US3958984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of removing a brazing alloy from stainless steel
Assignee: Individual
•
Filing: 1974-03-18
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Granted: 1976-05-25
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Expires: 1994-03-18
Abstract
Abstract A method of removing high temperature brazing alloys from a stainless steel base wherein the brazing alloy is treated with an aqueous solution of an alkali cyanide and a nitro-substituted aromatic compound and also with an acid solution containing a minor amount of a base metal attack inhibitor.
Inventors
- 👤 Laurence R. Fountain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:04
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
92 words
A method of removing a high temperature brazing alloy from stainless steel wherein said brazing alloy contains a major amount of a metal selected from the group consisting of gold, silver and nickel, said method comprising treating said brazing alloy with an aqueous solution of an alkali cyanide and a nitro-substituted aromatic compound at a temperature of about 160° to 180°F, rinsing said brazing alloy in water and treating said brazing alloy in an acid solution containing 40% to 50% by volume nitric acid at a temperature of about 100° to 120°F.
Claim 2
Independent Claim
92 words
A method of removing a high temperature brazing alloy from stainless steel wherein said brazing alloy contains a major amount of a metal selected from the group consisting of gold, silver and nickel, said method comprising treating said brazing alloy with an aqueous solution of an alkali cyanide and a nitro-substituted aromatic compound at a temperature of about 160° to 180°F, rinsing said brazing alloy in water and treating said brazing alloy in an acid solution containing 40% to 50% by volume nitric acid at a temperature of about 100° to 120°F.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said alkali cyanide is sodium cyanide and said nitro-substituted aromatic compound is sodium m-nitrobenzoate.
Claim 4
Dependent Claim
18 words
The method of claim 2 wherein said acid solution contains minor amounts of hydrochloric acid and copper sulfate.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said aqueous solution also contains a minor amount of a wetting agent.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein said wetting agent is ethylene diamine tetraacetic acid.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |