US4101345A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Galvanizing steel strip in selected areas thereof
Assignee: Steel Company of Canada Ltd
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Filing: 1976-11-26
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Granted: 1978-07-18
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Expires: 1996-11-26
Abstract
Abstract Mild steel strip is galvanized in selected areas only, typically on one side only of the strip, by pretreating the areas selected for absence of galvanizing to form thereon a readily chemically strippable coating of chemically hydrated compounds non-wetting in molten zinc. Preferably, the pretreatment is carried out using phosphoric acid solution to form thereon a thin coating of a composite of hydrated iron phosphates and iron hydroxides. After passing the thus-treated steel strip through the molten zinc bath and solidification of the zinc coating, the composite coating is removed by dilute mineral acid. Mild steel strip galvanized on one side using this procedure has particular utility in the automotive industry.
Inventors
- 👤 Robert F. Hunter
- 👤 Stephen R. Koprich
- 👤 Richard G. Baird-Kerr
- 👤 Daniel S. Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:35
CPC Classifications
C; C23; C23C; C23C2/00; C23C2/04; C23C2/06; C23C2/003; C23C2/0038; C23C2/02; C23C2/024
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
84 words
In a method of galvanizing only selected areas of a ferrous metal strip, the improvement which comprises contacting surface areas of said strip not to be galvanized with a phosphoric acid solution to cause a spontaneous reaction to form a readily chemically strippable coating of a composite comprising iron hydroxides and hydrated iron phosphates non-wetting in molten zinc on said surface areas not to be galvanized, and passing the so-treated strip through said molten zinc with the coating in contact with said molten zinc.
Claim 2
Dependent Claim
84 words
In a method of galvanizing only selected areas of a ferrous metal strip, the improvement which comprises contacting surface areas of said strip not to be galvanized with a phosphoric acid solution to cause a spontaneous reaction to form a readily chemically strippable coating of a composite comprising iron hydroxides and hydrated iron phosphates non-wetting in molten zinc on said surface areas not to be galvanized, and passing the so-treated strip through said molten zinc with the coating in contact with said molten zinc.
Claim 3
Dependent Claim
119 words
In the continuous galvanizing of steel strip wherein steel strip is continuously cleaned, pickled, fluxed and galvanized, the operations, after said pickling and before said fluxing, of contacting one side only of said strip with an inorganic acid medium containing phosphoric acid to form on said one side only a coating comprising iron hydroxides and hydrated iron phosphates, and washing said coating substantially free from any excess unreacted inorganic acid medium, whereby, upon said galvanizing, the coating on said one side and the side of said strip opposite to said one side contact molten zinc and, after said galvanizing, a continuous steel strip is formed having a galvanized coating only on the side thereof opposite to said one side.
Claim 4
Dependent Claim
119 words
In the continuous galvanizing of steel strip wherein steel strip is continuously cleaned, pickled, fluxed and galvanized, the operations, after said pickling and before said fluxing, of contacting one side only of said strip with an inorganic acid medium containing phosphoric acid to form on said one side only a coating comprising iron hydroxides and hydrated iron phosphates, and washing said coating substantially free from any excess unreacted inorganic acid medium, whereby, upon said galvanizing, the coating on said one side and the side of said strip opposite to said one side contact molten zinc and, after said galvanizing, a continuous steel strip is formed having a galvanized coating only on the side thereof opposite to said one side.
Claim 5
Dependent Claim
22 words
The process of claim 2 including the further step of, after said galvanizing, removing said coating with a dilute hydrochloric acid solution.
Claim 6
Dependent Claim
58 words
The process of claim 2 wherein said inorganic acidic medium has a total phosphate concentration of about 5 to about 50 g/l and said treatment includes preheating said steel strip and contacting said one side only of said preheated steel strip with said acidic medium at a temperature greater than about 140° F to form said coating thereon.
Claim 7
Dependent Claim
47 words
The process of claim 4 including the further step of, after said galvanizing, removing said coating by contacting said one side only of said steel strip with dilute hydrochloric acid of concentration about 1 to about 10% at a temperature of about 110° to about 180° F.
Claim 8
Dependent Claim
23 words
The process of claim 5 wherein said temperature is about 150° to about 160° F and said concentration is about 2 to 4%.
References Cited (Backward Citations)
US2137464A
Cited
US3104993A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |