US4526630A
Expired / Lapsed
US
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Heat treatment of aluminium alloys
Assignee: BRITISH ALUMINIUM Ltd
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Filing: 1983-03-22
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Granted: 1985-07-02
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Expires: 2003-03-22
Abstract
Abstract Aluminum alloys containing lithium and copper and/or magnesium as principal alloying constituents are homogenized at 530 DEG C. or above to take into solution as-cast intermetallic phases which do not fully go into solution at conventional homogenization temperatures for this class of alloy. Preferably the alloy ingots are slowly heated at rates not exceeding 50 DEG C./hour up to a final homogenization temperature in the region of 550 DEG -560 DEG C. and are then allowed to cool without prolonged holding at temperature.
Inventors
- 👤 David J. Field
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:49
CPC Classifications
C; C22; C22C; C22C21/00; C22C21/06; C22C21/12; C22F; C22F1/00; C22F1/04; C22F1/05; C22F1/057
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
193 words
A process for the homogenisation of ingots of ternary and quaternary alloys in the system in the system Al-Li-Cu-Mg which comprises heating the alloy ingot to a temperature of at least 530° C., but below the melting point of solid intermetallic phases contained therein and maintaining the alloy ingot at a temperature above 530° C. until such phases have entered solid solution in the alloy and then cooling the ingot, said ingot being formed of an alloy selected from the group consisting of (1) an alloy consisting essentially of 1-3% Li, 0.5-2% Cu, 0.2-2% Mg, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al; (2) an alloy consisting essentially of 1-3% Li, 2.4% Mg, below 0.1% Cu and having a total Li+Mg content of no more than 6.0%, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al; (3) an alloy consisting essentially of 1-3% Li, 0.5-4% Cu, up to 0.2% Mg, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al.
Claim 2
Dependent Claim
193 words
A process for the homogenisation of ingots of ternary and quaternary alloys in the system in the system Al-Li-Cu-Mg which comprises heating the alloy ingot to a temperature of at least 530° C., but below the melting point of solid intermetallic phases contained therein and maintaining the alloy ingot at a temperature above 530° C. until such phases have entered solid solution in the alloy and then cooling the ingot, said ingot being formed of an alloy selected from the group consisting of (1) an alloy consisting essentially of 1-3% Li, 0.5-2% Cu, 0.2-2% Mg, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al; (2) an alloy consisting essentially of 1-3% Li, 2.4% Mg, below 0.1% Cu and having a total Li+Mg content of no more than 6.0%, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al; (3) an alloy consisting essentially of 1-3% Li, 0.5-4% Cu, up to 0.2% Mg, (Zr+Mn+Cr) up to 0.6%, (Fe+Si) up to 0.4%, other elements up to 0.05% each, up to 0.15% total, balance Al.
Claim 3
Dependent Claim
32 words
A process according to claim 1 in which the ingot temperature is raised at a rate not exceeding 50° C./hr during the heating of the ingot from 400° C. to 530° C.
Claim 4
Dependent Claim
29 words
A process according to claim 1 in which the ingot temperature is raised at a rate not exceeding 50° C./hr during the heating of the ingot from 200° C.
Claim 5
Dependent Claim
47 words
A process according to claim 1 in which the alloy has the composition 1-3% Li 0.5-2% Cu 0.2-2% Mg up to 0.4% Fe+Si up to 0.6% (Mn+Cr+Zr) others (impurities) up to 0.15% total (up to 0.05% each) comprising heating the alloy to a temperature above 540° C.
Claim 6
Dependent Claim
25 words
A process according to claim 4 in which the alloy ingot is held at a temperature in the range of 540°-550° C. for 2-6 hours.
Claim 7
Dependent Claim
36 words
A process according to claim 4 in which the ingot is heated to a temperature of at least 550° C. from 530° C. at a rate not exceeding 50° C./hour and is then allowed to cool.
Claim 8
Dependent Claim
30 words
A process according to claim 4, in which the ingot is heated to above 540° C. from a temperature not exceeding 450° C. at a rate not exceeding 50° C./hr.
Claim 9
Dependent Claim
30 words
A process according to claim 5 in which the ingot is heated to above 540° C. from a temperature not exceeding 450° C. at a rate not exceeding 50° C./hr.
Claim 10
Dependent Claim
30 words
A process according to claim 6 in which the ingot is heated to above 540° C. from a temperature not exceeding 450° C. at a rate not exceeding 50° C./hr.
References Cited (Backward Citations)
US4094705A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |