Non-oriented electrical steel sheet and method for manufacturing slab used as material for the same

Patent metadata

Field	Value
Publication number	US-2021332463-A1
Application number	US-201917281075-A
Country	US
Kind code	A1
Filing date	Sep 5, 2019
Priority date	Oct 2, 2018
Publication date	Oct 28, 2021
Grant date	—

Abstract

Provided is a non-oriented electrical steel sheet having such a low Al concentration so that it is excellent in terms of the recycling efficiency of scrap iron and having a high magnetic flux density and low iron loss.
The non-oriented electrical steel sheet according to the present invention has a chemical composition containing C; 0.0050 mass % or less, Si; 1.5 mass % to 5.0 mass %, Mn; 0.2 mass % to 3.0 mass %, sol.Al; 0.0030 mass % or less, P; 0.2 mass % or less, S; 0.0050 mass % or less, N; 0.0040 mass % or less, T.Ca; 0.0010 mass % to 0.0080 mass %, T.O; 0.0100 mass % or less, REM; 0.0001 mass % to 0.0050 mass %, and a balance of Fe and inevitable impurities, in which a value of a mass-related fractional expression ((T.Ca+REM)/(T.O+S)), which is a relational expression for the masses of the four constituents described above, that is, T.Ca, REM, T.O, and S, is 0.4 or more.

First claim

1 . A non-oriented electrical steel sheet having
a chemical composition containing C; 0.0050 mass % or less, Si; 1.5 mass % to 5.0 mass %, Mn; 0.2 mass % to 3.0 mass %, sol.Al; 0.0030 mass % or less, P; 0.2 mass % or less, S; 0.0050 mass % or less, N; 0.0040 mass % or less, T.Ca; 0.0010 mass % to 0.0080 mass %, T.O; 0.0100 mass % or less, REM; 0.0001 mass % to 0.0050 mass %, and a balance of Fe and inevitable impurities, wherein a value of a mass-related fractional expression ((T.Ca+REM)/(T.O+S)), which is a relational expression for masses of four constituents including T.Ca, REM, T.O, and S, is 0.4 or more.

2 . A non-oriented electrical steel sheet having
a chemical composition containing C; 0.0050 mass % or less, Si; 1.5 mass % to 5.0 mass %, Mn; 0.2 mass % to 3.0 mass %, sol.Al; 0.0030 mass % or less, P; 0.2 mass % or less, S; 0.0050 mass % or less, N; 0.0040 mass % or less, T.Ca; 0.0010 mass % to 0.0080 mass %, T.O; 0.0100 mass % or less, REM; 0.0001 mass % to 0.0050 mass %, at least one of element group A through element group C below, and a balance of Fe and inevitable impurities, wherein a value of a mass-related fractional expression ((T.Ca+REM)/(T.O+S)), which is a relational expression for masses of four constituents including T.Ca, REM, T.O, and S, is 0.4 or more, where group A consists of one or both selected from Sn and Sb each in an amount of 0.01 mass % to 0.1 mass %, group B consists of Mg in an amount of 0.0001 mass % to 0.0050 mass %, and group C consists of one, two, or all selected from Cu, Ni, and Cr each in an amount of 0.01 mass % to 0.5 mass %.

3 . The non-oriented electrical steel sheet according to claim 1 , wherein a value of a mass-related fractional expression (T.Ca/REM), which is a relational expression for masses of two constituents including T.Ca and REM, is 1.0 or more.

4 . The non-oriented electrical steel sheet according to claim 1 , wherein an average crystal grain diameter of a metallographic structure is 40 μm or more.

5 . A method for manufacturing a slab used as a material for a non-oriented electrical steel sheet having a chemical composition containing Si, REM, and Ca,
in a process of refining molten steel, which has been tapped from a converter or an electric arc furnace, by using a vacuum degassing apparatus, adding a Ca-containing alloy to the refined molten steel, and continuously casting the molten steel, to which the Ca-containing alloy has been added, by using a continuous casting machine to obtain a slab, the method comprising: adding metallic Si or a Si-containing alloy to the molten steel during the refining performed by using the vacuum degassing apparatus to deoxidize the molten steel by utilizing Si; adding a REM-containing alloy to the molten steel, which has been deoxidized by utilizing Si, during the refining performed by using the vacuum degassing apparatus or after finishing the refining performed by using the vacuum degassing apparatus; and adding a Ca-containing alloy to the molten steel, to which the REM-containing alloy has been added, in a ladle.

6 . The non-oriented electrical steel sheet according to claim 2 , wherein a value of a mass-related fractional expression (T.Ca/REM), which is a relational expression for masses of two constituents including T.Ca and REM, is 1.0 or more.

7 . The non-oriented electrical steel sheet according to claim 2 , wherein an average crystal grain diameter of a metallographic structure is 40 μm or more.

8 . The non-oriented electrical steel sheet according to claim 3 , wherein an average crystal grain diameter of a metallographic structure is 40 μm or more.

9 . The non-oriented electrical steel sheet according to claim 6 , wherein an average crystal grain diameter of a metallographic structure is 40 μm or more.

Assignees

• Jfe Steel Corp

Inventors

• HARADA Akifumi
• Matsui Akitoshi
• Oda Yoshihiko
• Okubo Tomoyuki
• Uesaka Masanori

Classifications

• C21C7/06 Primary

  Deoxidising, e.g. killing · CPC title

• C22C38/40

  with nickel · CPC title

• C22C38/06 Primary

  containing aluminium · CPC title

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• C22C38/20

  with copper · CPC title