US3780555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a pipe with refined grain structure
Assignee: Sargent Industries Inc
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Filing: 1972-04-10
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Granted: 1973-12-25
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Expires: 1992-04-10
Abstract
Abstract A method of making a pipe comprising providing a pipe preform having a wall with relatively large columnar grains, refining the grain of the pipe preform by cold working and annealing, and cold working the wall subsequent to refining the grain to substantially axially elongate the pipe preform.
Inventors
- 👤 R Balthazar
- 👤 R Halberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:18
CPC Classifications
B; B21; B21C; B21C23/00; B21C23/001; B21C37/00; B21C37/06; C; C21; C21D; C21D7/00; C21D7/02; C21D7/10; C21D8/00; C21D8/10; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4998; Y10T29/49988; Y10T29/49991
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
176 words
A method of making a pipe comprising: providing a centrifugal stainless steel casting of generally tubular configuration having a wall with a relatively large columnar grain structure and with said wall defining a passage in said casting, said wall having a carbon content of no more than about 0.07 percent by weight; inserting a mandrel into the passage of the casting; providing tooling; radially compressing the wall of said casting between the mandrel and the tooling while advancing the tooling axially of the casting and while relatively rotating the casting and the tooling to thereby subject the casting to a first reverse extrusion operation which thins and axially elongates said wall; annealing said casting subsequent to said first reverse extrusion operation with the annealing and the first reverse extrusion operation refining the grain structure of the casting; and subjecting the casting into a second reverse extrusion operation subsequent to said step of annealing which thins and elongates said wall a greater percent than said first reverse extrusion operation whereby said casting is converted into the pipe.
Claim 2
Independent Claim
176 words
A method of making a pipe comprising: providing a centrifugal stainless steel casting of generally tubular configuration having a wall with a relatively large columnar grain structure and with said wall defining a passage in said casting, said wall having a carbon content of no more than about 0.07 percent by weight; inserting a mandrel into the passage of the casting; providing tooling; radially compressing the wall of said casting between the mandrel and the tooling while advancing the tooling axially of the casting and while relatively rotating the casting and the tooling to thereby subject the casting to a first reverse extrusion operation which thins and axially elongates said wall; annealing said casting subsequent to said first reverse extrusion operation with the annealing and the first reverse extrusion operation refining the grain structure of the casting; and subjecting the casting into a second reverse extrusion operation subsequent to said step of annealing which thins and elongates said wall a greater percent than said first reverse extrusion operation whereby said casting is converted into the pipe.
Claim 3
Dependent Claim
24 words
A method as defined in claim 1 wherein the first reverse extrusion operation is carried out with the axis of the mandrel generally vertical.
Claim 4
Dependent Claim
40 words
A method as defined in claim 1 wherein said reverse extrusion operation includes at least one pass of said tooling over the wall with said one pass reducing the thickness of said wall an amount no less than about 5%.
Claim 5
Dependent Claim
24 words
A method as defined in claim 1 wherein said step of radially compressing includes thinning the wall from about 5 to about 20 percent.
Claim 6
Dependent Claim
40 words
A method as defined in claim 1 wherein said first reverse extrusion operation includes advancing the tooling axially of the casting a plurality of times with each of said advances resulting in reverse extrusion of the wall of the casting.
Claim 7
Dependent Claim
81 words
A method as defined in claim 1 including subjecting the casting to a third reverse extrusion operation which thins and elongates the wall a lesser percent than said second reverse extrusion operation, annealing the casting after said third reverse extrusion operation, said last mentioned step of annealing and said third reverse extrusion operation being carried out after said first mentioned step of annealing and prior to said second reverse extrusion operation and causing further refinement of the grain of the casting.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |