EP0931607B1 - Procédé pour préparer un tronçon de mètal à l'état pâteux - Google Patents

Procédé pour préparer un tronçon de mètal à l'état pâteux Download PDF

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Publication number
EP0931607B1
EP0931607B1 EP97122594A EP97122594A EP0931607B1 EP 0931607 B1 EP0931607 B1 EP 0931607B1 EP 97122594 A EP97122594 A EP 97122594A EP 97122594 A EP97122594 A EP 97122594A EP 0931607 B1 EP0931607 B1 EP 0931607B1
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EP
European Patent Office
Prior art keywords
metal
slurry
semi
melted metal
melted
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EP97122594A
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German (de)
English (en)
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EP0931607A1 (fr
Inventor
Shunzo Aoyama
Chi Liu
Toshiyuki Sakazawa
Ye Pan
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Ahresty Corp
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Ahresty Corp
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Priority to DE69738657T priority Critical patent/DE69738657T2/de
Priority to EP97122594A priority patent/EP0931607B1/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/007—Semi-solid pressure die casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • 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
    • C22C1/12—Making non-ferrous alloys by processing in a semi-solid state, e.g. holding the alloy in the solid-liquid phase

Definitions

  • the present invention relates to rheocasting and thixocasting in mushy/semi-solid state of metals using high pressure part making machines.
  • high pressure part making machine is simply referred to as “part making machine”.
  • rheocasting is a process of producing a shaped part, comprising cooling a melted metal to a temperature range in which solids and liquids can be present concurrently, and charging the resultant metal slurry into the shot sleeve/prechamber of a part making machine.
  • Thixocasting is a process of producing a shaped part, comprising reheating a solid metal slug to a temperature range in which solids and liquids are concurrently present, and charging the resultant metal slurry into the shot sleeve/prechamber of a part making machine.
  • the metal slurry to be used in the semi-solid process is in a state that the primary crystals are separately distributed throughout in a liquid matrix, and the primary crystal particles are as fine as possible and as uniformly non-dendritic as possible, preferably spherical.
  • the metal slurry can be processed while being kept in a semi-solid state with a low viscosity and with a high fraction solid, whereby the shrinkage cavity/porosity in the resultant parts can be effectively decreased and the mechanical properties of the parts can be enhanced.
  • the quality of the resultant parts is not stable, disadvantageously.
  • the semi-solid metal slurry is easily attached and then deposited on a slurry discharge outlet, and therefore, the operation of the opening and closing valve of the slurry discharge outlet immediately fails.
  • the stable supply of the semi-solid metal slurry is difficult, and the shape deformation of the resultant semi-solid metal slurry via gravitative attraction is poorer than the deformation of its liquid substance, so that it is difficult to charge the semi-solid metal slurry into the shot sleeve/prechamber of a part making machine. Additionally, the shape is unstable.
  • the charging of the semi-solid metal slurry in its entirety is very difficult, involving difficulty in feeding stably the semi-solid metal slurry into the shot sleeve/prechamber of a part making machine.
  • the temperature control until the semi-solid metal slurry prepared in a rheomaker is charged into the shot sleeve/prechamber of a part making machine is difficult, disadvantageously.
  • the present inventors have found a method to granulate the primary crystal based on some fundamental experiments. Consequently, the inventors have theoretically elucidated the process of preparing a semi-solid metal slurry and the conditions therefor, which have been determined empirically up to now. Consequently, the inventors have found a process suitable for supplying a semi-solid metal slurry and the conditions therefor. Thus, a process of semi-solid slurry making which can be practiced industrially at a large scale has been developed. The present invention has a meaning at that point.
  • EP0745694 discloses the ability to cool a slug of molten metal in a container but the slug is removed from the container prior to being placed into a part making machine.
  • the slug of metal is cooled into a solid billet in the container rather than being passed into a forming machine.
  • a method of preparing a shot of semi-solid metal slurry including feeding it to a part making machine comprising providing a pre-determined amount of metal in a liquid state into a slurry preparing container of a volume to receive the said shot and of a material with the same matrix as the slurry and the slurry preparing container imparting the semi-solid metal slurry with a shape to e kept almost unchanged during being transferred, applying a motion after or when the pre-determined amount of metal in a liquid state pours into the tubular slurry preparing container, cooling the melted metal to a semi-solid metal slurry state thereafter, transferring the semi-solid metal slurry into the shot sleeve/prechamber of a part making machine and feeding the semi-solid metal slurry integrally along with the container into the shot sleeve/prcchamber, and making a casting in which the tubular slurry preparing container integrates with a biscuit of the made part.
  • the semi-solid metal making of the present invention which can achieve the object described above, is characterized that an amount of a metal to be prepared into a slurry is determined in its liquid state, and the determined melted metal is thereafter cooled in a slurry preparing container to prepare the metal as a metal slurry in a semi-solid state, while concurrently making preliminarily the semi-solid metal slurry in the slurry preparing container into a shape which can be charged as it is into the shot sleeve/prechamber of a part making machine, and charging the metal slurry into the shot sleeve/prechamber of the part making machine and processing the metal slurry therein in the semi-solid state while the slurry nearly keeping its shape.
  • a motion is applied through a mechanical or physical means to the melted metal, in the course of cooling and when at least a part of the melted metal is lowered at a temperature below the liquidus temperature. And thereafter, the melted metal is cooled and thereby becomes a semi-solid state.
  • a motion is applied to the melted metal while at least a part of the melted metal is at a temperature below the liquidus temperature; or by pouring the melted metal into a slurry preparing container when at least a part of the melted metal is at a temperature below the liquidus temperature, such motion is applied to the melted metal; or by applying supersonic vibration to the melted metal placed in the slurry preparing container directly or from the outside wall of the slurry preparing container, such motion is applied to the melted metal.
  • the slurry preparing container to be used in the present invention plural containers are used, each of a tubular shape with a bottom and with its top being opened, whose shape can be divided into halves, and slurry preparing containers are satisfactorily fed into the shot sleeve/prechamber of a part making machine one by one so that the individual slurry preparing container might reach the charge inlet of the shot sleeve/prechamber of the part making machine, just in time when the semi-solid metal slurry prepared in the slurry preparing container attains a predetermined fraction solid.
  • the slurry preparing container is satisfactorily made into a tubular shape with a bottom or into a tubular shape, comprising a thin metal plate, which is then charged integrally with the semi-solid metal slurry into the shot sleeve/prechamber of the part making machine.
  • time just at a temperature below the liquidus temperature means the time when the temperature of melted metal passes through the liquidus temperature for the first time.
  • the melted metal shows a phenomenon called as undercooling that the temperature is lowered slightly below the liquidus temperature and then is increased back to the liquidus temperature.
  • the phenomenon occurs when a large quantity of nuclei for the primary crystal of the melted metal generate instantly below the liquidus temperature because that release of latent heat due to solidification then heats the metal, so that the temperature is increased.
  • the present inventors have found that no undercooling phenomenon occurs if an appropriate motion is applied to the melted metal around the liquidus temperature. And then, the inventors have found that by gradually cooling the melted metal starting from the state with no occurrence of the undercooling phenomenon, the metal microstructure is in a granular crystal form in stead of dendritic morphology.
  • the melted metal to which the present invention is applicable includes metals such as aluminium and the alloys thereof, or magnesium alloys, zinc alloys, copper or the alloys thereof, iron alloys or the like.
  • An amount of a metal to be prepared is determined in its liquid state, and thereafter, the melted metal is cooled in a slurry preparing container, to prepare the metal as a semi-solid metal slurry. Then, a motion is applied to the melted metal within a temperature range predetermined correspondingly to each melted metal, more specifically when at least a past of each melted metal reaches a temperature below the liquidus temperature in the course of cooling of the melted metal, and then by cooling the melted metal at a predetermined rate, a metal slurry in a semi-solid state can be prepared.
  • a ratio of a part of the melted metal placed in the container at a temperature below the liquidus temperature is preferably larger.
  • a motion is applied to the melted metal placed in the container below the liquidus temperature and with a temperature distribution as uniform as possible.
  • the cooling rate is preferably slowed down to make the temperature distribution in the melted metal as uniform as possible.
  • any mechanical or physical means may be possible. More specifically, the following methods are possible; 1. a method for applying a motion to the melted metal, comprising pouring the melted metal drawn up from a reservoir furnace into a slurry preparing container; 2. a method for applying a motion to the melted metal, comprising placing a given amount [for example, an amount required for one shot] of the melted metal in a slurry preparing container and vibrating mechanically the slurry preparing container to apply a motion to the melted metal therein; 3.
  • a method for applying a motion to the melted metal comprising giving supersonic vibration to the melted metal in the slurry preparing container, directly or from the outside wall of the slurry preparing container; 4. a method for applying a motion to the melted metal, comprising stirring the melted metal in the slurry preparing container by using a high frequency induction stirring apparatus; 5. a method for applying a motion to the melted metal, comprising mechanically stirring the melted metal placed in the slurry preparing container with a stirring bar or a stirring vane or the like; 6.a method for applying a motion to the melted metal, comprising magnetically stirring the melted metal placed in the slurry preparing container; 7.
  • a method for applying a motion to the melted metal comprising blowing inert gas and the like into the melted metal placed in the slurry preparing container; or 8. a method for applying a motion to the melted metal, comprising inducing explosion in the melted metal placed in the slurry preparing container; or the like.
  • the melted metal When a motion is applied to the melted metal by pouring the melted metal into the slurry preparing container, the melted metal is drawn up with a drawing vessel such as ladle or melt metal reservoir, subsequently cooled to a predetermined temperature, and is then poured into the slurry preparing container.
  • a drawing vessel such as ladle or melt metal reservoir
  • the melted metal is poured into the slurry preparing container,at least a part of the melted metal is satisfactorily at a temperature below the liquidus temperature.
  • any one of the methods 1 to 8 may be adopted satisfactorily. However, a combination of two or more of these methods may be adopted, satisfactorily, and by an appropriately selected combination of the aforementioned methods depending on the structure elements of a semi-solid metal slurry making system, a motion can be applied to the melted metal, effectively.
  • the melted metal is cooled at an appropriate cooling rate in the slurry preparing container. If the cooling rate of the melted metal is too quick, the temperature un-uniform is induced in the metal slurry, so that the fraction solid of the resultant metal slurry is also un-uniform. If the metal slurry is used to produce a part the slurry flow is disordered during filling due to the difference in the fluidity, thus inducing air wrapping, or defects due to shrinkage easily occur because of the difference of the fraction solid. Therefore, preferably, the cooling rate of the melted metal is slow.
  • the melted metal is cooled at a cooling rate of 3 °C/sec or less, preferably 0.4 °C/sec or less.
  • the primary crystal can grow spherically, and almost uniformly granulated primary crystals can be obtained in a stable fashion.
  • the duration in which the semi-solid metal slurry is within the most appropriate temperature range for rheocasting can be prolonged.
  • the time when the semi-solid metal slurry prepared in the slurry preparing container is fed to the shot sleeve/prechamber of a part making machine can be adjusted readily to accommodate to the making cycle of the part making machine.
  • a semi-solid metal slurry with an almost constant fraction solid can be fed to the shot sleeve/prechamber of the part making machine.
  • the slurry preparing container in accordance with the present invention is preferably made into a structure with an approximate volume enough to place the amount of a melted metal for one shot, and with such a shape and a structure that the semi-solid metal slurry prepared therein can be readily charged into the shot sleeve/prechamber of a part making machine while the shape is approximately kept as it is.
  • slurry preparing container 1 shown in Fig. 1 is made, by vertically arranging member 11 of a block structure in halves along the axis direction and linking (the halves of) the member together by means of hinge 12 in such a manner that the member can be divided and opened and closed in the left and right direction. Then, the inner diameter is formed to be slightly smaller than charge inlet "a1" of shot sleeve/prechamber "a" of a part making machine.
  • slurry preparing container 1 as shown in Fig. 2 is made, by arranging along the horizontal direction two members 11' of a divided structure and linking the members along the left and right direction so that the members can be divided and opened and closed.
  • the inner shape is formed to be slightly smaller than the charge inlet "a1" at the shot sleeve/prechamber "a” of a part making machine.
  • the slurry preparing container 1 as the former can readily accommodate to a part making machine of a longitudinal injection type where shot sleeve/prechamber "a” is arranged vertically; the latter slurry preparing container 1 can easily accommodate to a part making machine of a crosswise injection type where shot sleeve/prechamber "a” is arranged along the horizontal direction.
  • a fine ceramic material such as silicon nitride,SIALON,alumina magnesia,which does not react on the melted metal, is coated preferably.
  • the melted metal is not dirtied due to the reaction of the slurry preparing container and the melted metal.
  • a solid lubricant such as graphite is coated or a powdery thermal insulation agent is coated in a dried powder state, preferably.
  • the melted metal fed into the slurry preparing container will not be attached on the face of the inner periphery, and thus, the semi-solid metal slurry prepared in the slurry preparing container can be readily dissociated and discharged; concurrently, the cooling rate of the melted metal placed in the slurry preparing container is slowed down to promote the uniformity of the temperature.
  • the slurry preparing container is made into a tubular shape with a bottom and with the upper top being opened, having a given size (volume), through deep drawing process using a thin metal plate or through impact shaping, or the slurry preparing container is formed into an appropriate length by using a metal pipe while the bottom part is freely opening and closing. And then, the resultant slurry preparing container is charged together with the semi-solid metal slurry prepared therein into the shot sleeve/prechamber of a part making machine.
  • the melted metal may satisfactorily be poured into the metal sheet at a horizontal state.
  • the slurry preparing container is formed from a metal material with a higher melting point than that of the melted metal placed therein (more specifically, if the melted metal is an aluminum alloy, for example, the container is formed from a steel material). Otherwise, the container is formed from a metal material of the same matrix as the melted metal placed therein.
  • the slurry preparing container is formed from a metal material with a higher melting point than that of the melted metal placed therein, the slurry preparing container itself is absolutely never melted in contact to the melted metal even if the container is formed from a plate material of a thin thickness. If the slurry preparing container is formed from a metal material of the same matrix as the melted metal, the semi-solid metal slurry prepared in the slurry preparing container is fed into the shot sleeve/prechamber of a part making machine, integrally together with the slurry preparing container, and the slurry preparing container integrated with the gate and biscuit of a made part can be remelted without any special treatment. Additionally, the composition variation due to reuse of the scrap can be reduced less, and therefore the scrap can be recycled readily.
  • holder 13 So as to easily discharge the semi-solid metal slurry prepared in the slurry preparing container together with the slurry preparing container, holder 13 to support the slurry preparing container 1 as shown in Fig. 3 is used,
  • the bottom part of the holder 13 may be structured in a free motion of opening and closing with an opening and closing lid, or the holder 13 may be divided into two or more parts, which can be opened and closed.
  • tubular part 13' composing the holder 13 is formed in a manner that the part is divided into two along the axis direction to be opened and closed, and additionally, bottom plate 13'' thereof is of such a structure that the plate can be separated from the tubular part 13' and can be opened and closed.
  • the semi-solid metal slurry prepared in the slurry preparing container may be drawn out from the slurry preparing container and be then fed into the shot sleeve/prechamber of a part making machine, or the slurry together with the slurry preparing container may be fed into the shot sleeve/prechamber of a part making machine.
  • the semi-solid metal slurry is made in a form, for example, tubular shape or bullet shape, and the slurry with the slurry preparing container can be fed into the shot sleeve/prechamber of a part making machine while the slurry keeps its shape, whereby a part can be made.
  • the semi-solid metal slurry "M2" may satisfactorily be charged then from charge inlet "a1" into the shot sleeve/prechamber "a".
  • the slurry may satisfactorily be fed into the shot sleeve/prechamber "a” from the divided face (parting surface)of a mold, particularly when a part making machine of a crosswise injection type is used.
  • conventional shot sleeve can be used without any changeing.
  • the fraction solid of the semi-solid metal slurry "M2" is preferably controlled in a range from 0.3 to 0.8. If the fraction solid is not more than 0.3, the metal slurry has a lower viscosity so that the flow of the slurry is disordered when the slurry is filled under pressure into a mold cavity, readily involving air wrapping, whereby the solidification shrinkage thereof is increased to easily develop a shrinkage defect in the made part. If the fraction solid is above 0.8, unpreferably, the metal slurry has a too high viscosity so that the fluidity is significantly lowered to cause difficulty in entirely filling the semi-solid metal slurry "M2" into the mold cavity.
  • the reservoir furnace “2” is structured, by placing and arranging graphite crucible “22" in electric furnace “21” well known, and connecting melted metal launder “24” equipped with heater “23” in communication with the graphite crucible "22". And the furnace “2" functions in such a manner that control rod "25” is immersed into the melted metal "M0” to freely control the feeding amount of the melted metal M0 on the basis of the immersed level of the control rod "25".
  • the cooling device “3” functions to apply a motion to the melted metal "M0", while cooling at least a part thereof at a temperature below the liquidus temperature through the flow of the melted metal "M0" poured from the melted metal launder "24" in the reservoir furnace "2".
  • the cooling device “3” is formed into a plane shape or a trough shape (a tubular shape divided in halves along the axis direction) with smooth surface, or a pipe shape (tubular shape with a circle or a rectangle), by using a material of a copper plate coated by a material difficult to resolve or melt.
  • cooling device "3" is arranged downward in a sloping manner, immediately below the port "24'" of the melted metal launder”24" in the reservoir furnace "2", in order that the melted metal "M0" can spontaneously flow down, and the surface thereof (face on which the melted metal "M0" is poured and then flow) is slope face "31".
  • the surface temperature of the slope face "31", to which the melted metal "M0" fed from the reservoir furnace "2" is in contact should be controlled appropriately at a constant temperature, for example by providing cooling pipe (cooling system) "32" to circulate the cooling water to the cooling device "3".
  • cooling pipe cooling system
  • some structure of the cooling device "3" can be designed to eliminated the cooling system.
  • the cooling device "3" is provided with one slope face "31", satisfactorily, but the cooling device “3” is provided with plural slope faces "31", so that a given amount, for example an amount required for one shot of the melted metal is poured on one slope face and then the slope face is removed thereon, and subsequently, the next slope face is transferred to the pouring position so as to be used for next pouring, whereby the making cycle can be promoted.
  • a given amount for example an amount required for one shot of the melted metal is poured on one slope face and then the slope face is removed thereon, and subsequently, the next slope face is transferred to the pouring position so as to be used for next pouring, whereby the making cycle can be promoted.
  • one rotation axis "33” is horizontally arranged through bearing "34", and plural slope faces "31", “31”, ---, formed in a plane shape, a trough shape, or a pipe shape, through frame “35” are radially arranged on the tip of the rotation axis "33", and concurrently, the slope faces "31", “31”, --- are arranged in a slanting manner toward the core of the axis of the rotation axis "33”, to structure the each slope faces "31", "31", --- in a free rotation fashion around the rotation axis "33” as the center.
  • no specific cooling system is needed to cool the individual slope face; and the plural slope faces 31, 31,can be arranged in a narrow space.
  • Feeding means "5" to feed semi-solid metal slurry "M2" prepared in the slurry preparing container "1" into the shot sleeve/prechamber "a" of a part making machine possibly includes those of various mechanisms and structures, but in this example, a well-known robot hand is used.
  • slurry preparing container "1" For practical production, one slurry preparing container “1" is satisfactorily used, but for efficient production, a plural slurry preparing containers 1, 1, ---, are preferably used. Then, slurry preparing containers 1,1,---are serially transferred to the side of a part making machine, so the semi-solid metal slurry "M2" might be fed into the shot sleeve/prechamber "a" of the part making machine just when the melted metal "M1" in the slurry preparing container is at a given fraction solid.
  • a rotation table as transfer means "6" capable of horizontal rotation is mounted between the cooling device “3” and the feeding means (robot hand) "5", and plural thermostat containers as the temperature control means "4" in a concentric manner are arranged on the transfer means (rotation table) "6". Then, after arranging the slurry preparing container “1" in the temperature control means (thermostat container) "4" to preliminarily heat the inside of the slurry preparing container around the temperature of the melted metal "M1", a given amount (for example, an amount required for one shot) of the melted metal "M1" is fed through the cooling device "3" into the slurry preparing container "1".
  • the semi-solid metal slurry "M2" charged in the shot sleeve/prechamber a is filled under pressure through pressure piston "b" into cavity “d” of mold "c", in the same manner as carried out conventionally, to be made therein into a part.
  • Example wherein a motion is applied to a melted metal placed in a slurry preparing container by giving supersonic vibration from the outside wall of the slurry preparing container;
  • AC4C a JIS standard of cast aluminum alloys.
  • the liquidus temperature of "AC4C” is about 610 °C.
  • the melted metal of "AC4C” is poured into an iron-made slurry preparing container which was structured in a tubular shape with a diameter of 63 mm and a height of 100 mm, and when the temperature of the melted metal at the center of the slurry preparing container reached a given temperature (635 °C to 595 °C), a supersonic vibrator is put in contact with the exterior of the slurry preparing container for 10 seconds, for vibrating the container, whereby a motion was applied to the melted metal therein.
  • Fig. 7 represents the time for applying supersonic vibration, on a graph depicting the temperature change with time of the melted metal placed in the slurry preparing container, when a motion is to be applied to the melted metal by giving supersonic vibration to the outside wall of the slurry preparing container.
  • Figs.9 to 11 depict microscopic photographs of metal microstructure after 20-sec supersonic vibration, 5-sec supersonic vibration and no applying of supersonic vibration, at the temperature of the V4(620°C).
  • the metal microstructure is modified under applying of supersonic vibration when the temperature of the center of the melted metal placed in the slurry preparing container reaches about 630 °C (629 °C at the time of initiation of supersonic vibration and 615 °C at the time of termination).
  • each part of the melted metal in the slurry preparing container are at different temperatures, such as about 630 °C at the center of the melted metal, despite of about 620 °C at the bottom part (620 °C at the time of initiation of supersonic vibration and 608 °C at the termination of supersonic vibration) below the liquidus temperature (610 °C).
  • a wholly well granulated microstructure was obtained when supersonic vibration was applied at 620 °C to 610 °C at the center. In this case, any part (center, peripheral part of the center, upper part and bottom part) is at a temperature below the liquidus temperature.
  • Example wherein a motion is applied on a melted metal placed in a slurry preparing container by mechanically stirring the melted metal;
  • Example 2 the same melted metal (AC4C) as in Example 1 was poured into a thermal insulation container formed in an approximately tubular shape of a diameter of 63 mm and a height of 100 mm, to examine (a) a case wherein the melted metal was mechanically stirred with a ceramics stirring rod by hands when the melted metal was at a temperature between 620 °C to 611 °C (for 39 seconds) and (b) a case wherein the melted metal was similarly stirred when the melted metal reached the liquidus temperature.
  • the metals were charged into water and were rapidly cooled therein. The metal microstructure was observed. Microscopic photographs of the resultant metal microstructure are shown in Fig. 13 .
  • the shape of the primary crystal was a fully developed dendritic shape when the melted metal was at a temperature between 620 °C to 611 °C.
  • the shape of the primary crystal was in complete granulation when stirring was carried out at the liquidus temperature.
  • the temperature change of the melted metal at the center of the slurry preparing container with time is shown in Fig. 14 .
  • a thermal insulation material was used for the slurry preparing container, and the cooling rate of the melted metal in the slurry preparing container was substantially slow, compared with the previous Example. It is therefore suggested that the temperature distribution in the melted metal is more uniform. Practically, the melted metal was at the liquidus temperature at the termination of the stirring (10 seconds after the liquidus temperature was reached), which possibly indicates that the temperature of the whole melted metal was almost uniform. Under the conditions described in (a), a dendritic structure was formed because any part in the slurry preparing container was not below the liquidus temperature.
  • the time for applying a motion to the melted metal is preferably the time when at least a part of the melted metal in the course of cooling is at the liquidus temperature or below the temperature (within a range of 620 °C to 610 °C in the present Example), and the (duration) extent of the motion applied is about 10 seconds of supersonic vibration or about 10 seconds of mechanical stirring. Consequently, the entirely granulated metal slurry with no dendritic structure is obtained.
  • a slurry preparing container use was made of a tube of an inner diameter of 63 mm and a height of 100 mm, being made of a thermal insulation material, where an iron block kept at 200 °C was arranged on the bottom.
  • Fig. 16 shows cooling curves at different positions (temperature change of melted metal vs. time).
  • the cooling rate was decreased at a longer distance (d) from the bottom of the melted metal. It is elucidated that the growth of the primary crystal occurs within a range from the liquidus temperature to the temperature at which the solidification of the eutectic mixture initiates. Thus, the average cooling rate was calculated within the range from the liquidus temperature to the temperature at which the solidification of the eutectic mixture was initiated, which was then plotted with the distance (d) from the bottom of the melted metal on a graph as shown in Fig. 17 .
  • the graph can be divided into 4 regions, depending on the shape of the primary crystal. More specifically, (I) represents a region of cooling rate (CR > 2.75 °C/sec) for forming a fine dendritic structure ; (II) represents a region of cooling rate (2.75 °C > CR > 0.4 °C/sec) for forming a transition region of the dendritic structure into a granular structure; (III) represents a region of cooling rate (CR ⁇ 0.4 °C/sec) for forming the granular structure; and (IV) represents a region of cooling rate for forming an enlarged dendritic structure.
  • the primary crystal structure with the dendritic morphology, prepared in the regions (I) and (II), was granulated under reheating within a range of semi-solid temperature, to prepare a granular structure of the same size as that of the metal microstructure prepared in the region (III).
  • Example 2 the same melted metal (AC4C) as in Example 1 was used and (a) poured into a thermal insulation container formed in an approximately tubular shape with a diameter of 63 mm and a height of 100 mm, thereby applying a motion to the melted metal, and (b) by stirring then the melted metal with a high frequency induction stirring system for 10 seconds, a motion was applied to the melted metal. Thereafter, when the melted metal reached 585 °C, the melted metal was charged into water for rapid cooling, to observe the metal microstructure in the center and superficial layer region, respectively. The metal microstructure thus obtained is shown in Fig. 18 .
  • the primary crystal was granulated in the metal microstructure at the center, while the metal microstructure in the superficial layer was in a dendritic shape, with no stirring with the high frequency induction stirring system, and while the microstructure was in granulation up to the superficial layer stirred with the high frequency induction stirring system.
  • the reason why the dendritic shape was formed without the high frequency induction stirring is that the slurry preparing container was heated during pouring of the melted metal, so that the temperature of the melted metal during the final pouring would not decrease less than the liquidus temperature of the melted metal. It was whereby assumed that a motion (pouring motion) was applied to the melted metal in the superficial layer region at a state of a temperature higher than the liquidus temperature and then, the structure in this region was prepared into a dendritic morphology. This is apparently shown in that the melted metal was granulated by pouring the metal into the slurry preparing container and further stirring the metal with the high frequency induction stirring system, thereby applying motions to the metal. It is apparently shown that the melted metal was granulated when the melted metal in the superficial layer was applied with a motion when the metal reached a temperature below the liquidus temperature, so that the microstructure of the melted metal was granulated.
  • a metal slurry of the primary non-dendritic (granulated) crystal particles being fine and almost uniform can be fed in a stable manner into a part making machine, to make a shaped part with high quality in a stable fashion, without specific need of complicated equipment.
  • an amount of a melted metal can be determined in its liquid state, and by cooling the melted metal thereafter in a slurry preparing container, a metal slurry in a semi-solid state can be prepared.
  • the resultant metal slurry at a high fraction solid, as it is as prepared in the slurry preparing container, can be fed into the shot sleeve/prechamber of a part making machine, with no transfer of the slurry into another container, so that the following disadvantages with a conventional method by a rheomaker can be almost eliminated; the sharply cutting of the semi-solid metal slurry is difficult, including the difficulty in the determination of the amount of the semi-solid slurry thereof; the semi-solid metal slurry is attached and is deposited on the slurry discharge outlet of the rheomaker, to immediately cause poor operations of the opening and closing valve; the prepared semi-solid metal slurry has such an inconstant shape that the charging thereof into the shot sleeve/prechamber of a part making machine is

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Claims (6)

  1. Procédé pour préparer un tronçon de bouillie métallique semi-solide, incluant l'action consistant à l'acheminer à une machine de fabrication de pièces, comprenant l'alimentation d'une quantité prédéterminée de métal à l'état liquide dans un contenant tubulaire (1) à préparation de bouillie ayant un volume lui permettant de recevoir ledit tronçon, et fabriqué en un matériau ayant la même matrice que la bouillie et le contenant à préparation de bouillie conférant à la bouillie métallique semi-solide une forme destinée à rester quasi-inchangée au cours de son transfert, l'application d'un mouvement après ou bien au moment où la quantité prédéterminée de métal à l'état liquide coule dans le contenant à préparation de bouillie, le refroidissement du métal fondu jusqu'à un état de bouillie métallique semi-solide à un stade ultérieur, le transfert de la bouillie métallique semi-solide dans la gaine/la préchambre à tronçons (a) d'une machine de fabrication de pièces et l'alimentation intégrale de la bouillie métallique semi-solide en conjonction avec le contenant en vue d'un acheminement dans la gaine/la préchambre à tronçons (a), et la fabrication d'une pièce coulée dans laquelle le contenant tubulaire à préparation de bouillie s'intègre à une galette de la pièce ainsi fabriquée.
  2. Procédé selon la revendication 1, le mouvement exercé sur le métal fondu étant fourni par des moyens mécaniques ou physiques.
  3. Procédé selon la revendication 2, le mouvement étant fourni grâce à l'agitation du métal fondu, ou suite à l'application de vibrations ultrasoniques ou d'une induction à haute fréquence.
  4. Procédé selon l'une quelconque des revendications précédentes, le tronçon de métal fondu étant refroidi dans le contenant à préparation de bouillie à une vitesse de refroidissement de 3°C/seconde ou une vitesse inférieure.
  5. Procédé selon l'une quelconque des revendications 1 à 4, le contenant à préparation de bouillie étant de forme tubulaire et ayant une partie supérieure ouverte et une partie inférieure fermée.
  6. Procédé selon l'une quelconque des revendications précédentes, des tronçons similaires de métal étant traités dans des contenants à préparation de bouillie respectifs, et étant amenés de façon séquentielle dans la gaine/la préchambre à tronçons lorsque le tronçon a atteint un état semi-solide prédéterminé.
EP97122594A 1997-12-20 1997-12-20 Procédé pour préparer un tronçon de mètal à l'état pâteux Expired - Lifetime EP0931607B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE69738657T DE69738657T2 (de) 1997-12-20 1997-12-20 Verfahren zur Bereitstellung eines Schusses aus breiartigem Metall
EP97122594A EP0931607B1 (fr) 1997-12-20 1997-12-20 Procédé pour préparer un tronçon de mètal à l'état pâteux

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP97122594A EP0931607B1 (fr) 1997-12-20 1997-12-20 Procédé pour préparer un tronçon de mètal à l'état pâteux

Publications (2)

Publication Number Publication Date
EP0931607A1 EP0931607A1 (fr) 1999-07-28
EP0931607B1 true EP0931607B1 (fr) 2008-04-30

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EP97122594A Expired - Lifetime EP0931607B1 (fr) 1997-12-20 1997-12-20 Procédé pour préparer un tronçon de mètal à l'état pâteux

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EP (1) EP0931607B1 (fr)
DE (1) DE69738657T2 (fr)

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US9382598B2 (en) 2010-04-09 2016-07-05 Southwire Company, Llc Ultrasonic device with integrated gas delivery system
US9528167B2 (en) 2013-11-18 2016-12-27 Southwire Company, Llc Ultrasonic probes with gas outlets for degassing of molten metals

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JP4195767B2 (ja) * 2000-03-08 2008-12-10 徹一 茂木 鋳造方法、鋳造設備、金属素材の製造方法および金属素材の製造装置
US6399017B1 (en) * 2000-06-01 2002-06-04 Aemp Corporation Method and apparatus for containing and ejecting a thixotropic metal slurry
EP1358956A1 (fr) * 2002-04-24 2003-11-05 Alcan Technology & Management Ltd. Procédé de traitement d'un alliage métallique pour l'obtention d'un article semi solide
WO2004070068A1 (fr) * 2003-02-10 2004-08-19 Csir Procede et appareil pour le traitement d'alliage de metaux semi-solides
KR100534568B1 (ko) * 2003-12-30 2005-12-08 한 중 이 반응고 금속 슬러리 제조방법 및 장치
ATE539823T1 (de) 2008-03-05 2012-01-15 Southwire Co Ultraschallsonde mit schutzschicht aus niobium
PL2556176T3 (pl) 2010-04-09 2020-08-24 Southwire Company, Llc Ultradźwiękowe odgazowywanie stopionych metali
ES2632181T3 (es) * 2011-06-16 2017-09-11 Cie Automotive, S.A. Dispositivo y procedimiento de obtención de lodos semisólidos
RU2590432C2 (ru) * 2014-11-18 2016-07-10 Российская Федерация от имени которой выступает Министерство промышленности и торговли Российской Федерации Способ и устройство для изготовления тиксозаготовок
BR112017016985B1 (pt) 2015-02-09 2022-01-04 Hans Tech, Llc Dispositivo de processamento de metal fundido, e, método para formar um produto de metal
US10233515B1 (en) 2015-08-14 2019-03-19 Southwire Company, Llc Metal treatment station for use with ultrasonic degassing system
RU2020124617A (ru) 2015-09-10 2020-08-04 САУТУАЙР КОМПАНИ, ЭлЭлСи Способы и системы для ультразвукового измельчения зерна и дегазации при литье металла
CN107186181A (zh) * 2017-05-23 2017-09-22 广东工业大学 一种制备半固态浆料的装置及方法

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NO950843L (no) * 1994-09-09 1996-03-11 Ube Industries Fremgangsmåte for behandling av metall i halvfast tilstand og fremgangsmåte for stöping av metallbarrer til bruk i denne fremgangsmåte
JP3474017B2 (ja) * 1994-12-28 2003-12-08 株式会社アーレスティ 鋳造用金属スラリーの製造方法
CA2177455C (fr) * 1995-05-29 2007-07-03 Mitsuru Adachi Methode et dispositif pour le faconnage de metaux a l'etat semi-solide

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9382598B2 (en) 2010-04-09 2016-07-05 Southwire Company, Llc Ultrasonic device with integrated gas delivery system
US9528167B2 (en) 2013-11-18 2016-12-27 Southwire Company, Llc Ultrasonic probes with gas outlets for degassing of molten metals

Also Published As

Publication number Publication date
EP0931607A1 (fr) 1999-07-28
DE69738657T2 (de) 2009-06-04
DE69738657D1 (de) 2008-06-12

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