METHOD OF MANUFACTURING AL ALLOY CAST MATERIAL

Abstract

Provided is a method of producing an Al alloy cast material capable of properly adjusting an additive amount of Ti. The present invention is directed to a method of producing an Al alloy cast material in which an Al alloy molten metal supplied to a casting machine through a molten metal passage is solidified by the casting machine to produce an Al alloy cast material. The production method of the present invention includes a primary Ti-addition step of preliminarily adding Ti to an Al alloy molten metal before flowing through a molten metal passage and a secondary Ti-addition step of adding Ti to an Al alloy molten metal flowing through a molten metal passage by a feeder.

Description

TECHNICAL FIELD

The present invention relates to a method of producing an Al alloy cast material for producing an Al alloy cast material which can be preferably used as a material of, for example, an aluminum (Al) alloy plastic worked product, and also relates to the related technique thereof.

BACKGROUND ART

The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.

In recent years, Al alloy plastic worked products are often used as structural materials (parts) of transportation machines, such as, e.g., vehicles, ships, aircrafts, automobiles, and motorcycles, which are required to have high strength and high corrosion resistance.

As an example of an Al alloy plastic worked product of such a structural material for use in a transportation machine, for automotive parts such as suspension arms, a plastic worked product made of an Al—Mg—Si based alloy which is excellent in workability and has both high strength and high corrosion resistance is used for weight reduction of a car body. Among Al—Mg—Si based alloys, an A6061 alloy is particularly frequently used, but high strength is required to further reduce the weight, and therefore improvements on the material side of Al alloys are being made.

For example, in order to increase the strength of an Al—Mg—Si based alloy, increasing the amount of excess Si or the additive amount of a Cu element has been performed. Particularly, a Cu element promotes precipitation of Mg₂Si and solidly dissolves in the matrix to contribute greatly to the improvement of the strength, so increasing the additive amount is an effective means for increasing the strength.

However, when the amount of the Cu element added for high strength exceeds a predetermined amount, the susceptibility of intergranular corrosion increases, which may cause stress corrosion cracking when used under a corrosive environment.

In addition, as disclosed in Patent Document 1 described below, adding Ti is also well known as an effective means in order to achieve high strength of an Al—Mg—Si based alloy. Ti is a refining element, and achieves refinement of crystal grains by the influence during solidification to greatly contribute to the strength improvement.

When adding Ti, for example, an Al alloy containing Ti-B is used, and an Al-5% Ti-1% B alloy is suitably used. It is said that it is most effective to add Ti immediately before casting. For this reason, conventionally, it is common to add Ti to an Al alloy molten metal using a rod feeder immediately before injecting an Al alloy molten metal into a casting machine, for example, in a casting trough for supplying an Al alloy molten metal to the casting machine.

PRIOR ART

Patent Document

Patent Document 1: Japanese Patent No. 5275321

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, in the aforementioned conventional method of producing an Al alloy cast material, Ti is added immediately before casting by using a rod feeder. Therefore, in some cases, Ti-B cannot be added sufficiently, which may result in insufficient strength. For example, in the case of adding Ti with a rod feeder, if the casting speed is increased, the amount (flow rate) flowing per unit time in an Al alloy molten metal flowing in the casting trough also increases. For this reason, the feeding capability by the rod feeder cannot follow the increased flow rate, which may sometimes result in insufficient Ti additive amount. Then, as described above, it is impossible to add an appropriate amount of Ti, which may result in insufficient strength of the Al alloy cast material.

In the above description, the case of producing a cast material of an Al—Mg—Si based alloy has been described by way of example. However, even in the case of producing a cast material of an Al alloy other than an Al—Mg—Si based alloy, similar problems arise when adding Ti.

The disclosed embodiments of this disclosure have been developed in view of the above-mentioned and/or other problems in the related art. The disclosed embodiments of this disclosure can significantly improve upon existing methods and/or apparatuses.

The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a method of producing an Al alloy cast material capable of appropriately adjusting an additive amount of Ti and producing a high strength Al alloy cast material and its related technology.

The other purposes and advantages of some embodiments of the present invention will be made apparent from the following preferred embodiments.

Means for Solving the Problems

In order to solve the aforementioned problems, the present invention provides the following means.

[1] A method of producing an Al alloy cast material in which an Al alloy molten metal supplied to a casting machine through a molten metal passage is solidified by the casting machine to produce an Al alloy cast material, the method comprising:

a primary Ti-addition step of preliminarily adding Ti to an Al alloy molten metal before flowing through the molten metal passage; and

a secondary Ti-addition step of adding Ti to the Al alloy molten metal flowing through the molten metal passage by a feeder.

[2] The method of producing an Al alloy cast material as recited in the aforementioned Item [1], wherein the Al alloy molten metal is composed of an Al—Mg—Si based alloy.

[3] The method of producing an Al alloy cast material as recited in the aforementioned Item [1] or [2], wherein when an additive amount of Ti to be added in the primary Ti-addition step is defined as “X” mass %, an additive amount of Ti to be added in the secondary Ti-addition step is adjusted to “0.1X” mass % to “2X” mass %.

[4] The method of producing an Al alloy cast material as recited in any one of the aforementioned Items [1] to [3],

wherein a time from an addition of Ti in the primary Ti-addition step to an addition of Ti in the secondary Ti-addition step is adjusted so as to fall within 5 minutes to 30 minutes.

[5] The method of producing an Al alloy cast material as recited in the aforementioned Item [2],

wherein a molten metal temperature in the molten metal passage is adjusted to 700° C.±30° C.

[6] A method of producing an Al alloy plastic worked product, comprising:

plastically working the Al alloy cast material produced by the method as recited in any one of the aforementioned Items [1] to [5] to produce an Al alloy plastic worked product.

[7] The method of producing an Al alloy plastic worked product as recited in the aforementioned Item [6],

wherein the Al alloy plastic worked product is used as a structural material of a transportation machine.

[8] A production apparatus of an Al alloy cast material, comprising:

a molten metal reservoir configured to store a Ti-added Al alloy molten metal;

a casting machine configured to cast an Al alloy cast material by solidifying an Al molten metal;

a molten metal passage configured to supply the Al alloy molten metal stored in the molten metal reservoir to the casting machine; and

a feeder configured to add Ti to the Al alloy molten metal flowing through the molten metal passage.

[9] The production apparatus of an Al alloy cast material as recited in the aforementioned Item [8],

wherein the molten metal reservoir is configured by a melting furnace for melting an Al alloy material or a holding furnace for performing a temperature adjustment of the Al alloy molten metal.

[10] The production apparatus of an Al alloy cast material as recited in the aforementioned Item [8],

wherein the molten metal reservoir is configured by a melting/holding furnace which serves as both a melting furnace for melting an Al alloy material and a holding furnace for performing a temperature adjustment of the Al alloy molten metal.

Effects of the Invention

According to the method of producing an Al alloy cast material of the invention recited in the aforementioned Item [1], since Ti is added in two steps of the primary Ti-addition step and the secondary Ti-addition step, it is possible to reliably add an appropriate amount of Ti. Accordingly, it is possible to prevent problems due to insufficient addition of Ti and to reliably produce an Al alloy cast material having sufficient strength.

According to the method of producing an Al alloy cast material of the invention recited in the aforementioned Item [2], an Al—Mg—Si based alloy excellent in workability, high in strength and high in corrosion resistance is used as the Al alloy. Therefore, it is possible to provide an Al alloy cast material having higher strength and corrosion resistance.

According to the method of producing an Al alloy cast material of the invention recited in the aforementioned Item [3], the Ti additive amount in the secondary Ti-addition step is set to a specific range with respect to the Ti additive amount in the primary Ti-addition step. Therefore, it is possible to add Ti effectively to thereby more reliably produce a high strength and high quality Al alloy cast material.

According to the method of producing an Al alloy cast material of the invention recited in the aforementioned Item [4], the time from the primary Ti-addition step to the secondary Ti-addition step is set within a specific range. For this reason, it is possible to add Ti more effectively to thereby more reliably produce a high strength and high quality Al alloy cast material.

According to the method of producing an Al alloy cast material of the invention recited in the aforementioned Item [5], in the secondary Ti-addition step, the molten metal temperature of the Al alloy molten metal is set within a specific range. For this reason, the addition of Ti in the secondary Ti-addition step can be performed more effectively.

According to the method of production an Al alloy plastic worked product of invention [6], the Al alloy cast material according to the aforementioned method invention is used. Therefore, an Al alloy plastic worked product having sufficient strength can be reliably produced in the same manner as described above.

According to the method of producing an Al alloy plastic worked product of the invention recited in the aforementioned Item [7], a structural material of a transportation machine with sufficient strength can be provided.

According to the production apparatus of an Al alloy cast material recited in the aforementioned Item [8], it is possible to implement the invention recited in the aforementioned Item [1]. Therefore, an Al alloy cast material having sufficient strength can be assuredly produced in the same manner as described above.

According to the production apparatus of an Al alloy cast material as recited in the aforementioned Items [9] and [10], the above-described effects can be obtained more assuredly.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures.

FIG. 1 is a block diagram showing a production apparatus to which the method of producing an aluminum alloy cast material according to an embodiment of the present invention can be applied.

FIG. 2 is a block diagram showing a production apparatus to which the method of producing an aluminum alloy cast material according to a modified embodiment of the present invention can be applied.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

In the following paragraphs, some preferred embodiments of the invention will be described by way of example and not limitation. It should be understood based on this disclosure that various other modifications can be made by those in the art based on these illustrated embodiments.

FIG. 1 is a block diagram showing a production apparatus of an Al alloy cast material for carrying out the method of producing an aluminum alloy cast material according to an embodiment of the present invention.

As shown in the figure, the production apparatus of an Al alloy cast material of this embodiment includes a melting furnace 11, a first trough 21, a holding furnace 12, a second trough 22, a molten metal treatment device 3, a casting trough 4, a rod feeder 5, and a casting machine 6 as basic constituent elements.

The melting furnace 11 is configured to melt an Al alloy material to produce an Al alloy molten metal W1.

The first trough 21 is configured to flow the Al alloy molten metal W1 in the melting furnace 11 along the trough 21 to supply the Al alloy molten metal to the holding furnace 12.

The holding furnace 12 is configured to stabilize the Al alloy molten metal W1 by adjusting the components such as degassing while adjusting the Al alloy molten metal W1 to an optimum temperature.

The second trough 22 is configured to flow the Al alloy molten metal W1 in the holding furnace 12 along the trough 22 to supply the Al alloy molten metal to the molten metal treatment device 3.

The molten metal treatment device 3 is configured to remove impurities in the Al alloy molten metal W1 by using a bubbling action, etc.

The casting trough 4 is configured to flow the Al alloy molten metal W1 in the molten metal treatment device 3 along the trough 4 to supply the Al alloy molten metal to the casting machine 6. In this embodiment, the molten metal passage is configured by this casting trough 4.

The rod feeder 5 is configured to add Ti to the Al alloy molten metal W1 flowing through the casting trough 4. The rod feeder 5 of this embodiment is provided with a coil 52 in which a rod 51 (Ti-containing material) made of an Al—Ti alloy or an Al—Ti—B alloy is wound, and is configured to add Ti to the Al alloy molten metal W1 flowing through the casting trough 4 by appropriately rewinding the rod 51 from the coil 52.

The casting machine 6 is configured by a vertical semi-continuous casting machine. In the casting machine 6 of this embodiment, the Al alloy molten metal W1 supplied from the casting trough 4 into the casting machine 6 solidifies while passing through the mold 61. The solidified Al alloy ingot W2 is fed downward together with the lower die 63 while being cooled down by the cooling water supplied from the cooler 62. Thus, a bar-shaped Al alloy ingot W2 (Al alloy cast material) such as an Al alloy billet and an Al alloy slab is cast.

In this embodiment, an Al—Mg—Si based alloy cast material to which Ti is added is produced by using the above-described Al alloy cast material production apparatus.

That is, in the melting furnace 11, an Al—Mg—Si based Al alloy molten metal W1, which is a 6000 series Al alloy (6000 series Al alloy), is produced by dissolving a predetermined alloy material. The Al alloy molten metal W1 is supplied to the holding furnace 12 through the first trough 21, and the temperature adjustment, etc., of the Al alloy molten metal W1 are performed. Subsequently, the Al alloy molten metal W1 is supplied from the holding furnace 12 to the molten metal treatment device 3 via the second trough 22.

In this embodiment, Ti is added in the melting furnace 11 or the holding furnace 12. For example, in the case where Ti is added in the melting furnace 11, Ti is added by melting an Al—Ti alloy or an Al—Ti—B alloy together with the aforementioned alloy material in the melting furnace 11. Further, in the case where Ti is added in the holding furnace 12, Ti is added by introducing an Al—Ti alloy or an Al—Ti—B alloy into the Al alloy molten metal in the holding furnace 12.

In this embodiment, the step of adding Ti in the melting furnace 11 or the holding furnace 12 is referred to as a primary Ti-addition step. Further, in this embodiment, among the melting furnace 11 and holding furnace 12, a molten metal reservoir is constituted by the furnace in which Ti is added.

The Al alloy molten metal W1 supplied to the molten metal treatment device 3 flows through the casting trough 4 and is supplied to the casting machine 6 after impurities are removed.

In this embodiment, Ti is added to the Al alloy molten metal W1 flowing through the casting trough 4. That is, as described above, in the rod feeder 5, the rod 51 (Ti-containing material) of an Al—Ti alloy or an Al—Ti—B alloy wound in a coil shape is appropriately rewound so as to be introduced into the Al alloy molten flowing metal W1 in the casting trough 4 to thereby add Ti. In this embodiment, the step of adding Ti by the rod feeder 5 is referred to as a secondary Ti-addition step.

The Al alloy molten metal W1 supplied to the casting machine 6 is solidified and the solidified Al alloy ingot W2 is fed downward to produce a rod-shaped Al alloy ingot W2.

In this embodiment, the additive amount (mass %) of Ti in the secondary Ti-addition step is preferably set so as to fall within the range of 0.1 times to 2 times with respect to the additive amount (mass %) of Ti in the primary Ti-addition step. In other words, when an additive amount of Ti to be added in the primary Ti-addition step is defined as “X” mass %, the Ti additive amount in the secondary Ti-addition step is preferably set to “0.1X” mass % to “2X” mass %. That is, in cases where the Ti additive amount in the secondary Ti-addition step by the rod feeder 5 is too large (in the case of more than 2×), for the purpose of preventing excessive addition of Ti, it is required to relatively increase the flowing rate of the Al alloy molten metal W1 in the casting trough 4. However, the casting speed becomes too fast, which makes it difficult to stabilize the quality of the Al alloy cast material W2, which is not preferable. On the other hand, when the Ti additive amount in the secondary Ti-addition step by the rod feeder 5 is too small (less than 0.1×), it may be difficult to obtain a sufficient strength improvement effect. The reason is as follows. Since it is said that it is most effective when Ti is added immediately before casting, it is more effective to add Ti in the secondary Ti-addition step than to add Ti in the primary Ti-addition step. Therefore, when the Ti additive amount in the secondary Ti-addition step is not sufficient, the additive amount of Ti in the primary Ti-addition step with less effect must be increased, making it difficult to obtain a sufficient strength improvement effect, which is not preferable.

Further in this embodiment, it is preferable to set the time from the addition of Ti in the primary Ti addition step to the addition of Ti in the secondary Ti addition step within 5 minutes to 30 minutes. In other words, considering the molten metal processing time in the melting furnace 1 and the holding furnace 2 and the molten metal velocity in the first trough 71 and the second trough 72, etc., it is difficult to construct a production facility in which the time from the primary Ti-addition step to the secondary Ti-addition step is less than 5 minutes in terms of structure, which is not preferable. As already mentioned, it is effective to add Ti immediately before casting. Therefore, if the time from the primary Ti-addition step to the secondary Ti-addition step exceeds 30 minutes, the time from the primary Ti-addition step to the casting becomes longer, and addition of Ti in the primary Ti-addition step becomes too quick. Therefore, the effect of addition of Ti in the primary Ti-addition step cannot be sufficiently obtained, which is not preferable.

Further in this embodiment, in the case of Al—Mg—Si based alloy, the molten metal temperature in the casting trough 4 when an Al—Ti alloy or an Al—Ti—B alloy is added from the rod feeder 5 is preferably 700° C.±30° C., or the liquidus temperature is preferably +55° C.±30° C.

The Al alloy cast material W2 of this embodiment produced by the above-described procedure is subjected to plastic working, such as, e.g., an extrusion process, a rolling process, a drawing process, and a forging process to produce an Al alloy plastic worked product.

Further, in this embodiment, the Al alloy plastic worked product can be suitably used as a structural material of a transportation machine, such as, e.g., a vehicle, a ship, an airplane, an automobile, and a motorcycle, which is required to have high strength and high corrosion resistance.

As described above, according to the method of production an Al alloy cast material of this embodiment, Ti is added in two steps of the primary Ti-addition step and the secondary Ti-addition step. Therefore, a sufficient amount of Ti can be added, and therefore the effect due to Ti addition can be obtained, that is, an Al alloy cast material having sufficient strength and corrosion resistance can be obtained.

Especially when merely carrying out the addition of Ti by the rod feeder 5 (corresponding to the secondary Ti-addition step) as in a conventional method, the supply capacity of Ti by the rod feeder 5 cannot follow as the casting speed increases, which may result in deteriorated strength due to the shortage of Ti. On the other hand, according to the production method of this embodiment, in addition to the Ti addition by the rod feeder 5 (secondary Ti-addition step), the primary Ti-addition step in which Ti is added in advance is performed. Therefore, even in the case where the supply capacity of Ti in the secondary Ti-addition step cannot follow, the deficiency can be reliably replenished in the primary Ti-addition step. Therefore, it is possible to assuredly add an appropriate amount of Ti, which can prevent the strength from being lowered due to the shortage of Ti and sufficient strength can be assuredly obtained.

Further, in this embodiment, since an Al—Mg—Si based alloy having excellent processability and high strength and high corrosion resistance is used as the Al alloy, an Al alloy cast material having higher strength and corrosion resistance can be produced, which in turn can provide an Al alloy plastic worked product having higher strength and corrosion resistance.

Further, in this embodiment, since the additive amount of Ti in the secondary Ti-addition step is set within the range of 0.1 times to 2 times with respect to the additive amount of Ti in the primary Ti-addition step, as already mentioned, it is possible to add Ti effectively, which enables more assured production of a high strength, high corrosion resistance and high quality Al alloy cast material.

Further, in this embodiment, since the time from the primary Ti-addition step to the secondary Ti-addition step is set within 5 minutes to 30 minutes, Ti can be added more effectively, which enables the production of an Al alloy cast material having high strength, high corrosion resistance and high quality in a more stable state.

In the above-described embodiment, the primary Ti-addition step is performed in the melting furnace 11 or the holding furnace 12, but not limited to this. In the present invention, the Ti addition in the primary Ti-addition step may be performed at any stage as long as it is performed before the Al alloy molten metal W1 flows through the casting trough 4 as the molten metal passage, that is, at the upstream side of the casting trough. For example, the addition of Ti in the primary Ti-addition step may be carried out in the first trough 21, in the second trough 22, or in the molten metal treatment device 3.

Further, in the above-described embodiment, the rod feeder 5 for supplying a Ti-containing material in the form of a rod or a wire rod is used for adding Ti in the secondary Ti-addition step, but the present invention is not limited to this. In the present invention, any feeder other than a rod feeder can be used. For example, a feeder for feeding a powdered or granular Ti-containing material to the Al alloy molten metal may also be used.

FIG. 2 is a block diagram showing a production apparatus of an Al alloy cast material for carrying out the method of producing an aluminum alloy cast material according to a modified embodiment of the present invention.

As shown in the drawing, in the production apparatus of an Al alloy cast material of this modified embodiment, the difference from the production apparatus of the embodiment shown in FIG. 1 is that the production apparatus of this modified embodiment is that a melting/holding furnace 10 is provided instead of the melting furnace 11 and the holding furnace 12 in the production apparatus of the above-described embodiment. This melting/holding furnace 10 serves both as the melting furnace 11 and the holding furnace 12, and also has the functions of both furnaces 11 and 12. In this modified embodiment, a molten metal reservoir is constituted by this melting/holding furnace 10.

In the production apparatus of the Al alloy cast material of this modified embodiment, the other configurations are substantially the same as those of the above embodiment, so the same or corresponding parts are denoted by the same reference numerals, and the redundant explanation will be omitted.

Even in the production apparatus of the Al alloy cast material of this modified embodiment, the same operational effects as those of the above embodiment can be obtained. Furthermore, in this production apparatus, since the single melting/holding furnace 10 serves as two melting furnace 11 and holding furnace 12, it is possible to reduce the size of the entire production facility.

INDUSTRIAL APPLICABILITY

The method of producing an Al alloy cast material according to the present invention can be suitably used in producing an Al alloy cast material used as a material for, e.g., an extruded material, an rolled material, a forged material of an Al alloy.

The present application claims priority to Japanese Patent Application No. 2018-24848 filed on Feb. 15, 2018, the entire disclosure of which is incorporated herein by reference in its entirety.

It should be understood that the terms and expressions used herein are used for explanation and have no intention to be used to construe in a limited manner, do not eliminate any equivalents of features shown and mentioned herein, and allow various modifications falling within the claimed scope of the present invention.

While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.

While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

DESCRIPTION OF REFERENCE SYMBOLS

• 10: melting/holding furnace (molten metal reservoir)
• 11: melting furnace (molten metal reservoir)
• 12: holding furnace (molten metal reservoir)
• 4: casting trough (molten metal passage)
• 5: rod feeder (feeder)
• 6: casting machine
• W1: Al alloy molten metal
• W2: Al alloy ingot (Al alloy cast material)

Claims

1. A method of producing an Al alloy cast material in which an Al alloy molten metal supplied to a casting machine through a molten metal passage is solidified by the casting machine to produce an Al alloy cast material, the method comprising:

a primary Ti-addition step of preliminarily adding Ti to an Al alloy molten metal before flowing through the molten metal passage; and

a secondary Ti-addition step of adding Ti to the Al alloy molten metal flowing through the molten metal passage by a feeder.

2. The method of producing an Al alloy cast material as recited in claim 1,

wherein the Al alloy molten metal is composed of an Al—Mg—Si based alloy.

3. The method of producing an Al alloy cast material as recited in claim 1,

wherein when an additive amount of Ti to be added in the primary Ti-addition step is defined as “X” mass %, an additive amount of Ti to be added in the secondary Ti-addition step is adjusted to “0.1X” mass % to “2X” mass %.

4. The method of producing an Al alloy cast material as recited in claim 1,

wherein a time from an addition of Ti in the primary Ti-addition step to an addition of Ti in the secondary Ti-addition step is adjusted so as to fall within 5 minutes to 30 minutes.

5. The method of producing an Al alloy cast material as recited in claim 2,

wherein a molten metal temperature in the molten metal passage is adjusted to 700° C.±30° C.

6. A method of producing an Al alloy plastic worked product, comprising:

plastically working the Al alloy cast material produced by the method as recited in claim 1 to produce an Al alloy plastic worked product.

7. The method of producing an Al alloy plastic worked product as recited in claim 6,

wherein the Al alloy plastic worked product is used as a structural material of a transportation machine.

8. A production apparatus of an Al alloy cast material, comprising:

a molten metal reservoir configured to store a Ti-added Al alloy molten metal;

a casting machine configured to cast an Al alloy cast material by solidifying an Al molten metal;

a molten metal passage configured to supply the Al alloy molten metal stored in the molten metal reservoir to the casting machine; and

a feeder configured to add Ti to the Al alloy molten metal flowing through the molten metal passage.

9. The production apparatus of an Al alloy cast material as recited in claim 8,

wherein the molten metal reservoir is configured by a melting furnace for melting an Al alloy material or a holding furnace for performing a temperature adjustment of the Al alloy molten metal.

10. The production apparatus of an Al alloy cast material as recited in claim 8,

wherein the molten metal reservoir is configured by a melting/holding furnace which serves as both a melting furnace for melting an Al alloy material and a holding furnace for performing a temperature adjustment of the Al alloy molten metal.