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EP0279941A2 - Procédé et installation pour la préparation par métallurgie des poudres d'ébauches en aluminium sans soufflures et à faible teneur en hydrogène et oxyde - Google Patents

Procédé et installation pour la préparation par métallurgie des poudres d'ébauches en aluminium sans soufflures et à faible teneur en hydrogène et oxyde Download PDF

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Publication number
EP0279941A2
EP0279941A2 EP87118794A EP87118794A EP0279941A2 EP 0279941 A2 EP0279941 A2 EP 0279941A2 EP 87118794 A EP87118794 A EP 87118794A EP 87118794 A EP87118794 A EP 87118794A EP 0279941 A2 EP0279941 A2 EP 0279941A2
Authority
EP
European Patent Office
Prior art keywords
powder
gas
semi
aluminum
protective gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87118794A
Other languages
German (de)
English (en)
Other versions
EP0279941A3 (fr
Inventor
Ignaz Dipl.-Ing. Mathy
Günther Dr.-Ing. Scharf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vereinigte Aluminium Werke AG
Original Assignee
Vereinigte Aluminium Werke AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vereinigte Aluminium Werke AG filed Critical Vereinigte Aluminium Werke AG
Publication of EP0279941A2 publication Critical patent/EP0279941A2/fr
Publication of EP0279941A3 publication Critical patent/EP0279941A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0408—Light metal alloys
    • C22C1/0416—Aluminium-based alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B22F1/142—Thermal or thermo-mechanical treatment

Definitions

  • a method for powder metallurgical production by gas atomization with subsequent degassing and further processing by pressing, forging or rolling is known from US Pat. No. 4,435,213.
  • the reason for the degassing is the reduction in the oxide content in the powder.
  • the oxides can be formed in the powder at any stage of processing as soon as it comes into contact with the atmosphere. This applies to atomization as well as to the grinding and storage of the powder.
  • the moisture in the atmosphere, the morphology of the powder and the way in which the powder particles are cooled apparently play a decisive role.
  • the oxide content of the powder has a detrimental effect on further processing, in particular in the case of subsequent heat treatment, which can lead to the formation of bubbles or a porous structure.
  • the object of the present invention is to produce pressed, forged and / or rolled products based on aluminum, in particular from aluminum alloys containing magnesium and / or lithium, which have a bubble-free and low-embrittlement structure after a temperature treatment of over 400 ° C. Furthermore, to implement the method according to the invention, a device is to be developed which enables pretreatment of the aluminum alloy powders processed further by powder metallurgy within a short time and with little energy expenditure.
  • a heating jacket 1 is shown in the form of a cylindrical shell which has protective gas connections 2, 3 arranged opposite one another on the end faces for the supply and discharge of the protective gas.
  • An additional heating device 6 is shown on the inlet side for the protective gas.
  • Loose powder grains can be received in an insert 4, which can be removed through charging openings 7a, b.
  • a gap 5 is provided between the furnace casing 1 and the insert 4 and has a plurality of flow guide plates (11).
  • the protective gas flows in the direction of the arrow and takes the H2O / H2 gas from the powder.
  • the powder is heated inductively via lines 8, but can also be carried out in a flame or air oven.
  • the inflowing protective gas can be preheated via the heating device 6.
  • the constant flow of dry protective gas keeps the H2O / H2 partial pressure inside the heating jacket low. There is a partial pressure drop from the middle of the furnace to the outer surface, which favors the removal of the oxides / hydroxides.
  • the device according to the invention works particularly effectively by attaching the flow guide plates (11), which are to be explained in more detail with reference to FIG. 2.
  • the air baffles are arranged offset in the flow direction between the furnace jacket 1 and the insert 4. This creates a pulsating swirl flow which is effective right into the interior of the powder bed and causes the powder particles to oscillate.
  • the oxide / hydroxide compounds are converted into H2O / H2 gas and this is removed in gap 5.
  • the end faces of the device according to the invention have radial flow guide plates, so that a flow profile as shown in FIG. 3 takes place.
  • the flow gas connection is designated by 2 and concentric to the central axis of the insert 4. In this case, it is the inlet for the protective gas flow.
  • the outlet on the opposite side is designed analogously, the protective gas flow running in the opposite direction from the outer zone to the center.
  • the process of "atomizing” is used to produce aluminum powder, in which a melt is atomized into powder and is thereby rapidly cooled. This process can be further improved by accelerating the liquid particles in their electrical potential (electro-hydro-dynamic technology) or by superimposing ultrasonic vibrations, which leads to even finer particles that solidify correspondingly faster. It is also known to prepare atomized powder in high-energy ball mills (attritors), with the formation of alloys even at grinding temperatures of around 50 ° C. due to the intensive pressing together of the finest particles. This method is used for separately added alloy components, with short diffusion paths being achieved for the unreacted components by intimately mixing the alloy components. Both cold-compacted powder and loose powder can be used, the latter being held together in a special application.
  • the device according to the invention can also be used for heat-resistant alloy powders based on iron, nickel, titanium, zirconium, manganese, chromium, cerium and / or molybdenum, these elements being brought into a supersaturated state by gas atomization and further processing of the powder after The method according to the invention takes place.
  • the results obtained show the following tests:
  • the powder is produced by gas atomization, the melt being atomized in the usual way through a ring and then solidifying into small melt droplets.
  • the average particle size of the powder is 60 to 80 ⁇ m, which means a particularly coarse fraction compared to conventionally used powder.
  • the process parameters flow rate and treatment time are increased to 4 m / sec or 1 h.
  • This powder can be coarsened into powder agglomerates by grinding in a ball mill, the average agglomerate size of which is 500 ⁇ m. It can also be degassed directly, which is explained below.
  • the ground powder is pre-compressed to a degree of compaction of 70 to 85% at room temperature and then degassed by the process according to the invention.
  • this degassing takes place at a flow rate of 0.8 m / sec at a temperature of 450 ° C. to 500 ° C. and a residence time of 20 minutes.
  • the degree of compaction indicates the ratio of theoretically achievable density with no pores to actual density.
  • the degassed product is further processed in the heat by extrusion at temperatures of 420 to 450 ° C with a compression ratio of 25: 1. After cooling, which takes place at a cooling rate of 50 ° C / min, a bubble-free and low-embrittlement structure is obtained, the magnesium or lithium content having decreased only slightly.
  • This is a particular advantage of the method according to the invention, which enables the alloy composition to be kept constant, particularly in the production of high-strength aluminum and / or lithium-containing aluminum alloys. In the high-alloy AlFeNi alloys, there is no coarsening of the intermetallic phases, for example due to "Oswald ripening".
  • the bathroom has the following composition:
  • the bath has a temperature of 90 ° C, the treatment time is 1 minute.
  • the sample to be examined is degassed in a high vacuum at a temperature below the solidus point.
  • the gases emerging from the sample by diffusion are collected.
  • the end of the diffusion process and the amount of gas released are determined by pressure measurements.
  • a subsequent analysis shows the percentage composition of the gas.
  • each sample In order to obtain the blank value, each sample must be subjected to a second hot extraction after the measurement and a further surface treatment.
  • the gas content of the metal results from the measured value minus the blank value.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
EP87118794A 1987-02-25 1987-12-18 Procédé et installation pour la préparation par métallurgie des poudres d'ébauches en aluminium sans soufflures et à faible teneur en hydrogène et oxyde Withdrawn EP0279941A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19873705976 DE3705976A1 (de) 1987-02-25 1987-02-25 Verfahren und vorrichtung zur pulvermetallurgischen herstellung von blasenfreiem, wasserstoff- und oxidarmen aluminiumhalbzeug
DE3705976 1987-02-25

Publications (2)

Publication Number Publication Date
EP0279941A2 true EP0279941A2 (fr) 1988-08-31
EP0279941A3 EP0279941A3 (fr) 1990-02-07

Family

ID=6321699

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87118794A Withdrawn EP0279941A3 (fr) 1987-02-25 1987-12-18 Procédé et installation pour la préparation par métallurgie des poudres d'ébauches en aluminium sans soufflures et à faible teneur en hydrogène et oxyde

Country Status (2)

Country Link
EP (1) EP0279941A3 (fr)
DE (1) DE3705976A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992019781A1 (fr) * 1991-04-29 1992-11-12 Allied-Signal Inc. Procede d'amelioration par degazage de la resilience de zirconium obtenu par la voie de la metallurgie des poudres et contenant des alliages aluminium-lithium
RU2184011C2 (ru) * 2000-04-19 2002-06-27 Государственное предприятие Всероссийский научно-исследовательский институт авиационных материалов Способ получения полуфабрикатов из титановых сплавов с интерметаллидным упрочнением

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE523356A (fr) *
CH291569A (de) * 1949-02-02 1953-06-30 Siepmann Heinrich Ing Dr Verfahren zur Behandlung von metallhaltigem Pulver und Vorrichtung zur Durchführung des Verfahrens.
US4104061A (en) * 1976-10-21 1978-08-01 Kaiser Aluminum & Chemical Corporation Powder metallurgy
US4435213A (en) * 1982-09-13 1984-03-06 Aluminum Company Of America Method for producing aluminum powder alloy products having improved strength properties
US4615735A (en) * 1984-09-18 1986-10-07 Kaiser Aluminum & Chemical Corporation Isostatic compression technique for powder metallurgy

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992019781A1 (fr) * 1991-04-29 1992-11-12 Allied-Signal Inc. Procede d'amelioration par degazage de la resilience de zirconium obtenu par la voie de la metallurgie des poudres et contenant des alliages aluminium-lithium
RU2184011C2 (ru) * 2000-04-19 2002-06-27 Государственное предприятие Всероссийский научно-исследовательский институт авиационных материалов Способ получения полуфабрикатов из титановых сплавов с интерметаллидным упрочнением

Also Published As

Publication number Publication date
EP0279941A3 (fr) 1990-02-07
DE3705976A1 (de) 1988-09-08

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