JP5136176B2 - Method for producing aluminum alloy molded product and mold thereof - Google Patents

Description

  The present invention relates to a method for producing a molded product of an aluminum alloy and a mold thereof. More specifically, the present invention relates to a method for producing a molded product of an aluminum alloy that can be partially subjected to a heat treatment such as a solution treatment while casting the aluminum alloy in a mold, and the mold.

  After the aluminum alloy molded product is cast, it may be subjected to heat treatment in order to improve mechanical properties such as strength. Examples of such heat treatment include T6 treatment (JIS) in which artificial aging treatment is performed after solution treatment. However, if the entire casting is reheated after the casting has cooled, neither energy efficiency nor production efficiency is good. Also, the mechanical strength may not need to be secured throughout the casting. For this reason, the heat treatment after casting may be partially applied only to places where strength is required.

  For example, Patent Document 1 discloses a light alloy casting manufacturing method having a preparation process, a casting process, a separation process, a quenching process, and an aging treatment process. In the light alloy casting manufacturing method, the casting is separated from the mold after casting, and quenching is performed by bringing a cooling medium into contact with the surface of the separated casting. As a result, it is possible to produce a casting that is partially heat-treated.

JP-A-2005-169498

  In such a heat treatment, it is desirable to perform temperature control of the target portion more strictly. This is because if the temperature varies from product to product, the quality of the castings produced is not stable. In addition, even within one product, if the temperature unevenness occurs in the place of heat treatment, the required mechanical properties may not be obtained. On the other hand, the higher the heat treatment temperature, the faster the diffusion rate of solute atoms, and the easier it is to dissolve in the main component metal. For this reason, it is preferable to hold the temperature immediately below the solidus temperature for a certain period of time. This is because an alloy with a more uniform concentration distribution of alloy elements can be manufactured. Furthermore, this is because heat treatment can be performed in a short time.

  However, with the method described in Patent Document 1, it is difficult to maintain the temperature of the heat treatment target portion at the target temperature for a certain period of time. This is because the temperature of the heat treatment target portion is manipulated by spraying water. This is because the temperature of water and the target temperature for heat treatment are greatly different. Furthermore, depending on the shape of the location to be heat-treated, there can be places where water is likely to be applied and places where it is difficult to apply water, and therefore, temperature unevenness is likely to occur. In addition, since the heat treatment is performed with the sand mold remaining after the mold is separated, the places where the heat treatment can be performed are limited (see FIG. 6 of Patent Document 1). In addition, since the method controls the temperature at the processing location by the time for spraying water, which is a refrigerant, there is uncertainty in temperature controllability.

  The present invention has been made to solve the above-described problems of the prior art. In other words, the problem is to form an aluminum alloy that can be heat-treated by accurately controlling the processing temperature and processing time on a part of the casting after being molded inside the mold and before being released. It is to provide a method for manufacturing a product and a mold thereof.

In order to solve this problem, a method of manufacturing a molded product of an aluminum alloy by using the mold of the present invention includes a local heat treatment part that performs heat treatment in contact with a part of the molded product, and a molded product as the mold. wherein possess a non-thermal processing unit in contact with the balance other than the part of the local heat treatment unit is disposed inside the mold body with a separate body from the die body constituting the non-heat-treatment unit Using a nesting tool, after forming and before taking out the molded product from the mold, the local heat treatment part keeps the part of the molded product at the solution temperature of the alloy to locally solution. It is characterized by having a local solution treatment step for performing the treatment. In such a method for producing a molded product of an aluminum alloy, a solution treatment can be performed on a part of the molded product of the aluminum alloy inside the mold.

  In the method for producing an aluminum alloy molded product described above, it is preferable to use a product having a gap between the insert and the mold body. This is because heat radiation from the insert to the mold body is suppressed by the gap between the insert and the mold body. Thereby, the heat retention of the location which performs a solution treatment improves.

  In the method for producing an aluminum alloy molded article described above, it is more preferable to use a mold having a fluid flow path formed in the local heat treatment section. This is because a thermal fluid can flow through the flow path of the mold. This is because the temperature of the local heat treatment portion and the location where the solution treatment is performed can be maintained for a certain period of time by flowing the thermal fluid held at the solution treatment temperature through the flow path.

The method of manufacturing a molded article of an aluminum alloy described above, the water-cooled process for a molded article was taken out from the front Kikin type after topical solution process cooling water, artificial aging the molded article after the water cooling step It is further preferable to have an artificial aging step for performing the treatment. This is because the mechanical properties of the aluminum alloy molded product are improved.

The mold for molding the molded article of the present invention has a local heat treatment part that contacts and heat-treats a part of the molded article, and a non-heat treated part that contacts the remaining part other than the part of the molded article, The local heat treatment part is provided with a heat source for heating the part of the molded product after molding and before being taken out from the mold, and the local heat treatment part is a mold body constituting the non-heat treatment part. It is a nesting member that is a separate body and is disposed inside the mold body . With such a mold, a molded product can be molded and heat treatment can be performed on a part of the alloy inside the mold.

  In the mold described above, it is more preferable that there is a gap between the insert and the mold body. This is because heat dissipation from the insert to the mold body is suppressed.

  In the mold described above, it is further preferable that a flow path for flowing a thermal fluid is formed in the local heat treatment section. This is because a thermal fluid can flow through the flow path of the mold. This is because the temperature of the local heat treatment portion and the location where the solution treatment is performed can be maintained for a certain period of time by flowing the thermal fluid held at the solution treatment temperature through the flow path.

  According to the present invention, a molded product of an aluminum alloy that can be heat-treated by accurately controlling the processing temperature and processing time on a part of the casting after being molded inside the mold and before being released. A manufacturing method and its mold are provided.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the present invention is embodied with respect to a method of manufacturing an aluminum alloy molded product and its mold.

[Mold]
The mold 10 of this embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a mold 10 according to this embodiment. The mold 10 according to this embodiment includes a lower mold 11 and an upper mold 12 as mold bodies. FIG. 2 is a plan view showing a product portion of the lower mold 11 of the mold 10. FIG. 3 is a plan view showing a product portion of the upper mold 12 of the mold 10. 1 corresponds to an XX cross section when the lower mold 11 of FIG. 2 and the upper mold 12 of FIG. 3 are integrated. For the sake of simplicity, the detailed shape of the mold 10 is simplified in FIG. The material of the lower mold 11 and the upper mold 12 is, for example, SKD61 (JIS).

  In addition, the mold 10 of this embodiment has an insert 101 and an insert 102 in addition to the lower mold 11 and the upper mold 12. The insert 101 and the insert 102 are adapted to be accommodated in the lower mold 11. FIG. 4 shows a state in which the insert 101 and the insert 102 are stored in the lower mold 11 of FIG. The cavity 200 is a closed space partitioned by the lower mold 11, the upper mold 12, the insert 101 and the insert 102. The shape of the cavity 200 determines the shape of a casting cast by casting a molten metal.

  As a part of the cavity 200, there is a location 201 for local heat treatment. This is a space that should become a part of a casting such as a product rib during casting. Further, the local heat treatment target portion 201 is a region that is mostly surrounded by the insert 101 and the insert 102, and is a place where solution treatment is performed in the casting manufacturing process.

As described above, the mold 10 according to the present embodiment is for manufacturing a cast product and locally heat-treating a part of the cast product. Here, a salt flow path 111 is formed as a space partitioned by the insert 101 and the insert 102. The salt flow path 111 is for flowing a fluid different from the molten metal. Therefore, the salt flow path 111 is provided with a fluid inlet and outlet so that the salt can be supplied from the outside of the mold 10. The salt flow path 111 is for flowing a fluid (salt) having a large heat capacity as will be described later. Examples of the salt include a mixture of KNO ₃ and NaNO _{2 at} a ratio of 50%. As a salt, another fluid may be used as long as it has a high heat capacity. The salt temperature is the same as or slightly higher than the solution treatment temperature of the aluminum alloy. By this salt, the temperature of the local heat treatment target portion 201 can be kept constant. As a result, the local heat treatment target portion 201 is subjected to the heat treatment locally. As described above, the nest 101 and the nest 102 are local heat treatment portions for performing heat treatment on the local heat treatment target portion 201. Further, the remaining portions other than the local heat treatment portion in the mold 10, that is, the lower die 11 and the upper die 12 are non-heat treatment portions. The material of the insert 101 and the insert 102 is the same as that of the lower mold 11 and the upper mold 12.

  An air layer 103 is formed between the lower mold 11 and the insert 102. Thereby, heat dissipation from the insert 102 to the lower mold 11 is suppressed. Thus, the local heat treatment target portion 201 is excellent in heat retention. For this reason, when performing heat processing locally, the temperature of the location 201 for local heat processing can be kept substantially constant.

  As described above, the mold according to the present embodiment is provided with a local heat treatment portion made of a nested structure. In this local heat treatment section, a flow path for flowing a fluid different from the molten metal is formed. For this reason, the temperature of a part of the casting can be maintained with high accuracy. Thus, an accurate heat treatment can be performed on a part of the casting.

  The nest may be accommodated in the upper mold 12. Further, the material of the lower mold 11, the upper mold 12, the insert 101, and the insert 102 may be other than SKD61. However, these are preferably made of the same material because of the coefficient of thermal expansion. Further, it is preferable that the salt flow path 111 has a large surface area. This is because the heat of the salt spreads to every corner of the child 101 and the child 102. Further, a heat insulating material may be inserted between the lower mold 11 or the upper mold 12 and the insert 101 or the insert 102.

[Production method]
Here, the manufacturing method of an aluminum alloy molded product will be described with reference to FIGS. An aluminum alloy molded product manufactured by the method of manufacturing an aluminum alloy molded product of this embodiment has a portion where stress is easily concentrated, such as a rib shape, in a part of a casting. In addition, in order to strengthen the part where stress is likely to concentrate, the part is subjected to local heat treatment.

  FIG. 5 is a flowchart for explaining a method for producing an aluminum alloy molded product of the present embodiment. In the method for producing an aluminum alloy molded product according to this embodiment, a solution treatment is performed on a part of the casting before it is taken out from the mold after casting. FIG. 6 is a graph showing a temporal change in temperature of a local heat treatment target portion 301 (see FIG. 8) where a solution treatment is locally performed. FIG. 7 is a graph showing a temporal change in temperature of a local heat treatment non-target portion 300 (see FIG. 8) which is a casting portion other than the local heat treatment target portion 301. Therefore, t1 to t7 in FIG. 6 and t1 to t7 in FIG. 7 indicate the same time. Further, S1 to S5 in FIGS. 6 and 7 correspond to steps S1 to S5 in FIG.

(Time t1 to time t2: Casting step S1)
In the method for producing an aluminum alloy molded product of this embodiment, first, a molten metal at 700 to 740 ° C. (temperature A in FIGS. 6 and 7) is poured into the cavity 200 of the mold 10 from the gate (S1: casting process). For this reason, the cavity 200 is almost filled with the molten metal. Further, the local heat treatment target portion 301 subjected to the solution treatment is also filled with the molten metal. Further, a portion that is not subjected to the solution treatment out of the molten metal is defined as a local heat treatment non-target portion 300. The temperature of the molten metal (temperature A in FIGS. 6 and 7), which is about 700 to 740 ° C., decreases after contacting the mold after casting (see FIGS. 6 and 7).

  When the molten metal temperature falls below the liquidus temperature of the alloy, the molten metal begins to solidify, and when the molten metal temperature falls below the solidus temperature, the molten metal finishes solidifying. Here, the time when the temperature of the solidified casting becomes the solution treatment temperature in FIG. 6 (temperature B in FIG. 6) is defined as t2. The solution treatment temperature set in this embodiment is a temperature just below the solidus temperature and not high enough to cause melting (burning) with oxidation.

(Time t2 to Time t3: Local solution treatment step S2)
After time t2, the salt flows through the salt flow path 111. As a result, the temperature of the local heat treatment target portion 301 is maintained at the solution treatment temperature (temperature B in FIG. 6). The solution treatment is performed by maintaining the temperature of the local heat treatment target portion 301 at the solution temperature for a certain time (local solution treatment step: S2). The state at this time is shown in FIG. The solution treatment temperature and the solution treatment time vary depending on the type of alloy or the like, and will be described in detail later. In addition, a salt may be flowed through the salt flow path 111 in advance before the time t2.

  Here, the salt temperature is assumed to be the same as or slightly higher than the solution treatment temperature. As the salt passes through the salt flow path 111, the heat of the salt is transmitted to the nest 101 and the nest 102 that form the salt flow path 111. Thereby, the temperature of the insert 101 and the insert 102 becomes substantially equal to the temperature of the salt. The heat of the insert 101 and the insert 102 is transferred to the local heat treatment target portion 301. For this reason, the temperature of the local heat treatment target portion 301 is substantially equal to the set solution treatment temperature. Here, the local heat treatment target portion 301 is almost covered with the nest 101 and the nest 102. For this reason, it is difficult for heat to escape from the local heat treatment target portion 301 to the local heat treatment non-target portion 300. Further, since there is an air layer 103 between the insert 102 and the lower mold 11, heat radiation from the insert 102 to the lower mold 11 is also suppressed.

  As described above, in the manufacturing method of the aluminum alloy molded product of this embodiment, in order to perform solution treatment on a part of the casting inside the mold, a salt having a temperature substantially equal to or slightly higher than the solution treatment temperature is added. It flows through the salt flow path 111 formed by the child 101 and the child 102. For this reason, while salt is flowing through the salt flow path 111, the local heat treatment target portion 301 is maintained at the solution treatment temperature (see FIG. 6). The temperature unevenness due to the position in the local heat treatment target portion 301 is only within a range of ± 2 ° C. (region α between two-dot chain lines in FIG. 6), if any. This is because the salt channel 111 is formed so that heat is transmitted to every corner of the nest. In addition, when the solution treatment is performed on the entire conventional casting, the temperature unevenness in the casting becomes about ± 10 ° C. Further, in the casting manufacturing method described in Patent Document 1, the temperature of the heat treatment part is not maintained for a certain period of time. This is because the temperature at the location subject to heat treatment and the temperature of water sprayed on the location are greatly different.

  In the period from time t2 to time t3, the temperature of the local heat treatment target portion 301 is maintained, while the local heat treatment non-target portion 300 that is not subjected to the solution treatment is in a naturally cooled state. For this reason, the temperature of that part continues to decrease (see FIG. 7).

  In the manufacturing method of the aluminum alloy molded product of this embodiment, the heat treatment temperature of the local heat treatment target portion 301 can be accurately controlled by adjusting the salt temperature. Moreover, the heat treatment time of the local heat treatment target portion 301 can be strictly managed by adjusting the time for flowing the salt. Therefore, after the heat treatment is performed for a necessary time (time t3), the supply of salt is stopped. Thereby, the solution treatment of the local heat treatment target portion 301 was completed.

(Time t3 to Time t4: Mold release step S3)
After time t3, the casting is separated from the mold (S3). At this time, the temperature of the local heat treatment target portion 301 is still high as shown in FIG. The temperature of the local heat treatment non-target portion 300 is sufficiently lowered as shown in FIG. Here, the time when the casting is released from the mold is assumed to be t4. At time t4, the temperature of the local heat treatment target portion 301 is slightly lower than the time t3. However, it remains high compared to room temperature.

(Time t4 to time t5: Submerged quenching step S4)
After mold release, the entire casting is submerged (S4). As a result, the entire casting is quenched. The time when the casting is taken out of the water is defined as t5.

(Time t6 to Time t7: Artificial aging treatment step S5)
Then, after performing submerged quenching (S4), the casting is subjected to artificial aging treatment (S5). In this case, the processing temperature (temperature C in FIGS. 6 and 7) and the processing time differ depending on the alloy and will be described later. As described above, an aluminum alloy molded product in which a part of the casting was heat-treated was manufactured. Here, the local heat treatment target portion 301 is subjected to an artificial aging treatment (S5) after being subjected to a solution treatment (S2). For this reason, the aluminum alloy molded product manufactured by the manufacturing method of the aluminum alloy molded product of this embodiment has been subjected to T6 treatment (JIS) on a portion 301 to be locally heat treated.

  In the method for manufacturing an aluminum alloy molded product of this embodiment, a solution treatment is performed on a part of a casting by using an insert together with a mold. In addition, since salt is flowed through the salt flow path formed by the nest and kept warm, a part of the casting surrounded by the nest can be maintained at a substantially constant temperature during the heat treatment. Compared with the case where solution treatment is applied to the entire casting, temperature unevenness at different positions in the solution treatment portion is small. Therefore, local heat treatment can be performed by setting the heat treatment temperature and heat treatment time according to the type of alloy. In other words, the target location for heat treatment can be kept constant both in time and space. Thereby, the manufacturing method of the aluminum alloy molded product which the casting process and the local solution treatment process were united in the metal mold | die is implement | achieved.

  In addition, an aluminum alloy molded product manufactured by the method of manufacturing an aluminum alloy molded product of this embodiment is a part of which is subjected to heat treatment. The heat treatment location in the casting is one in which solute atoms are supersaturated and uniformly dissolved. For this reason, the nonuniformity of the solid solution amount of the solute atoms in the heat treatment portion is small. There is also little variation in mechanical properties between products. In addition, since the manufacturing method of the aluminum alloy molded product of this form performs solution treatment inside a metal mold | die, the heating furnace for solution treatment is not required. In addition, energy is not wasted because heat treatment is performed using the heat of the molten metal temperature. Furthermore, since the casting process and the heat treatment process are integrated, the cycle time can be shortened.

[Example 1 of heat treatment]
In the method for producing an aluminum alloy molded product of this embodiment, heat treatment is locally applied to a part of a casting. Various heat treatment temperatures and heat treatment times can be set according to the target product, the alloy used, and the like. Examples of the tests conducted are shown below.

This test compares the mechanical properties of a comparative example in which the entire casting was heat-treated and a heat-treated portion in which a part of the casting was heat-treated. Comparison items follow JIS,
1. Tensile strength,
2. 0.2% yield strength,
3. Three items of elongation were used.

  First, in Example 1, JIS-AC4CH was used as the alloy 1. The main component of Alloy 1 was aluminum, and the ratio of other elements was as shown in Table 1. The solidus temperature of alloy 1 is 564 ° C.

  The graph of FIG. 10 shows the mechanical properties of the alloy 1 that has been heat-treated. Here, in the comparative example, the entire casting was subjected to a solution treatment at a temperature of 530 ° C. (± 10 ° C.) for 3 hours and then water-cooled. Thereafter, artificial aging treatment was performed at a temperature of 170 ° C. (± 5 ° C.) over 3 hours. This temperature corresponds to the temperature C in FIGS.

  In addition, regarding the mechanical properties of the local heat treatment target portion 301 of the aluminum alloy molded product manufactured by the method of manufacturing the aluminum alloy molded product of the present embodiment and the mold using the same, the results are shown on the right side of the comparative example in FIG. Show. After a local solution treatment at a temperature of 545 ° C (± 2 ° C) for 10 minutes, 20 minutes, and 30 minutes, respectively, it was cooled with water and subjected to artificial aging treatment at a temperature of 170 ° C (± 5 ° C) for 3 hours. The results are shown in order from the left side of FIG. Furthermore, after performing local solution treatment at a temperature of 555 ° C (± 2 ° C) for 10 minutes, 20 minutes and 30 minutes, respectively, water cooling and artificial aging treatment at a temperature of 170 ° C (± 5 ° C) for 3 hours The results of those subjected to are shown on the right side.

  The locations subject to local heat treatment of the aluminum alloy molded product of Example 1 showed slightly higher numerical values with respect to tensile strength and 0.2% yield strength than the comparative example in which the entire casting was heat treated. On the other hand, with regard to the elongation, although there was some variation, if an appropriate heat treatment temperature and heat treatment time (545 ° C., 30 minutes or 555 ° C., 20 minutes) were selected, the numerical values were comparable to the comparative examples. The time for the local heat treatment is shorter than that for the solution treatment as a whole.

[Example 2 of heat treatment]
Next, the test results of the alloy 2 will be described as Example 2. As alloy 2, JIS-AC2B was used. The main component of Alloy 2 was also aluminum, and the ratio of other elements was as shown in Table 2. The solidus temperature of alloy 2 is 520 ° C.

  The graph of FIG. 11 shows the mechanical properties of the alloy 2 that has been heat-treated. Alloy 2 was measured for tensile strength, 0.2% proof stress, and elongation after the following different heat treatments. Here, in the comparative example, the entire casting was subjected to a solution treatment at a temperature of 500 ° C. (± 10 ° C.) for 2 hours and then water-cooled. Thereafter, an artificial aging treatment was performed at a temperature of 220 ° C. (± 5 ° C.) over 2 hours.

  In addition, regarding the mechanical properties of the local heat treatment target portion 301 of the aluminum alloy molded product manufactured using the method for manufacturing the aluminum alloy molded product of the present embodiment and the mold using the same, the results are shown on the right side of the comparative example in FIG. Show. After local solution treatment at a temperature of 515 ° C (± 2 ° C) for 0 minutes, 10 minutes, and 20 minutes, respectively, it was cooled with water and subjected to artificial aging treatment at a temperature of 210 ° C (± 10 ° C) for 2 hours. The results are shown in order from the left side of FIG. Furthermore, after performing local solution treatment at a temperature of 525 ° C (± 2 ° C) for 0 minutes, 10 minutes, and 20 minutes, respectively, water cooling and artificial aging treatment at a temperature of 210 ° C (± 10 ° C) for 2 hours The results of those subjected to are shown on the right side. In addition, the local solution treatment of 0 minutes is to not hold the solution temperature after once setting the temperature of the local heat treatment target portion 301 to the solution temperature.

  The locally heat-treated portion of the aluminum alloy molded product of Example 2 showed almost the same numerical value regarding the tensile strength and 0.2% proof stress as compared with the comparative example in which the entire casting was heat-treated. A mechanical property comparable to that of the comparative example was obtained by subjecting the local heat treatment target portion to a heat treatment at a temperature of 525 ° C. for 10 minutes. As in the case of Example 1, the time for the local heat treatment is shorter than that in the case where the entire solution treatment is performed.

[Example 3 of heat treatment]
Next, the test results of the alloy 3 will be described as Example 3. As alloy 3, JIS-AC4CH to which 0.8 weight percent of Cu was added was used. Mg was 0.3 weight percent. The main component of Alloy 3 was also aluminum, and the ratio of other elements was as shown in Table 3. The solidus temperature of alloy 3 is 556 ° C.

  The graph of FIG. 12 shows the mechanical properties of the alloy 3 that was heat-treated. About the alloy 3, after performing the different heat processing shown below, the Vickers hardness Hv was measured. Here, in the comparative example, the entire casting was subjected to solution treatment at a temperature of 510 ° C. (± 10 ° C.) for 3 hours and then water-cooled. Thereafter, artificial aging treatment was performed at a temperature of 170 ° C. (± 5 ° C.) over 3 hours.

  FIG. 12 shows the results of the manufacturing method of the aluminum alloy molded product of the present embodiment and the mechanical properties of the location 301 subject to local heat treatment of the aluminum alloy molded product manufactured using the mold using the method. The horizontal axis represents the time required for the solution treatment, and the vertical axis represents the hardness. The line with a solution temperature of 510 ° C. shows that after a local solution treatment at a temperature of 510 ° C. (± 2 ° C.) for 5 minutes, 10 minutes, 20 minutes, and 30 minutes, respectively, the solution is cooled to a temperature of 170 ° C. This is the Vickers hardness Hv of the artificial aging treatment over 3 hours at (± 5 ° C.). The line with a solution temperature of 530 ° C. shows that after performing a local solution treatment at a temperature of 530 ° C. (± 2 ° C.) for 5 minutes, 10 minutes, 20 minutes, and 30 minutes, respectively, water cooling is performed at a temperature of 170 ° C. This is the Vickers hardness Hv of the artificial aging treatment over 3 hours at (± 5 ° C.). The line with a solution temperature of 545 ° C. shows that after performing a local solution treatment at a temperature of 545 ° C. (± 2 ° C.) for 5 minutes, 10 minutes, 20 minutes, and 30 minutes, respectively, the solution is cooled to a temperature of 170 ° C. This is the Vickers hardness Hv of the artificial aging treatment over 3 hours at (± 5 ° C.).

  The aluminum alloy molded product of Example 3 has a Vickers hardness Hv value that is the same as that of the comparative example in which the heat treatment was performed on the entire casting with respect to the one subjected to solution treatment at a solution treatment temperature of 530 ° C. or 545 ° C. Indicated. Further, it was found that if the solution treatment (530 ° C., 545 ° C.) was set at a temperature close to the solidus temperature of alloy 3, it was sufficiently dissolved even in about 5 minutes. This is a very short time compared to the comparative example in which the entire solution was treated for 3 hours. On the other hand, at a solution temperature of 510 ° C., solid solution does not progress sufficiently.

  From the above, the relationship between the processing temperature and the mechanical properties of the alloy can be read. That is, in order to obtain desired mechanical properties in an aluminum alloy molded product, it is necessary to maintain the temperature of the heat treatment target portion with high accuracy. To that end, a mold or manufacturing method that does not easily cause temperature unevenness is indispensable. Otherwise, it is difficult to set a solution temperature close to the solidus temperature. It was also found that the heat treatment time can be greatly shortened by controlling the temperature with high accuracy. Moreover, it is assumed that there is a place where the temperature does not rise locally due to insufficient temperature control. As a result, the strength of the portion is insufficient, and stress may concentrate on the portion when used as a product. As a result, the part may be damaged.

  In this embodiment, the local heat treatment unit has the insert 101 and the insert 102, but the insert 101 and the insert 102 may be integrated. Also, there may be three or more nestings. The insert is configured to form a part of the shape of the casting, and it is only necessary that the salt flow path for keeping the location is formed near the location.

  Further, the local heat treatment part may be integrated with the lower mold 11 or the upper mold 12. In that case, a salt flow path is formed inside the lower mold 11 or the upper mold 12.

  The mold of this embodiment was used for manufacturing a molded product of an aluminum alloy. However, other metals may be cast and used for manufacturing a product that is subjected to local heat treatment. It can also be applied to forging dies.

  As described above in detail, the method for manufacturing an aluminum alloy molded product according to the present embodiment involves heat-treating a part of the casting after casting the molten metal into the mold and before releasing the mold. . In addition, after mold release, it is submerged and quenched, followed by artificial aging treatment. In addition, the heat treatment applied to a part of the casting can make the temperature of the portion of the casting constant in time and space. As a result, an aluminum alloy molded product having a partially increased strength is manufactured. Moreover, the manufacturing method of the aluminum alloy molded product of this form integrally performs a casting process and a solution treatment process. For this reason, it is not necessary to prepare a heat treatment furnace separately. Furthermore, energy is not wasted because no heat treatment is required again. In addition, the time required for manufacturing the aluminum alloy molded product is shortened.

  In addition, the aluminum alloy molded product manufactured by the method for manufacturing an aluminum alloy molded product of this embodiment is a product in which heat treatment is performed on a portion where stress is easily concentrated, such as a rib shape. The heat treatment location in the casting is one in which solute atoms are supersaturated and uniformly dissolved. For this reason, the nonuniformity of the solid solution amount of the solute atoms in the heat treatment portion is small. There is also little variation in mechanical properties between products.

  In addition, the mold according to this embodiment can cast a casting and heat-treat a part of the casting. By adjusting the temperature of the salt flowing through the salt flow path formed by the insert and the flow time, the heat treatment temperature and treatment time can be set according to the type of alloy.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the material of the lower mold 11, the upper mold 12, the insert 101, and the insert 102 is not limited to SKD61. Any material that can be used as a mold may be used. However, since the expansion coefficient differs depending on the material, it is preferable to use a common material for the lower mold 11, the upper mold 12, the insert 101 and the insert 102.

  In this embodiment, a thermal fluid is used as the local heat treatment section, but other heating means such as an electric heater, superheated steam, induction heating, etc. may be used. This is because the same effect can be obtained if there is a means for locally heating or keeping the portion to be heat-treated.

It is sectional drawing for demonstrating the lower mold | type and upper mold | type of the metal mold | die of this invention. It is a figure which shows the lower mold | type of the metal mold | die of this invention for performing a local solution treatment to casting. It is a figure which shows the upper mold | type of the metal mold | die of this invention for giving a local solution treatment to casting. It is sectional drawing explaining the metal mold | die of this invention. It is a flowchart for demonstrating the manufacturing method of the aluminum alloy molded article which performs local heat processing. It is a graph explaining the temperature change accompanying the manufacturing process of the part which performs local heat processing. It is a graph explaining the temperature change accompanying the manufacturing process of the part which does not perform local heat processing. It is FIG. (1) for demonstrating the manufacturing method of the aluminum alloy molded product of this invention. It is FIG. (2) for demonstrating the manufacturing method of the aluminum alloy molded product of this invention. It is the graph (the 1) for demonstrating the mechanical property of the location which performed the local heat processing of the casting manufactured by the manufacturing method of the aluminum alloy molded product of this invention. It is a graph (the 2) for demonstrating the mechanical property of the location which performed the local heat processing of the casting manufactured by the manufacturing method of the aluminum alloy molded product of this invention. It is a graph (the 3) for demonstrating the mechanical property of the location which performed the local heat processing of the casting manufactured by the manufacturing method of the aluminum alloy molded product of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mold 11 ... Lower mold 12 ... Upper mold 101,102 ... Insert 103 ... Air layer 111 ... Salt flow path 200 ... Cavity 300 ... Local heat processing non-target location 201, 301 ... Local heat processing target location

Claims (7)

A method for producing a molded product of an aluminum alloy using a mold,
As the mold,
A local heat treatment part that performs heat treatment in contact with a part of the molded product;
And a non-heat unit contacting the balance other than the portion of the molded article possess,
The local heat treatment part is a separate body from the mold body that constitutes the non-heat treatment part and is a nest arranged inside the mold body ,
After the molding, before taking out the molded product from the mold, the local heat treatment step is performed by the local heat treatment unit to hold the part of the molded product at the solution temperature of the alloy and perform a solution treatment locally. A method for producing a molded product of an aluminum alloy, comprising: A method for producing a molded product of an aluminum alloy according to claim 1 ,
A method for producing a molded product of an aluminum alloy, wherein a material having a gap between the insert and the mold body is used. A method for producing a molded product of the aluminum alloy according to claim 1 or 2 ,
A method for producing a molded product of an aluminum alloy, characterized in that a metal flow path is formed in the local heat treatment section as the mold. A method for producing a molded product of an aluminum alloy according to any one of claims 1 to 3 ,
The molded article taken out from the front Kikin type after the local solution step and water cooling step of cooling with water,
And an artificial aging step of subjecting the molded product after the water cooling step to an artificial aging treatment. A mold for molding a molded article,
A local heat treatment part that performs heat treatment in contact with a part of the molded product;
A non-heat treated part that contacts the remaining part other than the part of the molded product,
The local heat treatment section is provided with a heat source for heating the part of the molded product after molding and before taking out from the mold ,
The metal mold characterized in that the local heat treatment part is a nesting member that is separate from the mold body constituting the non-heat treatment part and is disposed inside the mold body . The mold according to claim 5 , wherein
A mold having a gap between the insert and the mold body. A mold according to claim 5 or claim 6 ,
A mold characterized in that a flow path for flowing a thermal fluid is formed in the local heat treatment section.

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