US5932037A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making hollow bodies
Assignee: Luxfer Group Ltd
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Filing: 1994-04-15
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Granted: 1999-08-03
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Expires: 2014-04-15
Abstract
Abstract A method of making a pressurized gas cylinder comprises providing an ingot of composition (in wt %); Zn 5.0-7.0; Mg 1.5-3.0; Cu 1.0-2.7; recrystallization inhibitor 0.05-0.40; Fe up to 0.30; Si up to 0.15; other impurities up to 0.05 each and 0.15 in total, balance Al of at least commercial purity, if necessary homogenizing the ingot at a temperature of at least 470° C. and for a time sufficient to reduce the volume fraction of S phase to a value below 1.0%, extruding the ingot preferably by cold backward extrusion, and forming and over-aging the resulting pressurized gas cylinder.
Inventors
- 👤 Nigel John Henry Holroyd
- 👤 Warren Hepples
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:20
CPC Classifications
F; F17; F17C; F17C1/00; F17C1/14; B; B21; B21C; B21C23/00; B21C23/02; B21C23/20; C; C22; C22C; C22C21/00; C22C21/10; C22F; C22F1/00; C22F1/04; C22F1/053; F17C2201/00; F17C2201/01; F17C2201/0104; F17C2203/00; F17C2203/06; F17C2203/0602; F17C2203/0612; F17C2203/0614; F17C2203/0617; F17C2203/0634; F17C2203/0636; F17C2203/0646; F17C2203/0648; F17C2223/00; F17C2223/01; F17C2223/0107; F17C2223/0123; F17C2223/03; F17C2223/035; F17C2260/00; F17C2260/01; F17C2260/011; F17C2260/012; F17C2260/05; F17C2260/053; F17C2270/00; F17C2270/01; F17C2270/0102; F17C2270/0118; F17C2270/0121
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
81 words
A method of making a hollow body for a pressure container, which method comprises providing a billet of composition (in wt %) Zn 5.0-7.0 Mg 1.5-3.0 Cu 1.0-2.7 Recrystallisation inhibitor 0.05-0.4 Fe up to 0.30 Si up to 0.15 other impurities up to 0.05 each and 0.15 in total, Al balance said billet having a volume fraction of S phase below 1.0% extruding the billet, forming the extrusion into the shape of the desired hollow body, and over-ageing the hollow body.
Claim 2
Independent Claim
81 words
A method of making a hollow body for a pressure container, which method comprises providing a billet of composition (in wt %) Zn 5.0-7.0 Mg 1.5-3.0 Cu 1.0-2.7 Recrystallisation inhibitor 0.05-0.4 Fe up to 0.30 Si up to 0.15 other impurities up to 0.05 each and 0.15 in total, Al balance said billet having a volume fraction of S phase below 1.0% extruding the billet, forming the extrusion into the shape of the desired hollow body, and over-ageing the hollow body.
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1, wherein the billet has the composition: Zn 5.0-7.0 Mg 1.5-2.5 Cu 1.8-2.2 Cr and/or Zr 0.10-0.25 Fe up to 0.15 Si up to 0.08
Claim 4
Dependent Claim
37 words
A method as claimed in claim 1, wherein the billet is homogenised at a temperature of at least 470° C. for a time sufficient to reduce the volume fraction of S phase to a value below 0.2%.
Claim 5
Dependent Claim
17 words
A method as claimed in claim 3, wherein the homogenised billet is slowly cooled to ambient temperature.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 1, wherein the billet is cold or warm extruded.
Claim 7
Dependent Claim
13 words
A method as claimed in claim 5, wherein extrusion is by backward extrusion.
Claim 8
Dependent Claim
31 words
A method as claimed in claim 1, wherein forming the extrusion into the shape of the desired hollow body comprises swaging or spinning a neck at a temperature of 300-450° C.
Claim 9
Dependent Claim
20 words
A method as claimed in claim 1, wherein over-ageing is effected to an extent to reduce peak strength by 10-30%.
Claim 10
Dependent Claim
32 words
A method as claimed in claim 1, wherein over-ageing is effected by holding the hollow body at a first elevated temperature and then at a second elevated temperature higher than the first.
Claim 11
Dependent Claim
32 words
A method as claimed in claim 1, wherein over-ageing is effected by holding the hollow body at a first elevated temperature and then at a second elevated temperature lower than the first.
Claim 12
Dependent Claim
36 words
A method as claimed in claim 1, wherein over-ageing is effected by holding the hollow body at three elevated temperatures in sequence, of which the second elevated temperature is higher than the first and the third.
Claim 13
Dependent Claim
28 words
A method as claimed in claim 9, wherein one elevated temperature is within the range 80-150° C., and the other elevated temperature is within the range 160-220° C.
Claim 14
Dependent Claim
16 words
A method as claimed in claim 1, wherein the hollow body is a pressurised gas cylinder.
Claim 15
Dependent Claim
15 words
A method as claimed in claim 1, wherein the alloy contains up to 0.10% Fe.
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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) | 2002-08-02 | 2003-02-01 | 2003-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-02 | 2007-02-01 | 2007-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-02 | 2011-02-01 | 2011-08-03 | $7700.00 | Window Closed / Lapsed |