JP2011132604A - Aluminum alloy casting and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy casting which has excellent castability and corrosion resistance and has been subjected to die casting. <P>SOLUTION: It has been made clear that the contents of Mn, Fe and Cu among alloy component contents remarkably exert influence on the corrosion resistance of an aluminum alloy. Then, the aluminum alloy casting has a composition comprising 9.0 to 12.0 wt.% Si, 0.20 to 0.80 wt.% Mg and 0.7 to 1.1 wt.% Mn+Fe, and satisfying an Mn/Fe ratio of ≥1.5, with Cu as impurities regulated to ≤0.5 wt.%, and the balance aluminum with inevitable impurities, and is provided with a radiation fin 31 for an electric heat generating component 30. In a planar substrate 31a of the heat radiation fin 31, the flat part not formed with a thin fin part 31 is provided with a circular fitting hole 31c, and the electric heat generating component 30 with a columnar outer form is press-fitted and fixed to the circular fitting hole 31c. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a die-cast aluminum alloy casting excellent in castability and corrosion resistance and a method for producing the same.

  Conventionally, in Patent Document 1, a Cu content is regulated to 0.02% by weight or less, and Si is contained in an amount of 4 to 13% by weight. It is described that one or two of 0.3% by weight of Ti and 0.05 to 0.15% by weight of Be are contained, thereby improving the thread-like corrosion resistance.

JP-A-2-232331

  By the way, in the aluminum alloy composition of patent document 1, since Be is toxic, handling is required.

  Conventionally, JIS-ADC12 (JIS-H-5302-2000) alloy having excellent castability is generally used for aluminum die-cast parts for automobiles, but this JIS-ADC12 has low corrosion resistance. Therefore, in a product used in an environment where corrosion progresses quickly such as a wet environment, the material surface is corroded in a short period of time, and as a result, the strength is reduced, so JIS-ADC 12 is difficult to use.

  JIS-ADC5 and JIS-ADC6 have good corrosion resistance, but the melting point of the aluminum alloy is high, and the molten metal is cooled and solidified easily on the mold surface. Gets worse. In addition, the term “castability” in this specification includes “fluidity of molten metal”, “sinkability after solidification of molten metal”, “casting cracking property due to solidification of molten metal”, “seizure resistance to mold”, etc. Used in the sense of overall formability including evaluation items.

  In view of the above points, an object of the present invention is to provide a die-cast aluminum alloy casting excellent in castability and corrosion resistance.

  Another object of the present invention is to provide a die-cast aluminum alloy casting that does not contain a toxic component such as Be.

  Another object of the present invention is to provide a die-cast aluminum alloy casting having excellent strength.

  Another object of the present invention is to provide a die-cast aluminum alloy casting that can reduce the material hardness.

  As a result of repeated experimental studies on the cause of the corrosion resistance reduction of JIS-ADC12, the present inventors have found that the amount of Mn, Fe, and Cu among aluminum alloy components for die casting greatly affects the corrosion resistance of the aluminum alloy. found.

  That is, in JIS-ADC12, β-AlFeSi particles constituting a cathode electrode (a noble part of the potential) harmful to corrosion resistance are generated, and although it is weaker than β-AlFeSi particles, α constituting the cathode electrode is also formed. It has been found that -Al (Fe.Mn) Si particles are generated to reduce the corrosion resistance.

  The β-AlFeSi particles and α-Al (Fe · Mn) Si particles are generated because the additive ratio of Mn to Fe (Mn / Fe) in JIS-ADC12 is a low value around 0.34. Therefore, if the additive amount ratio (Mn / Fe) of Mn and Fe is regulated, the generation of β-AlFeSi particles can be suppressed and the corrosion resistance deterioration factor of α-Al (Fe · Mn) Si particles can be removed. I understood.

  In JIS-ADC12, the amount of Cu added is a relatively large amount of 1.5 to 3.5% by weight. For this reason, there are many noble Al2Cu phases, and the solid solution of Cu in the α-A1 (Fe · Mn) Si particles is promoted, thereby further increasing the potential of the α-A1 (Fe · Mn) Si particles. It becomes noble and causes the corrosion resistance to decrease.

The present invention has been devised based on the above knowledge, and in the invention according to claim 1, an aluminum alloy casting formed by die casting using an aluminum alloy for die casting,
Si: 9.0 to 12.0 wt%, Mg: 0.20 to 0.80 wt%, Mn + Fe: 0.7 to 1.1 wt%, Mn / Fe ratio: 1.5 or more,
Cu is regulated to 0.5% by weight or less,
Zn, Ni and Sn as inevitable impurities are regulated to 0.05% by weight or less,
Pb and Bi as inevitable impurities are regulated to 0.005% by weight or less,
The balance consists of aluminum and inevitable impurities,
It has heat dissipation fins (31) for electric heating parts (30),
The heat dissipating fin (31) is integrally formed with a plurality of thin fin portions (31b) on both the front and back surfaces of a flat substrate (31a),
Of the substrate (31a), provided with a circular mounting hole (31c) in a flat portion where the thin fin portion (31b) is not formed,
The electric heating component (30) is formed in a cylindrical outer shape, and the cylindrical outer heating component (30) is press-fitted and fixed in the circular mounting hole (31c). It is said.

The invention according to claim 2 is an aluminum alloy casting formed by die casting using an aluminum alloy for die casting,
Si: 9.0 to 12.0 wt%, Mg: 0.20 to 0.80 wt%, Mn + Fe: 0.7 to 1.1 wt%, Mn / Fe ratio: 1.5 or more,
Cu is regulated to 0.5% by weight or less,
Zn, Ni and Sn as inevitable impurities are regulated to 0.05% by weight or less,
Pb and Bi as inevitable impurities are regulated to 0.005% by weight or less,
The balance consists of aluminum and inevitable impurities,
It has heat dissipation fins (31) for electric heating parts (30),
The heat dissipating fin (31) is integrally formed with a plurality of thin fin portions (31b) on both the front and back surfaces of a flat substrate (31a),
Of the substrate (31a), provided with a circular mounting hole (31c) in a flat portion where the thin fin portion (31b) is not formed,
The electric heating component (30) is formed in a cylindrical outer shape, and the cylindrical heating electric component (30) is caulked and fixed in the circular mounting hole (31c). It is said.

  As described above, in the first aspect of the invention, the electric heating component (30) having a cylindrical outer shape is press-fitted and fixed in the circular mounting hole (31c) of the substrate (31a). In the invention described in 2, the electric heating component (30) having a cylindrical outer shape is caulked and fixed to the circular mounting hole (31c) of the substrate (31a). In this respect, the inventions described in claims 1 and 2 are different.

  According to the inventor's experimental research, by setting the Mn / Fe ratio to 1.5 or more, it is possible to suppress the generation of β-AlFeSi particles constituting a cathode electrode (a noble part of potential) harmful to corrosion resistance. At the same time, with respect to α-Al (Fe · Mn) Si particles similarly constituting the cathode electrode, by suppressing the Fe / Mn ratio in the particles to 1 or less, the potential of the particles can be lowered, and the corrosion resistance. It was found that the deterioration factor can be removed.

In addition, by controlling the amount of Cu added to 0.5% by weight or less, it is possible to reduce the noble Al ₂ Cu phase and to suppress Cu from being dissolved in α-A1 (Fe · Mn) Si particles. The potential of the α-A1 (Fe · Mn) Si particles can be lowered.

  Further, by restricting the amounts of Zn, Ni, Sn, Pb, and Bi as inevitable impurities as described above, it is possible to contribute to ensuring the corrosion resistance of the aluminum alloy casting.

  In combination with these, it was confirmed that the invention according to claims 1 and 2 can significantly improve the corrosion resistance as compared with JIS-ADC12 (see FIG. 5 described later).

  And in invention of Claim 1, 2, the fluidity substantially equivalent to JIS-ADC12 can be obtained by setting Si addition amount to the range of 9.0-12.0 weight%. Therefore, it is possible to realize both the castability and corrosion resistance of the aluminum alloy for die casting.

  In addition, when the amount of Cu added is regulated to 0.5% by weight or less, not only the corrosion resistance is improved, but also the material hardness can be greatly reduced as compared with JIS-ADC12 (see FIG. 6 described later). Thereby, according to invention of Claim 1, workability at the time of press-fitting and fixing an electrical heating component (30) to the radiation fin (31) with which the aluminum alloy casting is equipped becomes favorable.

  Moreover, according to the invention of Claim 2, workability at the time of caulking and fixing the electric heating component (30) to the heat radiation fin (31) provided in the aluminum alloy casting is improved.

  Therefore, in the invention described in claims 1 and 2, when connecting the heat dissipating fin (31) provided in the aluminum alloy casting and the electric heating component (30), both (31, 30) are press-fitted or caulked. It can be easily coupled with the mechanical coupling.

  Furthermore, if the Cu addition amount is restricted to 0.5% by weight or less and the above Cu solid solution is suppressed, the conductivity (thermal conductivity) of the aluminum alloy is improved, so the heat dissipation performance of the radiation fin (31) is also improved. It can be improved.

  Further, Mn and Fe have an effect of suppressing seizure of the aluminum alloy to the mold. Here, if the amount of Mn + Fe (total amount of Mn and Fe added) is reduced to less than 0.7% by weight, the effect of suppressing the seizure becomes insufficient. On the other hand, when the amount of Mn + Fe exceeds 1.1% by weight, the corrosion resistance and strength and elongation are lowered, and a massive Al-Si-Fe intermetallic compound is produced in the molten metal holding furnace to start cutting and other machines. The possibility of deteriorating workability is increased. Therefore, the amount of Mn + Fe is preferably in the range of 0.7 to 1.1% by weight.

  On the other hand, the addition of Mg is for improving the mechanical strength. If the amount of Mg added is less than 0.20% by weight, the effect of improving the strength is insufficient, while the amount of Mg added exceeds 0.80% by weight. And the strength improvement effect falls. Therefore, the Mg addition amount is preferably in the range of 0.20 to 0.80% by weight (see FIG. 8 described later).

  Further, since it does not contain a toxic component such as Be, it is easy to handle an aluminum alloy.

  In the third aspect of the present invention, in addition to the first and second aspects, Ti, B, Zr, Sr, Ca, Na, and Sb are further included as impurities. Thereby, it is possible to provide an aluminum alloy casting in which the primary α-Al phase is refined and the eutectic Si particles are improved, and the castability and strength are further improved.

  More specifically, Ti, B, and Zr are effective in refining the primary α-Al phase. Sr, Ca, Na, and Sb have the effect of improving the eutectic Si particles and improving the castability and strength.

  In the invention according to claim 4, in the aluminum alloy casting according to any one of claims 1 to 3, the upper limit of the Mn / Fe ratio is regulated to 5.0 or less. Thereby, the minimum required amount of Fe can be secured and the effect of preventing seizure of the aluminum alloy to the mold (seizure resistance) can be secured.

  In the invention according to claim 5, in the aluminum alloy casting according to any one of claims 1 to 4, the thickness (t) of the minimum plate thickness portion of the thin fin portion (31b) is 0.5 to 1. 0.5 mm.

  Since the fluidity of the aluminum alloy according to the present invention can be set to a high level in accordance with JIS-ADC12 by setting the Si addition amount in the above range, the thickness (t) of the minimum thickness portion as in claim 5. Even if it is the product shape which has a thin fin part (31b) whose thickness is 0.5-1.5 mm, it can cast favorably.

  As in the invention described in claim 6, in the aluminum alloy casting according to any one of claims 1 to 5, the electric heating component is specifically a diode (30).

In invention of Claim 7, it is a manufacturing method which manufactures the aluminum alloy casting as described in any one of Claim 1 thru | or 6,
A depressurization step of closing the mold (10, 11) and depressurizing the mold (10, 11) to a predetermined pressure lower than atmospheric pressure;
It is characterized by comprising a molten metal filling step of filling the mold (10, 11) with the molten aluminum alloy for die casting after the depressurizing step.

  According to this, since the mold (10, 11) is depressurized to a predetermined pressure lower than the atmospheric pressure or less, the molten aluminum alloy is filled in the mold (10, 11). It is possible to prevent the phenomenon that the back pressure) increases and hinders the flow of molten metal. Therefore, the fluidity of the molten metal can be further improved.

In invention of Claim 8, it is a manufacturing method which manufactures the aluminum alloy casting as described in any one of Claim 1 thru | or 6,
An exhaust step of closing the mold (10, 11) and discharging the air in the mold (10, 11);
After the exhausting step, an atmosphere adjusting step of supplying oxygen into the mold (10, 11) to replace the inside of the mold (10, 11) with an oxygen atmosphere;
It is characterized by comprising a molten metal filling step of filling the mold (10, 11) with the molten aluminum alloy for die casting after the atmosphere adjusting step.

  According to this, after replacing the inside of the mold (10, 11) with an oxygen atmosphere, the molten aluminum alloy is filled into the mold (10, 11), so that the oxidation of the aluminum alloy is promoted and the structure of the alloy material is increased. The material strength can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

It is a graph which shows the material component of Examples 1-5 of this invention, and Comparative Examples 1-3. It is a graph which shows the evaluation result of the fluidity | liquidity of the various aluminum alloy materials of FIG. It is a graph which shows the material component of the aluminum alloy material prescribed | regulated to JIS. In the chart which shows the material component of Examples 1-5 of this invention and Comparative Examples 2 and 3, Mn / Fe ratio and Mn + Fe amount are added to FIG. It is a graph which shows the evaluation result of the corrosion resistance of the various aluminum alloy materials of FIG. It is a graph which shows the relationship between the amount of Cu addition to aluminum alloy material, and material hardness. It is a graph which shows the material component of Examples 6-8 and Comparative Example 4 of this invention. It is a graph which shows the relationship between the amount of Mg addition to aluminum alloy material, and material hardness. It is a schematic sectional drawing which shows an example of the die-casting apparatus in embodiment of this invention. It is a schematic sectional drawing which shows the other example of the die-casting apparatus in embodiment of this invention. It is a perspective view which shows the specific product example of the aluminum alloy casting by this invention.

  Hereinafter, embodiments of the present invention will be described based on specific examples. FIG. 1 shows the material components of the die casting aluminum alloys of Examples 1 to 5 and Comparative Examples 1 to 3 of the present invention, and FIG. 2 shows the evaluation results of the fluidity of each material composition of FIG. Comparative Example 2 is JIS-ADC12, and Comparative Example 3 is JIS-AC4C.

  In addition, in the material component of FIG. 1 and FIG. 4 mentioned later, "-" has shown that the addition amount of each component is a very small amount of less than 0.01 weight%. 3A and 3B show material components of JIS-ADC12, JIS-ADC5, JIS-ADC6, and JIS-AC4C.

  In each of Examples 1 to 5, the Si addition amount is set to 9.1 to 10.8% by weight included in the Si addition range of the present invention.

  The fluidity evaluation results in FIG. 2 are expressed as a flow length ratio when the flow length of the JIS-ADC 12 of Comparative Example 2 is 1. Here, the flow length is the flow length in the direction of the molten metal until the molten aluminum alloy is solidified and the molten metal stops when the molten aluminum alloy is poured into a mold having a predetermined cross-sectional shape. is there.

  According to Examples 1-5, the flow length ratio of 0.8 or more can be obtained with respect to the flow length of JIS-ADC12 of Comparative Example 2, and a high level of fluidity according to JIS-ADC12 can be secured. I understand.

  On the other hand, Comparative Examples 1 and 3 have small amounts of Si addition of 6.7% by weight and 7.0% by weight, respectively. As a result, Comparative Examples 1 and 3 can obtain only a flow length ratio in the vicinity of 0.7 with respect to the flow length of JIS-ADC 12 of Comparative Example 2, which is much higher than that of Comparative Example 2 and Examples 1 to 5. Sex is reduced.

  Next, FIG. 4 shows the Mn / Fe ratio and the amount of Mn + Fe in Examples 1 to 5 and Comparative Examples 2 and 3, and the Mn / Fe ratio in Examples 1 to 5 is 2.2 to 4. The amount of Mn + Fe is in the range of 0.92 to 1.04% by weight.

  On the other hand, Comparative Example 2 has a Mn / Fe ratio of 0.34, which is a low value greatly deviating from the scope of the present invention. In Comparative Example 3, both the Mn / Fe ratio and the amount of Mn + Fe are greatly out of the scope of the present invention.

  FIG. 5 shows the evaluation results of the corrosion resistance of each material, and represents the corrosion weight loss ratio of each material when the corrosion weight loss of JIS-ADC12 of Comparative Example 2 is 1. Here, the corrosion resistance evaluation is performed using a salt spray test method (see JIS Z 2371 (2000)) which is the most general evaluation method.

  Specifically, the test pieces made of each alloy material of Examples 1 to 5 and Comparative Examples 2 to 5 are placed in a bathtub where spraying salt water can be taken out, and the test piece is taken out from the bathtub after a predetermined time, The amount of corrosion of the test piece (corrosion weight loss) is measured, and the corrosion resistance is evaluated to be lower as the corrosion weight loss increases.

  According to Examples 1-5, the corrosion weight loss ratio can be significantly reduced to 0.4 or less of JIS-ADC12 of Comparative Example 2, and the corrosion resistance can be remarkably improved.

  Incidentally, JIS-ADC12 of Comparative Example 2 has a low value of Mn / Fe ratio = 0.34 and a high value of Cu addition amount = 3.08% by weight. Corrosion resistance is reduced.

  Further, although JIS-AC4C of Comparative Example 3 has a Cu addition amount reduced to 0.09 wt%, it has a low value of Mn / Fe ratio = 0.33, so the corrosion weight loss ratio is around 0.5. The corrosion resistance of Comparative Example 3 is lower than in Examples 1-5.

  In addition, since JIS-AC4C of Comparative Example 3 has a low Mn + Fe amount of 0.24% by weight, the effect of suppressing seizure of the aluminum alloy to the mold is insufficient.

  Next, FIG. 6 shows the change in the material hardness depending on the amount of Cu added, with the relative hardness when the material hardness of JIS-ADC12 is 1. In the example of FIG. 6, the Cu addition amount of JIS-ADC12 is 2.5% by weight. On the other hand, the amount of Cu added in Examples 6, 7, 8 and Comparative Example 4 is 1.0% by weight or less. The material compositions of Examples 6, 7, and 8 and Comparative Example 4 are as shown in FIG.

  As shown in FIG. 6, it can be seen that the material hardness decreases as the Cu addition amount decreases in the order of Comparative Example 4 → Example 8 → Example 7 → Example 6. In particular, the relative hardness with respect to JIS-ADC12 can be greatly reduced to around 0.8 by regulating the Cu addition amount to 0.5 wt% or less. As a result, it is possible to press-fit, caulk and the like of the part into the die-cast aluminum alloy casting.

  Next, FIG. 8 shows the change in material strength depending on the amount of added Mg, with the relative strength when the strength (specifically, tensile strength) is 1 when the amount of added Mg = 0.

  As can be seen from FIG. 8, the tensile strength of the aluminum alloy can be effectively improved in the range of Mg addition amount = 0.20 to 0.80 wt% (more preferably in the range of 0.35 to 0.60 wt%). I understand.

  In addition, the tendency of the intensity | strength change of the aluminum alloy by the change of Mg addition amount shown in FIG. 8 appears in Examples 1-8 in common.

  In Examples 1 to 8, the contents of Zn, Ni, Sn, Pb, Bi, and the like that lower the corrosion resistance are particularly restricted as other inevitable impurities of the aluminum alloy. Zn, Ni, and Sn are desirably 0.05% by weight or less, and Pb and Bi are desirably 0.005% by weight or less.

  Next, a manufacturing method (die casting method) of an aluminum alloy casting using the aluminum alloy according to the present embodiment will be described. First, the die casting apparatus of this embodiment will be described with reference to FIG. The die casting apparatus has a mold composed of a fixed mold 10 and a movable mold 11 disposed opposite to the fixed mold 10.

  The movable mold 11 includes a movable block 12, a spacer 13, and a die base 14. A hydraulic drive mechanism (not shown) is connected to the die base 14 of the movable mold 11 so that the movable mold 11 can move in the left-right direction in FIG.

  FIG. 9 shows a state in which the movable block 12 of the movable mold 11 is moved to a position where it contacts the fixed mold 10 and the mold is closed, and an aluminum alloy is interposed between the movable block 12 and the fixed mold 10. A cavity 15 is formed which creates a cast product shape.

  A cylindrical injection sleeve 16 is disposed outside the fixed mold 10, and one end portion of the internal space of the injection sleeve 16 communicates with the cavity 15 via a spool bush 10 a penetrating the fixed mold 10. A hot water supply port 16 a is opened on the upper surface of the injection sleeve 16.

  An injection plunger 17 is fitted inside the injection sleeve 16. A hydraulic drive mechanism (not shown) is connected to the injection plunger 17 so that the injection plunger 17 can move in the axial direction of the injection sleeve 16 (left and right direction in FIG. 9).

  FIG. 9 shows a state in which the injection plunger 17 is retracted to a position where the hot water supply port 16a is opened. The ladle 18 serves as a handle (a molten metal injector) for injecting a molten aluminum alloy into the injection sleeve 16, and the molten aluminum alloy held in a furnace (not shown) is heated by the ladle 18 to the hot water inlet 16a. To the inside of the injection sleeve 16.

  The electric vacuum pump 19 and the vacuum tank 20 constitute a pressure reducing device for reducing the inner space of the mold including the cavity 15 to a predetermined pressure lower than the atmospheric pressure. The vacuum tank 20 includes a hose 21 and a movable side. The block 15 communicates with the cavity 15 via a communication path 22.

  Here, an electrically operated on-off valve 21 a is disposed in the middle of the hose 21. More specifically, the communication path 22 communicates with a portion of the cavity 15 opposite to the communication portion of the injection sleeve 16. Further, a pressure gauge (vacuum gauge) 23 is connected to the communication path 22, and the pressure inside the mold (degree of pressure reduction) can be measured by the pressure gauge 23.

  Further, the movable die 11 is equipped with a cut-off pin 25, an extrusion pin 26, an extrusion plate 27, and the like that constitute an opening / closing means capable of opening and closing the communication path 22.

  Next, a manufacturing method (die casting method) of an aluminum alloy casting using the above-described die casting apparatus will be described. First, the movable block 12 of the movable mold 11 is brought into contact with the fixed mold 10 as shown in FIG. 9 to close the mold (clamped state), and the injection plunger 17 is the maximum indicated by the solid line in FIG. The hot water supply port 16a is opened by retreating to the retreat position.

  In this state, a ladle 18 is used to inject molten aluminum alloy into the injection sleeve 16 from the hot water supply port 16a.

  After the injection of the molten metal into the injection sleeve 16 is completed, the injection plunger 17 is moved forward to the intermediate stop position indicated by the broken line 17a in FIG. At this time, the hot water supply port 16a does not have to be fully closed. In short, it is only necessary to seal the inside of the mold by the advancement of the injection plunger 17 and to shut off the inside of the mold and the atmosphere (outside air).

  Next, a depressurizing step is performed to depressurize the inner space of the mold including the cavity 15 to a predetermined pressure lower than atmospheric pressure. Specifically, the open / close valve 21a such as an electric type and the cut-off pin 25 are operated to open the air in the mold inner space through the communication path 22 and the hose 21 due to the high degree of vacuum in the vacuum tank 20. Suction to the vacuum tank 20 side reduces the pressure inside the mold.

  When the pressure in the mold internal space is measured by the vacuum gauge 23 and the mold internal pressure is reduced to a predetermined pressure (for example, 13.3 kPa) or less, the on-off valve is based on the measurement signal of the pressure gauge 23. 21a and the cut-off pin 25 are returned to the closed state.

  Next, advance of the injection plunger 17 is started based on the measurement signal of the pressure gauge 23, and the melt in the injection sleeve 16 is filled into the cavity 15. In this filling step, the inside of the mold is previously depressurized to the predetermined pressure or lower, so that back pressure (pressure in the front side space in the molten metal movement direction) accompanying the molten metal filling does not occur. For this reason, the molten metal can be smoothly filled into the cavity 15.

  The broken line 17b in FIG. 9 is the injection advance limit position of the injection plunger 17, and the filling of the molten metal into the cavity 15 is completed at the injection advance limit position 17b. Thereafter, the injection advance limit position 17b of the injection plunger 17 is maintained, and the molten metal inside the cavity 15 is solidified.

  After the molten metal has solidified, the movable mold 11 is moved in a direction away from the fixed mold 10 (left direction in FIG. 9) to open the mold, and the extrusion plate 27 and the extrusion pin 26 are advanced in the right direction in FIG. Then, the product (cast product) solidified inside the cavity 15 is taken out of the mold.

  Next, another example of the die casting apparatus of this embodiment will be described with reference to FIG. In the example of FIG. 10, an oxygen supply device 24 is added to the die casting apparatus shown in FIG. This oxygen supply device 24 is for supplying oxygen to the mold internal space including the cavity 15, and specifically, an oxygen tank 24a, a supply pipe 24b, and a supply pipe 24b for storing oxygen at a predetermined pressure. An electric on-off valve 24c for opening and closing the passage is provided.

  The distal end of the supply pipe 24b is opened in a portion of the internal space constituted by the injection sleeve 16 and the spool bush 10a on the more forward side than the intermediate stop position 17a of the injection plunger 17, and the inside of the mold is passed through the internal space of the spool bush 10a. Oxygen is supplied to the space.

  Next, an aluminum alloy casting manufacturing method (die casting method) using the die casting apparatus of FIG. 10 will be described. First, a molten aluminum alloy is injected into the injection sleeve 16 from the hot water supply port 16a. This molten metal injection process is the same as the example of FIG. 9, and after the molten metal injection into the injection sleeve 16 is completed, the injection plunger 17 is advanced to the intermediate stop position 17a.

  Next, an exhausting process (in other words, a vacuuming process) for discharging atmospheric components in the mold inner space including the cavity 15 is performed. This exhaust process corresponds to the decompression process in the example of FIG. 9, but its purpose is not the decompression inside the mold, but the discharge of atmospheric components inside the mold.

  After performing this exhaust process, the atmosphere adjustment process which substitutes the inside of a metal mold | die for an oxygen atmosphere is implemented. That is, in this atmosphere adjustment step, the on-off valve 24c of the supply pipe 24b is opened, and oxygen in the oxygen tank 24a of the oxygen supply device 24 is supplied into the cavity 15 through the supply pipe 24b, the injection sleeve 16 and the spool bush 10a. .

  When the pressure gauge 23 measures that the pressure of the oxygen atmosphere inside the mold has risen to a predetermined pressure exceeding the atmospheric pressure, the on-off valve 24c of the supply pipe 24b is automatically closed, and the atmosphere adjustment process is completed. .

  Next, similarly to the example of FIG. 9 described above, the molten metal filling step, the molten metal filling state is maintained, the product (cast product) is taken out by mold opening, and the like.

  According to the example of FIG. 10, since the molten aluminum alloy is filled in the mold after the inside of the mold is replaced with an oxygen atmosphere, the oxidation of the aluminum alloy can be actively promoted. It can be made dense and the material strength can be improved.

  Next, a specific product example of the aluminum alloy casting of the present invention will be described with reference to FIG. 11. FIG. 11 shows an example in which the heat radiating fins 31 of the electric heating component 30 are formed of the aluminum alloy casting of the present invention. More specifically, the electrical heating component 30 is a diode.

  The heat radiation fin 31 is integrally formed with a plurality of thin fin portions 31b on both front and back surfaces of a flat substrate 31a. A circular mounting hole 31c is formed in a flat portion of the substrate 31a where the thin fin portion 31b is not formed, and the electric heating component 30 formed in a cylindrical outer shape is press-fitted and fixed in the circular mounting hole 31c. It is supposed to be.

  The plate thickness t of the minimum plate thickness portion (tip portion) of the thin fin portion 31b is about 0.5 to 1.5 mm. Even with such a thin plate shape, molding is possible by improving fluidity during die casting of an aluminum alloy casting.

  In addition, according to the aluminum alloy casting of the present invention, the material hardness of the aluminum alloy is lowered, so that the electric heating component 30 can be press-fitted and fixed to the mounting hole 31c of the substrate 31a of the radiating fin 31 efficiently with good quality. Can do.

  In FIG. 11, the electric heat generating component 30 is press-fitted and fixed to the substrate 31 a of the radiating fin 31. However, even when the electric heating component 30 is fixed by caulking to the substrate 31 a of the radiating fin 31, the material hardness of the aluminum alloy is By lowering, the caulking process of the substrate 31a of the radiating fin 31 can be efficiently performed with good quality.

  In the die casting apparatus shown in FIGS. 9 and 10, the drive mechanism of the movable mold 11 is not limited to a hydraulic drive mechanism, and a drive mechanism using various power sources such as an electric motor, water pressure, and air pressure can be used. Similarly, as a power source for driving the vacuum pump 19, various power sources such as hydraulic pressure, water pressure, and air pressure can be used in addition to the electric motor.

10 Fixed mold (mold)
11 Movable type (mold)
16 Injection sleeve 16a Hot water inlet 17 Injection plunger

Claims (8)

An aluminum alloy casting formed by die casting using an aluminum alloy for die casting,
Si: 9.0 to 12.0 wt%, Mg: 0.20 to 0.80 wt%, Mn + Fe: 0.7 to 1.1 wt%, Mn / Fe ratio: 1.5 or more,
Cu is regulated to 0.5% by weight or less,
Zn, Ni and Sn as inevitable impurities are regulated to 0.05% by weight or less,
Pb and Bi as inevitable impurities are regulated to 0.005% by weight or less,
The balance consists of aluminum and inevitable impurities,
It has heat dissipation fins (31) for electric heating parts (30),
The heat dissipating fin (31) is integrally formed with a plurality of thin fin portions (31b) on both front and back surfaces of a flat substrate (31a),
Of the substrate (31a), provided with a circular attachment hole (31c) in a flat portion where the thin fin portion (31b) is not formed,
The electric heating component (30) is formed in a cylindrical outer shape, and the cylindrical outer heating component (30) is press-fitted and fixed in the circular mounting hole (31c). Aluminum alloy castings. An aluminum alloy casting formed by die casting using an aluminum alloy for die casting,
Si: 9.0 to 12.0 wt%, Mg: 0.20 to 0.80 wt%, Mn + Fe: 0.7 to 1.1 wt%, Mn / Fe ratio: 1.5 or more,
Cu is regulated to 0.5% by weight or less,
Zn, Ni and Sn as inevitable impurities are regulated to 0.05% by weight or less,
Pb and Bi as inevitable impurities are regulated to 0.005% by weight or less,
The balance consists of aluminum and inevitable impurities,
It has heat dissipation fins (31) for electric heating parts (30),
The heat dissipating fin (31) is integrally formed with a plurality of thin fin portions (31b) on both the front and back surfaces of a flat substrate (31a),
Of the substrate (31a), provided with a circular mounting hole (31c) in a flat portion where the thin fin portion (31b) is not formed,
The electric heating component (30) is formed in a cylindrical outer shape, and the cylindrical heating electric component (30) is caulked and fixed in the circular mounting hole (31c). Aluminum alloy castings.   The aluminum alloy casting according to claim 1 or 2, further comprising at least one of Ti, B, Zr, Sr, Ca, Na, and Sb as impurities.   The upper limit of Mn / Fe ratio is 5.0 or less, The aluminum alloy casting as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned.   The aluminum alloy casting according to any one of claims 1 to 4, wherein a thickness (t) of a minimum plate thickness portion of the thin fin portion (31b) is 0.5 to 1.5 mm.   The aluminum alloy casting according to any one of claims 1 to 5, wherein the electric heating part is a diode (30). A manufacturing method for manufacturing the aluminum alloy casting according to any one of claims 1 to 6,
A depressurization step of closing the mold (10, 11) and depressurizing the mold (10, 11) to a predetermined pressure lower than atmospheric pressure;
A method for producing an aluminum alloy casting, comprising: after the pressure reducing step, a molten metal filling step of filling the mold (10, 11) with the molten aluminum alloy for die casting. A manufacturing method for manufacturing the aluminum alloy casting according to any one of claims 1 to 6,
An exhaust step of closing the mold (10, 11) and discharging the air in the mold (10, 11);
After the exhausting step, an atmosphere adjusting step of supplying oxygen into the mold (10, 11) to replace the inside of the mold (10, 11) with an oxygen atmosphere;
A method for producing an aluminum alloy casting, comprising: a molten metal filling step of filling the mold (10, 11) with the molten aluminum alloy for die casting after the atmosphere adjusting step.

Images