Grain-oriented electrical steel sheet, method for manufacturing grain-oriented electrical steel sheet, and annealing separator utilized for manufacture of grain-oriented electrical steel sheet

Patent metadata

Field	Value
Publication number	US-2022064764-A1
Application number	US-202017421327-A
Country	US
Kind code	A1
Filing date	Jan 8, 2020
Priority date	Jan 8, 2019
Publication date	Mar 3, 2022
Grant date	—

Abstract

Grain-oriented electrical steel sheet excellent in magnetic properties and excellent in adhesion of primary coating to steel sheet provided with a base metal steel sheet having a predetermined chemical composition and a primary coating formed on a surface of the base metal steel sheet and containing Mg2SiO4 as a main constituent, where a peak position of Al emission intensity obtained when performing elemental analysis by glow discharge optical emission spectrometry from a surface of the primary coating in a thickness direction of the grain-oriented electrical steel sheet is arranged within a range of 2.4 to 12.0 μm from the surface of the primary coating in the thickness direction, a number density of Al oxides at the peak position of Al emission intensity and of a size of 0.2 μm or more in terms of a circle equivalent diameter based on the area is 0.03 to 0.18/μm2, and, in a plurality of Al oxides in an observed region in an observed region of 30 μm×50 μm at the peak position of Al emission intensity, a total cross-sectional area of identified Al oxides with cross-sectional areas of 0.4 to 10.0 μm2 is 75.0% or more of the total cross-sectional area of all Al oxides in the observed region.

First claim

1 . Grain-oriented electrical steel sheet comprising
a base metal steel sheet having a chemical composition containing, by mass %,
C: 0.005% or less,
Si: 2.5 to 4.5%,
Mn: 0.02 to 0.2%,
one or more elements selected from the group comprised of S and Se: total of 0.005% or less,
sol. Al: 0.01% or less, and
N: 0.01% or less and
having a balance comprised of Fe and impurities and
a primary coating formed on a surface of the base metal steel sheet and containing Mg 2 SiO 4 as a main constituent, where a peak position of Al emission intensity obtained when performing elemental analysis by glow discharge optical emission spectrometry from a surface of the primary coating in a thickness direction of the grain-oriented electrical steel sheet is arranged within a range of 2.4 to 12.0 μm from the surface of the primary coating in the thickness direction, a number density of Al oxides at the peak position of Al emission intensity and of a size of 0.2 μm or more in terms of a circle equivalent diameter based on the area is 0.03 to 0.18/μm 2 , and, in a plurality of Al oxides in an observed region of 30 μm×50 μm at the peak position of Al emission intensity, a total cross-sectional area of identified Al oxides with cross-sectional areas of 0.4 to 10.0 μm 2 is 75.0% or more of the total cross-sectional area of all Al oxides in the observed region.

2 . A method for manufacturing grain-oriented electrical steel sheet comprising
a process for cold rolling hot rolled steel sheet containing by mass %,
C: 0.1% or less,
Si: 2.5 to 4.5%,
Mn: 0.02 to 0.2%,
one or more elements selected from the group comprised of S and Se: total of 0.005 to 0.07%,
sol. Al: 0.005 to 0.05%, and
N: 0.001 to 0.030% and
having a balance comprised of Fe and impurities by a cold rolling rate of 80% or more to manufacture cold rolled steel sheet, a process for decarburization annealing the cold rolled steel sheet, a process for coating the surface of the cold rolled steel sheet after decarburization annealing with an aqueous slurry containing an annealing separator and drying the aqueous slurry on the surface of the cold rolled steel sheet in a 400 to 1000° C. furnace, and a process for performing finish annealing on the cold rolled steel sheet after the aqueous slurry has been dried, where the annealing separator contains
MgO,
at least one or more types of compounds selected from a group comprised of Y, La, and Ce,
at least one or more types of compounds of metal selected from a group comprised of Ti, Zr, and Hf, and
at least one or more types of compounds of metal selected from a group comprised of Ca, Sr, and Ba,
when a content of the MgO in the annealing separator is defined as 100% by mass %, a total content of the compounds selected from a group comprised of Y, La, and Ce converted to oxides is 0.8 to 8.0%, a total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 0.5 to 9.0%, and a total content of the compounds of metal selected from a group comprised of Ca, Sr, and Ba converted to sulfates is 0.5 to 8.0%, a mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba is 12 μm or less, a ratio of the mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba to the mean particle size of the compounds of metal selected from a group comprised of Y, La, and Ce is 0.1 to 3.0, a total of the total content of the compounds of metal selected from a group comprised of Y, La, and Ce converted to oxides and the total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 2.0 to 12.5%, a ratio of a sum of the numbers of Y, La, and Ce atoms to a sum of the numbers of Ti, Zr, and Hf atoms contained in the annealing separator is 0.18 to 4.0, still further a number density of particles of the compounds of metal selected from the group comprised of Y, La, and Ce which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, still further a number density of particles of the compounds of metal selected from the group comprised of Ti, Zr, and Hf which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, and still further a number density of particles of the compounds of metal selected from the group comprised of Ca, Sr, and Ba which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more.

3 . The method for manufacturing grain-oriented electrical steel sheet according to claim 2 in which method for manufacturing grain-oriented electrical steel sheet,
the chemical composition of the hot rolled steel sheet further contains, in place of part of the Fe, one or more elements selected from a group comprised of Cu, Sb and Sn in a total of 0.6% or less.

4 . The method for manufacturing grain-oriented electrical steel sheet according to claim 2 , in which method for manufacturing grain-oriented electrical steel sheet,
the chemical composition of the hot rolled steel sheet further contains, in place of part of the Fe, one or more elements selected from a group comprised of Bi, Te, and Pb in a total of 0.03% or less.

5 . An annealing separator used for manufacture of grain-oriented electrical steel sheet,
the annealing separator containing
MgO,
at least one or more types of compounds of metal selected from a group comprised of Y, La, and Ce,
at least one or more types of compounds of metal selected from a group comprised of Ti, Zr, and Hf, and
at least one or more types of compounds of metal selected from a group comprised of Ca, Sr, and Ba,
when a content of the MgO in the annealing separator is defined as 100% by mass %, a total content of the compounds selected from a group comprised of Y, La, and Ce converted to oxides is 0.8 to 8.0%, a total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 0.5 to 9.0%, and a total content of the compounds of metal selected from a group comprised of Ca, Sr, and Ba converted to sulfates is 0.5 to 8.0%, a mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba is 12 μm or less, a ratio of the mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba to the mean particle size of the compounds of metal selected from a group comprised of Y, La, and Ce is 0.1 to 3.0, a total of the total content of the compounds of metal selected from a group comprised of Y, La, and Ce converted to oxides and the total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 2.0 to 12.5%, a ratio of a sum of the numbers of Y, La, and Ce atoms to a sum of the numbers of Ti, Zr, and Hf atoms contained in the annealing separator is 0.18 to 4.0, still further a number density of particles of the compounds of metal selected from the group comprised of Y, La, and Ce which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, still further a number density of particles of the compounds of metal selected from the group comprised of Ti, Zr, and Hf which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, and still further a number density of particles of the compounds of metal selected from the group comprised of Ca, Sr, and Ba which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more.

Assignees

• Nippon Steel Corp

Inventors

• Yamagata Ryutaro
• Tanaka Ichiro

Classifications

• C21D8/02

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

• H01F1/14775

  in the form of sheets · CPC title

• H01F1/16

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

• C21D8/1283

  Application of a separating or insulating coating · CPC title

• C23C26/00

  Coating not provided for in groups C23C2/00 - C23C24/00 · CPC title