US4328044A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for cleaning metal parts
Assignee: University of Dayton
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Filing: 1980-02-06
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Granted: 1982-05-04
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Expires: 2000-02-06
Abstract
Abstract A method for relatively low temperature cleaning of metal parts, particularly stainless steels, superalloys, solid solution superalloys and gamma prime hardened nickel alloy parts, in order to render them brazable or otherwise bondable. The method makes use of a C--O--H--F atmosphere as the primary cleaning material. The preferred source of the C--O--H--F atmosphere is by thermal decomposition of a fluorocarbon resin and addition of a low moisture containing hydrogen gas.
Inventors
- 👤 Jack W. Chasteen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:49
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/20; B23K1/206; C; C23; C23G; C23G5/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
165 words
In a method for brazing or otherwise metallic bonding metal parts comprising cleaning said parts to depassivate the surface and thereafter brazing or forming a metal-metal bond, the improvement which comprises cleaning said parts by a process consisting essentially of: (a) placing the part in a hermetically sealed chamber, (b) subjecting said part to a gaseous atmosphere in said chamber, said atmosphere containing the elements C--O--H--F and including CF 4 , C 2 F 4 , HF and H 2 in amounts sufficient to clean said metal parts and having an H/O ratio of 10 4 or greater, (c) at the same time heating said chamber to a temperature of less than 1000° C., (d) allowing said part to remain in said heated chamber filled with said atmosphere for a period of time sufficient to clean said part and render it brazable or otherwise able to form a metal-metal bond, and (e) cooling said chamber and said part prior to removing it from said chamber.
Claim 2
Dependent Claim
165 words
In a method for brazing or otherwise metallic bonding metal parts comprising cleaning said parts to depassivate the surface and thereafter brazing or forming a metal-metal bond, the improvement which comprises cleaning said parts by a process consisting essentially of: (a) placing the part in a hermetically sealed chamber, (b) subjecting said part to a gaseous atmosphere in said chamber, said atmosphere containing the elements C--O--H--F and including CF 4 , C 2 F 4 , HF and H 2 in amounts sufficient to clean said metal parts and having an H/O ratio of 10 4 or greater, (c) at the same time heating said chamber to a temperature of less than 1000° C., (d) allowing said part to remain in said heated chamber filled with said atmosphere for a period of time sufficient to clean said part and render it brazable or otherwise able to form a metal-metal bond, and (e) cooling said chamber and said part prior to removing it from said chamber.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said H/O ratio is about 10 4 and said temperature is approximately 800°-1000° C.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein said H/O ratio is about 10 5 and said temperature is approximately 700°-1000° C.
Claim 5
Dependent Claim
40 words
The method of claim 1 wherein said C--O--H--F atmosphere is produced by the thermal decomposition of a fluorocarbon resin to which there is added a low moisture containing hydrogen gas without addition of any substantial amounts of other non-inert gases.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein said fluorocarbon resin is polytetrafluoroethylene resin.
Claim 7
Dependent Claim
19 words
The method of claim 5 wherein the moisture present in said hydrogen gas is less than approximately 200 ppm.
Claim 8
Dependent Claim
12 words
The method of claim 6 wherein said temperature is approximately 800°-1000° C.
Claim 9
Dependent Claim
19 words
The method of claim 6 wherein the moisture present in said hydrogen gas is less than approximately 20 ppm.
Claim 10
Dependent Claim
12 words
The method of claim 8 wherein the temperature is approximately 700°-1000° C.
Claim 11
Dependent Claim
30 words
The method of claim 1 wherein said metal part is a material selected from the group consisting of stainless steels, superalloys, solid solution superalloys, and gamma prime hardened nickel alloys.
Claim 12
Dependent Claim
21 words
The method of claim 1 further including the step of in situ brazing of said metal part following the cleaning steps.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-03 | 1985-11-02 | 1986-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-03 | 1989-11-02 | 1990-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-03 | 1993-11-02 | 1994-05-04 | $7700.00 | Window Closed / Lapsed |