Field of the invention.

The invention refers to a casting process of the aluminum and to the obtained piece having particular mechanical and thermal characteristic.

State of the art.

In the known art, the casting processes, in particular of the aluminum, provide three modalities: sand casting, shell casting and die casting. In the sand casting in foundry or in shell casting, the liquid aluminum is poured into molds by gravity, while in the die casting the aluminum is injected under pressure. At different casting processes correspond different characteristics of the piece obtained from the casting, i.e. different mechanical and chemical/physical characteristics. The known processes provide the casting of the aluminum, the placing into a ladle with the passing into a sprue, to reach the inside cavity of the melting case having the shape of the piece to be obtained and a vent channel for the exit of the air and of the material in excess. To avoid porosity or cracks in the sand casting and in the shell casting at the aluminum is added silicon, that makes the melting material more sliding and longer fluid. These alloys, specially studied for the castings, have a thermal conductivity very low, around 120-170 W/m°K. Further, having a low melting point, less than 580°C, these alloys cannot be used for parts to be welded/soldered, processing that occurs around 600°C. In the art is known also the document EP 2275584 wherein is described an aluminum alloy with silicon, but this alloy has not a high fusion point to permit welding/soldering or for uses at high thermal conductivity.

Summary of the invention.

The invention is able to avoid the cited disadvantages having a high fusion point and a bigger thermal conductivity in comparison with the casting containing consistent percentages of silicon. Further, the invented casting method permits to have a high fusion point, so to can arrange welding/soldering. The invented method permits to use alloys never used in sand casting or in shell casting using alloys with low silicon content, i.e. series 6000 alloys, as for example the AIMgSiO,5 alloy and also almost pure aluminum, i.e. series 1000 alloys, as for example the Al 99,5 alloy, which have thermal conductivity higher than 150 W/m°K and fusion point higher to 640°C. The high thermal conductivity of the aluminum alloys used in the invented process permits to make components to be cooling both to air than in liquid for electronic components, other than for all the uses wherein a high thermal conductivity is requested. The casting technology with 6000 series and 1000 series alloys comprises a plurality of sprues and a plurality of vent channels realized in the mold shape to have different velocities of filling and of cooling of the shape jet. The number of sprues and of the vent channels is different in relation to the piece to be obtained and this number is stated in advance to a thermodynamic/fluid dedicated simulation program. The realization technique of the molds is used both for the sand casting than for the shell casting. The plurality of the sprues and of the vent channels , i.e. of the enter channels into the fusion case and of the rising and vent stanchions, limits to the minimum the presence of silicon and permits to fill uniformly and widespread both the thin walls than those more massive, so avoiding both the crack formation than the porosity inside the jet, what often occurs in the known casting methods that provide one or at most two sprues and one or two vent channels with pieces of big dimension. These and others aims and advantages of the present invented process are more evident in the following description of a preferred embodiment but not exclusive with reference to the enclosed drawings, wherein the invented process is illustrated in a merely and not limiting way.

Brief description of the drawings.

Figure 1 is section view of an mold with plurality of sprues and plurality of vent channels with shape for sand casting. Figure 2 is perspective vies of a jet obtained with the casting process according the invention, i.e. with four sprues and five vent channels in the sand casting. Detailed description.

The casting process with 6000 series and 1000 series alloys comprises at least two sprues 1 and at least three vent channels 2 wherein, introducing cast aluminum alloys 3 into the shape 4 by the plurality of sprues 1 and with air outflow and of the excess molten material from the plurality of vent channels 2, the aluminum alloy flows in less time, allowing to also use alloys with low silicon content, with increasing of the filling speed of the shape 4. The number of the sprues 1 and of the vent channels 2 changes in relation to the piece to work and it is stated in advance to a thermodymanic/fluid dedicated simulated program. The sprues 1 and the vent channels 2 are in number very high in comparison with the known art. The casting method according the invention comprise the use of the alloy AIMgSi 0,5. Further said process uses also the alloy Al 99,5. Further, the casting process with more sprues and more vent channels permits to use also all the aluminum alloys. The plurality of sprues and of vent channels low lastly the inside tensions of the material in the passage from liquid state to the solid one. thanks to a more effective cooling due to the sliding of the material in more short routes given to the presence of sprues and vent channels close to each other and in number stated by flux and temperature simulation programs. In working the casting process with 6000 series and 1000 series alloys provides the filling from at least a ladle 5 with melting material 6 into the sprues 1 inside the shape 4, with exit of the air and of the cast aluminum 3 from the vent channels 2. Having a plurality of sprues 1 and of vent channels 2 the casting can be arranged without introduce silicon in high quantity. The minor presence of silicon in the jet gives to the obtained casting particular characteristics, such as raising of the casting point and of the thermal conductivity. This permits to use the casting piece for heat sinks with fins, both obtained in a sole casting body than added, finned containers for electronic components, cooling plates, cooling bodies for electric motors or similar. Further, these components, obtained with the invented process, has the advantage to permit welding/soldering processes not possible with the jets obtained with the known casting technologies. Further, having more sprues and more vent channels is increased the production velocity, being possible to actuate the cast from more ladles placed in parallel. The number and the dimension of the plurality of sprues 1 and of vent channels 2 change in relation to the jet to be obtained. The invention process is possible of numerous variations al part of the invented object. All the particulars can be changed with other technically equivalent without going out from the protection field given to the claims.