Method for Producing a Grain-Orientated Electric Strip
AssigneeThyssenkrupp Electrical Steel GmbH
InventorsChristof Holzapfel, Stefan Pahlke, Carsten Schepers, Heiner Schrapers
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Abstract
The invention relates to a method for producing a grain-orientated electric steel which is coated with a phosphate layer and in which there is applied to the electric steel a phosphate solution which contains a colloid component and at least one colloid stabiliser (A) and/or at least one pickling inhibitor (B), the phosphate solution containing at least one compound which has chromium in the oxidation stage III (chromium (III) compound). Grain-orientated electric steel produced with the method according to the invention is distinguished by excellent optical properties and a high tensile stress.
Claims21
-14. (canceled)
A method for producing a grain-orientated electric steel which is coated with a phosphate layer, the method comprising applying to the electric steel a phosphate solution, wherein the phosphate solution comprises:
- a colloid component;
- at least one of a colloid stabilizer or a pickling inhibitor;
- and
- at least one compound comprising chromium (III).
The method of claim 1, wherein the compound comprising chromium (III) comprises a chromium (III) salt.
The method of claim 2, wherein the chromium (III) salt is selected from the group consisting of chromium (III) nitrate, chromium (III) chloride, chromium (III) sulphate, chromium (III) acetate, chromium (III) sulphonate, and any combination thereof.
The method of claim 1 wherein the compound comprising chromium (III) is present in a quantity selected from about 0.2% to about 30% by weight, from about 5% to about 20% by weight, or from about 8% to about 15% by weight, with respect to the overall weight of the phosphate solution.
The method of claim 1 wherein the phosphate solution comprises less than about 0.2% or less than about 0.1% by weight of hexavalent chromium.
The method of claim 1, wherein the colloid stabilizer comprises a phosphoric acid ester.
The method of claim 1, wherein the pickling inhibitor is selected from the group consisting of a thiourea derivative, a C2-10-alkynol, a triazine derivative, thioglycolic acid, a C1-4-alkylamine, a hydroxy-C2-8-thiocarboxylic acid, a fatty alcohol polyglycol ether diethylthiourea, prop-2-in-1-ol, butin-1,4-diol, thioglycolic acid, hexamethylenetetramine, and any combination thereof.
The method of claim 1, wherein the phosphate solution further comprises a wetting agent.
The method of claim 1, wherein the colloid stabilizer is present in a quantity of from about 0.001% to about 20% by weight with respect to the overall weight of the phosphate solution.
The method of claim 1, wherein the pickling inhibitor is present in a quantity of from about 0.001% to about 10% by weight with respect to the overall weight of the phosphate solution.
The method of claim 1, wherein the phosphate solution further comprises aluminum phosphate, magnesium phosphate, or a combination thereof.
The method of claim 1, wherein the phosphate solution has a pH of less than about 3, or a pH of between about 1 and about 2.
The method of claim 1, further comprising burning the electric steel at a temperature of more than about 800° C.
A method for producing a grain-orientated electric steel which is coated with a phosphate layer, the method comprising applying to the electric steel a phosphate solution, wherein the phosphate solution comprises:
- a) aluminum phosphate, magnesium phosphate, or a combination thereof;
- b) colloidal silica dioxide;
- c) monoethylphosphate, diethylphosphate, or a combination thereof;
- d) a thiourea derivative, a C2-10-alkynol, a triazine derivative, thioglycolic acid, a C1-4-alkylamine, a hydroxy-C2-8-thiocarboxylic acid, a fatty alcohol polyglycol ether, diethylthiourea, prop-2-in-1-ol, butin-1,4-diol, thioglycolic acid, hexamethylenetetramine, or any combination thereof;
- e) a fluorosurfactant;
- and
- f) a compound comprising chromium (III).
A grain-orientated electric steel coated with a phosphate layer produced with a method according to claim 1.
Dependencies are inferred from the claim text.