US3720508A - Aluminum alloy - Google Patents

Aluminum alloy Download PDF

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Publication number
US3720508A
US3720508A US00148582A US3720508DA US3720508A US 3720508 A US3720508 A US 3720508A US 00148582 A US00148582 A US 00148582A US 3720508D A US3720508D A US 3720508DA US 3720508 A US3720508 A US 3720508A
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percent
alloy
alloys
silver
magnesium
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US00148582A
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A Brock
M Pryor
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Olin Corp
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Olin Corp
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    • 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
    • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
    • 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

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  • One of the problems in processing aluminum-magnesium alloys for bright anodizing is the necessity of retaining magnesium-silicide in solution during the hot rolling process. This is mandatory in order to obtain proper response to bright dipping and to sulphuric acid anodizing so that excellent specular reflectivity is obtained.
  • Retaining magnesium-silicide in solution during hot rolling involves initiating the rolling at unusually high temperature in the range of 850 to 975 F depending upon the magnesium content of the alloy. At these high temperatures, the oxidation resistance of aluminum-magnesium alloys deteriorates rapidly and copious amounts of loosely adherent magnesium oxide are formed as part of the high temperature oxidation product during hot rolling.
  • the magnesium oxide can either adhere to the rolls or can be ground into the soft metal surface. Either eventuality gives rise to surface defects known generically as hot' mill pickup. This pickup is never completely removed during subsequent processing and results in defects in the final bright anodized sheet that tend to detract from specular reflectivity and from subsequent corrosion resistance.
  • the improved alloys of the present invention consist essentially of from 0.5 to 3 percent magnesium, from 0.02 to 0.5 percent silver, from 0.001 to 0.2 percent iron, from 0.001 to 0.15 percent silicon, balance essentially aluminum, wherein the silver is substantially dissolved in solid solution in the matrix.
  • the alloys of the present invention are characterized by many desirableadvantages.
  • the alloys have markedly improved resistance to oxidation in the temperature range of 850 to 975 F which results in improved surface appearance after hot rolling.
  • the alloys are tolerant to a broader range of solution composition in which they can be bright dipped.
  • the alloys further exhibit substantially improved brightness after anodizing in sulphuric acid and sealing.
  • the present invention also provides a process for obtaining improved, bright anodizing alloys which comprises:
  • FIG. 1 is a graph of weight gain versus time when a comparative Alloy A is compared with Alloy B, an alloy of the present invention. The graph and results are discussed in the examples.
  • FIG. 2 shows a plot of comparative Alloy A and Alloy B of the present invention showing specimen potential versus nitric acid concentration in mixed nitric acid-phosphoric acid bright dipping solutions. The graph and results are discussed in the examples.
  • the alloys of the present invention are characterized by greatly improved resistance to oxidation within the temperature range of 850 to 975 F and exhibit 'a much superior hot rolled surface and specular reflectivity. after bright dipping. These improved surface characteristics are obtained in accordance with the alloys and process of the present invention. In addition, the alloys of the present invention have good mechanical properties and workability.
  • the favorable surface characteristics achieved by the alloys of the present invention result in greatly reduced product rejections due to hot mill pickup during hot rolling at high temperature.
  • the oxidation problem cannot be solved in conventional alloys by reducing hot rolling temperature and thereby increasing oxidation resistance because magnesium-silicide now forms in the microstructure of the alloy and detracts from the response to bright dipping and bright anodizing.
  • the alloys of the present invention do not completely inhibit the formation ofmagnesium oxide as a reaction product during heating in the temperature range from 850 to 975 F.
  • the amounts of magnesium oxide formed are tremendously reduced and it appears to exist as a compact transparent film that is not removed from the metal during hot rolling. It is a surprising feature of the present invention that the range of acid concentrations over which excellent brightening can be obtained in bright dipping is substantially increased with the alloys of the present invention. Accordingly, the incidence of unacceptable products in subsequent bright dipping and anodizing is significantly reduced. It has been found that due to the foregoing and due to the improved rolled surface, loss of brightness during anodizing in sulphuric acid is dramatically reduced.
  • the alloys contain from 0.5 to 3 percent magnesium, from 0.02 to 0.5 percent silver, from 0.001 to 0.2 percent iron, from 0.001 to 0.15 percent silicon, balance essentially aluminum. It is preferred that the magnesium content be from 0.8 to 2.8 percent and that the silver be from 0.02 to 0.1 percent.
  • the alloy may also contain one or more of the following: manganese in an amount up to 0.10 percent, copper in an amount up to 0.10 percent, zinc in an amount up to 0.10 percent, chromium in an amount up to 0.05 percent, and titanium in an amount up to 0.05 percent. Naturally, amounts as low as 0.001 percent of the foregoing may be present.
  • the process of the present invention is briefly described hereinabove.
  • the alloy is held within the temperature range 850 to 975 F for at least 15 minutes, with the maximum holding time not being critical.
  • the alloy is hot rolled, with the starting temperature being within said temperature range and with a preferred reduction of at least 70 percent.
  • the alloy may be cooled from hot rolling by any desired means, such as by water quenching.
  • the alloy is then cold rolled, with a preferred reduction of at least 50 percent followed by heating for from 5 seconds to 8 hours within the temperature range of 350 to 750 F.
  • the resultant material has been found to have many, highly desirable characteristics, such as improved response to bright dipping and bright anodizing and reduced oxidation rate.
  • EXAMPLE I A comparative Alloy A, containing 2.4 percent magnesium, 0.036 percent iron, 0.044 percent silicon, 0.041 percent copper, 0.0088 percent titanium, balance essentially aluminum, was cast as a direct chill ingot measuring 3 X 7 X 42 inches. One-eighth inch was milled off each face of the ingot. The ingot was preheated to 925 F and held at temperature for a period of 8 hours followed by rolling on polished steel rolls with two successive reductions in thickness of 20 and 30 percent. A substantial amount of oxide was transferred to the polished steel rolls and the surface of the hot rolled alloy was rough and discontinuous.
  • EXAMPLE II An alloy, Alloy B, containing 2.5 percent magnesium, 0.05 percent silver, 0.036 percent iron, 0.043 percent silicon, 0.045 percent copper, 0.0089 percent titanium, balance essentially aluminum, was direct chill cast, scalped and hot rolled in an identical fashion to that described in Example I. The polished steel rolls were essentially free from oxide transferred from the hot aluminum alloy and the hot rolled surface was uniform and free from defects.
  • EXAM PLE Ill Alloys A and B of Examples l and II were heated to 925 F, held for 8 hours and hot rolled in 10 passes to a final thickness of 0.1 inch. The temperature after the last pass was 700 F and the alloys were then quenched in still water. The alloys were subsequently cold rolled to a thickness of 0.030 inch and were partially annealed at 500 F for 2.5 hours. After processing, the surface of Alloy A showed extensive hot mill pickup of magnesium oxide. On the other hand, the alloy of the present invention, Alloy B, showed excellent surface smoothness and was substantially free from hot mill pickup.
  • EXAMPLE VI The bright dipped specimens of Example V were anodized for 20 minutes in 15 percent sulphuric acid at 25 C with a current density of 20 amps per square foot. After anodizing the alloys were rinsed and were sealed for 10 minutes in boiling water containing 3 ppm phosphate added as Na HPO,. The reflectivity of Alloy B after anodizing and sealing was 44 percent; whereas, the reflectivity of Alloy A was only 34 percent, with a silver mirror standard being rated at 90 percent in both cases.
  • An aluminum alloy having improved oxidation resistance at high temperature consisting essentially of 0.5 to 3 percent magnesium, 0.02 percent to 0.5 perstantially dissolved in solid solution in the matrix. cent silver, from 0.001 to 0.2 percent iron, from 0.001 2.
  • An alloy according to claim 1 wherein the magto 0.l5 percent silicon, up to 0.10 percent copper, up nesium te iS rom 0.8 to 2.8 percent. to 0.10 percent manganese, up to O l percent zinc, up 3.
  • An alloy according to claim 1 wherein the silver to 0.05 percent chromium, up to 0.05 percent titanium, 5 content from to P balance essentially aluminum, wherein the silver is sub-

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Metal Rolling (AREA)
  • Laminated Bodies (AREA)
  • Chemical Treatment Of Metals (AREA)
US00148582A 1971-06-01 1971-06-01 Aluminum alloy Expired - Lifetime US3720508A (en)

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US14858271A 1971-06-01 1971-06-01

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US (1) US3720508A (enrdf_load_stackoverflow)
CA (1) CA959304A (enrdf_load_stackoverflow)
DE (1) DE2226644C3 (enrdf_load_stackoverflow)
FR (1) FR2141158A5 (enrdf_load_stackoverflow)
GB (1) GB1379264A (enrdf_load_stackoverflow)
IT (1) IT958105B (enrdf_load_stackoverflow)
NO (1) NO131845C (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4601796A (en) * 1984-09-19 1986-07-22 Aluminum Company Of America High reflectance semi-specular anodized aluminum alloy product and method of forming same
US4702981A (en) * 1983-04-18 1987-10-27 Canon Kabushiki Kaisha Photoconductive member and support for said photoconductive member
US5032359A (en) * 1987-08-10 1991-07-16 Martin Marietta Corporation Ultra high strength weldable aluminum-lithium alloys
US5085830A (en) * 1989-03-24 1992-02-04 Comalco Aluminum Limited Process for making aluminum-lithium alloys of high toughness
US5122339A (en) * 1987-08-10 1992-06-16 Martin Marietta Corporation Aluminum-lithium welding alloys
US5637404A (en) * 1992-01-31 1997-06-10 Aluminum Company Of America Reflective aluminum strip
US5955147A (en) * 1992-01-31 1999-09-21 Aluminum Company Of America Reflective aluminum trim
US20080290296A1 (en) * 2007-05-22 2008-11-27 Jean-Pierre Tahon Radiation image phosphor or scintillator panel
CN108893658A (zh) * 2018-07-11 2018-11-27 合肥华盖光伏科技有限公司 一种高导电率耐热铝合金导线及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61201798A (ja) * 1985-03-01 1986-09-06 Citizen Watch Co Ltd 腕時計用外装部品

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2586647A (en) * 1946-02-08 1952-02-19 Rolls Royce Aluminum alloy
US3306717A (en) * 1964-02-01 1967-02-28 Svenska Metallverken Ab Filler metal for welding aluminumbased alloys

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB621617A (en) * 1946-02-08 1949-04-13 Harold Ernest Gresham Aluminium alloy

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2586647A (en) * 1946-02-08 1952-02-19 Rolls Royce Aluminum alloy
US3306717A (en) * 1964-02-01 1967-02-28 Svenska Metallverken Ab Filler metal for welding aluminumbased alloys

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4702981A (en) * 1983-04-18 1987-10-27 Canon Kabushiki Kaisha Photoconductive member and support for said photoconductive member
US4876185A (en) * 1983-04-18 1989-10-24 Canon Kabushiki Kaisha Aluminum support for a photoconductive member
US4601796A (en) * 1984-09-19 1986-07-22 Aluminum Company Of America High reflectance semi-specular anodized aluminum alloy product and method of forming same
US5032359A (en) * 1987-08-10 1991-07-16 Martin Marietta Corporation Ultra high strength weldable aluminum-lithium alloys
US5122339A (en) * 1987-08-10 1992-06-16 Martin Marietta Corporation Aluminum-lithium welding alloys
US5085830A (en) * 1989-03-24 1992-02-04 Comalco Aluminum Limited Process for making aluminum-lithium alloys of high toughness
US5637404A (en) * 1992-01-31 1997-06-10 Aluminum Company Of America Reflective aluminum strip
US5955147A (en) * 1992-01-31 1999-09-21 Aluminum Company Of America Reflective aluminum trim
US20080290296A1 (en) * 2007-05-22 2008-11-27 Jean-Pierre Tahon Radiation image phosphor or scintillator panel
US7554101B2 (en) 2007-05-22 2009-06-30 Agfa Healthcare Radiation image phosphor or scintillator panel
CN108893658A (zh) * 2018-07-11 2018-11-27 合肥华盖光伏科技有限公司 一种高导电率耐热铝合金导线及其制备方法

Also Published As

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NO131845B (enrdf_load_stackoverflow) 1975-05-05
FR2141158A5 (enrdf_load_stackoverflow) 1973-01-19
DE2226644B2 (de) 1980-07-17
NO131845C (enrdf_load_stackoverflow) 1975-08-13
DE2226644A1 (de) 1973-01-04
IT958105B (it) 1973-10-20
CA959304A (en) 1974-12-17
GB1379264A (en) 1975-01-02
DE2226644C3 (de) 1981-05-21

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