JP2005279712A - Method for producing semi-solidified metal and forming method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method, by which a semi-solidified metal finely and uniformly crystallized with the primary crystal Si in the hyper-eutectic Al-Si base alloy, is produced at low cost in a short time and thereafter, press-formation is applied to this metal. <P>SOLUTION: When the semi-solidified metal is produced by using the molten Al-Si base hyper-eutectic aluminum alloy containing 0.005-0.03% P at 50-150°C excess heating degree to the melting point, while moving during pouring the molten metal near the inner wall of a ladle for supplying the molten metal or near the inner wall of a holding vessel so that the temperature of the molten metal held in the ladle or in the holding vessel becomes uniformity, or while moving this molten metal since the molten metal is poured till it reaches the forming temperature, this molten metal is cooled at 3°C/sec-20°C/sec cooling velocity in the temperature range from the molten metal pouring temperature poured into the ladle or into the holding vessel to a prescribed temperature between the temperature not lower than Al-Si binary-system eutectic temperature and the temperature not higher than the melting point, and thereafter, the semi-solidified metal having the temperature not lower than the binary-system eutectic temperature and a prescribed liquid-phase ratio, is discharged from the holding vessel or the ladle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing and forming a semi-solid metal, and in particular, to hold a semi-solid metal of an Al-Si hypereutectic aluminum alloy having fine primary crystal Si and having a uniform distribution. Alternatively, a semi-solid metal that is manufactured directly from a molten Al-Si hypereutectic aluminum alloy in a hot water supply ladle, discharged from a holding container or a hot water supply ladle at a temperature that gives a predetermined liquid phase ratio, and then press-formed. The present invention relates to a manufacturing method and a molding method thereof.

  A molded product made of an aluminum alloy having heat resistance and wear resistance is cast using a gravity casting method, a high pressure casting method, a die casting method or the like. However, although a molten metal to which a predetermined amount of a Si micronizing agent is added is filled in a mold and cast, the degree of primary Si micronization and its distribution are not always at a satisfactory level. That is, the distribution of primary Si was not uniform, and segregation with different primary Si concentrations occurred due to differences in the solidification rate inside the molded product.

In order to solve these problems, molding using a semi-solid molding / semi-melt molding method in which molding is performed in a state where a liquid and a solid coexist has attracted attention. Prior art documents relating to these will be described below.
JP 2000-54047 A Japanese Patent Laid-Open No. 10-152731 JP 2003-126950 A Japanese Patent No. 3396833 Japanese Patent Laid-Open No. 9-327755

  In Patent Document 1, as a solution to “problem of primary crystal Si being coarsened”, which is a problem in hypereutectic Al—Si based alloys, primary crystal Si is used in hypoeutectic Al—Si based alloys with less Si. A crystallized alloy material and a method for producing the same are disclosed. Specifically, eutectic Si is temporarily formed by heating a primary casting of an Al alloy having 6.5 to 11.0% by weight of Si and 0.001 to 0.01% by weight of P to a solid-liquid coexistence state. It melts and then solidifies to crystallize 6-9 μm Si grains, which are larger in size than eutectic Si, in the metal structure, thereby providing wear resistance like a hypereutectic Al-Si alloy. It has been proposed. However, this method has a limitation in use and application because it cannot provide a sufficiently high wear resistance like a hypereutectic alloy. In addition, it is necessary to make a primary casting material once, and there is a problem in terms of cost.

In Patent Document 2, a hypereutectic Al-Si alloy melt is poured into a holding vessel and cooled at a predetermined rate to crystallize fine primary Si in the alloy melt, and then this alloy is added. A method of forming a semi-solid metal to be pressed is disclosed. Specifically, a hypereutectic Al—Si alloy having 0.005 to 0.03% by weight of P in a holding container having a thermal conductivity of 1 kcal / mhr ° C. or more is poured, and Al is poured from the pouring temperature. It has been proposed to produce a semi-solid metal by cooling to an -Si binary eutectic temperature at an average cooling rate of 0.15 to 2.0 [deg.] C./sec and press-molding this alloy.
However, in hypereutectic Al-Si alloys, skin formation is solidified, so if the liquid phase ratio is lowered, a solidified layer is likely to form on the inner surface of the container or the surface of the molten metal, making it difficult to discharge from the container. . For this reason, it is necessary to keep the holding container locally warmed or heated using an induction device to make the molten metal temperature uniform, which complicates the apparatus and complicates the molding operation.
Further, the effect of P contained in the alloy as a refining agent is that when the temperature of the molten metal is low, the core AlP is agglomerated and coarsened and loses its effect, making it difficult to obtain fine primary crystal Si. On the other hand, when the molten metal temperature is raised, it takes time to cool down if it is not in contact with the surface of the cooling jig, which is industrially complicated at the time of pouring, and it takes time to cool down. It causes generation of a layer and makes it difficult to operate for a long time.

In Patent Document 3, in order to obtain a semi-solid metal having a fine and spherical primary crystal and a good temperature distribution, the molten metal is stirred in the heat insulating container during or after pouring or the semi-solid metal is pressure-molded. Is disclosed. Specifically, a molten aluminum alloy having a superheat degree with respect to the melting point of less than 50 ° C. is poured into a heat insulating container and stirred to generate a spherical primary crystal having a predetermined liquid phase ratio, which is retained in the container. It has been proposed that a semi-solid metal having a target liquid phase ratio is generated by setting the time to 30 seconds to 30 minutes, and this is discharged from a container and subjected to pressure molding.
However, in a hypereutectic Al—Si alloy, the degree of superheat is less than 50 ° C. with respect to the melting point, so that there is a problem that primary Si is coarsened due to the aggregation of AlP.

Patent Document 4 discloses a method for producing a semi-solid metal, in which a molten metal is poured into a container to which an electric magnetic field is applied, the application is terminated when it reaches the vicinity of the liquidus, and the molten metal is subsequently cooled. Yes. Specifically, the molten metal is stirred by pouring in the applied state to uniformize the molten metal temperature in the container to suppress the generation of a solidified layer composed of dendritic crystals and to cool even after the application is completed. In particular, the application of the magnetic field is terminated at a solid phase ratio of maximum 0.1%, and thereafter the metal is cooled at a cooling rate of 0.2 to 5 ° C./second to produce a solid-liquid coexisting metal. is suggesting. In order to prevent the formation of a solidified layer during pouring, there is no latent heat of solidification due to the application of a magnetic field to the vessel and the molten metal.Therefore, many nuclei are formed by rapidly cooling the molten metal temperature to a temperature just below the liquidus line. It is a technique that occurs and a fine structure can be obtained in a short time.
However, in hypereutectic Al-Si alloys containing P, dendritic crystals are not naturally generated. In addition, unlike hypoeutectic alloys characterized by massey-type solidification in which the molten metal in the entire container is uniformly solidified, skin-forming solidification in which a solidified layer is clearly generated is exhibited in the portion where the temperature is lowered. In addition, when the molten metal was poured into the holding container or hot water supply ladle, a large number of AlP already existed as the primary crystal nuclei, and the molten metal was in contact with the inner wall of the holding container or the hot water ladle and was poured while being deprived of heat. The metal has the characteristic of gradually growing toward the center of the holding container or hot water supply ladle as a solidified layer while crystallizing primary Si.
Therefore, in order to obtain a semi-solid metal at a uniform temperature, the growth of the solidified layer in the vicinity of the inner surface of the holding container and the hot water supply ladle is not limited to the time of pouring, and preferably after molding, just before molding. However, stirring of the molten metal is indispensable for prompt cooling.

  Patent Document 5 discloses a method for producing a semi-solid metal, wherein a crystal nucleus is generated by inserting a cooling jig into a hot water supply ladle. Specifically, a semi-solid metal having a predetermined liquid phase ratio in which a spherical primary crystal is crystallized by generating a nucleus of a crystal by immersing and stirring a plurality of jigs having a cooling function in a molten metal in a hot water supply ladle A technique for generating the above has been proposed. However, the Si refinement effect in the hypereutectic Al—Si-based alloy is that primary crystal Si is formed mainly from the nuclei of AlP contained in the molten metal rather than the generation of nuclei by the cooling jig. Further, in order to refine the primary crystal Si, it is necessary to cool at a predetermined cooling rate to the molding temperature during hot water supply and after hot water supply, and to stir the vicinity of the inner wall of the hot water supply ladle to prevent the formation of a solidified layer. .

The present invention has been made in view of the above-mentioned circumstances, and a semi-solid metal crystallized uniformly and uniformly from a primary eutectic Si of a hypereutectic Al-Si alloy at low cost and in a short time. An object of the present invention is to provide a molding method that is manufactured and then pressure-molded. Specifically, an object is to obtain a molded product in which primary Si of 50 μm or less is uniformly dispersed in the molded product and no Si free zone where Si is not observed is generated.

  In order to solve the above-described problems, in the first invention according to the present invention, an Al—Si based superoxide having a superheating degree of 50 ° C. to 150 ° C. and 0.005% to 0.03% of P with respect to the melting point. When producing a semi-solid metal using a eutectic aluminum alloy molten metal, in the vicinity of the inner wall of the hot water supply ladle or the inner wall of the holding container so that the temperature of the molten metal held in the hot water supply ladle or the holding container is uniform. While melting the molten metal during pouring, or while moving the molten metal from pouring to the molding temperature, the melting point is higher than the Al-Si binary eutectic temperature from the pouring temperature of the molten metal poured into the hot water supply ladle or holding container. Cooling at a cooling rate of 3 ° C./s to 20 ° C./second in a temperature range up to a predetermined temperature below, and then a semi-solid metal having a predetermined liquid phase ratio above the binary eutectic temperature is held in a holding container or hot water supply Drain from ladle It decided to.

  In the second invention mainly composed of the first invention, the molten metal is stirred or rocked by a jig having no cooling function in the vicinity of the inner surface of the hot water supply ladle or holding container having a thermal conductivity of 3 kcal / mhr ° C. or more. Or the molten metal was moved by applying a magnetic field to the hot water supply ladle or holding container by means of an induction device.

In the third invention mainly composed of the first invention, the molten metal is poured into a holding container or a hot water supply ladle having a thermal conductivity of less than 3 kcal / mhr ° C., and the temperature of the molten metal is stirred or shaken by a jig having a cooling function. It was decided to cool to a temperature at which a predetermined liquid phase ratio was obtained while moving.

In the fourth invention mainly composed of the first invention, gravity casting, low pressure casting, laminar flow filling high pressure casting, high speed die casting casting, vertical mold using the semi-solid metal manufactured by the first to third inventions. Molding was performed by any of the pressing methods.

When producing a semi-solid metal by using an Al—Si hypereutectic aluminum alloy molten metal containing P at a superheat degree of 50 ° C. to 150 ° C. with respect to the melting point, the molten metal held in the hot water supply ladle or holding container In order to make the temperature uniform, the hot water ladle or molten metal near the inner wall of the holding container is moved to the hot water ladle or holding container while moving the hot water or while the molten metal is moved during cooling from the hot water to the molding temperature. In order to cool at a cooling rate of 3 ° C./second to 20 ° C./second in the cooling region between the hot water supply temperature of the molten metal and the Al—Si binary eutectic temperature to a predetermined temperature below the melting point, the primary crystal A hypereutectic Al-Si alloy semi-solid metal in which Si is crystallized finely and uniformly can be produced efficiently at low cost. Furthermore, after producing this hypereutectic Al—Si alloy semi-solid metal, it is possible to obtain a product in which a structure in which no Si is observed is not generated by pressure forming. In addition, by uniformly dispersing Si, the aluminum alloy can be applied even to products with higher load and severe usage conditions. In addition, since it is molded in a semi-solid state, a product having a small structure and a healthy structure can be obtained.

Compared to hypoeutectic alloys, the Al-Si hypereutectic alloy does not solidify in the mold as a whole, but a solidified layer that progresses from the mold surface toward the inside. It takes a solidified form. For this reason, if the hot water in the vicinity of the inner wall of the container is not moved, a strong solidified layer is formed in the vicinity of the inner wall where the temperature drop is large compared with the center of the container. It is difficult to achieve uniform temperature simply. Further, since the heat transfer from the molten metal to the container is reduced by the generation of the solidified layer, the rate of decrease in the molten metal temperature inside the container is slowed down.
As countermeasures, these conventional problems can be solved by moving hot water near the inner wall of the container during hot water supply or from the hot water supply to the molding temperature. When the molten metal moves, it is desirable to move the molten metal until the semi-solid metal is discharged from the container, except when molding directly below the melting point, since the solidification of the skin formation type will continue even when the melting point is below the melting point. .

  The present invention is a review of several publicly known numerical limits, and is a publicly known technology that is optimal for producing a semi-solid metal of an Al-Si hypereutectic alloy in which primary Si is crystallized finely and uniformly. In particular, we dealt with the Al-Si hypereutectic alloy that exhibits a solidified form of skin formation by continuing to move the molten metal until the semi-solid metal is discharged from the container. It is said. The reasons for limiting the numerical values such as the molten metal temperature, the cooling rate, and the P content will be described below.

First, the molten metal temperature will be described. In the present invention, when the degree of superheat with respect to the melting point of the molten metal temperature is lower than 50 ° C., the P added as a refining agent aggregates while holding the molten eutectic Al—Si alloy, and AlP As a result, the crystal Si becomes coarse Si of 100 μm or more. As a result, tissue uniformity cannot be obtained. On the other hand, even if the temperature is higher than 150 ° C., the molten metal is easily oxidized to form an oxide shell, and the gas is strongly absorbed, so that problems are likely to occur. Therefore, the temperature range of the molten metal optimal for the production of the semi-solid metal of the Al—Si hypereutectic alloy is set to 50 ° C. to 150 ° C.

Next, the reason for limiting the cooling rate will be described. When the temperature of the molten metal is such that the degree of superheat with respect to the melting point is 50 ° C. or less and the temperature reaches the melting point, the cooling rate of the molten metal is 1 ° C./second or more. A cooling rate of 3 ° C./second or more is desirable. This is because when the cooling rate is low, AlP which is a nucleus of primary Si present in the molten metal aggregates and does not have a function as a nucleus, and primary Si becomes coarse.
On the other hand, in the temperature range from the melting point to the Al—Si binary alloy alloy eutectic temperature, the temperature is set to 3 ° C./second to 20 ° C./second. This is because when the cooling rate is low, AlP grows independently of primary Si, and AlP aggregates and does not function as a nucleus, so primary Si becomes coarse. . In addition, when the cooling rate in this temperature range is low, primary Si floats, so that a structure in which primary Si does not exist is formed, or a solidified shell is easily formed near the container, resulting in a non-uniform structure. Moreover, if the cooling rate exceeds 20 ° C./second, it is difficult to prevent the formation of a solidified layer even if the molten metal is moved.

  Next, the reason for limiting the numerical value of the P (phosphorus) content will be described. The amount of P added to the melt of the hypereutectic Al—Si alloy varies depending on the amount of Si (silicon), but if it is less than 0.005%, the amount of Si in the hypereutectic Al—Si alloy is reduced. Regardless, the Si size cannot be less than 50 μm. On the other hand, even if P is added in excess of 0.03%, further improvement in the effect of miniaturization cannot be expected. As described above, the addition amount of P is set to 0.005 to 0.03 Wt%.

Further, the importance of continuing to move the molten metal near the inner wall surface of the container or the inner wall of the holding container during the hot water supply or until the semi-solid metal is discharged from the container holding the molten metal during the hot water supply will be described.
The hypereutectic Al—Si alloy is an alloy that exhibits skin-generating solidification in which a solidified layer is clearly generated in a portion where the temperature has dropped below the eutectic temperature. For this reason, if the molten metal comes into contact with the inner wall of the holding container or the hot water supply ladle when the molten metal is poured into the holding container or the hot water supply ladle and the heat is removed, the molten metal is the primary crystal in which the molten metal near the inner wall already exists. While the primary crystal Si is crystallized starting from the core AlP, the width of the solidified layer is increased while gradually growing toward the center of the holding vessel or the hot water supply ladle.

In this case, since the solidified layer prevents direct contact between the inner wall of the container and the molten metal, the heat transfer coefficient between the molten metal in the holding container or the hot water supply ladle and the holding container or the hot water supply ladle decreases with the growth of the solidified layer. The cooling rate is slow. In order to prevent this, the molten metal near the inner wall of the holding container or the hot water supply ladle is mainly moved, so that the temperature of the entire molten metal is lowered uniformly and the cooling rate is increased. Thereby, since the aggregation of AlP serving as the nucleus of primary Si can be prevented, a semi-solid metal obtained by crystallizing fine primary Si can be obtained.
In order to obtain a semi-solid metal having a uniform temperature by more effectively performing the above, it is not limited to the time of pouring, and preferably after the pouring, preferably immediately before forming, in the vicinity of the inner surface of the holding container or the hot water supply ladle. Stirring is required to cool quickly while suppressing the growth of the solidified layer

  Here, a supplementary explanation will be given regarding the period during which the molten metal is moved. When the liquid phase ratio of the target semi-solid metal is large (for example, 80% or more, preferably 90% or more), the target temperature for cooling is high. This is because, since the molten metal continues to move due to the inertia of the molten metal, it is possible to prevent the skin formation type solidification form. On the other hand, when the liquid phase ratio is small (for example, less than 80%), it is necessary to keep the molten metal moving until the semi-solid metal is discharged from the container holding the molten metal from the molten metal.

The hypereutectic Al—Si alloy referred to in the present invention is not limited to the Al—Si binary alloy, but other elements such as transition metals such as Cu, Mg and Fe, Mn, Ni, and Cr are also used. It also includes a multi-component alloy containing. For this reason, the alloy from which primary Si crystallizes is a hypereutectic Al-Si alloy.

As can be seen from the above description, the present invention is a semi-solid metal of an Al-Si hypereutectic aluminum alloy containing 0.005% to 0.03% P in which the solidification form of the molten metal exhibits a special skin formation type solidification. Focusing on the fact that a semi-solid metal of hypereutectic Al-Si alloy in which primary Si is crystallized finely and uniformly can be produced unless the formation of a solidified layer on the inner surface of the container is prevented. It was made.
Furthermore, Al containing P from 0.005% to 0.03% as the cooling rate of the molten metal in the cooling region from the hot water supply temperature to the temperature having a predetermined liquid phase rate is specified It is meaningful to specify a cooling rate suitable for a semi-solid metal of a Si-based hypereutectic aluminum alloy.

Hereinafter, a specific embodiment of a method for producing a semi-solid metal and a method for forming the same according to the present invention will be described with reference to FIG. 1, FIG. 2 and FIG.
FIG. 1 is an explanatory view showing the distribution of the molten metal temperature in the container in the process of cooling from the hot water supply temperature to the forming temperature, and FIG. 2 is an explanatory view of the process until the semi-solid metal is manufactured and formed in the holding container, FIG. 3 is an explanatory view of a process from manufacturing and forming a semi-solid metal from molten metal in a hot water supply ladle.

First, the importance of moving the molten metal in the vicinity of the inner wall of the container in order to make the temperature uniform in the hypereutectic Al-Si alloy exhibiting skin-generating solidification will be described with reference to FIG. In FIG. 1, T3 is the molten metal temperature near the inner wall of the holding container, T1 is the molten metal temperature at the center of the holding container, and T2 is the molten metal temperature at this intermediate position.
In the graph in which the vertical axis indicates the degree of superheat with respect to the melting point and the horizontal axis indicates the elapsed time from the start of pouring (also referred to as hot water supply), the melt temperatures (T1, T2, T3) at each position when the melt is not moved The time change is shown in FIG. In particular, the molten metal temperature (T3) in the vicinity of the inner wall decreases to near the binary eutectic temperature at the end of pouring. Further, the molten metal temperature (T1) at the center of the container has a superheat degree of 40 ° C. or more with respect to the melting point even at the end of pouring, and the temperature difference of the molten metal reaches about 100 ° C.
On the other hand, by moving the molten metal near the inner wall of the container, the temperature difference of the molten metal is almost uniform as shown by the thick line in FIG. 1, and the temperature drop of the molten metal is close to T3. . This makes it possible to understand the importance of moving the molten metal near the inner wall of the container.

  The rate of temperature change (temperature reduction rate) of the molten metal indicated by the thick line in FIG. 1 depends on the cooling rate. In the present invention, it is a condition that cooling is performed at a cooling rate of 3 ° C./s to 20 ° C./second in a temperature range from the pouring temperature to a predetermined temperature not lower than the melting point but not lower than the Al—Si binary eutectic temperature. By selecting a cooling rate within this range, a temperature decrease curve indicated by a thick line in FIG. 1 is obtained. However, the cooling rate when the temperature is lowered to the binary eutectic temperature is the time from the start of pouring to the arrival of the binary eutectic temperature, excluding the temperature that dropped from the pouring temperature to the eutectic temperature (temperature difference). Say the value you did. In Al-Si binary alloys, the liquidus ratio in the range up to the eutectic temperature is obtained from the metal phase diagram of the Al-Si binary alloy, but is maintained at the eutectic temperature even after the eutectic temperature is reached. Then, when the eutectic reaction is promoted and the liquid phase ratio is lowered to obtain a predetermined liquid phase ratio, the following is performed. That is, the coefficient obtained by dividing the liquid phase ratio at the time of completion of primary Si crystallization by the time from the start of the eutectic reaction to the end of the eutectic reaction and the time from the start of the eutectic reaction to the discharge of the semi-solid metal ( The value obtained by subtracting the value obtained by multiplying the value) by the liquid phase ratio at the time of completion of primary crystal crystallization is defined as the total liquid phase ratio. In an aluminum alloy containing other elements such as Cu and Mg in addition to Si, the liquid phase ratio is obtained from a calculation state diagram. In this case, the amount of P is 0.005 Wt% to 0.03 Wt%.

Next, based on FIG. 2, the case where this invention is implemented using the stainless steel holding | maintenance container whose heat conductivity is 27 kcal / mhr (degreeC), and the jig | tool which does not have a cooling function is demonstrated. (1) in FIG. 2 is that the stirring tool 3 having a stirring blade is rotated at the center of the container to mainly stir the vicinity of the inner wall of the holding container, and the cooling air 4 is blown to the outer surface of the holding container to Cooled at a cooling rate of 2 seconds. Stirring was also performed during and after pouring. While continuing the stirring, the semi-solid metal M2 in which the primary crystal Si is dispersed in the liquid is discharged from the holding container at the stage where the predetermined liquid phase ratio is reached, and is molded. Moreover, in order to prevent the local fall of temperature, the heat insulating material 5 whose heat conductivity is 0.4 kcal / mhr (degreeC) can also be provided in the lower part of the holding container 2 as needed.
Moreover, the cooling jig 3 which does not have a stirring blade as the stirring jig 3 can be used, and this stirring jig 3 can be moved along the inner surface of the container.

  (2) in FIG. 2 shows that the molten metal near the inner wall of the holding container is stirred up and down mainly by moving the stirring tool 3a up and down, and cooling air 4 is blown to the outer surface of the holding container to cool at 5 ° C./second. Cooled at speed. Stirring was also performed during and after pouring. While continuing the stirring, the semi-solid metal M2 in which the primary crystal Si is dispersed in the liquid is discharged from the holding container at the stage where the predetermined liquid phase ratio is reached, and is molded. Moreover, in order to prevent the local fall of temperature, the heat insulating material 5 whose heat conductivity is 0.4 kcal / mhr (degreeC) can also be provided in the lower part of the holding container 2 as needed.

  (3) of FIG. 2 shows the case where the induction coil 7 of an electromagnetic induction device is used as a stirring jig. Before pouring the holding container, a magnetic field is applied to the holding container by applying it to the induction coil 7 of the electromagnetic induction device. Thus, as described in Patent Document 4, the molten metal is electromagnetically stirred and a solidified layer is not generated on the inner wall of the holding container. In addition, in order to adjust a cooling rate, the air 4 for cooling can also be sprayed on the holding container outer surface. The electromagnetic field was applied until the semi-solid metal was discharged from the container. The semi-solid metal M2 in which the primary crystal Si is dispersed in the liquid is discharged from the holding container and molded at a stage where the predetermined liquid phase ratio is reached. Moreover, in order to prevent the local fall of temperature, the heat insulating material 5 whose heat conductivity is 0.4 kcal / mhr (degreeC) can also be provided in the lower part of the holding container 2 as needed.

In addition, as a method of discharging the semi-solid metal from the holding container or the hot water supply ladle and forming it with a mold, the horizontal die casting method shown in FIG. 2 (a), the vertical die casting method shown in FIG. 2 (c), FIG. There is a vertical press method shown in (b). In addition to the method shown in FIG. 2, an extrusion molding method can be applied as the molding method. If the liquid phase ratio is high and fluid, it can be applied to gravity casting, low pressure casting, and the like.
The molding speed and the molding pressure are similarly performed under conditions commonly used in each molding method. For example, the horizontal die casting method is 0.1 m / second to 10 m / second, the vertical die casting method is 0.05 m / second to 1 m / second, and the vertical pressing method is 0.05 m / second to 1 m / second.

  Next, based on FIG. 3, a case where a hot water supply ladle 1 having a thermal conductivity of 0.8 kcal / mhr ° C. and a stirring jig 8 having a cooling function is used is shown. By using the stirring jig 8 having a cooling function, the molten metal near the inner wall of the ladle is mainly stirred to reduce the temperature of the molten metal while suppressing the generation of the solidified layer. It is discharged from the hot water supply ladle and molded. In addition, about the shaping | molding method, it is the same as the case of the holding container mentioned above.

The relationship between the thermal conductivity of the container and the presence / absence of the cooling function of the molten metal stirring / rocking jig will be supplementarily described.
When the thermal conductivity of the molten metal holding container or hot water supply ladle is large, cooling from the container is sufficient. This is because it becomes difficult to maintain the temperature. That is, when the heat conductivity heat of the hot water supply ladle or holding container is 3 kcal / m · hr · ° C. or more (when stainless steel or the like is used as the container material), the stirring / swinging jig is not provided with a cooling function.
On the other hand, when the heat conductivity heat of the hot water supply ladle or holding container is less than 3 kcal / m · hr · ° C (when ceramic etc. is used as the container material), the cooling rate of the molten metal becomes slow, so it has a cooling function. This is because it is necessary to increase the cooling rate (capacity) of the molten metal with a jig for stirring and shaking the molten metal.

  The method for producing a semi-solid metal according to the present invention uses an Al—Si hypereutectic aluminum alloy molten metal having a superheat degree of 50 ° C. to 150 ° C. and a P content of 0.005% to 0.03% with respect to the melting point. When manufacturing semi-solid metal, the molten metal near the inner wall of the hot water supply ladle or the inner wall of the holding container is mainly used during hot water supply so that the temperature of the molten metal held in the hot water supply ladle or the holding container becomes uniform. While moving or moving the molten metal from the hot water supply to the molding temperature, the molten metal poured into the hot water supply ladle or holding container is moved from the initial temperature (also referred to as the hot water supply temperature) to a temperature not lower than the melting point and above the Al-Si binary eutectic temperature. In the temperature range of 3 ° C./second to 20 ° C./second, and then discharging a semi-solid metal having a predetermined liquid phase rate from the holding container or the hot water supply ladle, It can be obtained cast material suitable for solid molding. Further, by molding using the casting material, a high-quality product having a uniform and fine metal structure inside the molded product and having excellent mechanical properties and no shrinkage nest can be obtained. Therefore, it has become possible to efficiently produce an aluminum alloy having excellent heat resistance and wear resistance. This makes it possible to reduce the weight of automobile parts and replace steel parts, and has high industrial utility value.

It is explanatory drawing of the temperature change of the molten metal in the container concerning the Example of this invention, ie, explanatory drawing which shows the change of the molten metal temperature in a container in the process of cooling from hot water supply temperature to shaping | molding temperature. Explanatory drawing of the process until it manufactures and shape | molds a semi-solid metal in the holding | maintenance container whose thermal conductivity concerning the Example of this invention is 1 kcal / mhr (degreeC) or more. Explanatory drawing of the process until it manufactures and shape | molds a semi-solid metal from a molten metal in the hot water supply ladle whose thermal conductivity which concerns on the Example of this invention is less than 1 kcal / mhr (degreeC)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ladle 2 for hot water supply 3 Holding container 3 Stirring jig | tool which does not have a cooling function 4 Cooling air 5 Heat insulating material 6 Swing jig 7 Induction coil 8 of an electromagnetic induction device 10 Stirring jig 10 which has a cooling function Injection sleeve 11 Injection plunger 20 Mold apparatus M1 Molten metal M2 Semi-solid metal T1 Molten metal temperature T2 Molten metal temperature T3 between the middle of the container and the inner wall of the container T3 Molten metal temperature near the inner wall of the container

Claims (4)

When manufacturing a semi-solid metal using an Al-Si-based hypereutectic aluminum alloy molten metal having a superheat degree of 50 ° C to 150 ° C with respect to the melting point and containing 0.005% to 0.03% P, a hot water supply ladle The molten metal near the inner wall of the hot water supply ladle or near the inner wall of the holding container is moved during the pouring, or from the pouring to the molding temperature so that the temperature of the molten metal held in the inner or holding container is uniform. 3 ° C / s to 20 ° C / second in the temperature range from the pouring temperature of the molten metal poured into the hot water supply ladle or holding vessel to a predetermined temperature not lower than the melting point and higher than the Al-Si binary eutectic temperature. A method for producing a semi-solid metal, characterized in that the semi-solid metal having a predetermined liquid phase ratio at a temperature equal to or higher than the binary eutectic temperature is discharged from a holding container or a hot water supply ladle. A hot water supply ladle having a thermal conductivity of 3 kcal / mhr ° C. or more, or a molten metal is moved by stirring or rocking the vicinity of the inner surface of the holding container with a jig having no cooling function, or a hot water supply ladle or holding container by an induction device 2. The method for producing a semi-solid metal according to claim 1, wherein the molten metal is moved by applying a magnetic field to the metal. The molten metal is poured into a holding container or a hot water supply ladle having a thermal conductivity of less than 3 kcal / mhr ° C., and the temperature of the molten metal is cooled to a temperature at which a predetermined liquid phase ratio is obtained while stirring or swinging with a jig having a cooling function. The method for producing a semi-solid metal according to claim 1. A semi-solid metal is produced according to claims 1 to 3, and the semi-solid metal is formed by any one of gravity casting, low-pressure casting, laminar flow filling high-pressure casting, high-speed die casting, and vertical press method. A method for forming a semi-solid metal, comprising:

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