JPH08117946A - Die-casting method and heat-treatable die-cast article - Google Patents

Abstract

PURPOSE: To obtain a heat-treatable die-cast article capable of keeping the elongation-strength balance on a high level. CONSTITUTION: When oxygen-blown die casting is performed, a die casting alloy contg. the Cu, and Si equivalent to JIS-ADC10 and ADC12, 5-500ppm Be, minute amts. of Mg, Fe, Mn, Ni, Zn, etc., and the balance Al, a casting alloy contg. the Si and Mg equivalent to JIS-AC4A and AC4C, 5-500ppm Be, minute amts. of Cu, Fe, Mn, Ni, Ti, Cr, etc., and the balance Al or a hypereutectic aluminum alloy contg. 14-18wt.% Si and 5-500ppm Be is used as the molten metal to be injected and filled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention ensures a high level of balance between elongation and strength, which are the weak points of die casting products, without losing the excellent features of die casting products such as high precision, thinness, and high productivity. And a heat-treatable die-cast product produced by this die-casting method.

[0002]

2. Description of the Related Art As a method for obtaining a heat-treatable die cast product, there is an oxygen blown die cast in which oxygen is previously fed into a mold cavity to inject and fill molten metal into the mold cavity. According to this technique, oxygen in the mold cavity reacts with the injected molten aluminum alloy to form oxides, ideally there being no gas in the casting blank. Therefore, the generation of bubbles due to the inclusion of air, which cannot be avoided by ordinary die casting, is suppressed, and this oxygen-blown die casting product is called a blister due to the connection and expansion of bubbles even when exposed to the high temperature during heat treatment. It is said that swelling does not occur.

[0003]

However, even in the case of this oxygen-blown die casting, which is generally regarded as a method capable of obtaining a heat-treatable die casting product, the principle of the process is practically performed in an ideal state. It is difficult to realize by reflecting in. In other words, depending on the casting material, product shape, parts, melting / casting conditions, required heat treatment conditions, etc., it is not possible to eliminate harmful air bubbles in die cast products.
In some cases, there were limits and restrictions on the yield of good products, product shape, materials used, melting / casting conditions, required heat treatment conditions, etc., because blisters were generated during the solution treatment and there were parts.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional method, and provides a die casting method capable of obtaining a die cast product which can be stably heat treated under a wider range of conditions. It is intended to be provided.

[0005]

According to the die casting method of the present invention, as described in claim 1, oxygen is preliminarily fed into the mold cavity to inject and fill molten metal into the mold cavity. 5 to 50 beryllium is used as the molten metal to be injected and filled when the blow-in die casting is performed.
The structure is characterized by using a molten aluminum alloy containing 0 ppm.

In an embodiment of the die casting method according to the present invention, as described in claim 2,
As the aluminum alloy, an alloy for die casting containing 7.5 to 12% by weight of silicon can be used. In this case, as described in claim 3, JIS-ADC10 and ADC12 are used as the aluminum alloy. Corresponding to Cu: 1.5 to 4.0% by weight, Si: 7.5 to 1
2.0 wt% and further Be: 5-500 ppm, and other appropriate trace amounts of Mg, Fe, Mn, Ni, Zn.
It is possible to use a die-casting alloy including the above and the like, and the balance substantially consisting of Al.

Further, in the same embodiment, as described in claim 4, an aluminum-silicon-magnesium alloy containing 6.5 to 10% by weight of silicon may be used as the aluminum alloy. In this case, as described in claim 5, as the aluminum alloy, S corresponding to JIS-AC4A, AC4C is used.
i: 6.5 to 10.0% by weight, Mg: 0.2 to 0.6% by weight, Be: 5 to 500 ppm, and other appropriate trace amounts of Cu, Fe, Mn, Ni, Ti, Cr Etc., and the balance may be made of a casting alloy consisting essentially of Al.

Further, in the embodiment of the present invention, as described in claim 6, Cu: 4.0 equivalent to JIS-ADC14 as an aluminum alloy.
5.0 wt%, Si: 16-18 wt%, Mg: 0.4
5 to 0.65% by weight and further Be: 5 to 500 p
pm, and other appropriate trace amounts of Mn, Ni, Ti, P,
It is possible to use a die-casting alloy containing Fe, Zn and the like, and the balance being substantially Al.

Furthermore, in the same manner,
As described in claim 7, as an aluminum alloy, Cu: 2.0 to 5.0 wt%, Si: 14 to 16 wt%, Mg: 0.1 to 1.0 wt%, Mn: 0. .3 ~
0.8% by weight. Cr: 0.1 to 0.3% by weight, Ti:
0.05-0.20% by weight, P: 0.003-0.02
% By weight, Fe: 1.5% by weight or less, and Be:
An aluminum alloy containing 5 to 500 ppm, Ca: less than 0.005% by weight, and the balance substantially consisting of Al can be used.

Further, the heat-treatable die-cast product according to the present invention is constituted by the die-casting method according to any one of claims 1 to 7, as described in claim 8. It is characterized by that.

[0011]

In the die casting method according to the present invention, as described in claim 1, the die cavity is prefilled with oxygen, and then oxygen blown die casting is performed in which the molten metal is injected and filled in the die cavity. 5 to 500 ppm of beryllium as a molten metal for injection filling
By using the molten aluminum alloy containing the above, the problems that the conventional techniques have have been solved. In this case, if the beryllium content is less than 5 ppm, the effect of addition of beryllium does not sufficiently appear, and if it is contained up to 500 ppm, a sufficient effect can be obtained. Almost no difference appears. Also,
Even if an aluminum alloy containing beryllium is applied to a normal die cast instead of the oxygen blown die cast, the effect of suppressing the blister generation is exhibited, but it does not reach a level at which heat treatment is possible. Therefore, in the present invention, a heat-processable die-cast product is obtained by oxygen-blowing die-casting a molten aluminum alloy containing beryllium in an amount of 5 to 500 ppm.

It has been described above that it is difficult to actually realize the principle by reflecting it in an ideal state even by the oxygen blowing die casting method. According to the research conducted by the inventor of the present invention, this is due to the fact that the oxygen previously filled in the mold cavity and the molten alloy injection-filled in the mold cavity have not sufficiently reacted with each other.
Further, as an effective method for making the reaction between oxygen and the molten alloy in the mold cavity more ideal, the reactivity with oxygen is higher than that of aluminum, which is the main alloying component and highly reactive with oxygen. It has been clarified that it is effective to use an aluminum alloy alloyed with a high element.

Further, as another effective method for making the reaction between oxygen and the molten aluminum alloy more ideal, the scattering condition of the molten aluminum alloy, which is injected and filled in the mold cavity, is used as a reaction. On the other hand, we also found that optimization is effective.

As a method of achieving these, for example, a method of using a magnesium-containing alloy or an alloy containing a larger amount of magnesium, a method of using an alloy containing calcium, etc. have been considered as a method of increasing reactivity.
Further, for example, as a method of changing the scattering state of the molten aluminum alloy in the mold cavity, a method of increasing the injection speed of the molten aluminum alloy, a method of providing a large number of thin gates, and the like have been considered. And, as a result of extensive experimentation, they were found to be effective for each, but the effectiveness of the method of applying a beryllium-containing molten aluminum alloy to oxygen-blown die casting, which has never been proposed, is It proved to be outstanding compared to that of the method.

It can be understood that beryllium reacts with oxygen very easily, but since beryllium has a significant property improving effect even when added in an extremely small amount of 5 ppm, the effect of beryllium is only the reactivity with oxygen. Cannot be attributed to It is believed that this is due to the fact that beryllium has both high reactivity with oxygen and at the same time has the characteristics of spraying molten aluminum alloy finer. In addition to this effect, a mechanism that changes the surface state of the molten aluminum alloy and promotes the reaction of other elements such as aluminum with oxygen is also conceivable.

In any case, in the present invention, when performing the oxygen-blown die casting, by using the molten aluminum alloy containing beryllium in an appropriate amount, the reaction of beryllium with oxygen and the dispersion state of the molten aluminum alloy are optimized. , It reacts with oxygen in the mold cavity in a situation close to ideal, and suppresses the generation of harmful bubbles in the die cast product.

Therefore, even if the die cast product obtained by the method according to the present invention is heat-treated, no harmful blister is generated, and a high quality die cast product having a good balance of elongation and strength can be stably obtained. On the contrary, if the conventional level is secured as the obtained property, by using the method of the present invention, a die-cast casting product that can be heat-treated under a wider range of difficult conditions can be obtained, and the yield rate of casting is remarkably high. It will be improved.

And, as described in claim 2,
As the aluminum alloy, a die-casting alloy containing 7.5 to 12% by weight of silicon is used. As described in claim 3, the die-casting alloy containing 7.5 to 12% by weight of silicon is JIS-ADC10. , Corresponding to ADC12: Cu: 1.5 to 4.0% by weight, Si: 7.5 to 12.0
% By weight, and Be: 5 to 500 ppm,
Other trace amounts of Mg, Fe, Mn, Ni, Z, if necessary
By using a die-casting alloy containing n and the like and the balance substantially consisting of Al, a heat-treatable die-cast product excellent in strength and shape accuracy can be manufactured.

In this case, Cu is an element that contributes to the improvement of room temperature and high temperature strength by solid solution strengthening and age hardening. If it is less than 1.5% by weight, its effect is small, and if it exceeds 4.0% by weight, toughness deteriorates. It will tend to
It is preferable to be 5 to 4.0% by weight, and Si is an element that contributes to the improvement of castability, wear resistance and strength, and 7.5% by weight
If it is less than 1%, the effect is small, and if it exceeds 12.0% by weight, the solubility and machinability tend to be deteriorated.
It is preferably 12.0% by weight.

Further, as described in claim 4, an aluminum-silicon-magnesium alloy containing 6.5 to 10% by weight of silicon is used as the aluminum alloy, and as described in claim 5. 6.5 to 10% by weight of silicon
As an aluminum-silicon-magnesium alloy containing
Si equivalent to JIS-AC4A and AC4C: 6.5
10.0% by weight, containing Mg: 0.2-0.6% by weight,
Further, by including a Be: 5 to 500 ppm, if necessary, a trace amount of Cu, Fe, Mn, Ni, Ti, Cr, etc., and the balance being substantially Al, the casting alloy is used. Also, a heat-processable die-cast product having excellent elongation and shape accuracy can be manufactured.

In this case, Si is an element effective for improving castability, wear resistance, and strength, so 6.5 to 10.
The content is preferably in the range of 0% by weight, and Mg is an element effective in improving the strength by age hardening.
It is preferable to be in the range of 0.6 wt%.

In addition, as an aluminum alloy, as described in claim 6, Cu: 4.0 to 5.0% by weight, Si: 16 to 18% by weight, Mg: 0. For die-casting containing 45 to 0.65% by weight, further containing Be: 5 to 500 ppm, and optionally containing a trace amount of Mn, Ni, Ti, P, Fe, Zn, etc., with the balance substantially consisting of Al. The use of the alloy also makes it possible to produce a heat-treatable die-cast product having excellent strength and shape accuracy.

Further, as the aluminum alloy, as described in claim 7, as the aluminum alloy, Cu: 2.0 to 5.0% by weight, Si: 14 to 16% by weight, Mg: 0.1. ~ 1.0 wt%, Mn: 0.3 ~
0.8% by weight. Cr: 0.1 to 0.3% by weight, Ti:
0.05-0.20% by weight, P: 0.003-0.02
% By weight, Fe: 1.5% by weight or less, and Be:
By using an aluminum alloy containing 5 to 500 ppm, Ca: less than 0.005% by weight, and the balance substantially consisting of Al, a heat-treatable die cast product excellent in wear resistance, strength and shape accuracy can be obtained. Will be manufactured.

Thus, as described in claim 8, by carrying out the die-casting method according to any one of claims 1 to 7, a heat-processable die-cast product excellent in strength and shape accuracy is obtained. Will be manufactured.

[0025]

EXAMPLE The problem with the prior art was that blisters generated during heat treatment such as solution heat treatment could not be completely suppressed. Therefore, an experiment was conducted to evaluate the blister generated by applying the high temperature to which the die cast product is exposed to the solution heat treatment to the die cast product test piece. In this case, a horizontal die casting machine having a die clamping force of 250 tons was used, and the die cast product test piece had a size of 100 × 150 × 3 mm. Further, the die casting conditions such as the cycle and the injection conditions were constant. The holding temperature and the casting temperature of the molten aluminum alloy were set to 120 ° C. on the liquidus line in the case of hypereutectic aluminum-silicon alloy, and were set to 60 ° C. on the liquidus line in other alloys, which were changed depending on the alloy.

After the die-casting conditions became stable, continuous 10
0 test piece was cast and used as a test material. And
After the casting plan was trimmed and a heat history of 510 ° C. × 1 Hr simulating solution heat treatment was applied in a fluidized bed furnace, the test piece was rapidly cooled in water, and blisters generated on the surface were visually evaluated. And 5 points without blisters, 4 points with minute blister without problem, 3 points with problem blisters, 2 points with many blisters, beyond blisters A bulge is counted as 1 point and 10 points each
A total score of 0 sheets was used for comprehensive evaluation.

Oxygen-blown die-casting is originally used to provide die-cast products for parts and pressure-resistant parts that require high levels of elongation and strength, so the materials used are limited to some extent. Typical applicable alloys include die-casting alloys having good castability and aluminum-silicon-magnesium alloys having good balance of elongation and strength. Therefore, the material for ADC12 was used as the test material on behalf of the alloy for die casting, and the material for AC4C was used as the test material on behalf of the alloy for aluminum-silicon-magnesium casting. In addition, as a representative of wear-resistant aluminum alloys whose needs have been increasing in recent years, B
The materials for 390, and the materials disclosed in JP-A-5-078770 were added to the test materials. Table 1 shows the composition of the materials used in the experiment. Table 2 shows the evaluation results of the materials shown in Table 1.

[0028]

[Table 1]

[0029]

[Table 2]

Examples 1 to 4 and Reference Examples 1 to 3 are examples in which materials that can obtain ADC 12 on behalf of aluminum-silicon-copper-based die casting alloys were examined.

Reference examples 1 and 2 are comparisons between oxygen-blown die-casting and normal die-casting. As a result, the effect of oxygen injection die casting is clear, and the overall evaluation is about 300 improvement. However, as shown in the evaluation results of Reference Example 1, even when oxygen-blowing die casting is applied to the present alloy, the problem of blisters cannot be completely suppressed. In this case, there is still room for improvement by optimizing the die-casting conditions, but even if the same die-casting conditions are used, when the materials containing beryllium containing Examples 1 to 4 are cast, no blister becomes a problem. It has stopped happening.

In this case, a beryllium content of 5 ppm exerts a sufficient effect, and the characteristics are improved from the comprehensive evaluation 395 to 440 without addition. In addition, it is recognized that the score increases as the beryllium content increases. However, as shown in Examples 3 and 4, even if the beryllium content was increased from about 200 ppm to about 500 ppm, the improvement in characteristics was slight, and the inclusion of beryllium in excess of 500 ppm had a positive meaning. It is also clear that it is not.

Reference Example 3 is a study example when a similar alloy containing beryllium was usually die-cast, and Reference Example 2
It is shown that the blister expression situation is in the direction of improvement compared to. Therefore, it can be inferred that the properties of the raw material without heat treatment and its stability have been improved. However, in order to obtain a heat-treatable material, it is essential to combine it with oxygen-blown die casting. Also shows.

As described above, when the material from which the ADC 12 is obtained contains 5 ppm to 500 ppm of beryllium and is subjected to oxygen blow die casting, the reaction between oxygen and the molten alloy, which is the principle of oxygen blow die casting, is further promoted and stabilized. As a result, a heat-treatable die-cast raw material or die-cast product without blister can be obtained. Judging from the mechanism, it is easily inferred that the effect of beryllium is effective regardless of the amount of silicon and the amount of copper. Further, it has been confirmed that the effects of the present invention are exhibited also in a material from which ADC10 rough material, which is also an alloy for die casting, can be obtained.

Example 5 and Reference Example 4 are examples in which materials representative of aluminum-silicon-magnesium casting alloys having a good balance between elongation and strength were obtained, and materials capable of obtaining die-cast products corresponding to AC4C were studied. . Similar to the example of the aluminum-silicon-copper-based die casting alloy described above, the effect of beryllium is also exhibited in the oxygen-blown die casting, and the improvement effect of 50 or more is obtained. In Reference Example 4, the problem blister is 16
It should be noted that, in comparison with the case of the die-cast product of No. 5, the example 5 has no case.

As described above, by performing beryllium-containing aluminum-silicon-magnesium alloy for casting and performing oxygen-blown die casting, the reaction between oxygen and the molten alloy, which is the principle of oxygen-blown die casting, is further promoted and stabilized. As a result, a heat-treatable die-cast raw material or die-cast product without blister can be obtained. This is similar to the example of the aluminum-silicon-copper-based die casting alloy described above, but in the aluminum-silicon-magnesium-based casting alloy that emphasizes the balance between elongation and strength, especially the elongation value. However, it is unlikely that the function of producing the effects of the present invention will change due to changes in components such as silicon and magnesium. The effect of the present invention is that a similar alloy (for example, A
It has been confirmed that C7B) is also expressed.

Examples 6 and 7 and Reference Examples 5 and 6 are examples in which the effect of the present invention was examined for hypereutectic aluminum-silicon based wear resistant alloys. In Reference Examples 5 and 6, the occurrence of problematic blisters is not completely suppressed, whereas in Example 6 and 7 according to the present invention, there are no problematic blisters.

As described above, the beryllium-containing aluminum-silicon hypereutectic wear-resistant alloy is subjected to oxygen-blown die casting, whereby the reaction between oxygen and the molten alloy, which is the principle of oxygen-blown die casting, is further promoted. ,
It is possible to stably obtain a heat-treatable die-cast raw material or die-cast product in which no blister is generated.

[0039]

As described above, according to the present invention, as described in claim 1, oxygen is previously fed into the mold cavity to inject and fill molten metal into the mold cavity. 5 to 500 pp of beryllium is used as a molten metal to be injected and filled when oxygen-blown die casting is performed.
Since the molten aluminum alloy containing m is used, beryllium brings about a reaction with oxygen and a proper scattering condition of the molten aluminum alloy, and reacts with oxygen in the mold cavity in a state close to ideal to cause The effect of suppressing the generation of harmful bubbles can be obtained.

Therefore, even if the die cast product obtained by the method according to the present invention is subjected to heat treatment such as solution treatment, harmful blister is not produced, and a high quality cast product excellent in balance of elongation and strength is stable. Obtained. On the other hand, if the conventional level is secured as the obtained characteristics, by using the method of the present invention, it is possible to obtain a die-cast product that can be heat-treated under a wider range of conditions with high difficulty, and the yield of good casting products is improved. The effect that it can be remarkably improved is obtained.

In an embodiment of the die casting method according to the present invention, as described in claim 2, a die casting alloy containing 7.5 to 12% by weight of silicon is used as the aluminum alloy. As described in No. 3, as an aluminum alloy for die casting, JIS
Cu corresponding to ADC10 and ADC12: 1.5 to
4.0% by weight, Si: 7.5 to 12.0% by weight,
Further, it comprises a die-casting alloy containing Be: 5 to 500 ppm and other appropriate amounts of Mg, Fe, Mn, Ni, Zn, etc., and the balance Al, and as described in claim 4. , As an aluminum alloy,
An aluminum-silicon-magnesium alloy containing 6.5 to 10% by weight of silicon is used, and as described in claim 5, as an aluminum-silicon-magnesium alloy, Si corresponding to JIS-AC4A, AC4C:
6.5-10.0 wt%, Mg: 0.2-0.6 wt%
In addition to the above, since Be: 5 to 500 ppm is included, and a trace amount of Cu, Fe, Mn, Ni, Ti, Cr, and the like are appropriately included, and the balance is substantially composed of Al. It was confirmed that the fluidity of the molten aluminum alloy containing beryllium was clearly improved in the course of the experiment carried out using the molten aluminum alloy for die casting or casting containing various beryllium.

This fact brings several advantageous effects from the viewpoint of the hot water supply, and one of them is that the hot water supply serves as a neck, which makes it possible to reduce the thickness of parts that are thick. Allows parts to be cast on smaller die casting machines. Conversely, if the capabilities of the die casting machine are the same, a larger material can be cast. Oxygen-blown die casting is a method suitable for casting thin-walled products, but with the configuration according to the present invention,
It is possible to stably manufacture a high-quality thin-walled large die-cast product.

In the embodiment of the present invention, as described in claim 6, the aluminum alloy is JIS-AD.
Cu: 4.0 to 5.0% by weight corresponding to C14, Si:
16 to 18% by weight, Mg: 0.45 to 0.65% by weight, Be: 5 to 500 ppm, and a proper amount of Mn, Ni, Ti, P, Fe, Zn, etc.,
The balance is to use a die casting alloy consisting essentially of Al, or as described in claim 7, as an aluminum alloy, Cu: 2.0 to 5.0 wt%, Si:
14 to 16% by weight, Mg: 0.1 to 1.0% by weight, M
n: 0.3 to 0.8% by weight. Cr: 0.1 to 0.3% by weight, Ti: 0.05 to 0.20% by weight, P: 0.003
To 0.02% by weight, Fe: 1.5% by weight or less, Be: 5 to 500 ppm inclusive, Ca: 0.005%
Although the aluminum alloy is regulated to less than 1% by weight and the balance substantially consists of Al, when the present invention is applied to such a hypereutectic aluminum-silicon alloy, the primary crystal silicon is remarkably refined. It turned out to do. And
It is known that in this kind of wear-resistant aluminum alloy, a fine uniform distribution of silicon gives better results in workability and wear resistance. However, the die-casting of the hypereutectic aluminum-silicon alloy according to the present invention. In the case of products, it also has the effect that the distribution state of the primary crystal silicon becomes ideal.

Further, as mentioned in the description of the embodiments, even if the aluminum alloy containing beryllium is usually applied to the die casting, the blister cannot be prevented, but the blister is obviously improved. Is recognized.
This means that a die-cast product or a die-cast rough material that is used without being subjected to heat treatment has obtained a state with few bubbles, suggesting that the properties of strength and elongation are improved. ing.

Claims (8)

[Claims] 1. A molten aluminum alloy containing 5 to 500 ppm of beryllium is used as a molten metal to be injected and filled when oxygen is preliminarily fed into the mold cavity to perform an oxygen blowing die casting to inject and fill the molten metal into the mold cavity. A die casting method characterized in that 2. An aluminum alloy containing 7.5% silicon.
The die-casting method according to claim 1, wherein a die-casting alloy containing -12% by weight is used. 3. JIS-AD as an aluminum alloy
Cu: 1.5 to 4.0% by weight, Si: 7.5 to 12.0% by weight corresponding to C10 and ADC12, and further B
e: containing 5 to 500 ppm, and other appropriate trace amount of Mg,
The die-casting method according to claim 2, wherein a die-casting alloy containing Fe, Mn, Ni, Zn and the balance substantially consisting of Al is used. 4. An aluminum alloy containing 6.5% silicon.
The die casting method according to claim 1, wherein an aluminum-silicon-magnesium alloy containing 10 to 10% by weight is used. 5. JIS-AC as an aluminum alloy
4A and AC4C, Si: 6.5 to 10.0 wt% and Mg: 0.2 to 0.6 wt% are included, and Be:
5 to 500 ppm and other appropriate trace amounts of Cu and F
including e, Mn, Ni, Ti, Cr, the balance being substantially Al
The die casting method according to claim 4, wherein a casting alloy made of 6. JIS-AD as an aluminum alloy
Cu: 4.0 to 5.0% by weight corresponding to C14, Si:
16 to 18% by weight, Mg: 0.45 to 0.65% by weight, Be: 5 to 500 ppm, and other appropriate trace amounts of Mn, Ni, Ti, P, Fe, Zn, and the balance substantially. The die casting method according to claim 1, wherein an alloy for die casting made of Al is used as the material. 7. An aluminum alloy, Cu: 2.0
.About.5.0 wt%, Si: 14 to 16 wt%, Mg: 0.
1 to 1.0% by weight, Mn: 0.3 to 0.8% by weight. C
r: 0.1 to 0.3% by weight, Ti: 0.05 to 0.20
% By weight, P: 0.003 to 0.02% by weight, Fe: 1.
The die-casting method according to claim 1, wherein the aluminum alloy contains 5 wt% or less, further contains Be: 5 to 500 ppm, regulates Ca: less than 0.005 wt%, and uses the balance substantially Al. 8. A heat-processable die-cast product manufactured by the die-casting method according to any one of claims 1 to 7.