# US 12,760,384 B2 · Method of manufacturing grain-oriented electrical steel sheet and rolling apparatus for manufacturing electrical steel sheet

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- Number: US 12,760,384 B2
- Document ID: US12760384B2
- Status: Granted
- Kind: B2
- Application number: 18/260,473
- Filed: 2022-01-26
- Published: 2024-02-15
- Granted: 2026-10-13
- Earliest claimed: 2021-01-28
- Assignees: Jfe Steel Corporation
- Applicants: Jfe Steel Corporation
- Inventors: Yusuke Shimoyama; Yukihiro Shingaki; Hiroi Yamaguchi
- Web page: https://patentgrep.com/patent/US12760384B2

## CPC

- C21D 8/1272: {Final recrystallisation annealing}
- C21D 8/1222: {Hot rolling}
- C21D 8/1233: {Cold rolling}
- C21D 9/46: for sheet metals
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C21D 2201/05: Grain orientation
- 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)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Provided is a method of manufacturing a grain-oriented electrical steel sheet, with which a grain-oriented electrical steel sheet with low iron loss and little variation in iron loss can be stably manufactured by a tandem mill. The method includes subjecting a steel material to hot rolling to obtain a hot-rolled sheet, subjecting the hot-rolled sheet to cold rolling once or twice or more with intermediate annealing performed therebetween to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then to secondary recrystallization annealing, wherein final cold rolling is performed by a tandem mill, and in the final cold rolling, the hot-rolled sheet is heated to a temperature range of 70° C. or higher and 200° C. or lower, then cooled to 60° C. or lower, and then introduced into a first pass of the tandem mill.

## Claims

### Claim 1

A method of manufacturing a grain-oriented electrical steel sheet, comprising subjecting a steel material to hot rolling to obtain a hot-rolled sheet, subjecting the hot-rolled sheet to cold rolling once or twice or more with intermediate annealing performed therebetween to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then to secondary recrystallization annealing, wherein
final cold rolling is performed by a tandem mill, and in the final cold rolling, the hot-rolled sheet is heated to a temperature range of 70° C. or higher and 200° C. or lower, then, within 30 seconds after heating, cooled to 60° C. or lower by a method selected from injection of coolant liquid to the sheet, roll cooling, and oil bath, and then introduced into a first pass of the tandem mill.

### Claim 2 (depends on 1)

The method of manufacturing a grain-oriented electrical steel sheet according to claim 1, wherein the steel material comprises a chemical composition containing, in mass %,
C: 0.01% to 0.10%,
Si: 2.0% to 4.5%,
Mn: 0.01% to 0.5%,
Al: 0.01% to 0.04%,
S: 0.01% to 0.05%,
Se: 0.01% to 0.05%, and
N: 0.0050% to 0.012%,
with the balance being Fe and inevitable impurities.

### Claim 3 (depends on 1)

The method of manufacturing a grain-oriented electrical steel sheet according to claim 1, wherein the steel material comprises a chemical composition containing, in mass %,
C: 0.01% to 0.10%,
Si: 2.0% to 4.5%,
Mn: 0.01% to 0.5%,
Al: less than 0.0100%,
S: 0.0070% or less,
Se: 0.0070% or less, and
N: 0.0050% or less,
with the balance being Fe and inevitable impurities.

### Claim 4 (depends on 2)

The method of manufacturing a grain-oriented electrical steel sheet according to claim 2, wherein the steel material further contains, in mass %, at least one selected from the group consisting of
Sb: 0.005% to 0.50%,
Cu: 0.01% to 1.50%,
P: 0.005% to 0.50%,
Cr: 0.01% to 1.50%,
Ni: 0.005% to 1.50%,
Sn: 0.01% to 0.50%,
Nb: 0.0005% to 0.0100%,
Mo: 0.01% to 0.50%,
B: 0.0010% to 0.007%, and
Bi: 0.0005% to 0.05%.

### Claim 5 (depends on 3)

The method of manufacturing a grain-oriented electrical steel sheet according to claim 3, wherein the steel material further contains, in mass %, at least one selected from the group consisting of
Sb: 0.005% to 0.50%,
Cu: 0.01% to 1.50%,
P: 0.005% to 0.50%,
Cr: 0.01% to 1.50%,
Ni: 0.005% to 1.50%,
Sn: 0.01% to 0.50%,
Nb: 0.0005% to 0.0100%,
Mo: 0.01% to 0.50%,
B: 0.0010% to 0.007%, and
Bi: 0.0005% to 0.05%.