Patent US4426248A successfully refreshed from Google Patents.
US4426248A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for coating rifle tubes
Assignee: United States Department of the Army
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Filing: 1983-05-20
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Granted: 1984-01-17
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Expires: 2003-05-20
Abstract
Abstract A process for coating the inside diameter of a tube utilizes a coated manl which has been first coated in a Ni Cr Al Y slurry, air dried, vacuum sintered, and then inserted in a tube. A mandrel-tube assembly is then swaged and resintered under vacuum conditions. The sintered mandrel-tube assembly is first drilled and then chemically etched to remove remaining mandrel material.
Inventors
- 👤 Raymond P. Jackson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:24
CPC Classifications
C; C23; C23C; C23C10/00; C23C10/28; B; B22; B22F; B22F7/00; B22F7/06; B22F7/08; C23C10/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
A process for coating the inside diameter of a tube with a wear and erosion resistant coating which includes the steps of: preparing a slurry mixture of nickel, chromium, aluminum and yttrium powders in an aqueous solution; selecting a mandrel to fit inside of said tube; repetitively dip coating said mandrel in said slurry mixture; air drying said coated mandrel after each dip coating; sintering said coated mandrel in a vacuum furnace; inserting said coated mandrel into said tube to form a mandrel-tube assembly; swaging said mandrel-tube assembly to create a reduction in the outside diameter of said tube; vacuum sintering of said mandrel-tube assembly after it is swaged; axially drilling said mandrel in said sintered mandrel-tube assembly to remove material therefrom; chemically etching said drilled mandrel-tube assembly to remove the remaining mandrel material; rinsing said chemically etched coated tube in water; and air drying said coated tube.
Claim 2
Dependent Claim
148 words
A process for coating the inside diameter of a tube with a wear and erosion resistant coating which includes the steps of: preparing a slurry mixture of nickel, chromium, aluminum and yttrium powders in an aqueous solution; selecting a mandrel to fit inside of said tube; repetitively dip coating said mandrel in said slurry mixture; air drying said coated mandrel after each dip coating; sintering said coated mandrel in a vacuum furnace; inserting said coated mandrel into said tube to form a mandrel-tube assembly; swaging said mandrel-tube assembly to create a reduction in the outside diameter of said tube; vacuum sintering of said mandrel-tube assembly after it is swaged; axially drilling said mandrel in said sintered mandrel-tube assembly to remove material therefrom; chemically etching said drilled mandrel-tube assembly to remove the remaining mandrel material; rinsing said chemically etched coated tube in water; and air drying said coated tube.
Claim 3
Dependent Claim
36 words
A process as recited in claim 1 wherein said slurry mixture consists of: 187.50 grams of water; 0.42 grams of Kelzan; 8.30 grams of Polysilicate 48; and 118.80 grams of Ni Cr Al Y metal powders.
Claim 4
Dependent Claim
26 words
A process as recited in claim 2 wherein said nickel, chromium, aluminum, and yttrium metal powders have a particle size of less than to 20 microns.
Claim 5
Dependent Claim
23 words
A process as recited in claim 3 wherein said air drying step includes air drying at a temperature of at least 80° C.
Claim 6
Dependent Claim
25 words
A process as recited in claim 4 wherein said sintering step includes heating said coated mandrel in a vacuum to a temperature of 1100° C.
Claim 7
Dependent Claim
31 words
A process as recited in claim 5 wherein said swaging step includes a first reduction in the outside diameter of at least 3% and a second reduction of at least 17%.
Claim 8
Dependent Claim
28 words
A process as recited in claim 6 wherein said sintering of said mandrel-tube assembly includes heating said mandrel-tube assembly in a vacuum to a temperature of 1100° C.
Claim 9
Dependent Claim
25 words
A process as recited in claim 7 wherein said chemical etching step includes etching said drilled mandrel-tube assembly in a heated concentrated nitric acid solution.
Claim 10
Dependent Claim
30 words
A process as recited in claim 8 wherein said sintering of said mandrel-tube assembly is heated in a vacuum at a temperature of 1100° C. for at least 1 hour.
Claim 11
Dependent Claim
34 words
A process as recited in claim 5 wherein said sintering step of said coated mandrel includes heating said coated mandrel in a vacuum to a temperature of 1100° C. for at least 1 hour.
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) | 1987-01-16 | 1987-07-18 | 1988-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-16 | 1991-07-18 | 1992-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-16 | 1995-07-18 | 1996-01-17 | $7700.00 | Window Closed / Lapsed |