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US 5,296,042 AGranted
Composition and process for treating sheet steel
AssigneeC. L. R. Resources, Inc.
InventorsMichael S. Curran, Kenneth R. Kaluzny, William R. Moe
Life of this patent
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Abstract
Stain on sheet steel is removed by providing a solution of buffered chelating agent and applying the same to the sheet steel during processing and prior to coiling.
Claims11
A method of removing a stain from sheet steel during a sheet steel pickling process comprising:
- a) selecting at least one chelating agent from the group consisting if ethylenediaminetetraacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, and nitrilotriacetic acid at a concentration in a range of 1 gram to 100 grams per liter;
- b) selecting at least one buffering agent from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, triethanolamine, monoethanolamine, and diethanolamine;
- c) providing a mixture of at least one of said chelating agents and at least one of said buffering agents;
- and
- d) applying the mixture to the steel sheet at a temperature of 65.degree. C. to 110.degree. C. for 5 seconds to 2 minutes and at a pH of 4.0 to 10.5 to thereby remove the stain from the steel sheet and improve the appearance of the steel sheet.
2 more elements
Dependencies are inferred from the claim text.