JP6978481B2 - Aluminum alloy ingot - Google Patents

Description

The present invention relates to an aluminum alloy ingot containing a low melting point element.

In order to improve the machinability of the aluminum alloy, low melting point elements such as Pb (melting point 327 ° C.), Bi (melting point 271 ° C.), Sn (melting point 232 ° C.), and In (melting point 156 ° C.) may be added. These low melting point elements and these compounds are dispersed in the alloy, melted by the processing heat at the time of cutting, and cracks are generated and propagated from that portion. By repeating the generation and propagation of cracks, the chips are separated and the machinability is improved. Most of the aluminum alloy materials used for cutting are ingots that are continuously cast by melting the material metal, or extruded or rolled materials that are processed from the ingots.

It is known that in a continuous aluminum alloy casting apparatus, a carbon liner having self-lubricating property is attached to the inner surface of a mold to improve lubricity in order to prevent seizure and remelting of the ingot (Patent Document 1, Patent Document 1, See a few).

Patent Document 1 describes a mold for continuous casting of an Al—Mg-based alloy in which a graphite liner is attached to the inner peripheral surface of the mold body. Further, a carbon solution containing carbon particles and an organic adhesive is applied to the liner to maintain lubricity.

Patent Document 2 describes that a hot-top continuous casting apparatus incorporates a distributor for supplying a mold release agent to the inner peripheral surface of a mold and a functional ring made of graphite.

In Patent Document 3, a carbon sleeve having a thermal conductivity of 151 W / (m · K) or more (130 Kcal / mh ° C or more) is used in a horizontal continuous casting mold in order to prevent the solidified wall from being weakened due to insufficient cooling. Is described.

Japanese Unexamined Patent Publication No. 2009-39760 Japanese Unexamined Patent Publication No. 2002-301547 Japanese Unexamined Patent Publication No. 11-170008

In the casting of the free-cutting aluminum alloy described above, low melting point compounds such as Pb-Bi, Bi-Sn, Pb-Sn, In-Bi, and In-Sn are formed by solidification of the molten metal. Even if the surface of the ingot solidifies due to cooling from the mold, the low melting point compound is likely to remelt due to the heat of the continuously supplied molten metal, and the remelted low melting point compound adheres to the mold and is cast. There is a problem that the skin is scratched.

The mold described in Patent Document 1 is for an Al—Mg-based alloy. Since the Al—Mg-based alloy does not form a low melting point compound like the free-cutting aluminum alloy, it is not suitable for casting a free-cutting aluminum alloy. The mold described in Patent Document 2 cannot eliminate the deterioration of the casting surface quality due to the remelting of the low melting point compound. Moreover, it is necessary to form a mixture of gas and lubricating oil in order to form bubbles with high releasability, which is limited to hot-top continuous casting equipment and lacks versatility. Further, the carbon sleeve having high thermal conductivity described in Patent Document 3 is suitable for casting the Al—Si eutectic alloy of the embodiment, but is a low melting point compound in the casting of an aluminum alloy containing a low melting point element. It cannot prevent the remelting of aluminum.

In view of the background art described above, the present invention provides an ingot having a specific composition of an aluminum alloy containing a low melting point element and having a good casting surface quality.

That is, the present invention has the configurations described in the following [1] to [5].

[1] Pb: 0.2% by mass to 2% by mass, Bi: 0.01% by mass to 3% by mass, Sn: 0.01% by mass to 1.5% by mass, In: 0.01% by mass to 0 . An aluminum alloy ingot made of an aluminum alloy containing one or more elements of 2% by mass, wherein the unevenness difference of the casting surface is 1.5 mm or less.

[2] The aluminum alloy ingot according to item 1 above, wherein the aluminum alloy further contains Cu: 3.5% by mass to 6.5% by mass and Zn: 0.01% by mass to 1.2% by mass.

[3] The aluminum alloy further contains Si: 0.01% by mass to 1.0% by mass, Mg: 0.01% by mass to 2.0% by mass, and Ti: 0.01% by mass to 0.1% by mass. %, B: The aluminum alloy ingot according to item 2 above, which contains one or more elements from 0.0001% by mass to 0.01% by mass.

[4] The aluminum alloy ingot according to item 1 above, wherein the aluminum alloy further contains Mg: 0.3% by mass to 1.5% by mass and Si: 0.2% by mass to 1.0% by mass.

[5] The aluminum alloy further contains Cu: 0.01% by mass to 2.0% by mass, Zn: 0.01% by mass to 0.2% by mass, and Ti: 0.01% by mass to 0.1% by mass. %, B: The aluminum alloy ingot according to item 4 above, which contains one or more elements from 0.0001% by mass to 0.01% by mass.

The aluminum alloy ingots described in the above [1] to [5] have a difference in unevenness of the casting surface of 1.5 mm or less even though they contain a low melting point element, and have high surface smoothness.

It is sectional drawing which shows the continuous casting method of the aluminum alloy ingot of this invention.

[Aluminum alloy]
The aluminum alloy to which the present invention is applied is an alloy containing one or more of the low melting point elements Pb, Bi, Sn, and In, and is an aluminum alloy to which only the low melting point element is added or the low melting point element. It is an aluminum alloy to which elements other than the above are added.

The low melting point element is an element added to improve machinability, and one kind or two or more kinds are added in any combination. The melting point of Pb is 327 ° C, the melting point of Bi is 271 ° C, the melting point of Sn is 232 ° C, and the melting point of In is 156 ° C. These compounds, that is, Pb-Bi, Bi-Sn, Pb-Sn, In-Bi , In—Sn is also a low melting point compound having a eutectic temperature of 183 ° C. or lower. The eutectic temperature of each compound is 125 ° C. for Pb-Bi, 139 ° C. for Bi-Sn, 183 ° C. for Pb-Sn, 72 ° C. for In-Bi, and 117 ° C. for In-Sn.

The preferred concentrations of each element in the aluminum alloy are as follows. The Pb concentration is preferably 0.2% by mass to 2% by mass, the Bi concentration is preferably 0.01% by mass to 3% by mass, the Sn concentration is preferably 0.01% by mass to 1.5% by mass, and the In concentration is high. It is preferably 0.01% by mass to 0.2% by mass. For any of the elements, if the value is less than the lower limit, the effect of improving machinability is poor, and if the value exceeds the upper limit, the extrudability or corrosion resistance may decrease. Particularly preferable concentrations are Pb concentration of 0.3% by mass to 1.0% by mass, Bi concentration of 0.1% by mass to 0.6% by mass, Sn concentration of 0.2% by mass to 1.5% by mass, and so on. The In concentration is 0.08% by mass to 0.2% by mass.

The balance of the aluminum alloy to which only the low melting point element is added is Al and unavoidable impurities.

Examples of elements added in addition to the low melting point element include Cu, Mg, Si, Zn, Ti, and B. All of these elements are elements that contribute to the improvement of strength, and one kind or any two or more kinds of elements are added. The concentration of the low melting point element in these aluminum alloys is the same as the concentration in the aluminum alloy containing only the low melting point element described above. The preferable concentrations of Cu, Mg, Si, Zn, Ti and B are as follows.

In the 2000 series Al—Cu based alloy, the preferred Cu concentration is 3.5% by mass to 6.5% by mass, the Zn concentration is 0.01% by mass to 1.2% by mass, and the particularly preferable Cu concentration is It is 4.5% by mass to 6.0% by mass, and the Zn concentration is 0.01% by mass to 1.0% by mass. In addition to Cu and Zn, 0.01% by mass to 1.0% by mass of Si, 0.01% by mass to 2.0% by mass of Mg, and 0.01% by mass to 0.1% by mass of Ti. , 0.0001% by mass to 0.01% by mass, any one or more of B may be added. The balance is Al and unavoidable impurities.

In the 6000 series Al—Mg—Si alloy, the preferable Mg concentration is 0.3% by mass to 1.5% by mass, and the preferable Si concentration is 0.2% by mass to 1.0% by mass. A particularly preferable Mg concentration is 0.5% by mass to 0.8% by mass, and the Si concentration is 0.6% by mass to 0.9% by mass. In addition to Mg and Si, 0.01% by mass to 2.0% by mass of Cu, 0.01% by mass to 0.2% by mass of Zn, and 0.01% by mass to 0.1% by mass of Ti. , 0.0001% by mass to 0.01% by mass, any one or more of B may be added. The balance is Al and unavoidable impurities.

Further, the elements added other than the low melting point element are not limited to Cu, Mg, Si, Zn, Ti, and B, and an aluminum alloy to which an element having a melting point exceeding 327 ° C. is added is also included in the present invention. That is, as a low melting point element, Pb: 0.2% by mass to 2% by mass, Bi: 0.01% by mass to 3% by mass, Sn: 0.01% by mass to 1.5% by mass, In: 0.01% by mass. It is an aluminum alloy containing one or more of% to 0.2% by mass, further containing an element having a melting point of more than 327 ° C., and the balance consisting of Al and unavoidable impurities.

The aluminum alloy of the present invention is not limited to the alloy having the above-mentioned composition, and can be applied to all aluminum alloys containing one or more elements of Pb, Bi, Sn, and In.
[Mold and continuous casting method]
FIG. 1 shows a main part of a continuous casting die for continuously casting an aluminum alloy ingot of the present invention and a vertical continuous casting device using this die.

The mold 10 is a tubular mold in which both ends of a molding hole 11 having a circular cross section are opened, and is formed by a tubular mold main body 20 and a tubular liner 30 internally fitted in the molding hole 11 of the mold main body 20. It is configured. One end of the molding hole 11 is an injection port 12 for the molten metal M, and the other end is a casting outlet 13 for the ingot S.

The mold main body 20 has a cavity 21 for circulating cooling water C inside, an inlet 22 to the cavity 21 is provided at the upper portion, and a spout 23 is provided surrounding the casting outlet 13. The cooling water C introduced from the inlet 22 flows through the cavity 21 and primaryly cools the molten metal M in the molding hole 11 via the mold body 20 and the tubular liner 30 internally fitted in the molding hole 11. It is solidified and sprayed onto the ingot S that is ejected from the ejection port 23 and is cast to secondarily cool the ingot S. Further, a recess 26 corresponding to the thickness of the liner 30 is formed in a region excluding a part of the inner peripheral surface 25 of the mold main body 20 on the casting outlet 13 side. The material of the mold body 20 is not limited, and well-known metal materials such as aluminum, iron, and copper can be appropriately used.

The liner 30 is made of carbon having a thermal conductivity of 60 W / (m · K) to 139 W / (m · K), and the surface roughness of the inner peripheral surface 31 is the maximum height Rz specified by JIS B0601 2001. The inner peripheral surface 31 is adjusted to 1 μm to 25 μm and has high smoothness. The liner 30 is fitted into the recess 26 of the mold main body 20 by shrink fitting, and the inner peripheral surface 31 of the liner 30 and the lower portion of the inner peripheral surface 25 of the mold main body 25 form a continuous curved surface. Consists of the wall surface 11a of the molding hole 11 of the mold 10. The carbon liner used in the conventional mold, for example, the carbon liner (sleeve) described in Patent Document 3, has a thermal conductivity of 151 W / (m · K) or more (130 Kcal / mh ° C. or more), and the liner. Reference numeral 30 is made of carbon having a lower thermal conductivity than the conventional one.

In the continuous casting of an aluminum alloy, the molten metal M injected into the molding hole 11 from the injection port 12 of the mold 10 receives primary cooling from the wall surface 11a, solidifies from the outer peripheral surface to the center, and reaches the casting outlet 13. The surface of the ingot S is separated from the wall surface 11a by the solidification shrinkage. When the ingot S is separated from the wall surface 11a and a gap is formed between the ingot S and the wall surface 11a, heat transfer is hindered and the primary cooling capacity received from the mold 10 is reduced. At the position P where the ingot S separates from the wall surface 11a of the molding hole 11 (hereinafter referred to as “the ingot release position”), the larger the amount of heat removed from the mold 10, the faster the molten metal M cools and the injection port. It becomes closer to 12, and conversely, the smaller the amount of heat removed, the slower the cooling and the closer to the casting outlet 13. On the other hand, the ingot S being solidified in the forming hole 11 has a solidified wall formed on the surface, but the central portion is in a high-temperature molten state, and the surface of the ingot S being solidified is cooled from the mold 10. While receiving it, it receives heat from the center. Therefore, if the ingot S is released from the mold while the solidification wall is not sufficiently formed, the ingot surface, particularly the low melting point compound, may be remelted by the heat from the central portion.

In the solidification process of the molten metal M described above, the higher the thermal conductivity of the liner 30, the larger the amount of heat removed and the faster the cooling, and the mold release position P of the ingot S becomes closer to the injection port 12. On the contrary, the lower the thermal conductivity of the liner 30, the smaller the amount of heat removed and the slower the cooling, so that the mold release position P of the ingot S becomes closer to the casting outlet 13. In producing the aluminum alloy ingot of the present invention, the mold 10 uses a conventional carbon liner, for example, a liner 30 having a lower thermal conductivity than the above-mentioned carbon liner having a thermal conductivity of 162 W / (m · K). Therefore, the mold release position P of the ingot S moves to the casting outlet 13 side as compared with the conventional continuous casting. Then, since the mold release position P of the ingot S moves to the casting outlet 13 side, the time for receiving the primary cooling becomes longer and the period during which the primary cooling capacity decreases due to the mold release is shortened, which is sufficient from the mold 10. Can be cooled. Further, since the mold release position P of the ingot S is closer to the casting outlet 13, the distance to the ejection port 23 is shortened, so that it takes time for the released ingot S to receive secondary cooling by the cooling water C. It will be shortened. Therefore, by using the liner 30 having low thermal conductivity, the primary cooling time for cooling from the wall surface 11a of the molding hole 11 becomes long, the period during which the primary cooling capacity decreases due to the mold release is shortened, and the secondary cooling is performed after the primary cooling. The time to receive the next cooling is shortened. As a result, the ingot S is sufficiently cooled to suppress the remelting of the low melting point compound, and the leakage of hot water and the roughening of the casting surface due to the remelting are suppressed.

Further, the liner 30 has high surface smoothness, and the self-lubricating property and surface smoothness of carbon itself make the molten metal M and the solidified wall slippery, and the adhesion of these is suppressed to obtain a cast surface with high surface smoothness. Be done.

As described above, the liner 30 is made of carbon having a thermal conductivity of 60 W / (m · K) to 139 W / (m · K). If the thermal conductivity of the liner 30 is less than 60 W / (m · K), the cooling by the primary cooling is weak and the formation of the solidified wall is incomplete, and there is a risk of casting failure due to hot water leakage. With carbon exceeding the above, the effect of moving the mold release position P of the ingot S to the casting outlet 13 side is small. A particularly preferable thermal conductivity is 80 W / (m · K) to 130 W / (m · K). The surface of the liner 30 has a maximum height Rz of 1 μm to 25 μm defined by JIS B0601 2001. If the maximum height Rz is less than 1 μm, the lubricating oil supplied at the time of casting is not retained on the liner surface, and if a smooth surface is to be obtained by polishing or the like, the processing cost will increase significantly. If it exceeds 25 μm, the above effect is poor. A particularly preferable maximum height Rz of the surface is 5 μm to 25 μm.

The method for manufacturing the liner 30 is not limited, but in order to obtain a smooth surface having a maximum height Rz of 1 μm to 25 μm, a molded product by a cold isostatic pressing method (CIP) or a hot isostatic pressing method (HIP) can be obtained. ) Is preferable. This is because CIP molding and HIP molding have a denser structure than extrusion molding because they are isotropically pressurized, and a smooth surface can be easily obtained.

Further, it is preferable that the liner 30 is attached to the mold main body 20 by shrink-fitting using the difference in the coefficient of thermal expansion between the mold main body 20 and the liner 30. Since carbon has a smaller coefficient of thermal expansion than the metal constituting the mold body 20, the inner diameter of the mold body 20 is set smaller than the outer diameter of the liner 30 at room temperature, and the inner diameter of the mold body 20 liner 30 is expanded by heating. When the inner fitting is performed, the liner 30 is fixed in a state of being tightened to the mold main body 20 due to the temperature drop of the mold 10. When attached by shrink fitting, the mold body 20 and the liner 30 are in close contact with each other and no gap is formed between them, so that heat is quickly transferred from the liner 30 to the mold body 20 during continuous casting. Further, since the mold main body 20 and the liner 30 are in close contact with each other over the entire area in the circumferential direction, cooling unevenness in the circumferential direction does not occur.
[Continuous casting method]
In the vertical continuous casting apparatus of FIG. 1, the description of the molten metal M supply apparatus is omitted, but the molten metal supply method such as the DC casting method by float, the hot top casting method, and the gas pressure type hot top casting method is limited. Not done. Further, the continuous casting method of the mold and the aluminum alloy does not limit the casting direction to the vertical direction, and can be applied to horizontal continuous casting. The mold is characterized by the thermal conductivity and surface roughness of the liner and can be applied to any casting mold.

In the continuous casting of an aluminum alloy, the casting temperature (temperature of the molten metal M) is preferably in the range of 650 ° C to 750 ° C, and the casting speed is preferably in the range of 10 mm / min to 200 mm / min. The cooling water which spout 13 is ejected in the die 10 is preferably in the range of 0.01m ³ /min~0.5m ³ / min. These are conditions that affect solidification. If the casting temperature exceeds 750 ° C, the casting speed exceeds 200 mm / min, and the amount of cooling water is ^{less than 0.01 m 3} / min, solidification becomes too slow and smoothness is achieved. Ingot casting with a high casting surface becomes difficult. On the other hand, if the casting temperature is less than 650 ° C., the casting speed is less than 10 mm / min, and the amount of cooling water ^{exceeds 0.5 m 3} / min, the solidification becomes too fast. In the vertical continuous casting equipment, solidification progresses to the upper part of the molten metal, making it difficult to cast ingots with high smoothness. It can fail.

The ingot S produced by continuously casting the above-mentioned aluminum alloy containing a low melting point element using the mold 10 has high surface smoothness, and the unevenness difference of the casting surface, that is, the highest convex portion to the lowest concave portion. The distance to is 1.5 mm or less.

The configurations of suitable continuous casting dies and continuous casting methods for continuous casting of ingots having high surface smoothness with an aluminum alloy containing a low melting point element, and their effects are as described below.

[1] Continuous casting of an aluminum alloy including a mold body having one end of a molded hole serving as an injection port for molten metal and the other end serving as a casting outlet for an ingot, and a liner attached to the molding hole of the mold body. It is a mold,
The liner is made of carbon having a thermal conductivity of 60 W / (m · K) to 139 W / (m · K), and the inner peripheral surface has a maximum height Rz of 1 μm to 25 μm specified by JIS B0601 2001. A mold for continuous casting characterized by.

[2] The continuous casting die according to item 1 above, wherein a cooling water spout is provided around the casting outlet.

[3] The die for continuous casting according to item 1 or 2 above, wherein the liner is a molded product by a cold isostatic pressing method or a hot isostatic pressing method.

[4] The continuous casting die according to any one of items 1 to 3 above, wherein the liner is attached to the die body by shrink fitting.

[5] An aluminum alloy containing one or more elements of Pb, Bi, Sn, and In is continuously cast using the continuous casting mold according to any one of the above items 1 to 4. A method for continuous casting of aluminum alloys.

In the continuous casting die described in the above [1], the thermal conductivity of the liner attached to the molding hole is lower than that of the conventional liner, so that the cooling is delayed and the ingot release position. Approaches the casting outlet side. Therefore, the primary cooling time for removing heat from the wall surface of the molded hole becomes long, and the period during which the primary cooling capacity decreases due to mold release is shortened. As a result, the ingot is sufficiently cooled to suppress remelting of the ingot surface, and leakage of hot water and roughening of the casting surface due to remelting are suppressed. Moreover, since the surface roughness of the inner peripheral surface of the liner is formed on a smooth surface of 1 μm to 25 μm at the maximum height Rz specified by JIS B0601 2001, the ingot slips well and the difference in unevenness of the casting surface is small. Ingots can be continuously cast.

According to the continuous casting die described in [2] above, since the mold release position of the ingot is closer to the casting outlet side, the time required for secondary cooling by spraying cooling water is shortened. , The ingot is sufficiently cooled and the remelting of the ingot surface is suppressed.

The continuous casting die according to [3] above has high surface smoothness because the liner is a molded product by a cold isostatic pressing method or a hot isostatic pressing method.

In the continuous casting die described in [4] above, since the liner is attached to the mold body by shrink fitting, the adhesion between the two is high, heat transfer is performed quickly, and cooling unevenness in the circumferential direction occurs. Does not occur.

In the method for continuously casting an aluminum alloy according to the above [5], an aluminum alloy containing one or more of low melting point elements Bi, Sn, Pb and In is continuously cast using the above mold. In the continuous casting die, the thermal conductivity of the liner attached to the forming hole is lower than that of the conventional liner, so that the cooling is delayed and the mold release position of the ingot approaches the casting outlet side. Therefore, the primary cooling time for removing heat from the wall surface of the molded hole becomes long, and the period during which the primary cooling capacity decreases due to mold release is shortened. As a result, the ingot is sufficiently cooled to suppress the remelting of the low melting point compound on the surface of the ingot, and the leakage of hot water and the roughening of the casting surface due to the remelting are suppressed. Moreover, since the surface roughness of the inner peripheral surface of the liner is formed on a smooth surface of 1 μm to 25 μm at the maximum height Rz specified by JIS B0601 2001, the ingot slips well and the difference in unevenness of the casting surface is small. Ingots can be continuously cast.

Using the float type vertical continuous casting apparatus referred to in FIG. 1, the aluminum alloys of Examples 1 to 16 and Comparative Examples 1 to 18 were continuously cast.

The four types of aluminum alloys shown in Table 1 were used. These aluminum alloys are free-cutting aluminum alloys to which Si, Cu, Mg and Zn are added to improve the strength, and Bi, Sn, Pb and In are added to improve the machinability.

In the mold 10, a carbon cylindrical liner 30 is attached to a cylindrical mold main body 20 made of aluminum. The mold 10 has three types of molding holes 11 having diameters of 170 mm, 300 mm, and 380 mm. The diameters of the molding holes 11 of the mold 10 used in each example are as shown in Table 2.

The mold main body 20 has a cavity 12 for cooling water, and the molten metal M in the molding hole 11 is primarily cooled by the cooling water C introduced from the inlet 22, and cast with the cooling water C ejected from the ejection port 23. The structure is such that the ingot S is secondarily cooled. Further, a recess 26 for internally fitting the liner 30 is formed on the inner peripheral surface 25. The flow rate of the cooling water C is adjusted by a control device (not shown).

The liner 30 has a length of 100 mm in the casting direction, an inner diameter corresponding to the diameter of the forming hole 11, and a thickness of 5 mm. The liner 30 is a molded product obtained by compacting carbon powder by CIP molding, and the thermal conductivity of each liner 30 is as shown in Table 2, and the inner peripheral surface 31 is adjusted to the surface height Rz shown in Table 2. Has been done. The surface height Rz is the surface roughness defined by JIS B0601 2001.

Each of the molds 10 of Examples 1 to 16 and Comparative Examples 1 to 18 is a combination of the mold main body 20 and the liner 30 shown in Table 2, and the liner 30 is attached to the recess 26 of the mold main body 20 by shrink fitting. There is.

Each die 10 was incorporated into a vertical continuous casting apparatus referred to in FIG. 1, and the aluminum alloy shown in Table 1 was continuously cast. Table 2 shows the mold 10 and the aluminum alloy of each example. The continuous casting conditions of each example were the casting temperature, casting speed, and cooling water amount shown in Table 2.

The presence or absence of hot water leakage was investigated for the continuous casting of each example. Furthermore, for continuous casting without hot water leakage, the unevenness of the ingot's casting surface was examined, and ingots with an unevenness difference of 1.5 mm or less were good (〇), and ingots with an unevenness difference of more than 1.5 mm were defective (×). ). The evaluation results are shown in Table 2.

From the results shown in Table 2, it was confirmed that by defining the thermal conductivity and surface roughness of the liner, it was possible to prevent hot water leakage due to remelting of the solidified wall and to continuously cast ingots with high smoothness.

The aluminum alloy ingot of the present invention can be used as a free-cutting aluminum alloy containing a low melting point element.

10 ... Mold 11 ... Molding hole 12 ... Injection port 13 ... Casting outlet 20 ... Mold body 21 ... Cavity 23 ... Spout 30 ... Liner M ... Molten metal S ... Ingot C ... Cooling water

Claims (2)

Pb: 0.2% by mass to 2% by mass, Bi: 0.01% by mass to 3% by mass, Sn: 0.01% by mass to 1.5% by mass, In: 0.01% by mass to 0.2% by mass It contains one or more elements of%, and further contains Cu: 3.5% by mass to 6.5% by mass and Zn: 0.01% by mass to 1.2% by mass, and further Si: 0. 01% by mass to 1.0% by mass, Mg: 0.01% by mass to 2.0% by mass, Ti: 0.01% by mass to 0.1% by mass, B: 0.0001% by mass to 0.01% by mass An aluminum alloy containing one or more elements of%, the balance of which is an aluminum alloy composed of Al and unavoidable impurities, and the difference in unevenness of the casting surface is 1.5 mm or less. Ingot. Pb: 0.2% by mass to 2% by mass, Bi: 0.01% by mass to 3% by mass, Sn: 0.01% by mass to 1.5% by mass, In: 0.01% by mass to 0.2% by mass %, Which contains one or more elements, and further contains Mg: 0.3% by mass to 1.5% by mass and Si: 0.2% by mass to 1.0% by mass, and further Cu: 0. 01% by mass to 2.0% by mass, Zn: 0.01% by mass to 0.2% by mass, Ti: 0.01% by mass to 0.1% by mass, B: 0.0001% by mass to 0.01% by mass An aluminum alloy containing one or more elements of%, the balance of which is an aluminum alloy composed of Al and unavoidable impurities, and the difference in unevenness of the casting surface is 1.5 mm or less. Ingot.

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