Classifications

• • 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

• the thin, e.g. 0.51-2.54 cm (0.2-1.0 inch) solidified cast web is typically reduced in thickness to a gauge of about 0.033 cm (0.130 inch) by cold rolling with an intermediate recrystallization anneal at 316 ⁇ 482°C (600-900°F). Thereafter, as in the manufacture of direct chill ingot cast stock, the thinned, annealed stock is subjected to a final work hardening step by cold rolling to a final gauge of about 0.033 cm (0.013 inch) to produce the H19 temper required for can body manufacture.
• the present invention relates to a process for the preparation of non-galling, low earing can stock from continuously cast aluminium strip suitable for deep drawing and wall-ironing into hollow articles.
• the molten aluminium material is cast by continuous strip casting into a web generally of 2.54 cm (one inch) or less in thickness.
• the strip material is heated to a temperature of from 510 to 621°C (950 to 1150°F) for a time sufficient to homogenize the alloy.
• the homogenized strip material is cold rolled to effect a first reduction in sheet thickness of at least 25%.
• the cold rolled sheet is heated to a recovery temperature of from 177°C (350°F) to 288°C (550°F), and subjected to a second cold rolling to effect a reduction in thickness of at least 10%.
• the cold rolled sheet product is heated to effect recrystallization of the grain structure and then subjected to effect a final reduction in thickness which is at least about 50% and is preferably at least 75% of the original thickness of the sheet to impart an H19 temper to the sheet.
• Temperature of the web is raised from 566 to 593°C (1050 to 1100°F) over a 5 hour period.
• Web is homogenized at 593 ⁇ 5.5°C (1100 ⁇ 10°F) for 20 hours.
• continuous cast 3004 aluminium alloy strip cold rolled and size-reduced to 0.034 cm (0.0135 inch) gauge to H-19 temper by conventional practice typically has an intermetallic particle size in the order of 0.3-0.7 microns.
• this strip when subjected to ironing operations encounters severe galling.
• the inter-metallic particle size increases with increasing homogenization temperature which results in a proportionate decrease in galling when the homogenized strip is subjected to wall-ironing conditions.
• the web may be cooled to room temperature between the second recovery heating step and the recrystallization step.
• the recrystallization heating is carried out without prior cooling to room temperature by direct heating from the second recovery temperature to the recrystallization temperature.
• the cooled strips were rolled in successive passes using a commercial rolling mill until the strip was reduced to varying degrees of thickness ranging from 66 to 75% (0.41 to 0.30 cm) (0.160 to 0.120 inch).
• Cold roll/anneal cycle 6 which is identical to cycle 5, except that a second cold roll reduction of 25% is used instead of 10%, produces a reduction in earing, but the reduction achieved is less than that achieved using cycle 5, indicating that a second cold roll reduction of 10% is more advantageous in effecting a reduction in earing.
• cycle 8 produces a reduction in earing when compared to control cycle C 3 , but does not provide an advantage over cycle 5 which utilizes only one recrystallization heating.
• the strips were subjected to a second recovery heating at 260°C (500°?) for one hour and then heated to recrystallization temperature of 427°C (800°F) for 2 hours.
• the first series of cold roll recovery-recrystallization heatings was varied whereby in a first variation the second cold reduction was eliminated and recrystallization carried out immediately after the first recovery heating. In a second variation, the recovery heating was eliminated and recrystallization was carried out immediately after the cold reduction.
• the H19 tempered strips were examined under a scanning electron microscope in the back scattering mode and found to have an intermetallic particle size in the 1 to 3 microns range, indicating that no galling would occur when the strips were subjected to the wall-ironing conditions of can making.
• the tensile ultimate strength, along with the tensile total elongation, is a measure of sheet formability. To be suitable for can body manufacture, the sheet must have a tensile ultimate strength of at least 289x10 6 N/m 2 (42,000 psi).

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Metal Rolling (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Chemical Treatment Of Metals (AREA)

Priority Applications (1)

Applications Claiming Priority (8)

Publications (3)

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• 1983
  • 1983-07-14 ES ES524111A patent/ES524111A0/es active Granted
  • 1983-07-14 DK DK324383A patent/DK324383A/da not_active Application Discontinuation
  • 1983-07-14 NO NO832560A patent/NO165349C/no unknown
  • 1983-07-14 AR AR29360983A patent/AR231408A1/es active
  • 1983-07-14 PT PT7703083A patent/PT77030B/pt unknown
  • 1983-07-14 BR BR8303778A patent/BR8303778A/pt not_active IP Right Cessation
  • 1983-07-15 DE DE8383304131T patent/DE3378640D1/de not_active Expired
  • 1983-07-15 GB GB08319199A patent/GB2123319B/en not_active Expired
  • 1983-07-15 AU AU16875/83A patent/AU557719B2/en not_active Ceased
  • 1983-07-15 EP EP19830304131 patent/EP0099739B1/en not_active Expired
• 1985
  • 1985-07-31 GB GB08519274A patent/GB2172303B/en not_active Expired

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