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
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
  • C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B21/00—Obtaining aluminium
  • C22B21/0038—Obtaining aluminium by other processes
  • C22B21/0069—Obtaining aluminium by other processes from scrap, skimmings or any secondary source aluminium, e.g. recovery of alloy constituents
• • 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
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• This invention relates to aluminum alloys obtained from aluminum scrap containing high levels of iron and silicon, the alloys being suitable for use in the production of can ends and can bodies, as well as building and industrial products, and to processes of manufacture thereof.
• can end alloy is a highly engineered and rigidly controlled AA 5182 alloy.
• the composition and processing are controlled within strict limits.
• the important properties are mechanical strength, earing and the ability to be released in a die after forming. For these reasons, practically every aluminum manufacturer uses the same alloy. Attempts to modify the composition have not been successful primarily because the earing and mechanical properties are significantly effected by these changes.
• the maximum iron allowed in AA 5182 is 0.35% by weight and the maximum silicon allowed is 0.2% by weight.
• AA 5010 Other aluminum alloy products that have required close control of iron and silicon contents are alloys used in building and industrial products. These are typically AA 3105, AA 5052 and AA 5010.
• the important properties to control are mechanical strength, formability, rollability and scrap compatibility.
• the iron is limited to less than 0.7% by weight and the silicon is limited to less than 0.4% by weight, preferably about 0.35% ( ⁇ 0.03%) and 0.37% ( ⁇ 0.03%) respectively.
• the maximum iron is limited to less than 0.7% and the maximum silicon to less than 0.6%, preferably around 0.55% ( ⁇ 0.15%) and the maximum of 0.3% respectively.
• AA 5052 it is generally limited to maximum iron content of less than 0.4% and the maximum silicon content of less than 0.25%, preferably around 0.25% ( ⁇ 0.15%) and a maximum of 0.08% respectively.
• FeAl 3 or FeAl 6 Another problem that has been encountered with high levels of iron is precipitation of iron-aluminide particles (FeAl 3 or FeAl 6 ). These are large crystals in the order of 10 to 15 microns.
• Robertson et al. U.S. Pat. No. 4,282,044, issued Aug. 4, 1981 relates to an aluminum alloy derived in part from scrap and containing 0.1-1.0% silicon, 0.1-0.90% iron, 0.4-1.0% manganese, 1.3-2.5% magnesium, 0.005-0.4% copper, 0-0.2% titanium and the balance aluminum and incidental impurities. This alloy is primarily used for the production of containers.
• the present invention in its broadest aspect relates to aluminum alloys that are variants of AA 3000 and AA 5000 series alloys containing higher than the usual amounts of silicon and iron.
• the alloys containing in percentages by weight, more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1.
• Other components of the alloys may include 0-0.4% copper, 0-1.5% manganese, 0-5.0% magnesium, 0-0.5% zinc, 0-3.5% chromium, 0-0.1% titanium and the balance aluminum and incidental impurities.
• the silicon is present at such a level that no FeAl 3 is precipitated out during casting, but all iron is precipitated as Fe 3 SiAl 12 ( ⁇ ) particles. These are quite small particles of 3 to 5 microns and do not interfere with rolling operations.
• the ratio of iron to silicon according to the invention is preferably in the range, of 1.3-1.6:1 and a range of 1.4-1.5:1 is most preferred.
• the silicon is preferably present in the range of 0.7-2.0%, more preferably 0.7-1.5%, while the preferred range for iron is 0.9-2.0%, with a range of 0.9-1.5% being most preferred.
• an alloy is developed as a recycle friendly can end alloy.
• This alloy contains more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1, 0-0.4% copper, 0.2-0.5% manganese, 4-5% magnesium, 0-0.1% chromium, 0-0.1% titanium, 0-0.5% zinc and the balance aluminum and incidental impurities.
• a further embodiment is a recycled friendly aluminum alloy for making can bodies.
• the alloy contains more than 0.6-1.0% silicon, 0.9-1.2% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1, 0-0.4% copper, 0.7-1.5% manganese,. 0.8-1.5% magnesium, 0-0.50% zinc and the balance aluminum and incidental impurities.
• FIG. 1 Further embodiments of the invention relate to variants of building and industrial product alloys AA 3105, AA 5052 and AA 5010 suitable for recycling purposes, these variants being capable of withstanding high levels of iron and silicon without an adverse affect on their mechanical properties.
• a variant of AA 3105 contains more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1, 0-0.3% copper, 0.3-0.8% manganese, 0.2-0.8% magnesium, 0-0.5% zinc and the balance aluminum and incidental impurities.
• a variant of AA 5052 according to the invention contains more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1, 0-0.1% copper, 0-0.1% manganese, 2.2-2.8% magnesium, 0-0.1% zinc, 0.15-0.35% chromium and the balance aluminum and incidental impurities.
• a variant of AA 5010 according to the invention contains more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount. of iron to the amount of silicon is in the range of 1.2-1.8:1, 0-0.25% copper, 0.1-0.3% manganese, 0.2-0.6%.magnesium, 0-0.5% zinc and the balance aluminum and incidental impurities.
• scrap may be obtained from sources such as plant scrap, can scrap, consumer scrap, etc.
• the scrap to be recycled is charged into a furnace to form a melt composition.
• the initial melt will vary in composition according to the compositions and amounts of the various types of scrap charged in the furnace.
• This initial melt is then adjusted as necessary to bring the composition within the ranges stated above and treated as necessary to remove impurities.
• the alloy composition is then cast e.g. by the direct chill (DC) process into ingots which are formed into sheet products.
• DC direct chill
• the alloys were cast into ingots. These ingots were pre-heated at 593° C. for 2 hours and hot rolled to a thickness of 0.090′′. This was subsequently cold rolled in three passes to a sheet having thickness of 0.01040′′.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Processing Of Solid Wastes (AREA)

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Cited By (10)

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Citations (7)

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• 2004
  • 2004-03-30 WO PCT/CA2004/000477 patent/WO2004094679A1/en active Application Filing
  • 2004-03-30 BR BRPI0409700-9A patent/BRPI0409700A/pt not_active IP Right Cessation
  • 2004-03-31 US US10/815,602 patent/US20040213695A1/en not_active Abandoned
• 2008
  • 2008-03-26 US US12/079,466 patent/US20080181812A1/en not_active Abandoned

Patent Citations (7)

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