Non-oriented electrical steel sheet and manufacturing method thereof
View Patent ↗In a non-oriented electrical steel sheet, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, and so on are contained. (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]. [Ti]≦0.8×[Bi]+0.002 (1)
1. A manufacturing method of a non-oriented electrical steel sheet, comprising:
producing molten steel consisting essentially of:
Si: not less than 1.0 mass % nor more than 3.5 mass %;
Al: not less than 0.1 mass % nor more than 3.0 mass %;
Mn: not less than 0.1 mass % nor more than 2.0 mass %/o; and
Ti: not less than 0.001 mass % nor more than 0.01 mass %,
a C content being 0.01 mass % or less,
a P content being 0.1 mass % or less,
a N content being 0.005 mass % or less,
a S content being 0.005 mass % or less, and
a balance comprising Fe and inevitable impurities;
adding Bi to the molten steel such that a Bi content in the non-oriented electrical steel sheet becomes not less than 0.001 mass % nor more than 0.01 mass %, and (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and the Bi content (mass %) is represented as [Bi]; and
pouring the molten steel into a mold and solidifying the molten steel after adding the Bi,
wherein adding the Bi comprises supplying a wire-shaped metallic Bi covered with Fe into the molten steel in the vicinity of a pouring port of a tundish into the mold within three minutes before the molten steel starts to solidify,
[Ti]≦0.8×[Bi]+0.002 (1).
2. The manufacturing method of a non-oriented electrical steel sheet, according to claim 1 , wherein, in said adding Bi, an added amount of Bi is adjusted such that (2) expression described below is further satisfied
[Ti]≦0.65×[Bi]+0.0015 (2).
3. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the molten steel further contains at least one member selected from the group consisting of Cu: 0.5 mass % or less and Cr: 20 mass % or less.
4. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the molten steel further contains at least one member selected from the group consisting of Sn and Sb being 0.3 mass % or less in total.
5. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the molten steel further contains Ni: 1.0 mass % or less.
6. A manufacturing method of a non-oriented electrical steel sheet, comprising:
producing molten steel consisting essentially of:
Si: not less than 1.0 mass % nor more than 3.5 mass %;
Al: not less than 0.1 mass % nor more than 3.0 mass %;
Mn: not less than 0.1 mass % nor more than 2.0 mass %;
Ti: not less than 0.001 mass % nor more than 0.01 mass %; and
at least one member selected from the group consisting of REM and Ca,
a C content being 0.01 mass % or less,
a P content being 0.1 mass % or less,
a N content being 0.005 mass % or less,
a S content being 0.01 mass % or less, and
a balance comprising Fe and inevitable impurities,
adding Bi to the molten steel such that a Bi content in the non-oriented electrical steel sheet becomes not less than 0.001 mass % nor more than 0.01 mass %, and (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and the Bi content (mass %) is represented as [Bi]; and
pouring the molten steel into a mold and solidifying the molten steel after adding the Bi, wherein
when the S content (mass %) in the molten steel is represented as [S], a REM content (mass %) in the molten steel is represented as [REM], and a Ca content (mass %) in the molten steel is represented as [Ca], (3) expression described below is satisfied, and
wherein adding the Bi comprises supplying a wire-shaped metallic Bi covered with Fe into the molten steel in the vicinity of a pouring port of a tundish into the mold within three minutes before the molten steel starts to solidify,
[Ti]≦0.8×[Bi]+0.002 (1),
[S]−(0.23×[REM]+0.4×[Ca])≦0.005 (3).
7. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the molten steel further contains at least one member selected from the group consisting of Cu: 0.5 mass % or less and Cr: 20 mass % or less.
8. The manufacturing method of a non-oriented electrical steel sheet according to claim 6 , wherein the molten steel further contains at least one member selected from the group consisting of Sn and Sb being 0.3 mass % or less in total.
9. The manufacturing method of a non-oriented electrical steel sheet according to claim 6 , wherein the molten steel further contains Ni: 1.0 mass % or less.