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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
  • F28F21/081—Heat exchange elements made from metals or metal alloys
  • F28F21/084—Heat exchange elements made from metals or metal alloys from aluminium or aluminium alloys
• • 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
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/10—Alloys based on aluminium with zinc as the next major constituent

Definitions

• the present invention is directed to a corrosion resistant aluminium alloy and, in particular, to an AA3000 series type aluminium alloy including controlled amounts of one or more of titanium, vanadium and zirconium for improved extrudability and/or drawability.
• aluminium is well recognized for its corrosion resistance.
• AA1000 series aluminium alloys are often selected where corrosion resistance is needed.
• AA1000 series alloys have been replaced with more highly alloyed materials such as the AA3000 series types aluminium alloys.
• AA3102 and AA3003 are examples of higher strength aluminium alloys having good corrosion resistance.
• Aluminium alloys of the AA3000 series type have found extensive use in the automotive industry due to their combination of high strength, light weight, corrosion resistance and extrudability. These alloys are often made into tubing for use in heat exchanger or air conditioning condenser applications.
• U.S. Patent no. 5,286,316 discloses an aluminium alloy with both high extrudability and high corrosion resistance.
• This alloy consists essentially of about 0.1 - 0.5 % by weight of manganese, about 0.05-0.12 % by weight of silicon, about 0.10 - 0.20 % by weight of titanium, about 0.15 - 0.25 % by weight of iron, with the balance aluminium and incidental impurities.
• the alloy preferably is essentially copper free, with copper being limited to not more than 0.01 %.
• a still further object of the present invention is to provide an aluminium alloy which has good both hot- and cold- formability, corrosion resistance.
• the present invention provides a corrosion resistant aluminium alloy consisting essentially of, in weight percent, 0,05 - 1,00 % of iron, 0,05 - 0,60 % of silicon, up to 0,70 % of copper, up to 1,20 % of manganese, 0,02 - 0,20 % of zirconium, up to 0,50 % of chromium, up to 1,00 % of zinc, 0,02 - 0,20 % of titanium, 0,02-0,20 % of vanadium, up to 2,00 % of magnesium, up to 0,10 % of antimony, up to 0,02 % of incidental impurities and the balance aluminium.
• iron preferably is between 0,05 - 0,55 %, more preferably, between 0,05 - 0,25 %. Reducing the Fe content improves the corrosion resistance.
• Silicon is preferably between 0,05 and 0,20 %, more preferably, not more than 0,15 %.
• Copper is preferably not more than 0,05 %, zirconium is preferably between 0,02 and 0,18 %, zinc is preferably between 0,10 and 0,50 %, more preferably between 0,10 and 0,25 %, titanium is preferably between 0,02 and 0,15 %, vanadium is preferably between 0,02 and 0,12 %.
• the preferred amount of manganese is highly dependent on the intended use of the article because manganese impacts extrudability, especially with thin sections.
• manganese is preferably present in amounts between 0,05 - 0,30 % by weight.
• Fe is preferably present in the amounts between 0,05 - 0,25 % by weight.
• the preferred amount of chromium is between 0,02 and 0,25%.
• the magnesium amount is preferably below 0,03 %.
• Zn is preferably present in amounts between 0,10 - 0,5 % by weight.
• the alloy When the alloy is intended to be used in applications, in which after extrusion further deformation processes will be used in order to obtain a final product, nsuch as cold deforming as e.g. drawing and/or bending, and where higher strength is required, it is preferredto have the amount of manganese between 0,50 and 0,80 % by weight. In this application chromium is preferably between 0,02 and 0,18 % by weight. When the alloy is intended to be used in applications, in which after extrusion further deformation processes will be used in order to obtain a final product, such as cold deforming as e.g. drawing and/or binding, it is preferred to have the amount of manganese between 0,50 and 0,80 % by weight.
• chromium is preferably between 0,02 and 0,18 % by weight and magnesium below 0,30 % by weight, for brazeability reasons.
• the Fe content should be kept low for improved corrosion resistance.
• chromium is added to further improve corrosion resistance.
• Zn is added to further improve corrosion resistance.
• controlled additions of V, Zr and Ti are made to further improve corrosion resistance.
• the role of V, Ti and especially Zr becomes important.
• the amounts added of each of these elements will depend on the functional requirements, however, the amount of zirconium is preferably between 0,10 and 0,18 % by weight.
• post treatment of the cast alloy in that it is heated to a temperature between 450 and 550°C with a heating rate of less than 150°C/hour, and maintain the alloy at that temperature between 2 and 10 hours.
• the final product may also for certain applications and especially after cold working, require a "back annealing" treatment consisting of heating the work piece to temperatures between 150 and 350 degrees Centigrade and keep at temperature for between 10 and 10000 min.
• Zr and Ti in solid solution are used separately to improve corrosion resistance in low alloy highly extrudable alloys for use in extruded tubes for automotive A/C systems.
• the useful maximum additions of Zr and Ti when added separately is about 0,2% by weight. Above this level primary compounds are formed that reduces the level of these elements in solid solution.
• the primary compounds from Zr and Ti Al3Zr, Al3Ti
• Both Zr and Ti will upon solidification go through a peritectic reaction.
• the product of this reaction is revealed as a highly concentrated region of the elements in the centre of the grain (positive partition ratio). These regions or zones will upon rolling or extrusion form a lamellae structure parallel to the surface of the work piece and slow down the corrosion in the through thickness direction. Additions of both Zr and Ti in combination, will give larger and more concentrated zones and hence improve corrosion resistance.
• V is an element with much the same behaviour and effect as Zr and Ti, but has up to now not been used much in these type of alloys. V will improve corrosion resistance in the same way as Zr and Ti. However, due to the smaller atomic radius compared to Zr and Ti the negative effect on the high temperature deformation resistance (extrudability) will be smaller.
• Combination of all three elements will give the most optimal balance of the corrosion, strength and workability properties.
• concentration of the elements in this enriched central zone of the grain is different for the three elements and is also sensitive to casting speed. While the total amount of the element added separately before deleterious primary particles are formed is approx. 0,2wt%, dependent on melt temperature and casting conditions, the amount of the sum of the elements added together is significantly higher.
• a combination of the three elements will give a higher concentration in the enriched central zone of the grains and therefore steeper concentration gradients between matrix and the lamellae and enhanced effect with respect to stopping through thickness corrosion propagation.
• transition elements such as Zr, Ti, and V is known to improve formability by increasing the work hardening coefficient ("n"). (Ref. latest Reynolds patent). The "n” increases with increased amount of the transition elements almost linearly up to some 0,5%. By combining Zr, Ti and V up to 0,45% of the transition elements may be added as opposed to approx. 0,2% if only one of the elements is added.
• Zr, Ti and V, and in particular Zr are known to impede the tendency of recrystalization, provided optimum heat treatment before high temperature processing.
• the ability to retard recrystallization is related to the number and size of small coherent precipitates that are stable at temperature up to 300- 400 degrees Centigrade for prolonged times.
• the fine polygenized structure that will result from back annealing at temperatures in the 150 to 350 degrees Centigrade range will have higher mechanical strength than the corresponding recrystalized structure resulting in the absence of such transition elements.

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• 2000
  • 2000-05-22 EP EP00201808A patent/EP1158063A1/fr not_active Withdrawn
• 2001
  • 2001-05-21 RU RU2002134484/02A patent/RU2002134484A/ru not_active Application Discontinuation
  • 2001-05-21 EP EP01940521A patent/EP1287175A1/fr not_active Withdrawn
  • 2001-05-21 BR BR0111053-5A patent/BR0111053A/pt not_active IP Right Cessation
  • 2001-05-21 CA CA002409870A patent/CA2409870A1/fr not_active Abandoned
  • 2001-05-21 CN CN01813222A patent/CN1443249A/zh active Pending
  • 2001-05-21 US US10/296,335 patent/US20030165397A1/en not_active Abandoned
  • 2001-05-21 WO PCT/EP2001/005920 patent/WO2001090430A1/fr not_active Application Discontinuation
  • 2001-05-21 AU AU2001274064A patent/AU2001274064A1/en not_active Abandoned
  • 2001-05-21 KR KR1020027015760A patent/KR20030013427A/ko not_active Application Discontinuation
  • 2001-05-21 JP JP2001586624A patent/JP2003534455A/ja active Pending
• 2002
  • 2002-11-19 IS IS6629A patent/IS6629A/is unknown
  • 2002-11-20 NO NO20025562A patent/NO20025562L/no not_active Application Discontinuation

Patent Citations (8)

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