20% or less, S: 0.0050% or less, N: 0.0050% or less, and Al: 0.0050 % or less, with the balance being Fe and inevitable impurities, in which Si—Mn nitrides having an average diameter of 50 nm to 500 nm has a number density of 1/μm3 or less.

First claim

The invention claimed is:

1. A non-oriented electrical steel sheet comprising a chemical composition containing, by mass %,
C: 0.0050% or less,
Si: 2.0% to 6.0%,
Mn: 1.0% to 3.0%,
P: 0.20% or less,
S: 0.0050% or less,
N: 0.0050% or less, and
Al: 0.0050% or less,

with the balance being Fe and inevitable impurities, wherein Si—Mn nitrides having an average diameter of 50 nm to 500 nm has a number density of 1/μm 3 or less.

2. The non-oriented electrical steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Sn: 0.01% to 0.50% and
Sb: 0.01% to 0.50%.

3. The non-oriented electrical steel sheet according to claim 2 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ca: 0.0001% to 0.0300%
Mg: 0.0001% to 0.0300% and,
REM: 0.0001% to 0.0300%.

4. The non-oriented electrical steel sheet according to claim 3 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ni: 0.01% to 5.00% and
Co: 0.01% to 5.00%.

5. The non-oriented electrical steel sheet according to claim 2 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ni: 0.01% to 5.00% and
Co: 0.01% to 5.00%.

6. The non-oriented electrical steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ca: 0.0001% to 0.0300%
Mg: 0.0001% to 0.0300% and,
REM: 0.0001% to 0.0300%.

7. The non-oriented electrical steel sheet according to claim 6 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ni: 0.01% to 5.00% and
Co: 0.01% to 5.00%.

8. The non-oriented electrical steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, at least one selected from the group consisting of
Ni: 0.01% to 5.00% and
Co: 0.01% to 5.00%.

9. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising: hot rolling a slab having the chemical composition as recited in claim 1 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower.

10. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising: hot rolling a slab having the chemical composition as recited in claim 1 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; subjecting the hot-rolled sheet to hot band annealing and subsequently cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower, and
the hot-rolled sheet after subjection to the hot band annealing is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C.

11. A method for manufacturing the non-oriented electrical steel sheet according to claim 2 , comprising: hot rolling a slab having the chemical composition as recited in claim 2 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower.

12. A method for manufacturing the non-oriented electrical steel sheet according to claim 2 , comprising: hot rolling a slab having the chemical composition as recited in claim 2 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; subjecting the hot-rolled sheet to hot band annealing and subsequently cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower, and
the hot-rolled sheet after subjection to the hot band annealing is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C.

13. A method for manufacturing the non-oriented electrical steel sheet according to claim 6 , comprising: hot rolling a slab having the chemical composition as recited in claim 6 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower.

14. A method for manufacturing the non-oriented electrical steel sheet according to claim 6 , comprising: hot rolling a slab having the chemical composition as recited in claim 6 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; subjecting the hot-rolled sheet to hot band annealing and subsequently cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower, and
the hot-rolled sheet after subjection to the hot band annealing is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C.

15. A method for manufacturing the non-oriented electrical steel sheet according to claim 8 , comprising: hot rolling a slab having the chemical composition as recited in claim 8 to obtain a hot-rolled sheet; coiling the hot-rolled sheet into a coil; cold rolling the hot-rolled sheet once, or twice with intermediate annealing therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein
the hot-rolled sheet after subjection to the hot rolling is subjected to cooling at an average cooling rate of 30° C./s or higher in a temperature range from 800° C. to 650° C., and then the coiling is performed at 650° C. or lower.

16. A method for manufacturing the non-oriented el

Assignees

• Jfe Steel Corp

Inventors

• Nakajima Hiroaki
• Uesaka Masanori
• Zaizen Yoshiaki
• Okubo Tomoyuki
• Oda Yoshihiko

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• Y02P10/20

  Recycling · CPC title

• C21D8/12 Primary

  during manufacturing of articles with special electromagnetic properties · CPC title

• C21D8/1222

  Hot rolling · CPC title

• C21D6/008 Primary

  containing Si · CPC title