WO1997012709A1 - A method and device for the thixotropic casting of metal alloy products - Google Patents
A method and device for the thixotropic casting of metal alloy products Download PDFInfo
- Publication number
- WO1997012709A1 WO1997012709A1 PCT/IT1996/000183 IT9600183W WO9712709A1 WO 1997012709 A1 WO1997012709 A1 WO 1997012709A1 IT 9600183 W IT9600183 W IT 9600183W WO 9712709 A1 WO9712709 A1 WO 9712709A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- metal alloy
- container
- thixotropic
- injection chamber
- outlet
- Prior art date
Links
- 229910001092 metal group alloy Inorganic materials 0.000 title claims abstract description 62
- 230000009974 thixotropic effect Effects 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000005058 metal casting Methods 0.000 title claims abstract description 10
- 238000002347 injection Methods 0.000 claims abstract description 33
- 239000007924 injection Substances 0.000 claims abstract description 33
- 229910052751 metal Inorganic materials 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 17
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 13
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 238000001816 cooling Methods 0.000 claims description 7
- 239000011261 inert gas Substances 0.000 claims description 5
- 239000000654 additive Substances 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 3
- 230000008569 process Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 238000010117 thixocasting Methods 0.000 description 7
- 238000010118 rheocasting Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 210000001787 dendrite Anatomy 0.000 description 2
- 238000004512 die casting Methods 0.000 description 2
- 208000015181 infectious disease Diseases 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000012809 cooling fluid Substances 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003670 easy-to-clean Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- 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
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/08—Cold chamber machines, i.e. with unheated press chamber into which molten metal is ladled
- B22D17/10—Cold chamber machines, i.e. with unheated press chamber into which molten metal is ladled with horizontal press motion
Definitions
- the present invention relates to a method for the thixotropic casting of metal alloy products.
- the invention applies in particular to the manufacture of aluminium alloy wheel rims and it is to this field of application that the description below expressly refers but without thereby restricting the scope of the disclosure.
- the thixo-casting process consists basically in preparing a solid block (in the form of a billet, ingot, bloom, etc.) of material (the metal alloy) with a thixotropic structure, heating the block to a ductile semi-solid state and then injecting the semi-solid block into a mould.
- the thixo-casting process presents a number of disadvantages, however.
- the first disadvantage is that the heat cycle envisages two heating operations and two cooling operations, requiring considerable quantities of energy; moreover, two different machines are necessary, one for forming the intermediate, thixotropic product (usually billets) that will be formed into the desired shape by the other machine, that is, the die casting machine. Moreover, the process requires a smelting furnace, a reheating furnace to heat the thixotropic billets to a semi-solid state and suitable means for transferring the
- the second disadvantage of the thixo-casting process is that it has a high wastage rate of material in the thixotropic state, that is, material with a high unit cost.
- the billets are usually obtained by cutting a continuous bar. Moreover, considerable amounts of material are lost by dripping off the billets during reheating and during their transfer from the furnace to the casting machine.
- the third disadvantage is that the surface of the billets oxidizes very easily, thus causing further loss of material and making it necessary to inhibit oxidization so as to prevent the formation of oxide inclusions during the moulding stage.
- a further disadvantage of the thixo-casting process is the difficulty of obtaining parts with complex shapes and good mechanical properties. This is because the metal which fills the mould is not very fluid since it has to be injected at a relatively low temperature, very near the solidus, in order to reduce dripping, oxidation, billet deformation, etc.
- thixotropic metal alloy In rheocasting, a mass of thixotropic metal alloy is prepared at a temperature between liquidus and solidus and the metal is then poured directly into the mould. Unlike thixo-casting, there is no need for an intermediate step to produce a solid block with a thixotropic structure.
- a rheocasting machine usually includes a large chamber into which the metal alloy in the form of pellets is fed. The metal is heated to a preset temperature in this chamber. At the same time, a screw unit agitates the metal to obtain the thixotropic structure. The screw is also used to inject the metal into the mould.
- Rheocasting also has several disadvantages, however.
- the first is that the machine required for rheocasting is considerably complex and expensive.
- the second is that, like thixo-casting, rheocasting is unsuitable for making parts with complex shapes and good mechanical properties.
- rheocasting is unsuitable for making parts with complex shapes and good mechanical properties.
- the aim of the present invention is ,to provide a simple, economical method for the thixotropic casting of metal alloy products that is capable of overcoming the abovementioned drawbacks.
- the present invention discloses a method for the thixotropic casting of metal alloy products characterized in that it comprises the following stages: pouring a quantity of molten metal alloy into a container; cooling and, at the same time, agitating the metal alloy until it reaches a thixotropic state; feeding the metal alloy in the thixotropic state into an injection chamber; injecting the metal alloy into a mould cavity.
- the present invention also discloses a device for the thixotropic casting of metal alloy products.
- the present invention provides a device for the thixotropic casting of metal alloy products characterized in that it comprises: a container for a molten metal alloy equipped with at least one inlet and one outlet for the metal alloy; means for agitating and means for cooling the metal alloy in the said container in order to give the metal a thixotropic structure; a cutoff valve on the said outlet, an injection chamber connected to the said container through the outlet; means for transferring the metal alloy from the container to the injection chamber; a mould for metal alloy products connected to the infection chamber; means for injecting the metal alloy from the injection chamber into the mould.
- An advantage of the present invention is that it permits the forming of parts with complex shapes - such as, wheel rims, for example - and good mechanical properties.
- the fluidity of the thixotropic metal alloy when it is injected into the mould cavity is relatively high.
- the invention permits injection of a thixotropic metal alloy having a relatively high percentage of liquid.
- Another advantage is that it prevents the formation of undesirable non-globular dendrites .
- Yet another advantage of the invention is that the heat cycle envisages only one heating operation and only one cooling operation. This reduces waste of thixotropic material with a high unit cost and minimizes the risk of oxidation of the metal alloy.
- FIG. 1 is a schematic cross section of an embodiment of the device disclosed by the present invention.
- FIG. 2 is a cross section of another embodiment of the device disclosed by the present invention.
- FIG. 3 is a cross section of a part of the device showing a different embodiment of the valve 9;
- FIG. 4 schematically illustrates yet another embodiment of the valve 9 in cross section through a plane normal to the axis of the injection chamber 12;
- FIG. 5 shows a cross section through the V-V plane traced in Fig. 4.
- the numeral 1 indicates as a whole a device for the thixotropic casting of products in aluminium, magnesium or other metal alloy.
- the part to be made is a wheel rim.
- the device 1 comprises an upright container 2 for a molten metal alloy (for example, an ordinary crucible) having at least one inlet 3 and one outlet 4 for the metal alloy located, respectively, at the top and bottom of the container
- a molten metal alloy for example, an ordinary crucible
- a defined quantity of metal alloy at a temperature equal to, or just above, the liquidus is fed into the container 2 through the inlet 3.
- the quantity of molten alloy fed in is measured by an appropriate metering device of known type and not illustrated in the drawings.
- the means for heating the alloy until it reaches the liquid state so that it can be fed into the container 2 are also of known type and not illustrated.
- the device 1 also includes means 5, of known type and hence only schematically illustrated, to agitate the metal alloy in the container 2.
- the said means are preferably magnetodynamic devices capable of generating an electromagnetic field whose flux acts on the alloy in the container 2 to induce magnetodynamic forces strong enough to move and hence agitate the alloy in at least two directions of rotational motion transverse to each other, the two directions of rotational motion are preferably vertical and horizontal, as indicated by the arrows 6.
- Means 7 are envisaged to cool the metal alloy in the container 2, the said means preferably consisting of a coil 8 around the container 2 with a cooling liquid flowing through it.
- valve 9 shuts off the outlet 4 on command.
- the valve 9 includes a shutter 10 solidly connected to a sealed vertical stem 11 which moves relative to the container 2.
- a horizontal injection chamber 12 connected to the container 2 through the outlet 4 and connected at one end to a mould 13 of the part to be formed; at the opposite end, there is a plunger 14 that slides axially in a horizontal direction inside the injection chamber 12.
- the plunger 14 is used to force the metal alloy from the injection chamber 12 into the mould 13.
- the moulding device or press including the injection chamber 12 and the plunger 14 may, for example, be similar to that used for the injection of semi-solid billets in the known thixo-casting process
- Means 15 are also envisaged to transfer the metal alloy from the container 2 to the injection chamber 12.
- these means include a channel 16 having one end 17 leading into the top part of the container 2, and the opposite end connected to a source of fluid under pressure, preferably an inert gas.
- a source of fluid under pressure preferably an inert gas.
- This source is of known type and is not illustrated.
- the inert gas for example, argon
- the inert gas can be fed into the container 2 under pressure in order to generate an overpressure which, combined with the weight of the alloy, forces the latter out of the container through the outlet 4
- the device 1 also includes ultrasonic means 18 of known type to agitate the metal alloy in the container 2, in the proximity of the outlet 4. These ultrasonic means are arranged in such way as to operate in the lower part, usually narrower, of the container 2.
- the cooling fluid is then circulated in the coil 8 in order to cool the alloy and, at the same time, the magnetodynamic means 5 are activated to agitate the alloy until it reaches a thixotropic state.
- the metal is agitated by rotational motion in two directions normal to each other simultaneously.
- Ultrasonic means 8 are also envisaged to further agitate the metal.
- the metal alloy in the thixotropic state is fed into the injection chamber 12.
- the valve 9 is opened and an overpressure is generated inside the container 2 by feeding an inert gas under pressure into the top part of the container 2.
- the thixotropic alloy is forced into the injection chamber by the combined action of its own weight and the overpressure in the container 2.
- the plunger 14 is in the retracted position, that is, as far to the right as possible, with reference to Fig.1.
- the plunger 14 is moved towards the left in such a manner as to inject the metal alloy into the cavity 27 of the mould 13.
- the subsequent stages in the process to obtain the moulded product are known.
- the device illustrated in Fig. 2 is equipped with means 19 to inject special additives into the metal alloy so as to obtain a composite material.
- These injection means are of known type and include at least one ionization chamber 20, a first and second feed duct 21 and 22, respectively.
- the ionization chamber 20 is mounted at the top of the container 2.
- the first duct 21 feeds an inert gas to the ionization chamber 20.
- the second duct 22 feeds the said additives in solid particle form from a hopper 23 to the ionization chamber 20.
- Fig. 3 shows a cutoff valve 9 designed to close the outlet 4, a slide 24 moving backwards and forwards in the horizontal direction to open and close the outlet 4.
- Figs. 4 and 5 illustrate another embodiment of the valve 9 including a vertical rotating disc 25 having a number of holes 26 equidistant from the centre of the disc 25.
- the disc is made in such a way that, as it rotates, the outlet 4 of the container is opened when it corresponds with one of the holes 26, allowing the alloy to flow through into the injection chamber 12, and closed when it corresponds with one of the full areas of the disc 25 between the holes 26.
- the valve 9 shown in Figs . 4 and 5 is easy to clean.
- the thixotropic structure is obtained during the cooling of the molten metal, which greatly simplifies the control of the heat cycle itself and permits a high-quality thixotropic structure to be obtained easily.
- the temperature of the thixotropic metal in the injection chamber 12 is relatively high, even several Celsius degrees higher than the solidus, without giving rise to any of the problems usually encountered in the known processes such as, for example, high material wastage rate, oxidation, and formation of non-globular dendrites; in fact, the high temperature constitutes an advantage in that it allows parts with complex shapes, such as wheel rims, to be obtained.
- the parts made according to the present invention have a homogeneous structure, that is, their globules are distributed uniformly in the mass of the metal.
- the effect of agitating the alloy in two directions of rotational motion 6 transverse to each other combined with the action of the ultrasonic means 18, greatly facilitates the transfer of the metal from the container 2 to the injection chamber 12 without having to subject the argon to very high pressure.
- the cavity 27 of the mould 13 is well filled since the plunger can operate effectively even at a relatively low speed, allowing the metal to flow into the mould quietly and without undue turbulence.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
Abstract
A method and device for the thixotropic casting of metal alloy products, especially wheel rims, envisages that a quantity of metal alloy in the liquid state be poured into a container (2), cooled and simultaneously agitated until it reaches a thixotropic state; the metal allow in the thixotropic state is then fed directly into an injection chamber (12) and injected into the forming cavity of a mould (13); magnetodynamic devices (5) agitate the metal alloy in the container (2) in two directions of rotational motion, one horizontal and one vertical; the bottom of the container (2) has an outlet (4) with a valve (9) to stop the flow of metal alloy and the injection chamber (12) is equipped with a plunger (14) that slides axially inside the chamber itself so as to inject the alloy into the mould (13).
Description
Description
A method and device for the thixotropic casting of metal alloy products
Technical Field
The present invention relates to a method for the thixotropic casting of metal alloy products.
The invention applies in particular to the manufacture of aluminium alloy wheel rims and it is to this field of application that the description below expressly refers but without thereby restricting the scope of the disclosure.
The thixo-casting process consists basically in preparing a solid block (in the form of a billet, ingot, bloom, etc.) of material (the metal alloy) with a thixotropic structure, heating the block to a ductile semi-solid state and then injecting the semi-solid block into a mould.
Background Art
The thixo-casting process presents a number of disadvantages, however.
The first disadvantage is that the heat cycle envisages two heating operations and two cooling operations, requiring considerable quantities of energy; moreover, two different machines are necessary, one for forming the intermediate, thixotropic product (usually billets) that will be formed into the desired shape by the other machine, that is, the die casting machine. Moreover, the process requires a smelting furnace, a reheating furnace to heat the thixotropic billets to a semi-solid state and suitable means for transferring the
"hot" billets from the furnace to the infection chamber of the die casting machine.
The second disadvantage of the thixo-casting process is that it has a high wastage rate of material in the thixotropic state, that is, material with a high unit cost. The billets are usually obtained by cutting a continuous bar. Moreover, considerable amounts of material are lost by dripping off the billets during reheating and during their transfer from the furnace to the casting machine.
The third disadvantage is that the surface of the billets oxidizes very easily, thus causing further loss of material and making it necessary to inhibit oxidization so as to prevent the formation of oxide inclusions during the moulding stage.
A further disadvantage of the thixo-casting process is the difficulty of obtaining parts with complex shapes and good mechanical properties. This is because the metal which fills the mould is not very fluid since it has to be injected at a relatively low temperature, very near the solidus, in order to reduce dripping, oxidation, billet deformation, etc.
Yet another disadvantage is that the billets have to be stored and transported from the place where they are produced to the place where they are formed.
In rheocasting, a mass of thixotropic metal alloy is prepared at a temperature between liquidus and solidus and the metal is then poured directly into the mould. Unlike thixo-casting, there is no need for an intermediate step to produce a solid block with a thixotropic structure.
A rheocasting machine usually includes a large chamber into which the metal alloy in the form of pellets is fed. The metal is heated to a preset temperature in this chamber. At the same time, a screw unit agitates the metal to obtain the thixotropic structure. The screw is also used to inject the
metal into the mould.
Rheocasting also has several disadvantages, however.
The first is that the machine required for rheocasting is considerably complex and expensive.
The second is that, like thixo-casting, rheocasting is unsuitable for making parts with complex shapes and good mechanical properties. When the metal fills the mould cavity, its fluidity is very low (usually, its temperature is just above the solidus) otherwise the screw cannot mix and inject it.
Disclosure of the Invention
The aim of the present invention is ,to provide a simple, economical method for the thixotropic casting of metal alloy products that is capable of overcoming the abovementioned drawbacks.
The present invention discloses a method for the thixotropic casting of metal alloy products characterized in that it comprises the following stages: pouring a quantity of molten metal alloy into a container; cooling and, at the same time, agitating the metal alloy until it reaches a thixotropic state; feeding the metal alloy in the thixotropic state into an injection chamber; injecting the metal alloy into a mould cavity.
The present invention also discloses a device for the thixotropic casting of metal alloy products.
The present invention provides a device for the thixotropic casting of metal alloy products characterized in that it comprises: a container for a molten metal alloy equipped with at least one inlet and one outlet for the metal alloy; means for agitating and means for cooling the metal
alloy in the said container in order to give the metal a thixotropic structure; a cutoff valve on the said outlet, an injection chamber connected to the said container through the outlet; means for transferring the metal alloy from the container to the injection chamber; a mould for metal alloy products connected to the infection chamber; means for injecting the metal alloy from the injection chamber into the mould.
An advantage of the present invention is that it permits the forming of parts with complex shapes - such as, wheel rims, for example - and good mechanical properties.
Moreover, thanks to the method disclosed by the present invention, the fluidity of the thixotropic metal alloy when it is injected into the mould cavity is relatively high. In other words, the invention permits injection of a thixotropic metal alloy having a relatively high percentage of liquid.
Another advantage is that it prevents the formation of undesirable non-globular dendrites .
Yet another advantage of the invention is that the heat cycle envisages only one heating operation and only one cooling operation. This reduces waste of thixotropic material with a high unit cost and minimizes the risk of oxidation of the metal alloy.
The invention will now be described with reference to the accompanying drawings which illustrate embodiments of the invention by way of example only and in which:
- Figure 1 is a schematic cross section of an embodiment of the device disclosed by the present invention;
- Figure 2 is a cross section of another embodiment of the device disclosed by the present invention;
- Figure 3 is a cross section of a part of the device showing
a different embodiment of the valve 9;
- Figure 4 schematically illustrates yet another embodiment of the valve 9 in cross section through a plane normal to the axis of the injection chamber 12;
- Figure 5 shows a cross section through the V-V plane traced in Fig. 4.
With reference to the accompanying drawings, the numeral 1 indicates as a whole a device for the thixotropic casting of products in aluminium, magnesium or other metal alloy. In the embodiments illustrated, the part to be made is a wheel rim.
The device 1 comprises an upright container 2 for a molten metal alloy (for example, an ordinary crucible) having at least one inlet 3 and one outlet 4 for the metal alloy located, respectively, at the top and bottom of the container
2.
A defined quantity of metal alloy at a temperature equal to, or just above, the liquidus is fed into the container 2 through the inlet 3. Preferably, the quantity of molten alloy fed in is measured by an appropriate metering device of known type and not illustrated in the drawings. The means for heating the alloy until it reaches the liquid state so that it can be fed into the container 2 are also of known type and not illustrated.
The device 1 also includes means 5, of known type and hence only schematically illustrated, to agitate the metal alloy in the container 2. The said means are preferably magnetodynamic devices capable of generating an electromagnetic field whose flux acts on the alloy in the container 2 to induce magnetodynamic forces strong enough to move and hence agitate the alloy in at least two directions
of rotational motion transverse to each other, the two directions of rotational motion are preferably vertical and horizontal, as indicated by the arrows 6.
Means 7 are envisaged to cool the metal alloy in the container 2, the said means preferably consisting of a coil 8 around the container 2 with a cooling liquid flowing through it.
A valve 9 shuts off the outlet 4 on command. In the embodiment illustrated in Fig. 1, the valve 9 includes a shutter 10 solidly connected to a sealed vertical stem 11 which moves relative to the container 2.
Below the container 2, there is a horizontal injection chamber 12 connected to the container 2 through the outlet 4 and connected at one end to a mould 13 of the part to be formed; at the opposite end, there is a plunger 14 that slides axially in a horizontal direction inside the injection chamber 12. The plunger 14 is used to force the metal alloy from the injection chamber 12 into the mould 13. The moulding device or press including the injection chamber 12 and the plunger 14 may, for example, be similar to that used for the injection of semi-solid billets in the known thixo-casting process
Means 15 are also envisaged to transfer the metal alloy from the container 2 to the injection chamber 12. In the embodiment being described, these means include a channel 16 having one end 17 leading into the top part of the container 2, and the opposite end connected to a source of fluid under pressure, preferably an inert gas. This source is of known type and is not illustrated. On command, the inert gas (for example, argon) can be fed into the container 2 under pressure in order to generate an overpressure which, combined
with the weight of the alloy, forces the latter out of the container through the outlet 4
The device 1 also includes ultrasonic means 18 of known type to agitate the metal alloy in the container 2, in the proximity of the outlet 4. These ultrasonic means are arranged in such way as to operate in the lower part, usually narrower, of the container 2.
The functioning of the device 1 is described below.
First, with the valve 9 closed, a quantity of metal alloy in the liquid state, previously melted and measured by known means, is fed into the container 2 through the inlet 3 at the top of the container itself. Inside the container 2, an inert atmosphere is constantly maintained.
The cooling fluid is then circulated in the coil 8 in order to cool the alloy and, at the same time, the magnetodynamic means 5 are activated to agitate the alloy until it reaches a thixotropic state. As mentioned above, the metal is agitated by rotational motion in two directions normal to each other simultaneously.
Known means are envisaged to measure and control the temperature so that the metal undergoes a heat cycle which permits the formation of a thixotropic structure.
Ultrasonic means 8 are also envisaged to further agitate the metal.
Next, the metal alloy in the thixotropic state is fed into the injection chamber 12. During this stage, the valve 9 is opened and an overpressure is generated inside the container 2 by feeding an inert gas under pressure into the top part of the container 2. The thixotropic alloy is forced into the injection chamber by the combined action of its own weight and the overpressure in the container 2. At this
stage, the plunger 14 is in the retracted position, that is, as far to the right as possible, with reference to Fig.1.
Once the metal alloy has been transferred to the injection chamber 12, the plunger 14 is moved towards the left in such a manner as to inject the metal alloy into the cavity 27 of the mould 13. The subsequent stages in the process to obtain the moulded product are known.
The device illustrated in Fig. 2 is equipped with means 19 to inject special additives into the metal alloy so as to obtain a composite material. These injection means are of known type and include at least one ionization chamber 20, a first and second feed duct 21 and 22, respectively. The ionization chamber 20 is mounted at the top of the container 2. The first duct 21 feeds an inert gas to the ionization chamber 20. The second duct 22 feeds the said additives in solid particle form from a hopper 23 to the ionization chamber 20.
Fig. 3 shows a cutoff valve 9 designed to close the outlet 4, a slide 24 moving backwards and forwards in the horizontal direction to open and close the outlet 4.
Figs. 4 and 5 illustrate another embodiment of the valve 9 including a vertical rotating disc 25 having a number of holes 26 equidistant from the centre of the disc 25. The disc is made in such a way that, as it rotates, the outlet 4 of the container is opened when it corresponds with one of the holes 26, allowing the alloy to flow through into the injection chamber 12, and closed when it corresponds with one of the full areas of the disc 25 between the holes 26. The valve 9 shown in Figs . 4 and 5 is easy to clean.
In the heat cycle envisaged by the method disclosed, the thixotropic structure is obtained during the cooling of
the molten metal, which greatly simplifies the control of the heat cycle itself and permits a high-quality thixotropic structure to be obtained easily.
The temperature of the thixotropic metal in the injection chamber 12 is relatively high, even several Celsius degrees higher than the solidus, without giving rise to any of the problems usually encountered in the known processes such as, for example, high material wastage rate, oxidation, and formation of non-globular dendrites; in fact, the high temperature constitutes an advantage in that it allows parts with complex shapes, such as wheel rims, to be obtained.
The parts made according to the present invention have a homogeneous structure, that is, their globules are distributed uniformly in the mass of the metal.
Moreover, the effect of agitating the alloy in two directions of rotational motion 6 transverse to each other, combined with the action of the ultrasonic means 18, greatly facilitates the transfer of the metal from the container 2 to the injection chamber 12 without having to subject the argon to very high pressure.
Even in the case of complex shapes, the cavity 27 of the mould 13 is well filled since the plunger can operate effectively even at a relatively low speed, allowing the metal to flow into the mould quietly and without undue turbulence.
All the details of the invention described can be subject to modifications and variations for purposes of practical application without thereby departing from the scope of the inventive concept as claimed hereunder.
Claims
Claims
1) A method for the thixotropic casting of metal alloy products, characterized in that it comprises the following stages:
- pouring a quantity of molten metal alloy into a container (2);
- cooling and, at the same time, agitating the metal alloy until it reaches a thixotropic state;
- feeding the metal alloy in the thixotropic state into an injection chamber (12);
- injecting the metal alloy into a cavity (27) of a mould (13) .
2) The method according to claim 1, characterized in that magnetodynamic means (5) are used to agitate the metal alloy in the said container (2).
3) The method according to claim 2 characterized in that the said magnetodynamic means agitate the alloy in at least two directions of rotational motion transverse to each other.
4) The method according to claim 2 or 3 characterized in that ultrasonic means (18) are used to agitate the metal alloy in the container (2), in a zone near an outlet (4). 5) The method according to any of the foregoing claims characterized in that the stage of feeding the thixotropic metal alloy into the injection chamber (12) envisages the following steps:
- generating an overpressure inside the container (2);
- opening a valve (9) which connects the said container (2) to the said injection chamber (12).
6) The method according to any of the foregoing claims characterized in that the stage of injecting the metal alloy into the cavity of the mould (13) envisages the use of a plunger (14) that slides axially inside the injection cnamber (12) and acts on the metal alloy. 7) The method according to any of the foregoing claims characterized in that the quantity of molten alloy fed into the container (2) is predetermined by an appropriate metering device. 8) The method according to any of the foregoing claims characterized in that an inert atmosphere is maintained inside the container (2).
9) The method according to any of the foregoing claims characterized in that additives are injected into the metal alloy in the container (2) through an ionization cnamber (20) so as to obtain a composite material.
10) A device for the thixotropic casting of metal alloy products characterized in that it comprises.
a container (2) for a metal alloy in the liquid state equipped with at least one inlet (3) and one outlet (4) for the metal alloy;
- means (5) for agitating and means (7) for cooling the metal alloy in the said container (2) in order to give the metal a thixotropic structure,
- a cutoff valve (9) on the said outlet,
- an injection chamber (12) connected to the said container (2) through the outlet (4),
- means (15) for transferring tne metal alloy from the container (2) to the injection chamoer (12),
- a mould (13) for metal alloy products connected to the injection chamber (12);
- means (14) for injecting the metal alloy from the injection chamber (12) into the mould (13) .
11) The device according to claim 10 characterized in that the said means (15) for transferring the metal alloy from the container (2) to the injection chamber (12) include a channel
(16) having one end leading into the top part of the container (2) and the other end connected to a source of fluid under pressure.
12) The device according to claim 11 characterized in that the said fluid is an inert gas.
13) The device according to one of the claims from 10 to 12 characterized in that the said injection means comprise a plunger (14) that slides axially inside the injection chamber
(12).
14) The device according to claim 13 characterized in that the said plunger (14) runs in a horizontal direction
15) The device according to one of the claims from 10 to 14 characterized in that the said container (2) is mounted above the injection chamber (12), the inlet (3) and the outlet (4)
being located, respectively, at the top and bottom of the container (2).
16) The device according to one of the claims from 10 to 15 characterized in that it comprises means (19) for injecting additives into the metal alloy in the container (2) so as to obtain a composite material.
17) The device according to one of the claims from 10 to 16 characterized in that it comprises ultrasonic means (18) designed to agitate the metal alloy in the container (2) in the proximity of the outlet (4).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT95BO000471A IT1279642B1 (en) | 1995-10-05 | 1995-10-05 | METHOD AND DEVICE FOR THIXOTROPIC FORMING OF METAL ALLOY PRODUCTS |
ITBO95A000471 | 1995-10-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997012709A1 true WO1997012709A1 (en) | 1997-04-10 |
Family
ID=11340840
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IT1996/000183 WO1997012709A1 (en) | 1995-10-05 | 1996-10-02 | A method and device for the thixotropic casting of metal alloy products |
Country Status (2)
Country | Link |
---|---|
IT (1) | IT1279642B1 (en) |
WO (1) | WO1997012709A1 (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998016334A3 (en) * | 1996-10-04 | 1998-08-06 | Semi Solid Technologies Inc | Apparatus and method for integrated semi-solid material production and casting |
US5887640A (en) * | 1996-10-04 | 1999-03-30 | Semi-Solid Technologies Inc. | Apparatus and method for semi-solid material production |
EP0960672A1 (en) * | 1998-05-26 | 1999-12-01 | Yukihisa Choshi | Automatic molten metal supply and injection device |
DE10003791A1 (en) * | 2000-01-28 | 2001-08-09 | Forschungsges Umformtechnik | Production of a wheel rim e.g. bicycle wheel rim comprises deforming a thixoforged preform of the rim by pressure rolling, quenching to room temperature, and pressure rolling to give the final end product |
DE10043717A1 (en) * | 2000-09-04 | 2002-03-14 | Buehler Druckguss Ag Uzwil | Process for compressive reforming of aluminum or magnesium alloys comprises conveying the liquid or liquid material from a preparation chamber into a casting chamber of a die casting machine |
DE10212349C1 (en) * | 2002-03-13 | 2003-08-28 | Evgenij Sterling | Production of an alloy melt for casting comprises placing the melt having a temperature lying above the liquidus temperature of the alloy in a crystallization vessel, adding an alloy as a powder, and mixing the melt and powder |
EP1405684A3 (en) * | 2002-09-25 | 2005-06-22 | Chunpyo Hong | Metallic materials for rheocasting or thixoforming and method for manufacturing the same |
DE19943096B4 (en) * | 1999-09-09 | 2008-07-03 | Kahn, Friedhelm, Prof. Dr. Ing. | Method and devices for filling the pressure chamber of a horizontal die casting machine with metal and alloys |
US7870885B2 (en) | 2004-12-10 | 2011-01-18 | Magnus Wessen | Method of and a device for producing a liquid-solid metal composition |
CN105705271A (en) * | 2013-09-05 | 2016-06-22 | 通用汽车环球科技运作有限责任公司 | Methods and apparatus to produce high performance axisymmetric components |
JP2016159336A (en) * | 2015-03-03 | 2016-09-05 | 株式会社豊田中央研究所 | Magnesium alloy casting apparatus, nozzle for the casting apparatus, and magnesium alloy casting method |
CN106413940A (en) * | 2014-05-16 | 2017-02-15 | 吉斯科有限公司 | Process for preparing molten metals for casting at a low to zero superheat temperature |
DE102016110679B4 (en) * | 2015-06-12 | 2019-10-10 | Aida Engineering, Ltd. | Method and apparatus for producing a semi-solid metal material |
CN110508773A (en) * | 2019-09-12 | 2019-11-29 | 福建省鼎智新材料科技有限公司 | A kind of semisolid ultrasonic wave pulping device and its working method |
US12179258B2 (en) * | 2023-02-04 | 2024-12-31 | Qingyou Han | Method and apparatus for extending service life of shot chamber for die casting application |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01166874A (en) * | 1987-12-21 | 1989-06-30 | Akio Nakano | Casting device for composite metal product |
EP0657235A1 (en) * | 1993-12-08 | 1995-06-14 | Rheo-Technology, Ltd | Process for the production of semi-solidified metal composition |
-
1995
- 1995-10-05 IT IT95BO000471A patent/IT1279642B1/en active IP Right Grant
-
1996
- 1996-10-02 WO PCT/IT1996/000183 patent/WO1997012709A1/en active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01166874A (en) * | 1987-12-21 | 1989-06-30 | Akio Nakano | Casting device for composite metal product |
EP0657235A1 (en) * | 1993-12-08 | 1995-06-14 | Rheo-Technology, Ltd | Process for the production of semi-solidified metal composition |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 013, no. 434 (M - 875) 28 September 1989 (1989-09-28) * |
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5881796A (en) * | 1996-10-04 | 1999-03-16 | Semi-Solid Technologies Inc. | Apparatus and method for integrated semi-solid material production and casting |
US5887640A (en) * | 1996-10-04 | 1999-03-30 | Semi-Solid Technologies Inc. | Apparatus and method for semi-solid material production |
US6308768B1 (en) | 1996-10-04 | 2001-10-30 | Semi-Solid Technologies, Inc. | Apparatus and method for semi-solid material production |
WO1998016334A3 (en) * | 1996-10-04 | 1998-08-06 | Semi Solid Technologies Inc | Apparatus and method for integrated semi-solid material production and casting |
EP0960672A1 (en) * | 1998-05-26 | 1999-12-01 | Yukihisa Choshi | Automatic molten metal supply and injection device |
DE19943096B4 (en) * | 1999-09-09 | 2008-07-03 | Kahn, Friedhelm, Prof. Dr. Ing. | Method and devices for filling the pressure chamber of a horizontal die casting machine with metal and alloys |
DE10003791A1 (en) * | 2000-01-28 | 2001-08-09 | Forschungsges Umformtechnik | Production of a wheel rim e.g. bicycle wheel rim comprises deforming a thixoforged preform of the rim by pressure rolling, quenching to room temperature, and pressure rolling to give the final end product |
DE10003791B4 (en) * | 2000-01-28 | 2004-06-17 | Forschungsgesellschaft Umformtechnik Mbh | Process for manufacturing rims |
DE10043717A1 (en) * | 2000-09-04 | 2002-03-14 | Buehler Druckguss Ag Uzwil | Process for compressive reforming of aluminum or magnesium alloys comprises conveying the liquid or liquid material from a preparation chamber into a casting chamber of a die casting machine |
DE10212349C1 (en) * | 2002-03-13 | 2003-08-28 | Evgenij Sterling | Production of an alloy melt for casting comprises placing the melt having a temperature lying above the liquidus temperature of the alloy in a crystallization vessel, adding an alloy as a powder, and mixing the melt and powder |
EP1344589A3 (en) * | 2002-03-13 | 2005-05-18 | Evgenij Dr. Sterling | Process and device for treating an alloy melt before a casting operation |
EP1405684A3 (en) * | 2002-09-25 | 2005-06-22 | Chunpyo Hong | Metallic materials for rheocasting or thixoforming and method for manufacturing the same |
US7870885B2 (en) | 2004-12-10 | 2011-01-18 | Magnus Wessen | Method of and a device for producing a liquid-solid metal composition |
CN105705271A (en) * | 2013-09-05 | 2016-06-22 | 通用汽车环球科技运作有限责任公司 | Methods and apparatus to produce high performance axisymmetric components |
CN106413940A (en) * | 2014-05-16 | 2017-02-15 | 吉斯科有限公司 | Process for preparing molten metals for casting at a low to zero superheat temperature |
US20170080484A1 (en) * | 2014-05-16 | 2017-03-23 | Gissco Company Limited | Process for preparing molten metals for casting at a low to zero superheat temperature |
US10675676B2 (en) * | 2014-05-16 | 2020-06-09 | Grissco Company Limited | Process for preparing molten metals for casting at a low to zero superheat temperature |
CN106413940B (en) * | 2014-05-16 | 2020-08-25 | 吉斯科有限公司 | Method for producing molten metal for casting at low to zero superheat temperatures |
JP2016159336A (en) * | 2015-03-03 | 2016-09-05 | 株式会社豊田中央研究所 | Magnesium alloy casting apparatus, nozzle for the casting apparatus, and magnesium alloy casting method |
DE102016110679B4 (en) * | 2015-06-12 | 2019-10-10 | Aida Engineering, Ltd. | Method and apparatus for producing a semi-solid metal material |
CN110508773A (en) * | 2019-09-12 | 2019-11-29 | 福建省鼎智新材料科技有限公司 | A kind of semisolid ultrasonic wave pulping device and its working method |
US12179258B2 (en) * | 2023-02-04 | 2024-12-31 | Qingyou Han | Method and apparatus for extending service life of shot chamber for die casting application |
US20250091122A1 (en) * | 2023-02-04 | 2025-03-20 | Qingyou Han | Apparatus for extending service life of shot chamber for die casting application |
Also Published As
Publication number | Publication date |
---|---|
ITBO950471A0 (en) | 1995-10-05 |
ITBO950471A1 (en) | 1997-04-05 |
IT1279642B1 (en) | 1997-12-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO1997012709A1 (en) | A method and device for the thixotropic casting of metal alloy products | |
EP0859677B1 (en) | Apparatus for processing semisolid thixotropic metallic slurries | |
US5979534A (en) | Die casting method | |
CN100566890C (en) | A kind of equipment for preparation and rheological molding of semi-solid alloy slurry | |
US20030006020A1 (en) | Semi-solid casting apparatus and method | |
EP0867246B1 (en) | Method and apparatus for injection molding of semi-molten metals | |
CN110814305B (en) | A kind of Cu-Fe composite material double melt mixed casting equipment and technology | |
GB2354471A (en) | Producung semisolid metal slurries and shaped components therefrom | |
KR100554093B1 (en) | Reactor High Molding Device | |
JP3125878B2 (en) | Method and apparatus for producing die casting of casting made of thixotropic alloy | |
CN100532596C (en) | Preparation and rheological forming method of semi-solid alloy slurry | |
EP1132162B1 (en) | Metal casting method and apparatus | |
US6298901B1 (en) | Method and apparatus for semi-molten metal injection molding | |
CN108262455A (en) | A kind of integrated reho-forming method for manufacturing high-quality semi-solid light alloy casting | |
CN101406941A (en) | Material forming method for preparing composite product using semi-solid state forming technique | |
EP2574411A2 (en) | Rheocasting method and apparatus | |
CN100531964C (en) | Apparatus and method for preparing and forming metal semi-solid slurry | |
US20240278315A1 (en) | Method of producing large thin-walled sand castings of high internal integrity | |
CN101130207A (en) | A kind of equipment for preparation and rheological molding of semi-solid metal slurry | |
JPH01192447A (en) | Continuous forming method and device for metal slurry for continuous casting | |
CN100574939C (en) | A device for preparing and forming semi-solid alloy slurry | |
US3771588A (en) | Direct melt injection casting centre | |
CN1186722A (en) | Method and apparatus for semi-solid metal injection molding | |
JP3487315B2 (en) | Die casting method | |
US20020179280A1 (en) | Diecasting method and device for carrying out the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): CA US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
122 | Ep: pct application non-entry in european phase |