JP2007181874A - Manufacturing method of aluminum alloy casting material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an aluminum alloy casting material capable of providing a material suitable for a semi-solid molding process simply at low costs without using a large manufacturing apparatus. <P>SOLUTION: The manufacturing method of the aluminum alloy casting material is used to produce the material suitable for the semi-solid molding by pouring an aluminum alloy molten metal into a cylindrical stainless container 1, on condition that the temperature of the aluminum alloy molten metal poured in the stainless steel container 1 is 640°C or lower; the temperature of the stainless steel container 1 is 300°C or lower, and the inner diameter of which is 5 cm or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an aluminum alloy casting material that obtains a material suitable for semi-melt molding by pouring molten aluminum alloy into a stainless steel container.

  The semi-molten molding method is a method of filling a mold with a semi-molten material (for example, an aluminum alloy casting material) in which a solid phase and a liquid phase coexist, and then cooling and solidifying to obtain a product. It is roughly divided into a rheocasting method in which a liquid material is cooled and solidified to obtain a semi-molten material, and a thixocasting method in which the solidified material is reheated to obtain a semi-molten material. Since such a semi-melt molding method can be molded from the solid-liquid coexistence region, it has the effect of increasing the cooling rate and improving the mechanical properties of the product, and has been attracting attention in recent years.

  However, if the cooling rate is increased, the solidification at the time of molding is naturally increased. Therefore, molding may be difficult unless the material is filled in the mold in a short time. Therefore, the fluidity (that is, the filling property) to the mold is good, and the semi-molten material that can be filled in the mold in a short time is suitable for the semi-melt molding. It is necessary to use a semi-molten material with a granulated solid phase (primary crystal).

  In order to obtain such a semi-molten material, conventionally, the molten metal is mechanically or electromagnetically stirred, and the generated dendritic crystals (dendrites) are sheared to obtain an equiaxed primary crystal or granulation. Although it does not go, internal strain is generated by solidifying while splitting the dendrites, or internal strain is generated by plastic processing of the material, and those materials are reheated to be in a semi-molten state. In some cases, a method of granulating a solid phase using a recrystallization phenomenon due to strain has been proposed. Specifically, a billet is manufactured while electromagnetically stirring from the outside of the stainless steel container in which the molten metal is contained, or being forcedly stirred by applying electromagnetic force from the outside of the jacket portion of the continuous casting apparatus. The aluminum alloy casting material (semi-molten material) suitable for the semi-molten forming method was obtained by the method of making it into a semi-molten state by heating. In addition, since this prior art does not relate to the literature known invention, there is no prior art document information to be described.

  However, in the above-described conventional method for producing an aluminum alloy casting material, it is necessary to shear the dendritic solid phase by stirring, so a stirring device (such as an electromagnetic stirring device) is required, and the manufacturing device is large. There is a problem that the manufacturing cost increases. Therefore, the present applicant has found that when the crystal nucleus grows as it solidifies, the solid phase becomes granulated by controlling the cooling under a predetermined condition, and the aluminum alloy casting suitable for the semi-melt molding method. We have intensively studied to manufacture the material more easily and at low cost.

  The present invention has been made in view of such circumstances, and manufacture of an aluminum alloy casting material that can easily and inexpensively obtain a material suitable for a semi-melt forming method without using a large-scale manufacturing apparatus. It is to provide a method.

  The invention according to claim 1 is a method for producing an aluminum alloy casting material in which a material suitable for semi-molten forming is obtained by pouring molten aluminum alloy into a cylindrical stainless steel container. The temperature of the molten aluminum alloy is 640 ° C. or less, the temperature of the stainless steel container is 300 ° C. or less, and the inner diameter is 5 inches or less.

  The invention according to claim 2 is a method for producing an aluminum alloy casting material in which a material suitable for semi-molten forming is obtained by pouring molten aluminum alloy into a cylindrical stainless steel container. The temperature of the molten aluminum alloy is 640 ° C. or less, the temperature of the stainless steel container is 400 ° C. or less, the inner diameter is 6 inches, and the wall thickness is 7 mm or more.

  According to the first and second aspects of the invention, the equiaxed crystal can be obtained simply by setting the temperature of the molten aluminum alloy poured into the stainless steel container, the size (inner diameter) of the stainless steel container and the temperature thereof to predetermined conditions. Therefore, an aluminum alloy casting material suitable for the semi-melt molding method can be obtained easily and at a low cost without using a large-scale production apparatus.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The method for producing an aluminum alloy casting material according to the present embodiment is for pouring molten aluminum alloy into a stainless steel container under a predetermined condition. As shown in FIG. 1, in the holding furnace 2 obtained by heating. This aluminum alloy molten metal is introduced into a cylindrical stainless steel container 1 having an inner diameter D and a wall thickness L to obtain an aluminum alloy casting material suitable for the semi-melt molding method.

  In the manufacturing process, when the stainless steel container 1 having an inner diameter D of 5 inches or less is used, the temperature of the molten aluminum alloy poured into the stainless steel container 1 is 640 ° C. or less, and the temperature of the stainless steel container 1 is It is 300 degrees C or less. That is, assuming that the temperature of the molten aluminum alloy to be poured and the temperature and inner diameter of the stainless steel container are the above conditions, the aluminum alloy molten metal in the holding furnace 2 is simply filled into the stainless steel container 1 and is equiaxed and granular. A material with a transformed primary crystal is obtained.

  When the stainless steel container 1 having an inner diameter D of 6 inches is used, the temperature of the molten aluminum alloy poured into the stainless steel container 1 is 640 ° C. or less, the temperature of the stainless steel container 1 is 400 ° C. or less, and the stainless steel container The wall thickness L of 1 is 7 mm or more. That is, also in this case, if the temperature of the molten aluminum alloy and the temperature, inner diameter and thickness of the stainless steel container are set as the above conditions, the molten aluminum alloy in the holding furnace 2 is simply filled in the stainless steel container 1. A material having an equiaxed granulated primary crystal can be obtained. However, the aluminum alloy cast material (semi-molten material) obtained by the above manufacturing method is once naturally solidified and stored, and after reheating to a semi-molten state, it is filled while pressing into the mold cavity. Trying to get the product.

  Hereinafter, an experiment that can prove the technical superiority of the present embodiment will be described. In such experimental results, the aluminum alloy casting materials according to the example and the comparative example were each manufactured under predetermined conditions, naturally cooled, and then compared with micrographs when reheated to a semi-melting temperature range. It is a thing.

First, an experiment was conducted on the influence of the temperature of the stainless steel container when a stainless steel container having an inner diameter D of 3 inches was used. Of course, other conditions are substantially the same (in particular, the pouring temperature is 635 ° C. or less).
(Example 1) The temperature of the stainless steel container is 300 ° C., and the thickness L is 10 mm.
(Example 2) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 6 mm.
(Example 3) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 4 mm.
(Example 4) The temperature of the stainless steel container is 300 ° C, and the thickness L is 0.5 mm.
(Comparative example 1) The temperature of the stainless steel container is 400 ° C., and the thickness L is 4 mm.
(Comparative example 2) The temperature of the stainless steel container is 400 ° C., and the thickness L is 2 mm.
(Comparative example 3) The temperature of the stainless steel container is 400 ° C., and the thickness L is 0.5 mm.
(Comparative example 4) The temperature of the stainless steel container is 500 ° C., and the thickness L is 10 mm.
(Comparative example 5) The temperature of the stainless steel container is 500 ° C., and the thickness L is 6 mm.

  The micrographs in Examples 1 to 4 and Comparative Examples 1 to 5 are shown in FIGS. Example 1 is shown in FIG. 2 (a), Example 2 is shown in FIG. 2 (b), Example 3 is shown in FIG. 2 (c), and Example 4 is shown in FIG. 1 is shown in FIG. 3A, Comparative Example 2 is shown in FIG. 3B, Comparative Example 3 is shown in FIG. 3C, Comparative Example 4 is shown in FIG. 3D, and Comparative Example 5 is shown in FIG. Has been.

  According to these micrographs, the shapes of solid phases (relatively white portions in the figure) can be compared, and those of Examples 1 to 4 are solid phase (primary crystals) granulated with equiaxed crystals. ) Was obtained, while those of Comparative Examples 1 to 5 were found to be amoeba-shaped solid phases. Therefore, it is recognized that Examples 1 to 4 are aluminum alloy casting materials that have good fluidity (that is, fillability) into the mold and can be filled in the mold in a short time.

  Similarly, Table 1 below shows the results of similar experiments in which the temperature and wall thickness L of the stainless steel container were performed under other conditions. The circles in the table indicate the solid phase (primary crystal) that is granulated with equiaxed crystals as shown in FIG. 1, and the crosses indicate the amoeba (rough shape) as shown in FIG. It became a solid phase.

  As can be seen from the above table, when a stainless steel container having an inner diameter D of 3 inches is used, if the temperature of the stainless steel container is set to 300 ° C. or less and the molten aluminum alloy is poured, a solid phase (initial Crystal) is formed, the fluidity (that is, the filling property) to the mold is good, and an aluminum alloy casting material that can be filled in the mold in a short time can be obtained.

Next, it experimented about the influence of the temperature of the said stainless steel container when the internal diameter D used the stainless steel container of 4 inches. Of course, other conditions are substantially the same (in particular, the pouring temperature is 635 ° C. or less).
(Example 5) The temperature of the stainless steel container is 300 ° C., and the thickness L is 10 mm.
(Example 6) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 7 mm.
(Example 7) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 5 mm.
(Example 8) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 0.5 mm.
(Comparative Example 6) The temperature of the stainless steel container is 400 ° C, and the wall thickness L is 10 mm.
(Comparative example 7) The temperature of the stainless steel container is 400 ° C., and the thickness L is 0.5 mm.
(Comparative Example 8) The temperature of the stainless steel container is 500 ° C., and the thickness L is 5 mm.

  The micrographs in Examples 5 to 8 and Comparative Examples 6 to 8 are shown in FIGS. Example 5 is shown in FIG. 4 (a), Example 6 is shown in FIG. 4 (b), Example 7 is shown in FIG. 4 (c), and Example 8 is shown in FIG. 6 is shown in FIG. 5A, Comparative Example 7 is shown in FIG. 5B, and Comparative Example 8 is shown in FIG.

  According to these micrographs, the shapes of solid phases (relatively white portions in the figure) can be compared, and those of Examples 5 to 8 are solid phase (primary crystals) granulated with equiaxed crystals. On the other hand, it can be seen that those in Comparative Examples 6 to 8 are amoeba-like solid phases. Therefore, it is recognized that Examples 5 to 8 are aluminum alloy casting materials that have good fluidity (that is, fillability) into the mold and can be filled in the mold in a short time.

  Similarly, Table 2 below shows the results of experiments in which the temperature and wall thickness L of the stainless steel container were performed under other conditions. The circles in the table indicate the solid phase (primary crystal) granulated with equiaxed crystals as shown in FIG. 4, and the crosses are in the shape of an amoeba (irregular shape) as shown in FIG. It became a solid phase.

  As can be seen from the above table, when a stainless steel container having an inner diameter D of 4 inches is used and the temperature of the stainless steel container is set to 300 ° C. or less and the molten aluminum alloy is poured, a solid phase (initial Crystal) is formed, the fluidity (that is, the filling property) to the mold is good, and an aluminum alloy casting material that can be filled in the mold in a short time can be obtained.

Next, an experiment was conducted on the influence of the temperature of the stainless steel container when a stainless steel container having an inner diameter D of 5 inches was used. Of course, other conditions are substantially the same (in particular, the pouring temperature is 635 ° C. or less).
(Example 9) The temperature of the stainless steel container is 300 ° C., and the wall thickness L is 10 mm.
(Example 10) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 5 mm.
(Example 11) The temperature of the stainless steel container is 300 ° C, and the wall thickness L is 0.5 mm.
(Comparative Example 9) The temperature of the stainless steel container is 400 ° C., and the thickness L is 10 mm.
(Comparative Example 10) The temperature of the stainless steel container is 400 ° C., and the thickness L is 5 mm.
(Comparative Example 11) The temperature of the stainless steel container is 400 ° C., and the wall thickness L is 0.5 mm.

  The micrographs in Examples 9 to 11 and Comparative Examples 9 to 11 are shown in FIGS. Example 9 is shown in FIG. 6A, Example 10 is shown in FIG. 6B, and Example 11 is shown in FIG. 6C. Comparative Example 9 is shown in FIG. 10 (b) and Comparative Example 11 are shown in FIG.

  According to these micrographs, the shapes of solid phases (relatively white portions in the figure) can be compared, and those of Examples 9 to 11 are solid phase (primary crystals) granulated with equiaxed crystals. ) Was obtained, while those of Comparative Examples 9 to 11 were found to be amoeba (irregular) solid phases. Therefore, the examples 9 to 11 have good fluidity (that is, filling property) into the mold, and are recognized as aluminum alloy casting materials that can be filled in the mold in a short time.

  Similarly, Table 3 below shows the results of experiments in which the temperature and thickness L of the stainless steel container were performed under other conditions. The circles in the table indicate the solid phase (primary crystal) that is granulated with equiaxed crystals as shown in FIG. It became a solid phase.

  As can be seen from the above table, when a stainless steel container having an inner diameter D of 5 inches is used, if the temperature of the stainless steel container is set to 300 ° C. or less and the molten aluminum alloy is poured, a solid phase (initial Crystal) is formed, the fluidity (that is, the filling property) to the mold is good, and an aluminum alloy casting material that can be filled in the mold in a short time can be obtained.

Next, an experiment was conducted on the influence of the temperature of the stainless steel container when a stainless steel container having an inner diameter D of 6 inches was used. Of course, other conditions are substantially the same (in particular, the pouring temperature is 635 ° C. or less).
(Example 12) The temperature of the stainless steel container is normal temperature and the wall thickness L is 7 mm.
(Example 13) The temperature of the stainless steel container is 400 ° C., and the thickness L is 10 mm.
(Example 14) The temperature of a stainless steel container is 400 ° C, and the thickness L is 7 mm.
(Comparative example 12) The temperature of the stainless steel container is normal temperature, and the thickness L is 5 mm.
(Comparative example 13) The temperature of the stainless steel container is 400 ° C., and the thickness L is 5 mm.
(Comparative Example 14) The temperature of the stainless steel container is 500 ° C., and the thickness L is 10 mm.

  The micrographs in Examples 12 to 14 and Comparative Examples 12 to 14 are shown in FIGS. Example 12 is shown in FIG. 8 (a), Example 13 is shown in FIG. 8 (b), and Example 14 is shown in FIG. 8 (c). Comparative example 12 is shown in FIG. 9 (a), Comparative example. 13 is shown in the same figure (b) and the comparative example 14 is shown in the same figure (c).

  According to these micrographs, the shapes of solid phases (relatively white portions in the figure) can be compared, and those of Examples 12 to 14 are solid phase (primary crystals) granulated with equiaxed crystals. ) Was obtained, while those of Comparative Examples 12 to 14 were found to be amoeba-like solid phases. Therefore, it is recognized that Examples 12 to 14 are aluminum alloy casting materials that have good fluidity (that is, fillability) into the mold and can be filled in the mold in a short time.

  Similarly, Table 4 below shows the results of an experiment in which the temperature and thickness L of the stainless steel container were measured under other conditions. The circles in the table are obtained by obtaining a solid phase (primary crystal) granulated with equiaxed crystals as shown in FIG. 8, and the crosses are in an amoeba (rough shape) as shown in FIG. It became a solid phase.

  As can be seen from the above table, when a stainless steel container having an inner diameter D of 6 inches is used, the temperature of the stainless steel container is set to 400 ° C. or less, and the thickness of the stainless steel container is 7 mm or more. Is poured, a solid phase (primary crystal) granulated with equiaxed crystals is formed, the fluidity (that is, the filling property) to the mold is good, and the mold can be filled in a short time. An aluminum alloy casting material can be obtained.

Next, it experimented about the influence of the pouring temperature (temperature of the molten aluminum alloy to pour) in the case of using a stainless steel container having an inner diameter D of 3 inches. Of course, other conditions are substantially the same.
(Example 15) The temperature of the stainless steel container is 100 ° C, and the pouring temperature is 635 ° C.
(Comparative example 15) The temperature of the stainless steel container is 100 ° C, and the pouring temperature is 680 ° C.
(Comparative Example 16) Stainless steel container temperature is 100 ° C, pouring temperature is 665 ° C
(Comparative example 17) The temperature of the stainless steel container is 100 ° C, and the pouring temperature is 645 ° C.

  The micrographs in Example 15 and Comparative Examples 15 to 17 are shown in FIG. In addition, Example 15 is shown by the same figure (a), the comparative example 15 is shown by the same figure (b), the comparative example 16 is shown by the same figure (c), and the comparative example 17 is shown by the same figure (d). ing.

  According to these photomicrographs, the shapes of the solid phase (relatively white portions in the figure) can be compared, and in Example 15, a solid phase (primary crystal) granulated with equiaxed crystals is obtained. On the other hand, it can be seen that those in Comparative Examples 15 to 17 are dendritic solid phases. Therefore, it is recognized that Example 15 is an aluminum alloy casting material that has good fluidity (that is, filling property) into the mold and can be filled in the mold in a short time.

  Similarly, Table 5 below shows the results of experiments in which the temperature and thickness L of the stainless steel container were performed under other conditions. The circles in the table indicate solid phases (primary crystals) granulated with equiaxed crystals as shown in FIG. 10 (a), and the crosses indicate the same figures (b) to (d). It becomes a dendritic solid phase like this.

  As can be seen from the above table, if the temperature of the stainless steel container is set to 300 ° C. or lower and the pouring temperature is set to 640 ° C. or lower and the molten aluminum alloy is poured, a solid phase (primary crystal) granulated with equiaxed crystals. Is formed, the fluidity (that is, the filling property) to the mold is good, and an aluminum alloy casting material that can be filled in the mold in a short time can be obtained.

  As is clear from Examples 1 to 15 in the above experiment, the temperature of the molten aluminum alloy poured into the stainless steel container is 640 ° C. or less, the temperature of the stainless steel container is 300 ° C. or less, and its inner diameter is 5 inches or less. Conditions were set such that the temperature of the molten aluminum alloy poured into the stainless steel container was 640 ° C. or less, the temperature of the stainless steel container was 400 ° C. or less, the inner diameter was 6 inches, and the wall thickness was 7 mm or more. Then, by simply filling the stainless steel container 1 with the molten aluminum alloy in the holding furnace 2, it is possible to obtain a primary crystal granulated with equiaxed crystals, so that it is simple and low without using a large-scale manufacturing apparatus. An aluminum alloy casting material suitable for the semi-melt molding method can be obtained at a low cost.

  Here, in the present invention, the aluminum alloy cast material (semi-molten material) obtained by the production method as described above is once naturally solidified and stored, and is reheated to be in a semi-molten state, and then the mold is molded. In addition to what is filled into the cavity of the mold to obtain a product (thixocasting), the aluminum alloy cast material (semi-molten material) obtained by the production method is filled into the mold cavity while being pressed. It can be applied to both obtaining products (reocasting). That is, even when the molten aluminum alloy poured into the container under the above conditions is cooled to the semi-molten temperature range and kept as it is, the result is obtained in the same manner as when reheated after natural cooling and solidification. Regardless of thixocasting and rheocasting, an aluminum alloy casting material suitable for the semi-melt molding method can be obtained under the above production conditions.

  The temperature of the molten aluminum alloy poured into the stainless steel container is 640 ° C. or less, the temperature of the stainless steel container is 300 ° C. or less and the inner diameter is 5 inches or less, or the temperature of the molten aluminum alloy poured into the stainless steel container is An aluminum alloy casting material manufacturing method for obtaining a material suitable for semi-melt molding under conditions of 640 ° C. or lower, a temperature of the stainless steel container of 400 ° C. or lower, an inner diameter of 6 inches, and a wall thickness of 7 mm or more. If so, the present invention can also be applied to those to which other manufacturing processes are added.

The schematic diagram for demonstrating the manufacturing method of the aluminum alloy casting raw material which concerns on embodiment of this invention. Micrographs of Examples 1 to 4 of the present invention Micrographs of Comparative Examples 1 to 5 of the present invention Micrographs of Examples 5 to 8 of the present invention Micrographs of Comparative Examples 6 to 8 of the present invention Micrographs of Examples 9 to 11 of the present invention Micrographs of Comparative Examples 9 to 11 of the present invention Micrographs of Examples 12 to 14 of the present invention Micrographs of Comparative Examples 12 to 14 of the present invention Micrographs of Example 15 and Comparative Examples 15 to 17 of the present invention

Explanation of symbols

1 Stainless steel container 2 Holding furnace D Inner diameter L Thickness

Claims (2)

In the method for producing an aluminum alloy casting material, by pouring molten aluminum alloy into a cylindrical stainless steel container, a material suitable for semi-melt molding is obtained.
Manufacturing of an aluminum alloy casting material characterized in that the temperature of the molten aluminum alloy poured into the stainless steel container is 640 ° C. or lower, the temperature of the stainless steel container is 300 ° C. or lower, and its inner diameter is 5 inches or less. Method. In the method for producing an aluminum alloy casting material, by pouring molten aluminum alloy into a cylindrical stainless steel container, a material suitable for semi-melt molding is obtained.
The temperature of the molten aluminum alloy poured into the stainless steel container is 640 ° C. or less, the temperature of the stainless steel container is 400 ° C. or less, the inner diameter is 6 inches, and the wall thickness is 7 mm or more. A method for producing an aluminum alloy casting material.