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
  • C22F1/05—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 of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions

Definitions

• the invention relates to a method for cold extrusion of aluminum or aluminum alloys, a slug (also called butze, round blank or blank) being used as the blank.
• extrusion processes differ in their process management in particular by the starting materials chosen in each case, namely aluminum or naturally hard (solid solution strengthened) alloys and alloys hardenable by precipitation.
• Pure aluminum and non-hardenable aluminum alloys are extruded only in the “soft annealed” condition.
• the state “soft annealed” describes the state of lowest strength.
• hardenable alloys are extruded only in the “soft annealed” condition.
• the formability of the materials is determined with the help of the reproducing test methods (compression, tensile and torsion tests) and essentially determined by the following parameters.
• the formability decreases with an increasing proportion of alloying elements and with an increasing proportion of hardening phases.
• the degree of deformation also drops in cases where the materials are pre-consolidated, e.g. B. by cold rolling, drawing etc.
• the degree of deformation also decreases depending on the particular structure. For this reason, casting alloys are not used at all for cold extrusion.
• Alloys of the type AIMgSi are an exception. From the aluminum paperback, 14th edition, 1984, page 472, it is known to process AIMgSi alloys in the “freshly quenched” or “cold-hardened” state using cold extrusion. The reason for this is that after solution annealing and quenching, these alloys are not significantly stronger than in the "soft annealed” condition. The deformability does not decrease very much either. AIMgSi alloys show no particularly pronounced cold hardening. The strength of this alloy does not increase significantly due to cold hardening, in contrast to other hardenable alloys, e.g. B. of the type AICuMg or AIZnMgCu.
• Naturally hard alloys of the type AIMg with an alloy content of 2 to 3% by weight of magnesium, are only processed if it is absolutely necessary, since the shape change capacity compared to pure aluminum is significantly reduced (K. Mayerhofer «Cold extrusion of steel and non-ferrous metals» , 1983, pages 29, 30).
• alloys that can only be poured in the “soft annealed” condition according to “Aluminum-Taschenbuch, 14th edition, 1984, pages 471, 472” and K. Mayerhofer “Cold extrusion of aluminum and non-ferrous metals, 1983, pages 30, 31 »AICuMg1 and AlZnMgCu0.5. Responsible for this is the low formability of the hardenable alloys.
• non-hardenable materials especially pure aluminum is used due to the low strength values and the associated high deformation characteristics. Despite the high forming characteristics, the extruded parts made with pure aluminum are often inadequate in terms of their absolute strength values.
• the invention is intended to show a way to improve the strength values of extruded parts made of pure aluminum and aluminum alloys, regardless of their manufacture and their assembly, with good elongation properties, without adversely affecting the economy of cold extrusion.
• the aim is also to use this process to produce moldings which have hitherto not been able to be produced by cold extrusion
• the invention offers three alternative methods depending on the aluminum materials used for the production of bodies by cold extrusion, which are described in detail by the features of claims 1 to 3.
• Pure aluminum may be mentioned as an example of the first-mentioned materials. Pure aluminum, for example, has a tensile strength of approximately 45% in tensile tests, and extruded parts made from pure aluminum have a deformability of over 90% according to the prior art.
• Common wrought alloys e.g. B. AICuMg alloys have a maximum tensile strength in the tensile test in the fully hardened state of 10 to 15%. Without an upstream soft annealing, only extruded parts with a degree of deformation of approximately 30% can be produced therefrom in the direct process according to the prior art.
• the invention offers methods with which much higher degrees of deformation can be achieved, in particular starting from bodies made of aluminum or aluminum alloys with originally lowest deformation characteristics, without, for example, prior to cold extrusion. B. to be soft annealed.
• the invention is based on the knowledge that the deformability of all aluminum materials can be significantly increased by a hydrostatic compressive stress state superimposed on the stress.
• aluminum-lithium alloys can also be used, which are characterized by a particularly high strength and a particularly high modulus of elasticity. Such materials are also characterized by a low specific weight, which results in further areas of application.
• the methods according to the invention relate to blanks obtained directly from the casting and subsequently heat-treated, this is understood to mean soft annealing or heat treatment in the form of homogenization.
• the heat treatment can also consist of solution annealing with subsequent quenching and subsequent cold and / or warm delivery tion exist.
• deformation hardening is also possible.
• This deformation hardening can be achieved, for example, by extrusion, extrusion, forging and / or rolling.
• Such pretreatment methods prior to cold extrusion reduce the deformation characteristics of the aluminum materials, but nevertheless enable higher degrees of deformation when using the methods according to the invention in order to achieve increased strengths.
• the slugs are additionally annealed at 360 ° for four hours, then slowly cooled.
• the state “hardened in deformation” is applied by extrusion.
• the extruded moldings of the reference example are then solution-annealed (7 minutes at 525 ° C.), then quenched and age-hardened (10 hours at 180 ° C.) in order to achieve an increase in strength.
• bodies made of aluminum or aluminum alloys in which the body is formed from a blank formed from powder metallurgically produced material by subsequent cold extrusion.

Landscapes

• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Extrusion Of Metal (AREA)
• Forging (AREA)
• Powder Metallurgy (AREA)
• Secondary Cells (AREA)
• Glass Compositions (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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Family Applications (1)

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• 1984
  • 1984-03-19 DE DE19843410037 patent/DE3410037A1/de not_active Withdrawn
• 1985
  • 1985-02-16 EP EP85901347A patent/EP0211831B2/de not_active Expired - Lifetime
  • 1985-02-16 JP JP60501121A patent/JPS61501458A/ja active Pending
  • 1985-02-16 BR BR8505858A patent/BR8505858A/pt unknown
  • 1985-02-16 AU AU40698/85A patent/AU583816B2/en not_active Ceased
  • 1985-02-16 WO PCT/DE1985/000043 patent/WO1985004194A1/de active IP Right Grant
  • 1985-02-16 DE DE8585901347T patent/DE3566556D1/de not_active Expired
  • 1985-03-19 IT IT19950/85A patent/IT1184738B/it active
  • 1985-10-24 NO NO854266A patent/NO854266L/no unknown

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