JPH0350619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method and apparatus for melting and casting metal alloys. The conventional casting method is as follows. () Melt metal in a melting furnace (crucible), tilt the furnace and pour out the hot water; () Send the hot water to the casting department via a receiver, etc.; () Cast the hot metal by pouring it into a mold. In such a process, the steps in parentheses are omitted,
In some cases, hot water is poured directly from the furnace into the mold. Although it is a less commonly used method, a low-pressure casting method is also known, in which hot water is poured into a furnace or crucible in a pressure vessel by pressing, and the hot water is then forced through a pipe into a mold located above using gas pressure. . Since this method pushes up the hot water, the problem of turbulence that occurs during pouring does not occur, and high-quality castings are obtained. If turbulence occurs when pouring or pouring hot water, metals containing large amounts of aluminum, magnesium, etc. will undergo oxidation, making it difficult to remove the oxides, making it difficult to obtain high-quality cast products. do not have. In the case of the above-mentioned known method, the hot water flowing from the furnace etc. to the casting station is caused to flow down by the head of the flow path, but this head ranges from 0.5 meters to several meters, and the flow rate is fast. , the flow of hot water becomes violent, creating a turbulent, stirring flow. In addition, the method of melting metal in a furnace directly connected to the mold and pumping it into the mold is suitable for casting oxidizing alloys because there is no turbulence of hot water, and high-quality cast products can be obtained.
However, this method is inferior in productivity due to batch production. In addition, processes such as degassing from the flowing line may introduce impurities into the hot water, and intermediate means are required to remove these impurities, but this requires an extremely long removal process time, and the casting process production efficiency will be significantly reduced. As described above, it is difficult to efficiently obtain high-quality cast products using known methods. In an attempt to solve the above-mentioned problems, G.I.
A paper entitled "Production of Aluminum Alloy Castings" by Campbell was published in "Engineering" in March 1981.
Published in No.3, Vol.221. according to this,
The hot water from the furnace flows down to the casting department and is pumped up into the mold for casting.
No satisfactory results have been obtained. Therefore, this invention solves the problem of hot water turbulence and oxidation caused by it, which could not be solved by conventional techniques, and makes it possible to cast high-quality cast products with high efficiency even when using metals that are easily oxidized. and equipment. According to this invention, the flow of hot water flowing down from the furnace or the like toward the casting section is extremely gentle, and no turbulence occurs. In this discussion, highly turbulent or turbulent flow refers to flows that result in large amounts of oxides on metals. If the head in the hot water flow path is 200 mm or more, the amount of oxides generated will increase and the quality of the casting will deteriorate significantly. Also, the head is 200
mm or less, oxidation occurs, but the minimum acceptable quality can be ensured. Furthermore, when the head is 100 mm, the deterioration in quality is prevented to some extent, and when the head is around 50 mm, there is no oxidation phenomenon that causes quality deterioration, and high-quality cast products can be obtained. This invention consists of a process of melting metal in a melting furnace, flowing the molten metal from the melting furnace to a casting section using gravity, and pumping the molten metal to a mold in the casting section, and transferring the molten metal from the melting furnace. When flowing into the casting section, the height difference between the highest water level of the molten metal in the pouring section of the melting furnace and the highest water level of the molten metal in the casting section is such a distance as to not cause severe turbulence. The main subject is metal melting and casting methods. Further, the present invention includes a melting furnace, a casting section, a pump for sending molten metal from the casting section to the mold, and means for flowing the molten metal from the melting furnace to the casting section by gravity, and the molten metal is transported by using the head difference between the respective sections. Another gist of the present invention is a metal melting and casting apparatus which has a configuration in which the metal is allowed to flow down, and the head is such that severe turbulence does not occur in the flowing molten metal. In this invention, the receiver is located below the lowest water level of the hot water in the casting section, and during the casting operation,
It is possible to ensure that hot water is always present in the basin. Alternatively, the bottom of the basin may be placed above the lowest level of hot water in the casting section, so that it remains empty unless hot water is continuously supplied from the furnace. The channel may be sloped or curved downwards, ie towards the casting section. When the tray is curved downward, the curve on the upstream side is steeper than the downstream side, and the downstream side should be horizontal or gently curved to slow the flow rate of hot water and prevent turbulent flow of hot water. You can also do it. The hot water stored in the casting section is pumped to the mold using an electromagnetic pump or a pneumatic pump. These pumps have no moving parts, so there is no turbulence in the pumping of hot water. A storage furnace-like structure can also be attached to the casting section so that hot water accumulates at a predetermined level in the casting section. This storage furnace constitutes a part of the casting section. If the surface area of the storage furnace is increased, more castings can be cast, and in order to prevent the gap between the melting furnace and the casting section from widening, it is necessary to re-inject hot water from the furnace to raise the water level in the casting section. disappears. Furthermore, since there is no need to perform such re-pouring, there is no need to interrupt the casting operation, which must be interrupted for re-pouring, and productivity can be greatly improved. A filter device is provided in the hot water flow path,
For example, it is installed between the receiver or the receiver and the casting part,
As a result, the present invention also makes it possible to remove impurities from the hot water flowing down to the casting section. According to this invention, all pretreatments for the metal to be cast, such as defoaming, degassing, fluxing, atomization, and alloying, are performed in a melting furnace, and impurities generated by such treatments are removed. is removed by the filter device, making it possible to cast with pure hot water. Since all the hot water that flows into the casting section is clean, the casting section is also kept in a clean state, freeing you from troublesome maintenance problems. The spout (rip) installed in the melting furnace is designed to allow the melt to flow into a receiver by tilting the melting furnace, or to allow the hot water to flow directly into the casting section if there is no receiver. Because it is smooth, the difference in head when pouring hot water can be reduced, and quality does not deteriorate. According to the invention, an inclined hearth with a roof of radiation heating means can be used as the melting device, in which case the metal ingots or scraps are melted on the hearth and passed through a receiver or through a It flows down to the casting part without any problem. In this case, the head of the hot water can be shortened by bringing the downstream end of the pan closer to the casting part, and when there is no pan,
By passing the outflow part at the downstream end of the hearth into the casting part, hot water can be supplied without flowing down through the atmosphere. A plurality of melting furnaces can be installed in parallel, and they can be communicated with the casting section through separate pipes or manifold pipes, or they can be connected to the casting section without using a pipe or via a filter device. ,
Alternatively, the furnace and the casting section can be directly connected without intervening. Heating in a melting furnace uses electrical energy, which prevents surface oxidation of hot water and generation of hydrogen gas due to the generation of water vapor caused by oil-fired heating. This electrical energy serves as driving energy for heating means, pumps, filter devices, etc. provided in the device. In metal melting, it is preferable to prevent turbulence from occurring in the hot water. Therefore, the furnace (crucible) may be surrounded by heating wires or may be heated by dielectric heating means (the crucible is electrically conductive). By preventing the occurrence of turbulence in the melted hot water, sending it in a gentle flow to the casting department, and slowly injecting it into the mold, it is possible to prevent the formation of blowholes and to make the structure denser. This invention applies to castings of all metals, especially non-ferrous metals such as aluminum, magnesium,
These alloys are ideal for casting. Aluminum alloy castings (e.g. Al-7Si-0.5Mg
type) porosity ranges from 1 vol.% (with a range of 0.5 to 2 vol.%) to at least 0.1 vol.%, typically 0.01
It can be reduced to ~0.001vol%. The cast product according to the present invention does not contain defective factors such as sand, oxides, and oxide films. Containing sand particles or oxide particles causes wear of molds, etc., but the casting method according to the present invention can extend the life of molds and other tools. The formation of an oxide film reduces the liquid tightness of the casting, and reduces the mechanical strength and
Decreases durability. The cast product according to this invention is
As measured by an elongation test, the strength is at least
Improved by 20%. According to this invention, the quality of the cast product is high and the productivity is also high. With a high quality mold and proper alloy composition, castings according to the invention can be cast in mass production. When an aluminum alloy having the following composition was cast according to the present invention, unexpectedly good results were obtained. Si 10.0~11.5 Cu 2.5~4.0 Mg 0.3~0.6 Fe 0~0.8 Mn 0~0.4 Ni 0~0.3 Zn 0~3.0 Pb 0~0.2 Sn 0~0.1 Ti 0~0.08 Cr 0~0.05 Normal accompaniments 0~ 0.09 (for each) Aluminum Balance The contents of silicon, copper and magnesium are as follows; Si 10.5-11.5 Cu 2.5-3.5 Mg 0.3-0.5 The alloy may be heat treated. For example, 190℃～
Aging treatment held at 210℃ for 1 to 8 hours, or
After solution heat treatment held at 490°C to 510°C for 1 to 8 hours, quenching with water or polymer, and
Heat treatment such as aging treatment is performed by holding at 190°C to 210°C for 1 to 8 hours. The alloy has the following mechanical properties. [Table] In the above, 1 is "casting only", 2 is "aging treatment", and 3 is "solution heat treatment, quenching and aging treatment". According to this invention, a high quality product can be obtained by casting an alloy having the above composition. The cost of casting secondary aluminum alloys has become as low as that of scrap casting. The alloy composition that provides the lowest cost is as follows. Si 6.0~7.0 Cu 1.5 Mg 0.5~1.0 Fe 0.7 Mn 0.3 Ni 0.15 Zn 1.5 Pb 0.2 Sn 0.1 Ti 0.04~0.05 Cr 0.02~0.05 P 20ppm The alloy composition according to the present invention is substantially the same as the aforementioned alloy composition that can be cast at the lowest cost. It has become the same. The main components of the alloy according to the invention are silicon, copper and magnesium suitable for casting, the magnesium being strengthened by heat treatment. In order to increase the aging effect, the copper content should be about 2.5% or more, but if the content exceeds 3.5 to 4%, the castability deteriorates and cavities, shrinkage, etc. occur. To maintain strength, the magnesium content should be 0.3-0.5%. If it is less than this, the strength will be insufficient, and if it is more than this, the strength will decrease.
It loses ductility and becomes brittle. Titanium improves the mechanical properties of aluminum alloys, but is harmful at concentrations above 0.08%. To obtain good castability, the alloy is desirably eutectic and can have zero or narrow freezing range. The reason for this is as follows. (a) Improved productivity by low-temperature casting, suppressing hydrogen gas, preventing oxidation and metal loss, and increasing the freezing rate in the mold; (b) Improving fluidity, allowing thin casting parts to be cast over a wide range without high-temperature casting. Formation; (c) Skinning of the surface by forming a skin layer solidified by the eutectic alloy, thereby ensuring liquid tightness and pressure resistance. This point is ideal for automobile parts. Concentrates the porosity in the deep part of the cast body and makes it possible to remove the porosity. Casting of high quality castings. According to the invention, the copper content in the alloy is 2.5-4% and silicon 10-11.5% (giving eutectic properties). High silicon content impairs mechanical properties. As a result of the above, extremely excellent castability can be obtained. Next, the present invention will be explained in detail with reference to illustrated embodiments. As shown, the apparatus includes a melting furnace 10. This melting furnace is equipped with a spout 12 that is commonly used, and can be tilted to open the spout 1.
Molten metal is poured out from 2. The molten metal M is kept in a molten state in a lining 13 such as refractory bricks, the furnace is electrically heated by an induction coil 15, a steel case 14 is surrounded outside the furnace, and an insulating lid 1
It is covered by 6. A trough-shaped channel 17 is provided from the spout 12 to the casting part 20. This receiver is made of ceramic and has a lid 18 equipped with an electric heating element 19. The casting section 20 is a large furnace equipped with a lid 21 equipped with an electric heating element 22, and has a capacity of, for example, one ton. Its shape is rectangular in plan, and the hearth 23 is inclined upward toward the receiving tray 17. Between the receiving tray 17 and the mouth of the hearth 23, a weir 27 is provided extending from both sides of the filter box 24.
8 is further away than the bottom 29 of the box. A filter 30 made of a heat-resistant, fire-resistant porous material is arranged between the weir 27 and the downstream end wall 31 of the filter box, and the filter 30 is freely replaceable. A pump 32 is provided in the casting section 20, and a suction port 33 of the pump is immersed in the molten metal in the casting section 20, and a suction pipe 34 reaches a mold 35 located at the upper part. . During casting work, molten metal (hereinafter referred to as "hot water")
) is sent to the mold by the pump 32, so the level L ₂ of the hot water in the casting section 20 drops from the highest level (water level) L ₂ max to the lowest level L ₂ min. Furnace 1
The hot water M melted by 0 is poured into the receiver 17, passes through the filter 30, reaches the casting part 20,
The water level L ₂ of the hot water in the casting section 20 is maintained between the highest water level L ₂ max and the lowest water level L ₂ min. Receiver 1
The water level L ₁ of the hot water No. 7 is kept the same as the water level L ₂ and the water level L ₃ of the filter box. Depending on the position of the shaft 11 that tilts the furnace 10, the water level of the hot water poured out from the furnace 10 is 100 mm higher than the lowest water level.
When the lowest water level L ₁ min to L ₃ min reaches a predetermined lowest level, hot water is poured out with a head difference of 100 mm. This 100mm drop can be increased to a maximum of 200mm, but this is not very desirable. Since the casting part 20 has a relatively large volume, the water level L ₁ to _{L 3} of the hot water can be maintained within a range of approximately ±50 mm at a level approximately 50 mm lower than the shaft 11 of the furnace 10, and the pump 32 pumps the hot water. Even when the mold 35 is pumped up, the water levels L ₁ to _{L 3} do not deviate from the range. In the example, the capacity of the casting section 20 is 1 ton, and one pour can supply hot water to 20 molds (10 kg capacity), before the casting section needs to be refilled from the furnace 10. , the head can be 50mm or more than the lowest point and 50mm or less than the highest point. In an embodiment of this invention,
Approximately 1.5 hours of automotive engine cylinder head casting can be completed before refilling is required. Furnace 1
To refill the casting from scratch, there is no need to interrupt the casting operation. According to the embodiment described above, casting can be performed continuously with high efficiency, turbulence of hot water and its adverse effects can be eliminated, and a cast product of good quality can be obtained. This is because the head when hot water flows from the furnace spout 12 through the outside air to the receiver 17 is relatively short.For example, as mentioned above, the head when pouring hot water is
100mm, the maximum is 200mm, and with such a short head, the time of contact with the atmosphere is short, and the generation of oxides is small, and the generated oxides are filtered through the filter 3.
Can be removed by 0. As described above, the elements of the filter 30 are replaceable, and can be replaced as necessary, for example, every time approximately 100 tons are cast. In the embodiment described above, a neutral pump is used as the pump 22, but it may be of an electromagnetic type or other type, and in either case, the hot water is sent to the mold without exposure to the atmosphere and without turbulence. In addition to the illustrated structure, other suitable melting furnaces 10 may be used, such as a tilted hearth type. In this case, since the hearth has reached the lowest water level L ₁ min of the receiving hot water,
The ingots or scraps in the hearth melt and flow through the receiver and do not flow down into the atmosphere. Furthermore, in some cases, even if the hearth is not extended to the lowest water level of the hot water, but ends just short of it, the head is extremely short, so severe turbulence will not occur. A plurality of melting furnaces may be used, and the hot water may be supplied to the casting section through respective receivers or multi-shaped receivers. Furthermore, hot water may be directly supplied from the melting furnace to the casting section via a filter. As shown in FIG. 1, the bottom surface B of the tray 17
is below the lowest water level L ₂ of the hot water supplied from the furnace, so the receiver 17 is always filled with hot water during the casting operation. However, as shown in Figure 2, the receiver 1
The bottom surface Bb of 7a may be higher than the lowest water level _L2 (the lowest water level of the hot water in the casting part 20a ). In this case, if hot water is poured from the furnace 10 in batches, the receiver will be emptied after pouring one batch of hot water. In the example shown in FIG. 3, the bottom surface b of the tray 17b
slopes downstream, and its bottom is at the lowest water level.
L ₂ min (at the casting section 20 b ), and a part of the bottom surface B c may be above the lowest water level L ₂ min as shown in FIG. Furthermore, the bottom surface Bd of the receiving basin 17d is curved in the downstream direction as shown in FIG. It is also possible to make the flow into the casting section slow. In this case, the outlet of the receiver 17d is located at the casting part 20 as shown in FIG.
It is above the lowest water level L ₂ min of hot spring d, and
In the example shown in FIG. 6, it is below the lowest water level L ₂ min of the casting section 20e . The method and apparatus according to the invention are suitable, for example, for casting low melting point alloys such as lead, bismuth, tin, intermediate melting point alloys such as magnesium, aluminium, high melting point alloys such as copper, aluminium-bronze, cast iron. Steel can also be cast using the method and apparatus of this invention, but this requires expensive refractory materials. As a result of casting an aluminum alloy having the composition described above using the method and apparatus of the present invention described above, unexpectedly good results were obtained. Alloys with the following compositions were tested. [Table] This alloy has excellent castability, and a cylinder head with a thin web of 3 mm, good weight balance, and a dense structure (pore distribution of 0.01% by volume or less) could be cast. This casting temperature is below 630℃,
Melting energy was saved, there was little oxidation on the surface of the hot water, and almost no problems occurred. The tolerance to high amounts of Zn and relatively high levels of Pb, Sn in the alloy is noteworthy. The suitability of the alloy for grinding in sand casting by the method described below is also very satisfactory. A surface finish of 0.3 mm requires only one grinding with a diamond tool.ALAR: The Association of Light Alloy
Refiners)/LMFA; Light Metal Finishers Association grinding classification
It corresponds to Class B in 1982. There is no damage to the edges due to cracking, etc., and the edges are sharp and gradually wear out. DTD sand casting bars made of the above alloy were tested in the following manner, and the properties shown in Table 1 were obtained. In the “Cosalloy2” section of Table 1,
(1) shows the characteristics when the sample bar was only cast, and (2) shows the characteristics when aged at 205℃ for 2 hours.
(3) shows the characteristics obtained after solution heat treatment by holding at 510°C for 1 hour, quenching, and aging by holding at 205°C for 8 hours. Table 1 also shows LM13 (main composition other than Al; 10.0
−13.0%Si, 0.7−1.5%Cu, 0.8−1.5%Mg),
LM27 (main composition other than Al; 6.0-8.0%Si, 1.5-2.5
%Cu, 0.2−0.6%Mn), LM21 (main composition other than Al; 5.0−7.0%Si, 3.0−5.0%Cu, 0.1−0.3%Mg,
0.2−0.6%Mn), LM4 (main composition other than Al; 4.0−6.0
%Si, 2.0−4.0%Cu, 0.2−0.6%Mn) DTD with Si, Cu, and Mg alloys respectively
The mechanical properties of the sand cast samples (bars) are also shown. Table 1 also shows that LM2 (main composition other than Al; 9.0−
11.5%Si, 0.7-2.5%Cu), LM24 (main composition other than Al; 7.5-9.5%Si, 3.0-4.0%Cu), LM26 (main composition other than Al; 8.5-10.5%Si, 2.0-4.0%) Cu, 0.5−
We also present the mechanical properties of DTD chill test cast bars with Si, Cu, Mg alloys known as 1.5% Mg (these are alloys that apply only to pressure die casting and weight die casting). Table: As is clear from the above table, only the chill cast samples (bars) come close to the results obtained with the sand cast alloys. The test results in Table 1 for the alloys were obtained by treatment with an alkali or alkaline earth metal such as sodium or strontium to reduce the silicon particle size of the casting. Although this treatment is difficult to adjust, it helps improve strength and durability. The properties of the known alloys shown in Table 1 were obtained by this cumbersome and unreliable method. The properties of the alloy were achieved without such measures and are extremely reliable.
It is easy to process and inexpensive. By modifying the above-mentioned alloys, even better properties can be obtained. Table 2 shows the test results as follows. Group 1: DTD test bars were obtained by zircon sand casting. 1st term a()Cosalloy2 - Casting only 1st term a()Cosalloy2 - Aging treatment 1st term b()LM25 - Casting only 1st term b()LM25
- Solution heat treatment/aging treatment group 2: DTD test bars were obtained by die casting using a zircon sand mold (hot water was poured manually). 2nd term a() Cosalloy - Casting only 2nd term a() Cosalloy - Aging treatment 2nd term b() LM25 - Casting only 2nd term b() LM25
- Solution heat treatment/aging treatment group 3: A DTD test bar was obtained by die casting using a silica sand mold (hot water was poured manually). 3rd term a()Cosalloy2 - Casting only 3rd term a()Cosalloy2 - Aging treatment 3rd term b()LM25 - Casting only 3rd term b()LM25
- Solution heat treatment/aging treatment In all groups, Cosalloy2 has a
℃, 4 hours of aging treatment, LM25 was aged at 530℃,
12 hour solution heat treatment, polymer quenching, 190
Aging treatment was performed at ℃ for 2 hours. The results in Table 2 are the average of a number of tests, with an exception of 3-4% or less in the croup 1 test. Tests in groups 2 and 3 were conducted to simulate conventional sand casting techniques, and exceptions up to 10% were observed. The numbers in groups 2 and 3 are highly variable and are averages of very careful tests and represent the best results for hand casting. [Table] These numbers indicate the following. (a) Comparing the numbers of Group 1 with those of Groups 2 and 3, the method of this invention has considerably superior characteristics compared to the conventional method. (b) 1st term a()(); 2nd term a()();
Comparing the numbers in Section 3 a()() with others, the properties of the above-mentioned alloys are better than those of known alloys.
It's pretty good. (c) Comparing the numbers in item 1 a() and () with others, the properties obtained using the alloy, method, and apparatus described above are extremely excellent. The alloy test bar according to the present invention and the LM25 alloy test bar were obtained using the method and apparatus described above. In this specification, compositions are given in % by weight.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing an example of a casting apparatus according to the present invention, and FIGS. 2 to 6 are explanatory views showing modifications of the apparatus shown in FIG. 1, respectively. 10, 10a, 10b, 10c, 10d, 10
e... Melting furnace, 11... Axis of melting furnace rotation, 12...
... Outlet, 17, 17a, 17b, 17c, 17
d, 17e...Reception, 20, 20a, 20b,
20c, 20d, 20e... Casting department, 24, 24
a, 24b, 24c, 24d, 24e...filter box, 32, 32a, 32b, 32c,
32d, 32e...Pump, 35, 35a, 35
b, 35c, 35d, 35e...mold.

Claims (1)

[Scope of Claims] 1. A method comprising the steps of melting metal in a melting furnace, flowing the molten metal from the melting furnace to a casting section using gravity, and pumping the molten metal into a mold in the casting section. When flowing from the melting furnace to the casting section, the head difference between the highest water level of the molten metal in the pouring section of the melting furnace and the highest water level of the molten metal in the casting section is set within the range of 50 to 200 mm. Metal melting and casting methods. 2. At the process stage in which molten metal flows from the melting furnace to the receiver, and then from the receiver to the casting section,
The first method characterized in that the highest water level of the molten metal is highest in the pouring part of the melting furnace, then gradually lowers in the receiving part and then in the casting part.
The method described in section. 3 A melting furnace, a casting section, a pump for sending molten metal from the casting section to the mold, and means for flowing the molten metal from the melting furnace to the casting section by gravity, and the molten metal is made to flow down by utilizing the head difference between the above-mentioned parts. , a metal melting and casting device in which the head is in the range of 50 to 200 mm. 4.Equipped with a receiver whose one end is located at the spout of the melting furnace and the other end is located at the entrance of the casting section, and the highest water level of the molten metal in the receiver is the same as the molten metal at the spout of the melting furnace and the casting section. 3. The device according to claim 3, which is located midway between the highest water level of . 5. Said No. 4 in which the bottom surface of the basin is at the same height as or lower than the highest water level of the molten metal in the casting section.
Apparatus described in section. 6. The apparatus according to item 4 above, wherein the bottom surface of the basin is above the lowest water level of the molten metal in the casting section. 7. The device according to any one of items 4 to 6 above, wherein the bottom surface of the tray is horizontal. 8. The device according to any one of items 4 to 6 above, wherein the bottom surface of the tray is inclined toward the casting section. 9. The device according to any one of items 4 to 6, wherein the bottom surface of the tray is curved downward, and the curve on the upstream side is steeper than on the downstream side. 10. The apparatus according to any one of items 3 to 9, wherein the casting section is provided with a furnace part for maintaining the water level of the molten metal. 11. The device according to any one of items 3 to 10, wherein a filter device is provided in the flow path from the melting furnace to the casting section. 12. The method according to any one of items 1 to 11, wherein the molten metal is an iron-free metal such as aluminum, magnesium, or an alloy thereof. 13. The method according to item 12, wherein the molten metal is an aluminum alloy having the following composition. Si 10.0~11.5 Cu 2.5~4.0 Mg 0.3~0.6 Fe 0~0.8 Mn 0~0.4 Ni 0~0.3 Zn 0~3.0 Pb 0~0.2 Sn 0~0.1 Ti 0~0.08 Cr 0~0.05 Normal accompaniments 0~ 0.09 (for each) Aluminum Balance 14 The method of claim 13, comprising silicon, copper, and magnesium as follows: The method according to item 13 or 14, wherein the Si 10.5-11.5 Cu 2.5-3.5 Mg 0.3-0.5 15 alloy is hardened and aged after aging treatment or solution treatment. 16 Melt the following alloy composition in a melting furnace, and measure the difference between the highest water level of the molten metal in the pouring part of the melting furnace and the highest water level of the molten metal in the casting part by 50~
A cast product characterized by being low-pressure cast by setting a range of 200 mm to flow molten metal from a melting furnace to a casting section using gravity, and in the casting section, pumping the molten metal to a mold. . Si 10.0~11.5 Cu 2.5~4.0 Mg 0.3~0.6 Fe 0~0.8 Mn 0~0.4 Ni 0~0.3 Zn 0~3.0 Pb 0~0.2 Sn 0~0.1 Ti 0~0.08 Cr 0~0.05 Normal accompaniments 0~ 0.09 (for each) Aluminum Balance 17 When flowing molten metal from the melting furnace to the casting section using gravity, a receiver is interposed so that the highest water level of the molten metal is the highest at the pouring section of the melting furnace, and then the highest at the pouring section of the melting furnace. 17. The cast product according to item 16, characterized in that the receiving channel and the casting part are lowered in stages. 18 A melting furnace, a casting section, a pump for sending molten metal from the casting section to the mold, and means for flowing the molten metal from the melting furnace to the casting section by gravity, and the molten metal is made to flow down by utilizing the head difference between the above-mentioned parts. A cast product, characterized in that the alloy composition described in item 16 is melted and low-pressure cast using a metal melting and casting apparatus having a head in the range of 50 to 200 mm. 19 The means for flowing molten metal from the melting furnace to the casting section by gravity is a receiver, one end of which is located at the spout of the melting furnace, the other end located at the entrance of the casting section, 19. The cast product according to item 18, wherein the highest water level of the metal is located midway between the highest water level of the molten metal at the spout of the melting furnace and the casting section. 20. The cast product according to item 19, which is cast with the bottom surface of the basin being at the same height as or lower than the lowest water level of the molten metal in the casting section. 21. Said first casting machine, which is cast with the bottom surface of the basin placed above the lowest water level of the molten metal in the casting section.
Cast product described in item 9. 22. The cast product according to any one of Items 19 to 21 above, which is cast with the bottom surface of the tray being horizontal. 23. The cast product according to any one of Items 19 to 21, wherein the bottom surface of the tray is inclined toward the casting part. 24 The bottom of the tray is curved downward,
22. The cast product according to any one of items 19 to 21, which is cast with a curve on the upstream side being tighter than on the downstream side. 25. The cast product according to any one of Items 18 to 24, wherein the casting part is provided with a furnace part for maintaining the water level of molten metal. 26. The cast product according to any one of Items 18 to 25, which is cast with a filter device provided in the flow path from the melting furnace to the casting section. 27. The cast product according to any one of items 16 to 26, wherein the alloy is subjected to aging treatment or solution treatment followed by quenching and aging treatment. 28. The cast article according to item 27 above, having the following mechanical properties: [Table] In the above, 1 is "casting only", 2 is "aging treatment", and 3 is "solution heat treatment, quenching and aging treatment". Free from detectable defects.