Claims
- 1. A continuous high-speed process for producing permanent domain refinement in grain oriented electrical steel strip having a glass film, said process comprising:
- (a) removing said glass film in narrow regions about 0.0025 to about 0.0125 mm deep, about 0.05 to 0.3 mm wide about 4 to about 10 mm apart, said regions being substantially perpendicular to the rolling direction of said strip;
- (b) depositing by electrophoresis an aluminum coating into said regions;
- (c) bonding the aluminum coating to the steel strip by heating the aluminum coated steel strip;
- (d) subsequent cooling causing localized stress to develope in the aluminum coated steel strip as the result of differential thermal contraction between the aluminum coating and the electrical steel, said localized stress causing magnetic domain refinement in the electrical steel strip.
- 2. The process of claim 1 wherein the glass film is removed using a laser and the regions deepened using an electrolytic etch.
- 3. The process of claim 1 wherein the grain oriented electrical steel uses an aluminum nitride inhibitor system.
- 4. The process of claim 1 wherein the coating material is heated by induction to bond said coating.
- 5. The process of claim 3 wherein said aluminum coating is provided using an electrophoretic bath containing:
- (a) up to 10 grams of aluminum powder per liter of methanol,
- (b) 20 to 50 milligrams of aluminum chloride per liter of methanol, and
- (c) 20 to 50 milligrams of tannic acid per liter of methanol, said strip being subjected to a voltage of 30 to 50 volts for 5 to 15 seconds to electrophoretically deposit said aluminum coating in said regions.
- 6. The process of claim 2 wherein said electrolytic etch is conducted in a water bath at 65.degree. C. to 80.degree. C. containing 5 to 15% nitric acid and uses a current of 25-75 milliamps per cm of region length.
- 7. The process of claim 1 wherein said strip is rinsed with water and dried after said regions of no glass film are formed.
- 8. A high speed method for producing permanent domain refinement in coated grain oriented electrical steel strip after the final high temperature anneal, said method comprising:
- (a) scribing said strip after said final anneal to remove said glass coating and expose said electrical steel said exposed steel being in narrow regions about 0.0025 to about 0.0125 mm deep, about 0.05 to 0.03 mm wide, and spaced about 4 to about 10 mm apart, said regions being substantially perpendicular to said strip's rolling direction;
- (b) electrophoretically depositing aluminum into said scribed regions;
- (c) bonding the aluminum cooling to the steel strip by heating the aluminum coated steel strip;
- (d) subsequent cooling causing localized stress to develope in the aluminum coated steel strip as the result of differential thermal contraction between the aluminum coating and the electrical steel, said localized stress causing magnetic domain refinement in the electrical steel strip.
- 9. The method of claim 8 wherein said steel is exposed in said narrow regions by laser scribing to remove said coating and electroetching to control said depth for optimum magnetic properties.
- 10. The method of claim 8 wherein said electrophoretic deposition of aluminum is provided by a bath containing:
- (a) up to 10 grams of aluminum powder per liter of methanol;
- (b) 20 to 50 milligrams of aluminum chloride per liter of methanol; and
- (c) 20 to 50 milligrams of tannic acid per liter of methanol, said strip being subjected to a voltage of 30 to 50 volts to electrophoretically apply said aluminum.
- 11. A high speed method for producing permanent domain refinement in grain oriented electrical steel strip after the final high temperature anneal, said strip having a glass coating with narrow regions of exposed base metal spaced about 4 to about 10 mm apart, about 0.05 to 0.03 mm wide and about 0.0025 to about 0.0125 mm deep, said regions being substantially perpendicular to said strip's rolling direction, the improvement comprising:
- (a) depositing an aluminum coating by electrophoresis into said regions of exposed base metal;
- (b) bonding the aluminum coating to the steel strip by heating the aluminum coated steel strip;
- (c) subsequent cooling causing localized stress to develope in the aluminum coated steel strip as the result of differential thermal contraction between the aluminum coating and the electrical steel, said localized stress causing domain refinement in the electrical steel strip.
- 12. The process of claim 11 wherein said electrophoresis coating is provided by a bath containing:
- (a) up to 10 grams of aluminum powder per liter of methanol;
- (b) 20 to 50 milligrams of aluminum chloride per liter of methanol; and
- (c) 20 to 50 milligrams of tannic acid per liter of methanol.
- 13. The process of claim 11 wherein said electrophoresis coating is deposited using 30 to 50 volts for 5 to 15 seconds.
- 14. The process of claim 11 wherein said grain oriented electrical steel has an aluminum nitride inhibitor system.
- 15. The process of claim 11 wherein said strip is heated by induction to bond said aluminum coating.
- 16. A high speed process for producing permanent domain refinement in grain oriented electrical steel having a glass coating after the final temperature anneal, said process comprising:
- (a) subjecting said strip to a laser at spaced regions which are perpendicular to the rolling direction to remove said glass coating and expose said electrical steel;
- (b) electrolytically etching said regions of exposed base metal in a nitric acid bath having 5 to 15% nitric acid, the balance chosen from the group of water and methanol, said bath being from 65.degree. to 80.degree. C., said etching being accomplished in less than about 10 seconds using a current of 0.5-1.0 amps per square centimeter of exposed base metal;
- (c) depositing an aluminum coating by electrophoresis into said exposed regions;
- (d) bonding the aluminum coating to the steel strip by heating the aluminum coated steel strip;
- (e) subsequent cooling causing localized stress to develope in the aluminum coated steel strip as the result of differential thermal contraction between the aluminum coating and the electrical steel, said localized stress causing magnetic domain refinement in the electrical steel strip.
- 17. The process of claim 16 wherein said strip is rinsed with water and dried after said electroetching is complete.
Parent Case Info
This is a continuation of copending application Ser. No. 07/173,697 filed on Mar. 25, 1988 now abandoned.
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Non-Patent Literature Citations (1)
Entry |
"Heatproof Domain Refining Method Using Chemically Etched Pits on the Surface of Grain-Oriented 3% Si-Fe", IEEE Transactions on Magnetics, vol. MAG-23, No. 5, Sep. 1987, pp. 3062-3064. |
Continuations (1)
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Number |
Date |
Country |
Parent |
173697 |
Mar 1988 |
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