US3826124A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of tubes with improved metallic yield strength and elongation properties
Assignee: Cabot Corp
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Filing: 1972-10-25
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Granted: 1974-07-30
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Expires: 1992-10-25
Abstract
Abstract A process for the manufacture of metal tubes, wherein the tubes exhibit improved yield strength, axial elongation and circumferential elongation properties. The tube is initially cold worked to obtain final size, which develops a certain strength to the metal of the tube and produces uniformity in the dimensions of the tube. A subsequent annealing increases the ductility of the metal in the tube. After annealing the tube is stretched significantly with the simultaneous reduction of the diameter thereof, to obtain a final product where the wall of the tube has been work hardened by such stretching. The latter operation increases the yield strength in the tube wall without failure occurring. A process of the type indicated where the annealing is a recrystallizing annealing, effective to produce recrystallizing of the microstructure of the tube''s metal, and wherein the stretching is done without internal or external support of the tube wall.
Inventors
- 👤 I Baksay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:10
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/10; C22; C22F; C22F1/00; C22F1/16; C22F1/18; C22F1/186
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
144 words
A process for the manufacture of a metal tube comprising cold working a tube to reduce the tube wall area thereof and by such cold working increasing the yield strength in the metal of the tube and obtaining a uniformly dimensioned tube, after such cold working annealing the tube by heating the tube at an elevated temperature and then cooling the tube, to increase the ductility of the metal in the tube and to obtain improved axial and circumferential elongation properties, and with the tube in the state that results from the annealing subsequently stretching the tube, to obtain a reduction in the outer diameter thereof ranging from 0.75 to 6 percent, to obtain a resultant tube where the metal of the tube has been work hardened by the stretching, the resultant tube having yield strength properties which are substantially increased by said stretching.
Claim 2
Dependent Claim
144 words
A process for the manufacture of a metal tube comprising cold working a tube to reduce the tube wall area thereof and by such cold working increasing the yield strength in the metal of the tube and obtaining a uniformly dimensioned tube, after such cold working annealing the tube by heating the tube at an elevated temperature and then cooling the tube, to increase the ductility of the metal in the tube and to obtain improved axial and circumferential elongation properties, and with the tube in the state that results from the annealing subsequently stretching the tube, to obtain a reduction in the outer diameter thereof ranging from 0.75 to 6 percent, to obtain a resultant tube where the metal of the tube has been work hardened by the stretching, the resultant tube having yield strength properties which are substantially increased by said stretching.
Claim 3
Dependent Claim
34 words
The process of claim 1, wherein the annealing is a recrystallizing annealing, effective to produce recrystallizing of the microstructure of the metal in the tube, with the formation of equiaxed grains in said microstructure.
Claim 4
Dependent Claim
21 words
The process of claim 2, wherein the stretching is performed without external and internal support of the wall of the tube.
Claim 5
Dependent Claim
39 words
The process of claim 1, wherein the annealing is a stress-relief annealing carried out without recrystallizing of the microstructure of the metal in the tube, and stretching is performed with support of the wall of the tube during stretching.
Claim 6
Independent Claim
116 words
A method of manufacturing a metal tube exhibiting improved yield strength, axial elongation and circumferential elongation properties comprising cold working the tube to produce a reduction in the tube wall area of the tube, recrystallizing annealing the tube after such cold working by heating the tube at an elevated temperature and then cooling the tube, with such being effective to produce recrystallizing of the microstructure of the tube''s metal with the formation of equiaxed grains in said microstructure, and stretching the tube in the state that it has after such annealing to reduce the outer diameter thereof and to obtain a final product where the wall of the tube has been work hardened by such stretching.
Claim 7
Independent Claim
116 words
A method of manufacturing a metal tube exhibiting improved yield strength, axial elongation and circumferential elongation properties comprising cold working the tube to produce a reduction in the tube wall area of the tube, recrystallizing annealing the tube after such cold working by heating the tube at an elevated temperature and then cooling the tube, with such being effective to produce recrystallizing of the microstructure of the tube''s metal with the formation of equiaxed grains in said microstructure, and stretching the tube in the state that it has after such annealing to reduce the outer diameter thereof and to obtain a final product where the wall of the tube has been work hardened by such stretching.
Claim 8
Dependent Claim
34 words
The method of claim 5, wherein the cold working of the tube is performed by passing the tube through a tube reducer with working of the metal of the tube against an internal mandrel.
Claim 9
Independent Claim
141 words
A method of manufacturing a metal tube exhibiting improved yield strength, axial elongation and circumferential elongation properties comprising cold working the tube to produce a reduction in the tube wall area of the tube, stress-relief annealing the tube after such cold working by heating and then cooling the tube, without recrystallizing the microstructure of the tube''s metal, and by such annealing increasing the ductility of the metal in the tube, thus to obtain improved axial and circumferential elongation properties, and subsequent to such annealing and with the tube in the state that results from the annealing, stretching the tube to obtain a reduction in the outer diameter thereof, with such stretching being effective to work harden the metal of the tube thereby to increase the yield strength, said stretching being performed with support of the tube wall during the stretching process.
Claim 10
Independent Claim
141 words
A method of manufacturing a metal tube exhibiting improved yield strength, axial elongation and circumferential elongation properties comprising cold working the tube to produce a reduction in the tube wall area of the tube, stress-relief annealing the tube after such cold working by heating and then cooling the tube, without recrystallizing the microstructure of the tube''s metal, and by such annealing increasing the ductility of the metal in the tube, thus to obtain improved axial and circumferential elongation properties, and subsequent to such annealing and with the tube in the state that results from the annealing, stretching the tube to obtain a reduction in the outer diameter thereof, with such stretching being effective to work harden the metal of the tube thereby to increase the yield strength, said stretching being performed with support of the tube wall during the stretching process.
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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) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |