Grain oriented electrical steel sheet having excellent core loss, and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-9847158-B2
Application number	US-201214758219-A
Country	US
Kind code	B2
Filing date	Dec 28, 2012
Priority date	Dec 27, 2012
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

The present invention relates to a grain oriented electrical steel sheet having excellent core loss and to a method for manufacturing same. The electrical steel sheet according to one aspect of the present invention may have a composition comprising, by weight %, Si: 1.0 to 4.0%, Al: 0.1 to 4.0%, and a rare earth element: 0.0001 to 0.5% by the total content of the whole rare earth element.

First claim

The invention claimed is:

1. A grain oriented electrical steel sheet having a low degree of core loss of 0.901 W/kg or lower (W17/50), the electrical steel sheet comprising, by wt %, silicon (Si): 1.0% to 4.0%, aluminum (Al): 0.1% to 4.0%, at least one rare earth element: 0.065% to 0.4%, and at least one selected from the group consisting of phosphorus (P): 0.5% or less, tin (Sn): 0.3% or less, antimony (Sb): 0.3% or less, chromium (Cr): 0.3% or less, copper (Cu): 0.4% or less, and nickel (Ni): 1% or less in total content,
wherein the at least one rare earth elements exist individually or in the form of a compound with sulfur (S) or oxygen (O) and the at least one rare earth element or the compound of the at least one rare earth element is used as an inhibitor.

2. The grain oriented electrical steel sheet of claim 1 , further comprising carbon (C): 0.003 wt % or less, manganese (Mn): 0.03 wt % to 0.2 wt %, sulfur (S): 0.001 wt % to 0.05 wt %, and nitrogen (N): 0.01 wt % or less.

3. A method for manufacturing the grain oriented electrical steel sheet of claim 1 , the method comprising:
heating a slab to 1050° C. to 1300° C., the slab comprising, by wt %, silicon (Si): 1.0% to 4.0%, aluminum (Al): 0.1% to 4.0%, and at least one rare earth element: 0.065% to 0.4% in total content;
hot rolling the slab;
cold rolling the slab;
primarily recrystallizing the slab; and
secondarily recrystallizing the slab.

4. The method of claim 3 , wherein the slab further comprises carbon (C): 0.1 wt % or less, manganese (Mn): 0.03 wt % to 0.2 wt %, sulfur (S): 0.001 wt % to 0.05 wt %, and nitrogen (N): 0.01 wt % or less.

5. The method of claim 3 , wherein after the hot rolling of the slab, the method further comprises at least one selected from;
annealing the hot-rolled slab; and
pickling the hot-rolled slab.

6. The method of claim 3 , wherein the cold rolling is performed at a reduction ratio of 85% to 90%.

7. The method of claim 6 , wherein the cold rolling is performed two or more times with an intermediate annealing process therebetween, and a reduction ratio of the final cold rolling is 50% or greater.

8. The method of claim 3 , wherein the primary recrystallizing is performed within a temperature range of 700° C. to 950° C.

9. The method of claim 3 , wherein the secondary recrystallizing is performed by heating the slab to a maximum temperature of 1100° C. to 1300° C. at a heating rate of 5° C./hr to 30° C./hr.

Assignees

• Posco

Inventors

• Hong Byung-Deug
• Kim Dong-Kyun

Classifications

• C21D8/1233

  Cold rolling · CPC title

• C21D8/1261

  following hot rolling · CPC title

• H01F1/16

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

• C22C38/02

  containing silicon · CPC title

• C22C38/16

  containing copper · CPC title