US4533806A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing bimetallic tubes
Assignee: JFE Steel Corp
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Filing: 1982-06-01
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Granted: 1985-08-06
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Expires: 2002-06-01
Abstract
Abstract A method of manufacturing bimetallic tubes is disclosed. In this method, after an inner tube is inserted into an outer tube, the resulting tube assembly is heated, while pressurizing the inside of the inner tube with a gas, in the presence or absence of a solder material. When using no solder material, the materials of the inner and outer tubes are so selected that a thermal expansion coefficient of the inner tube is smaller than that of the outer tube.
Inventors
- 👤 Tatsuo Kawasaki
- 👤 Isao Takada
- 👤 Hiroshi Ohtsubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:52
CPC Classifications
B; B23; B23K; B23K13/00; B23K1/00; B23K1/002
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
166 words
In a method of manufacturing bimetallic tubes by inserting an inner tube into an outer tube, filling a solder material in a space defined between the inside of said outer tube and the outside of said inner tube, and zone-heating the resulting tube assembly by applying heat from a heating unit to each part of the tube assembly, while pressurizing the inside of said inner tube with a gas, so as to effect brazing of said inner tube to said outer tube, the improvement which comprises placing a flux with said solder material in the space between the inside of said outer tube and the outside of said inner tube, while the zone-heating and pressurizing of said tube assembly takes place moving the heating unit over the whole length of said tube assembly so as to expand both the tubes and cause the flux to successively melt and move out of the space between the tubes, effecting brazing of said inner tube to said outer tube.
Claim 2
Dependent Claim
166 words
In a method of manufacturing bimetallic tubes by inserting an inner tube into an outer tube, filling a solder material in a space defined between the inside of said outer tube and the outside of said inner tube, and zone-heating the resulting tube assembly by applying heat from a heating unit to each part of the tube assembly, while pressurizing the inside of said inner tube with a gas, so as to effect brazing of said inner tube to said outer tube, the improvement which comprises placing a flux with said solder material in the space between the inside of said outer tube and the outside of said inner tube, while the zone-heating and pressurizing of said tube assembly takes place moving the heating unit over the whole length of said tube assembly so as to expand both the tubes and cause the flux to successively melt and move out of the space between the tubes, effecting brazing of said inner tube to said outer tube.
Claim 3
Dependent Claim
17 words
The method as claimed in claim 1, wherein said solder material is previously mixed with a flux.
Claim 4
Dependent Claim
26 words
The method as claimed in claim 1, wherein after the filling of the solder material and the flux, the space is maintained under a reduced pressure.
Claim 5
Dependent Claim
46 words
The method as claimed in claim 1, wherein at least one joint surface of said inner and outer tubes is subjected to a metal plating or metal spraying with at least one of solder materials selected from the group consisting of Ni, Cr, Cu and Fe.
Claim 6
Dependent Claim
32 words
The method as claimed in claim 1, wherein a compressive force is applied to both ends of said inner tube toward the axial direction thereof during the heating of said tube assembly.
Claim 7
Dependent Claim
29 words
The method as claimed in claim 1, wherein, after the filling of said solder material and said flux, said space is maintained in an inert or reducing gas atmosphere.
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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) | 1988-08-05 | 1989-02-04 | 1989-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-05 | 1993-02-04 | 1993-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-05 | 1997-02-04 | 1997-08-06 | $7700.00 | Window Closed / Lapsed |