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
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
• • 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
• • 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
  • C22F1/043—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 of alloys with silicon as the next major constituent

Definitions

• the invention relates to thin sheets or strips with a thickness of less than 200 ⁇ m, and preferably 50 ⁇ m, made of aluminum alloy with iron and silicon, substantially free of manganese, and a method of manufacturing such leaves or strips.
• These strips can be obtained by semi-continuous casting of conventional plates or by continuous casting, for example the continuous casting between belts ("twin-belt casting") or between cylinders ("twin-roll casting”).
• Very thin alloys of manganese such as for example alloy 81 1 1 of composition (% by weight) recorded in the Aluminum Association, are often used for thin sheets: Si: 0.30 - 1, 1 Fe: 0.40 - 1.0 Cu ⁇ 0.10 Mn ⁇ 0.10
• manganese such as in alloy 8006, whose composition recorded in the Aluminum Association is as follows (% by weight): Si ⁇ 0.40 Fe: 1 , 2 - 2.0 Cu ⁇ 0.30 Mn: 0.30 - 1.0 Mg ⁇ 0.10
• the addition of manganese has the effect of hardening the material.
• the mechanical characteristics can also be improved by the addition of manganese in small quantities in iron-loaded 8000 series alloys.
• the patent application WO 02/64848 (Alcan International) describes the continuous casting of thin strips of AlFeSi alloy containing from 1.2 to 1.7% Fe and from 0.35 to 0.8% Si. high mechanical strength by adding to the alloy from 0.07 to 0.20% manganese. This addition of manganese is recognized as necessary to obtain a small grain size after the final annealing.
• manganese in solid solution or in the form of fine precipitates can block or delay the recrystallization during the final annealing. It is therefore necessary to precisely control the precipitation of the phases containing manganese during each step of the range, which is often difficult. Any drift in the transformation range has significant consequences on the effectiveness of the final annealing. It is therefore very interesting to develop an alloy that does not contain manganese, but nevertheless has high mechanical characteristics.
• US Pat. No. 5,503,689 discloses a method of manufacturing a thin alloy strip containing from 0.30 to 1.1% Si and from 0.40 to 1.0% Fe, less than 0.25% Cu. and less than 0.1% Mn, by continuous casting and cold rolling without intermediate annealing.
• the preferred levels of iron and silicon are between 0.6 and 0.75%.
• US Patent 5,725,695 discloses for the same compositional range a range with intermediate annealing between 400 and 440 ° C (750 - 825 ° F) and final recrystallization annealing at 288 ° C (550 ° F).
• the ratio of Si / Fe contents is equal to or greater than 1.
• the maximum ultimate tensile strength obtained is 90 MPa (13.13 ksi)
• the maximum yield strength is 39.1 MPa (5.68 ksi)
• the elongation is 1 1, 37% for thicknesses of 46 ⁇ m (0.00185 ').
• the alloys obtained by continuous casting it is often necessary to carry out a heat treatment at high temperature in order to reduce the harmfulness of the segregations, by resorbing the clusters of precipitation and by homogenizing the structure in the thickness.
• the effect of a homogenization at 600 ° C. is described for the alloy 801 1 (of composition: 0.71% Fe, 0.77% Si, 0.038% Cu, 0.006% Mn, 98.45% Al) obtained by casting between rolls in the steel. article by Y. Birol "Centerline Segregation in Twin-Roll Cast AA801 1 Alloy" Aluminum, 74, 1998, pp. 318-321.
• a modification of the precipitated phases and a reduction in heterogeneities are obtained.
• the reduction of the central segregation makes it possible later to limit the porosity of the very thin leaves, and to improve their formability.
• the object of the invention is to obtain thin sheets or strips of AlFeSi alloy without the addition of manganese, having a high mechanical strength, while maintaining a good formability, with an industrial manufacturing range that is as economical as possible.
• the subject of the invention is a thin sheet with a thickness of between 6 and 200 ⁇ m, and preferably between 6 and 50 ⁇ m, of alloy composition (% by weight): Si: 1.0 - 1 , Fe: 1.0 - 1.5 Cu ⁇ 0.2 Mn ⁇ 0.1, other elements ⁇ 0.05 each and ⁇ 0.15 in total, remain Al, preferably with the Si / Fe> 0 condition, 95, having in the annealed state a tensile strength R m > 1 10 MPa for thicknesses> 9 ⁇ m, and> 100 MPa for thicknesses of 6 to 9 ⁇ m.
• the thin sheet preferably has a yield strength R o , 2 (measured on sheared specimens)> 70 MPa.
• the elongation at break is greater than the following values depending on the thickness of the sheet:
• the alloy preferably has a silicon content of between 1.1 and 1.3% and an iron content of between 1.0 and 1.2%.
• the invention also relates to a process for producing thin strips with a thickness of less than 200 ⁇ m in Al-Fe-Si alloy of composition (% by weight): Si: 1.0 - 1.5 Fe: 1.0 - 1, 5 Cu ⁇ 0.2 Mn ⁇ 0, 1 other elements ⁇ 0.05 each and ⁇ 0.15 in total, remains Al, with preferably the Si / Fe condition> 0.95, comprising the preparation of a first band is by vertical semi-continuous casting of a plate and hot rolling, or by continuous casting possibly followed by hot rolling, the cold rolling of this first band to the final thickness with possibly a intermediate annealing of 2 to 20 hours at a temperature between 250 and 350 ° C, and preferably between 280 and 340 ° C, and a final annealing at a temperature between 200 and 370 ° C.
• the thin sheets or strips according to the invention are manufactured from 8000 AlSiFe alloys substantially free of manganese, with a content typically less than 0.1%.
• the iron and silicon contents are significantly higher than those of alloys 8011 and 8111, which are the AlSiFe alloys for the most commonly used manganese-free thin sheets.
• a preferred composition range is an alloy containing from 1.1 to 1.3% silicon and 1.0 to 1.2% iron.
• the alloys according to the invention should preferably have a composition such that the Si / Fe ratio of the respective silicon and iron contents is> 0.95. They have, in the annealed state (state O), an unusual mechanical strength for alloys of this composition, with a tensile strength R m > 1 10 MPa, or even 1 MPa, for thicknesses> 9 ⁇ m and> 100 MPa for thicknesses from 6 to 9 ⁇ m, and a yield strength of 0.2% Ro, 2 > 70 MPa. This high mechanical strength is not obtained at the expense of the formability, because, compared to the alloys 801 1 or 81 1 1, the elongations are at least the same, and the burst pressures are increased.
• the strips are then cold rolled, either to the final thickness, or to an intermediate thickness of between 0.5 and 5 mm, to which they are subjected to an intermediate annealing.
• this intermediate annealing at a relatively low temperature, between 250 and 350 ° C, and preferably between 280 and 340 ° C, for a duration greater than 2 hours.
• a relatively low temperature between 250 and 350 ° C, and preferably between 280 and 340 ° C, for a duration greater than 2 hours.
• Such a temperature range although described in the literature, especially in the patent application WO 02/064848 mentioned above, is below the usual range which is above 400 ° C.
• the Applicant has found that the application to an AlFeSi alloy, more particularly of composition such as Si / Fe> 0.95, of low temperature heat treatments, possibly with the suppression of the intermediate annealing when it is technically possible, leads to a significantly improved mechanical strength, at least 15% compared to the usual intermediate annealing. This superior mechanical strength is obtained while improving the formability measured by burst pressure or dome height according to ISO 2758.
• the final annealing is carried out at a temperature of between 200 and 370 ° C. for a duration of between 1 and 72 hours.
• the annealing times are conditioned by the quality of the degreasing of the sheet.
• a fine grain structure with an average grain size, measured by scanning electron microscope image analysis, of less than 3 ⁇ m is obtained.
• the conjunction of a homogenization at low temperature or a lack of homogenization and an intermediate annealing at low temperature or completely suppressed, in addition to its economic advantage, is favorable to obtaining a fine size of grains.
• the grain size is reduced by about 30% compared with heat treatments at higher temperatures, which therefore leads to an increase in the mechanical characteristics R 0 - 2 and R m , which for thin thicknesses are related to number of grain boundaries. This gain is not at the expense of elongation, as increasing the number of grains in the thickness also limits the risk of damage located in one or two single grains of the thickness of the sheet.
• the thin sheets according to the invention are particularly suitable for applications requiring both a good mechanical strength and a high formability, such as for example the manufacture of multilayer complexes, in particular for the lids of fresh product packaging, overcap caps or of household aluminum.
• the strips were cold rolled to a thickness of 2 mm and then subjected to a 5 hour intermediate anneal at 320 ° C. The strips were then cold rolled in several passes until the final thickness of 38 microns. They were then subjected to a final annealing of 40 h at 270 ° C.
• Example 1 An alloy strip A of Example 1 with a thickness of 6.1 mm was cast in continuous casting between rolls. The strip was then cold rolled to a thickness of 2 mm. Part of the strip was subjected to a usual intermediate anneal for such a 5 hour alloy at 500 ° C. The other part of the strip has undergone an intermediate anneal according to the invention for 5 hours at 320 ° C. The two parts of the strip were then cold rolled in several passes until the final thickness of 10.5 microns. They were then subjected to a final annealing of 40 h at 270 ° C. The same properties as in Example 1 were measured, the values of which are given in Table 3:
• the average grain size measured by SEM image analysis, is 3.6 ⁇ m for annealing at 470 ° C, and 2.3 ⁇ m for annealing at 320 ° C.
• the increase in the mechanical characteristics for the low temperature annealing is therefore related to a reduction in the grain size obtained after final annealing.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Continuous Casting (AREA)
• Laminated Bodies (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Closures For Containers (AREA)
• Wrappers (AREA)
• Catalysts (AREA)
• Metal Rolling (AREA)
• Containers Having Bodies Formed In One Piece (AREA)

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• 2003
  • 2003-07-21 FR FR0308864A patent/FR2857981A1/fr active Pending
• 2004
  • 2004-06-23 AR ARP040102197A patent/AR044882A1/es not_active Application Discontinuation
  • 2004-07-19 ES ES04767726T patent/ES2281831T3/es not_active Expired - Lifetime
  • 2004-07-19 EA EA200600276A patent/EA009227B1/ru not_active IP Right Cessation
  • 2004-07-19 JP JP2006520859A patent/JP4989221B2/ja not_active Expired - Lifetime
  • 2004-07-19 ZA ZA200600425A patent/ZA200600425B/en unknown
  • 2004-07-19 PL PL04767726T patent/PL1644545T3/pl unknown
  • 2004-07-19 CA CA002532585A patent/CA2532585A1/fr not_active Abandoned
  • 2004-07-19 AU AU2004259877A patent/AU2004259877A1/en not_active Abandoned
  • 2004-07-19 UA UAA200601770A patent/UA80778C2/uk unknown
  • 2004-07-19 US US10/565,219 patent/US20060213590A1/en not_active Abandoned
  • 2004-07-19 BR BRPI0412775-7A patent/BRPI0412775A/pt not_active IP Right Cessation
  • 2004-07-19 AT AT04767726T patent/ATE355392T1/de not_active IP Right Cessation
  • 2004-07-19 PT PT04767726T patent/PT1644545E/pt unknown
  • 2004-07-19 CN CNB2004800210038A patent/CN100445405C/zh not_active Expired - Fee Related
  • 2004-07-19 EP EP04767726A patent/EP1644545B1/de not_active Expired - Lifetime
  • 2004-07-19 DK DK04767726T patent/DK1644545T3/da active
  • 2004-07-19 DE DE602004005045T patent/DE602004005045T2/de not_active Expired - Lifetime
  • 2004-07-19 WO PCT/FR2004/001902 patent/WO2005010222A2/fr not_active Ceased
  • 2004-08-11 SA SA04250245A patent/SA04250245B1/ar unknown
• 2006
  • 2006-01-31 NO NO20060508A patent/NO338970B1/no unknown

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