# US 2019/0316221 A1 · Non-oriented electrical steel sheet and method for manufacturing non-oriented electrical steel sheet

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- Number: US 2019/0316221 A1
- Document ID: US20190316221A1
- Status: Published application
- Kind: A1
- Application number: 16/470,078
- Filed: 2018-01-16
- Published: 2019-10-17
- Earliest claimed: 2017-01-16
- Assignees: Nippon Steel Corporation
- Applicants: Nippon Steel Corporation
- Inventors: Hiroyoshi YASHIKI; Yoshiaki NATORI; Kazutoshi TAKEDA; Susumu MUKAWA; Takuya MATSUMOTO; Koji FUJITA; Takashi MOROHOSHI; Masafumi MIYAZAKI
- Web page: https://patentgrep.com/patent/US20190316221A1

## CPC

- C21D 9/46: for sheet metals
- H01F 1/16: in the form of sheets (H01F1/147 takes precedence)
- C21D 6/008: {containing Si}
- C21D 8/12: during manufacturing of articles with special electromagnetic properties
- C21D 8/1222: {Hot rolling}
- C21D 8/1233: {Cold rolling}
- C21D 8/1261: {following hot rolling}
- C21D 8/1272: {Final recrystallisation annealing}
- C22C 38/00: Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00)
- C22C 38/001: {containing N}
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/008: {containing tin}
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/14: containing titanium or zirconium
- C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
- C22C 2202/02: Magnetic
- H01F 1/1475: {the particles being insulated}
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A non-oriented electrical steel sheet contains, as a chemical composition, by mass %, C: more than 0% and 0.0050% or less, Si: 3.0% to 4.0%, Mn: 1.0% to 3.3%, P: more than 0% and less than 0.030%, S: more than 0% and 0.0050% or less, sol. Al: more than 0% and 0.0040% or less, N: more than 0% and 0.0040% or less, O: 0.0110% to 0.0350%, Sn: 0% to 0.050%, Sb: 0% to 0.050%, Ti: more than 0% and 0.0050% or less, and a remainder including Fe and impurities, in which Sn+Sb: 0.050% or less, Si−0.5×Mn: 2.0% or more, and an O content in a sheet thickness central portion excluding a surface layer portion which is a range from a front surface and a rear surface to a position of 10 μm in a depth direction is less than 0.0100%.

## Claims

### Claim 1

A non-oriented electrical steel sheet comprising, as a chemical composition, by mass %,
C: more than 0% and 0.0050% or less;
Si: 3.0% to 4.0%;
Mn: 1.0% to 3.3%;
P: more than 0% and less than 0.030%;
S: more than 0% and 0.0050% or less;
sol. Al: more than 0% and 0.0040% or less;
N: more than 0% and 0.0040% or less;
O: 0.0110% to 0.0350%;
Sn: 0% to 0.050%;
Sb: 0% to 0.050%;
Ti: more than 0% and 0.0050% or less; and
a remainder including Fe and impurities, wherein
Sn+Sb: 0.050% or less,
Si−0.5×Mn: 2.0% or more, and
an O content in a sheet thickness central portion excluding a surface layer portion which is a range from a front surface and a rear surface to a position of 10 μm in a depth direction is less than 0.0100%.

### Claim 2

A method for manufacturing a non-oriented electrical steel sheet, comprising:
hot rolling a steel ingot including, as a chemical composition, by mass %, C: more than 0% and 0.0050% or less, Si: 3.0% to 4.0%, Mn: 1.0% to 3.3%, P: more than 0% and less than 0.030%, S: more than 0% and 0.0050% or less, sol. Al: more than 0% and 0.0040% or less, N: more than 0% and 0.0040% or less, O: less than 0.0100%, Sn: 0% to 0.050%, Sb: 0% to 0.050%, Ti: more than 0% and 0.0050% or less, and a remainder including Fe and impurities, Sn+Sb: 0.050% or less, Si−0.5×Mn: 2.0% or more to produce a hot-rolled steel sheet;
annealing the hot-rolled steel sheet;
cold rolling the hot-rolled steel sheet after the annealing to produce a cold-rolled steel sheet; and
final annealing the cold-rolled steel sheet, wherein,
in the final annealing, a final annealing condition is controlled so that an average O content in the entire cold-rolled steel sheet in a sheet thickness direction after the final annealing becomes 0.0110 mass % to 0.0350 mass %.

### Claim 3 (depends on 2)

The method for manufacturing a non-oriented electrical steel sheet according to claim 2, wherein,
in the final annealing, a dew point of an atmosphere during temperature rising and during soaking is controlled so as to be in a range of −10° C. to 40° C.