US20120227873A1 - Method for tempering an aluminum alloy - Google Patents
Method for tempering an aluminum alloy Download PDFInfo
- Publication number
- US20120227873A1 US20120227873A1 US13/445,427 US201213445427A US2012227873A1 US 20120227873 A1 US20120227873 A1 US 20120227873A1 US 201213445427 A US201213445427 A US 201213445427A US 2012227873 A1 US2012227873 A1 US 2012227873A1
- Authority
- US
- United States
- Prior art keywords
- desired shape
- controlled temperature
- range
- soaking
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000005496 tempering Methods 0.000 title claims abstract description 4
- 229910000838 Al alloy Inorganic materials 0.000 title claims description 5
- 229910001148 Al-Li alloy Inorganic materials 0.000 claims abstract description 16
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000001989 lithium alloy Substances 0.000 claims abstract description 15
- 230000007797 corrosion Effects 0.000 claims abstract description 10
- 238000005260 corrosion Methods 0.000 claims abstract description 10
- 238000005336 cracking Methods 0.000 claims abstract description 10
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 5
- 239000000956 alloy Substances 0.000 claims abstract description 5
- 238000002791 soaking Methods 0.000 claims abstract 7
- 238000010791 quenching Methods 0.000 claims description 10
- 238000009987 spinning Methods 0.000 claims description 9
- 238000012360 testing method Methods 0.000 claims description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 6
- 230000000171 quenching effect Effects 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000011825 aerospace material Substances 0.000 claims description 4
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims 3
- 230000032683 aging Effects 0.000 claims 1
- 238000000137 annealing Methods 0.000 claims 1
- 238000001816 cooling Methods 0.000 claims 1
- 230000035882 stress Effects 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 12
- 238000005482 strain hardening Methods 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
Definitions
- This present invention relates to the manufacture of metallic domes and conical components used in launch vehicles, and in particular, components produced using the aluminum lithium alloy known as 2195.
- Aluminum lithium alloy, 2195 is used in launch vehicle applications where its lower density, higher modulus and comparable strength, and desirable cryogenic service properties make it attractive. When components are manufactured to industry guidelines for this material, the 2195 aluminum lithium alloy also possesses resistance to stress corrosion cracking. As the mass for launch vehicle payloads continues to grow, use of this alloy for fuel tanks and vehicle structures has become a requirement by NASA and other launch vehicle service providers. In supporting this requirement, it becomes necessary to supply 2195 alloy in its highest strength condition and possessing resistance to stress corrosion cracking.
- temper designation T8X where the 2195 material is solution heat treated, quenched, cold worked (stretched) 1% to 3% to an intermediate temper T3X, and artificially aged to T8X.
- T8X temper designation
- the invention is a method of manufacturing domes and cones using the metal spinning process and alternative heat treatment parameters to achieve the same properties attainable as if the part were cold worked although this step has been eliminated.
- the preferred embodiment of the method includes the steps of forming and heat treating 2195 aluminum lithium alloy domes and cones.
- FIG. 1 is an illustration of a multi-stage rocket, which shows the type of components that can be made using the process taught by the invention.
- FIG. 2 is a flow chart of the preferred embodiment of the method in accordance with the present invention.
- FIG. 3 is a table of material properties that have been achieved by producing parts in accordance with the present invention compared to material produced with the cold work outlined in a published industry material standard.
- the illustration of the multi-stage rocket 10 is a typical structure that has parts that can be made using the method taught herein.
- Payload 15 is placed within the payload fairing structure.
- Second stage rocket engine 17 powers payload 15 during the final leg of the journey to achieve a successful orbit.
- primary tank 12 and secondary tank 14 have a domed top and bottom 16 and 18 respectively. These tanks have an extremely large diameter 11 and are particularly well suited to be manufactured using the present invention.
- the thrust cone 17 (typically composite materials) is also a component part that would be preferably made using the method disclosed herein.
- the starting material form 20 is in the mill temper known as the F condition.
- the material plate 20 is annealed in step 22 in accordance SAE Aerospace Material Specification AMS 2770 for 2XXX aluminum alloy.
- the dome or cone forming is done in step 24 by a spinning process.
- the dome or cone forming is performed in steps 26 , 28 at a controlled temperature of 725° F. ⁇ 25° F. using the metal spinning process and/or the stretch forming process developed as disclosed in U.S. Pat. No. 6,199,419.
- the component Upon completing the forming operation, the component is solution heat treated, in accordance with SAE Aerospace Material Specification AMS 2770 using a set temperature of 950° F. ⁇ 10° F. for a time in accordance with AMS 2770 Table 3 and then rapid quenched in either water or glycol water solution as indicated in step 30 . If necessary, the component may be straightened after solution heat treatment to remove minor distortion resulting from the rapid quench, step 32 . The component is then artificially aged in step 34 . In step 36 , the component temperature is raised to 340° F., ⁇ 5° F. The component is then “soaked” (industry term of art meaning to allow it to remain at that temperature) for 32 hours ⁇ 5 minutes.
- step 38 the component temperature is lowered to 250° F. ⁇ 5° F. at a decreasing rate of 45° F. per hour. Then, the component part is “soaked” again for 72 hours ⁇ 5 minutes in step 40 . Finally, in step 42 , the component part is air cooled to room temperature.
- the component part carries the T62 temper designation and is tested for its properties beginning in step 44 .
- the various parameters that are tested are hardness, step 46 ; electrical conductivity, step 48 ; minimums achieved when practicing the invention, step 50 and, finally in step 52 , a SCC Test as specified.
Abstract
A process for tempering large aluminum lithium alloy component parts to achieve high strength capability and resistance to stress corrosion cracking without the need for the prior art step of cold working the alloy components parts. The process achieves the desired material properties by the use of two novel soaking time periods and the use of novel controlled temperature selection at the two respective soaking times as well as carefully controlling the temperature decrease from one soaking time period to the other.
Description
- This application is a continuation-in-part of U.S. application Ser. No. 12/387,966 filed May 8, 2008 that claims priority from Provisional Application Serial No. 61/133,207 filed Jun. 26, 2008.
- This present invention relates to the manufacture of metallic domes and conical components used in launch vehicles, and in particular, components produced using the aluminum lithium alloy known as 2195.
- Aluminum lithium alloy, 2195, is used in launch vehicle applications where its lower density, higher modulus and comparable strength, and desirable cryogenic service properties make it attractive. When components are manufactured to industry guidelines for this material, the 2195 aluminum lithium alloy also possesses resistance to stress corrosion cracking. As the mass for launch vehicle payloads continues to grow, use of this alloy for fuel tanks and vehicle structures has become a requirement by NASA and other launch vehicle service providers. In supporting this requirement, it becomes necessary to supply 2195 alloy in its highest strength condition and possessing resistance to stress corrosion cracking.
- To achieve the high strength capability and resistance to stress corrosion cracking of this material, manufacturers solution heat treat the material which is then followed by a rapid quenching in water or in a solution of glycol and water. After the quench, the material is uniformly cold worked. The cold working process is typically a stretching operation that is controlled from 1 to 3 percent. Upon completing the cold working operation, the component is then artificially aged to achieve high strength and resistance to stress corrosion cracking. The thermal treatment and cold working parameters are well known and have been established as the industry standard practice by 2195 material producers to achieve ideal conditions for 2195 aluminum lithium alloy. This ideal condition would be defined as temper designation T8X where the 2195 material is solution heat treated, quenched, cold worked (stretched) 1% to 3% to an intermediate temper T3X, and artificially aged to T8X. For some launch vehicle tank and structural components, it is not possible to uniformly apply the cold work that is required to achieve the desired characteristics of 2195 aluminum lithium alloy due to the size and geometric shape of the parts. Single piece tank domes and cones produced from a 2195 aluminum lithium plate/blank using the metal spinning process fall into this category. It is in the manufacture of these components that current manufacturing methods fall short.
- One possible solution is to manufacture metal spinning equipment capable of uniformly applying the cold work necessary to achieve the high strength and resistance to stress corrosion cracking of 2195 aluminum lithium alloy. However, it is unlikely that metal spinning manufacturers will invest in this equipment given the relatively low volume of parts. There is also the question as to whether cold work using compressive forces developed from metal spinning is likely to yield the desired condition given that industry data is based on cold work using tension forces. The unfavorable return on investment and questionable success of this solution make this an unattractive option.
- A method of manufacturing these components and achieving the high strength and resistance to stress corrosion cracking without the addition of cold work after solution heat treatment and quench is not known in the art. Parts produced using 2195 material without the post quench cold work would carry the T62 temper designation for which there is no published industry standard for strength and resistance to stress corrosion cracking requirements.
- The invention is a method of manufacturing domes and cones using the metal spinning process and alternative heat treatment parameters to achieve the same properties attainable as if the part were cold worked although this step has been eliminated. The preferred embodiment of the method includes the steps of forming and heat treating 2195 aluminum lithium alloy domes and cones.
- It is an aspect of the invention to provide a method of treating 2195 aluminum lithium alloy in order to achieve the same favorable properties obtained using prior art methods requiring cold working of the produced part.
- It is another aspect of the invention to provide a method of treating 2195 aluminum lithium alloy that can be used with extremely large parts requiring spinning techniques to manufacture such parts.
- It is still another aspect of the invention to provide a method of treating 2195 aluminum lithium alloy that possesses high tensile and yield strengths.
- It is another aspect of the invention to provide a method of treating 2195 aluminum lithium alloy that has a high resistance to stress corrosion cracking
- Finally, it is an aspect of the invention to provide a method of treating 2195 aluminum lithium alloy that provides parts for launch vehicles which meet performance parameters yet can be made using existing manufacturing equipment.
- These aspects of the invention are not meant to be exclusive and other features, aspects, and advantages of the present invention will be readily apparent to those of ordinary skill in the art when read in conjunction with the following description and accompanying drawings.
-
FIG. 1 is an illustration of a multi-stage rocket, which shows the type of components that can be made using the process taught by the invention. -
FIG. 2 is a flow chart of the preferred embodiment of the method in accordance with the present invention. -
FIG. 3 is a table of material properties that have been achieved by producing parts in accordance with the present invention compared to material produced with the cold work outlined in a published industry material standard. - As shown in
FIG. 1 , the illustration of themulti-stage rocket 10 is a typical structure that has parts that can be made using the method taught herein. Payload 15 is placed within the payload fairing structure. Second stage rocket engine 17 powers payload 15 during the final leg of the journey to achieve a successful orbit. In the first stage ofrocket 10, note that primary tank 12 and secondary tank 14 have a domed top andbottom 16 and 18 respectively. These tanks have an extremelylarge diameter 11 and are particularly well suited to be manufactured using the present invention. The thrust cone 17 (typically composite materials) is also a component part that would be preferably made using the method disclosed herein. - Referring now to
FIG. 2 , the flow chart showing process 54 for tempering 2195 aluminum lithium alloy is described. The startingmaterial form 20 is in the mill temper known as the F condition. Thematerial plate 20 is annealed in step 22 in accordance SAE Aerospace Material Specification AMS 2770 for 2XXX aluminum alloy. The dome or cone forming is done in step 24 by a spinning process. The dome or cone forming is performed insteps step 30. If necessary, the component may be straightened after solution heat treatment to remove minor distortion resulting from the rapid quench,step 32. The component is then artificially aged in step 34. Instep 36, the component temperature is raised to 340° F.,±5° F. The component is then “soaked” (industry term of art meaning to allow it to remain at that temperature) for 32 hours±5 minutes. Then, instep 38, the component temperature is lowered to 250° F.±5° F. at a decreasing rate of 45° F. per hour. Then, the component part is “soaked” again for 72 hours±5 minutes instep 40. Finally, in step 42, the component part is air cooled to room temperature. After the completion of the above referenced steps, the component part carries the T62 temper designation and is tested for its properties beginning in step 44. The various parameters that are tested are hardness, step 46; electrical conductivity, step 48; minimums achieved when practicing the invention, step 50 and, finally in step 52, a SCC Test as specified. - Although the present invention has been described with reference to certain preferred embodiments thereof, other versions are readily apparent to those of ordinary skill in of the preferred embodiments contained herein.
Claims (15)
1. A process for tempering an aluminum alloy blank to achieve high strength capability and resistance to stress corrosion cracking, said process comprising the steps of:
annealing said alloy blank in accordance with Aerospace Material Specification AMS 2770 for 2XXX aluminum alloy;
hot spinning the annealed alloy blank into a desired shape at a first controlled temperature;
solution heat treating said desired shape in accordance with SAE Aerospace Material Specification AMS 2770 using a set temperature of 950° F.±10° F. for a time in accordance with AMS 2770 Table 3;
rapidly quenching said desired shape in a liquid;
a first aging said desired shape to a second controlled temperature;
a first soaking of said desired shape at a first predetermined length of time;
lowering the second controlled temperature of said desired shape at a predetermined rate of decrease to a third controlled temperature;
a second soaking of said desired shape at a second predetermined length of time; and
air cooling said desired shape until said desired shape reaches room temperature.
2. The process of claim 1 comprising the additional step after said quenching step of:
straightening said desired shape to remove minor distortions that may be introduced by said quenching step.
3. The process of claim 1 comprising the additional step of:
testing said desired shape to determine the properties of said desired shape.
4. The process of claim 3 wherein said testing step has a least one test selected from the group of tests consisting of hardness, electrical conductivity, mechanical ASTM test, and a SCC test.
5. The process of claim 1 wherein said quenching liquid is water.
6. The process of claim 1 wherein said quenching liquid is a glycol water solution.
7. The process of claim 1 wherein said first controlled temperature is in the range of 725 degrees F.
8. The process of claim 1 wherein said second controlled temperature is in the range of 340 degrees F.
9. The process of claim 1 wherein said third controlled temperature is in the range of 250 degrees F.
10. The process of claim 1 wherein said temperature rate of decrease is in the range of 45 degrees F. per hour.
11. The process of claim 1 wherein said first soaking time is in the range of 32 hours.
12. The process of claim 1 wherein said soaking time is in the range of 72 hours.
13. The process of claim 1 wherein said aluminum alloy blank is made from 2195 aluminum lithium alloy.
14. The process of claim 1 wherein said desired shape is a domed top of a rocket.
15. The process of claim 1 wherein said desired shape is a thrust cone of a rocket.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/445,427 US20120227873A1 (en) | 2008-06-26 | 2012-04-12 | Method for tempering an aluminum alloy |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13320708P | 2008-06-26 | 2008-06-26 | |
US12/387,966 US20090320972A1 (en) | 2008-06-26 | 2009-05-08 | Method for tempering an aluminum alloy |
US13/445,427 US20120227873A1 (en) | 2008-06-26 | 2012-04-12 | Method for tempering an aluminum alloy |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/387,966 Continuation-In-Part US20090320972A1 (en) | 2008-06-26 | 2009-05-08 | Method for tempering an aluminum alloy |
Publications (1)
Publication Number | Publication Date |
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US20120227873A1 true US20120227873A1 (en) | 2012-09-13 |
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Family Applications (1)
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US13/445,427 Abandoned US20120227873A1 (en) | 2008-06-26 | 2012-04-12 | Method for tempering an aluminum alloy |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140291048A1 (en) * | 2013-03-28 | 2014-10-02 | GM Global Technology Operations LLC | Tank for storing compressed natural gas |
WO2015112799A1 (en) * | 2014-01-24 | 2015-07-30 | Magna International Inc. | High strength aluminum stamping |
CN108688829A (en) * | 2018-05-28 | 2018-10-23 | 北京航空航天大学 | Solid-liquid power sub-orbital booster |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5076859A (en) * | 1989-12-26 | 1991-12-31 | Aluminum Company Of America | Heat treatment of aluminum-lithium alloys |
US5620652A (en) * | 1994-05-25 | 1997-04-15 | Ashurst Technology Corporation (Ireland) Limited | Aluminum alloys containing scandium with zirconium additions |
-
2012
- 2012-04-12 US US13/445,427 patent/US20120227873A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5076859A (en) * | 1989-12-26 | 1991-12-31 | Aluminum Company Of America | Heat treatment of aluminum-lithium alloys |
US5620652A (en) * | 1994-05-25 | 1997-04-15 | Ashurst Technology Corporation (Ireland) Limited | Aluminum alloys containing scandium with zirconium additions |
Non-Patent Citations (1)
Title |
---|
"Heat Treating Aluminum Alloys." Heat Treater's Guide: Practices and Procedures for Nonferrous Alloys. ASM International 1996. Pages 131-145. * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140291048A1 (en) * | 2013-03-28 | 2014-10-02 | GM Global Technology Operations LLC | Tank for storing compressed natural gas |
WO2015112799A1 (en) * | 2014-01-24 | 2015-07-30 | Magna International Inc. | High strength aluminum stamping |
US10774408B2 (en) | 2014-01-24 | 2020-09-15 | Magna International Inc. | High strength aluminum stamping |
CN113832417A (en) * | 2014-01-24 | 2021-12-24 | 麦格纳国际公司 | Stamping of high strength aluminum |
CN108688829A (en) * | 2018-05-28 | 2018-10-23 | 北京航空航天大学 | Solid-liquid power sub-orbital booster |
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AS | Assignment |
Owner name: STANDEX INTERNATIONAL CORPORATION, NEW HAMPSHIRE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MORGANTI, RICHARD J., MR.;REEL/FRAME:028269/0841 Effective date: 20120514 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |