Claims
- 1. A high speed method for permanent domain refinement by selective coating and base metal removal in linearly spaced regions on final high high temperature annealed grain oriented electrical steel strip with removal depths controlled for optimum improvements in magnetic quality, said method comprising:
- (a) removing said coating in linearly spaced regions having a width of about 0.05 to 0.3 mm and spaced about 5 to 20 mm apart to slightly expose said base metal;
- (b) electroetching said expose metal regions to provide a depth from about 0.012 to about 0.075 mm; and
- (c) monitoring the permeability of said electrical steel during said electroetching and controlling said removal depth in response to the permeability to provide uniform core loss improvement.
- 2. The method of claim 1 wherein said grain oriented electrical steel strip is high permeability grain oriented electrical steel and said electroetching depth is increased until said permeability is between 1870 to 1890 at 796 amps per meter.
- 3. The method of claim 1 wherein said strip after electroetching is rinsed and dried.
- 4. The method of claim 1 wherein a rust inhibitor coating is applied after electroetching.
- 5. The method of claim 1 wherein a nitric acid bath at a concentration of 5 to 15% in solution with water at a temperature above 40.degree. C. is used for said electroetching with a current of 0.1 to 0.5 amps per square centimeter of said exposed base metal.
- 6. The method of claim 1 wherein a nitric acid bath at a concentration of 5 to 15% in solution with methanol at a temperature above 40.degree. C. is used for said electroetching with a current of 0.1 to 0.5 amps per square centimeter of said exposed base metal.
- 7. A method for selective coating and base metal removal at speeds above 100 feet per minute (30 meters per minute) in linearly spaced regions on final high temperature annealed grain oriented electrical steel strip, said method comprising:
- (a) laser treating said strip to remove said coating in linearly spaced regions to expose said base metal;
- (b) electroetching said strip for a time under 10 seconds with a nitric acid bath at a concentration of 5 to 15% in solution with a liquid selected from the group of water and methanol at a temperature above 40.degree. C. with a current of 0.1 to 0.5 amps per square centimeter of exposed base metal to provide a removal depth of about 0.012 to about 0.075 mm whereby said coating has a minimized damage caused by ridges in said base metal and base metal splatter on said coating; and
- (c) rinsing said strip.
- 8. The method of claim 7 wherein a corrosion inhibitor coating is applied after said rinsing step.
- 9. The method of claim 7 wherein permeability is monitored during electroetching to determine when the electretching is complete and the improvements in magnetic quality are optimized.
- 10. The method of claim 9 wherein said electroetching is complete when said permeability is between 1870 to 1890 at 796 amps per meter.
Parent Case Info
This is a continuation of copending application(s) Ser. No. 07/173,696 filed on Mar. 25, 1988, now abandoned.
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2167324 |
May 1986 |
GBX |
Non-Patent Literature Citations (1)
Entry |
M. Yabumoto et al., "Heatproof Domain Refining Method Using Chemically Etched Pits on the Surface of Grain Oriented 3% Si-Fe," IEEE Transactions on Magnetics, Sep. 1987, vol. MAG-23, No. 5, pp. 3062-3064. |
Continuations (1)
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Number |
Date |
Country |
Parent |
173696 |
Mar 1988 |
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