JP6061833B2 - Metal lump for casting - Google Patents

Description

  In the present invention, for example, in casting using a die casting machine for producing a cast product by extrusion molding of an aluminum alloy, a quantity of semi-solid slurry corresponding to the weight of the product to be molded is determined in the injection sleeve of the die casting machine. The present invention relates to a metal block for casting made of a semi-solid slurry formed by solidification into a spherical block having a desired fixed size so that it can be supplied in a form.

  Conventionally, a die casting machine is used for casting a metal material. Die casting is one of the mold casting methods. By casting molten aluminum, magnesium, zinc and other non-ferrous metal alloys into the mold at high speed and high pressure, a large amount of high dimensional accuracy castings are produced in a short time. This is a casting method to produce. The die in the die casting machine used for casting is composed of at least two parts, one fixed die and the other movable die so that the cast die cast can be taken out. Each of these fixed mold and movable mold is attached to a fixed die plate and a movable die plate of a die casting machine, and a charging injection sleeve is provided on the fixed die plate side. A plunger provided with an injection tip slides back and forth to inject molten metal into the mold.

  In addition, a hot chamber system that enables the molten metal to be efficiently press-fitted into the mold by integrating the melting furnace and casting machine, so-called thixotropy molding system that injection-molds a semi-solid slurry in a semi-molten state called so-called thixotropy (Hereinafter abbreviated as thixo molding). The semi-solid slurry flow is a continuous, constant-velocity flow that resembles the plastic flow, so it is not necessary to entrain air, and no nest is formed, so cast injection is possible. Thus, it is understood that the semi-solid slurry has a fine metal structure, so that the flow of hot water is good, and that it flows like a resin by using this.

  By the way, since magnesium and zinc do not react with iron, magnesium and zinc can be hot chambered or thixo-molded. On the other hand, aluminum reacts with iron because of the electrode, and cannot be formed by oxidation. In recent years, hot chambers for aluminum alloys exist on the market, which use heat-resistant ceramics for the injection mechanism. However, when an aluminum alloy is used, if an excessive pressure is applied to enable reliable molding, the ceramic itself constituting the injection mechanism is weak and is broken. Therefore, the hot chamber for aluminum alloy can only be applied up to about 15 to 20 tons even if the press pressure is high, so it can be used only for the manufacture of small precision products such as camera parts, and the press pressure is at least 50 tons. This was not possible in the manufacture of large automotive parts that needed to be. Thus, since an aluminum alloy cannot perform hot chamber or thixo forming, it has been concluded that the aluminum alloy can only be formed by die casting. Among them, the idea of a semi-solid slurry in a solid-liquid coexistence state has been proposed, which can withstand a press pressure of up to 50 tons.

  In addition, in conventional injection molding using a die-casting machine, an alloy of non-ferrous metal such as aluminum, magnesium, or zinc is melted and poured into the injection sleeve, so that accurate measurement and temperature control are difficult. In thixo molding, a semi-solid slurry in a semi-molten state coexisting with solid and liquid is heated and then poured into the injection sleeve. This is also an accurate measurement due to the continuous fluidity of the semi-solid slurry itself. Is cumbersome and difficult. Moreover, in thixo molding, the semi-solid state cannot be maintained unless the temperature control of the semi-solid slurry is strict.

  Further, when a semi-solid slurry in a semi-molten state is poured directly from the charging injection sleeve, burrs are generated due to the surplus if the charging amount is large due to a measurement error of the semi-solid slurry. Once burrs are generated, heat is added to the mold and the temperature of the mold rises. As a result, the semi-solid slurry becomes easier to flow, so it will go out further and generate new burrs. .

  Therefore, conventionally, as disclosed in Patent Document 1, in order to provide an efficient raw material and a manufacturing method for thixoforming, it is made of an alloy containing at least two or more elements, and has an average particle size Intermittently pressurizing metal particles for casting having a spherical shape of 1 to 5 mm and a primary crystal structure of 10 to 60% by volume with respect to the whole and a semi-solid slurry in a solid-liquid coexistence state A method for producing metal particles for casting has been proposed which comprises a step of dropping from a nozzle to form semi-spherical semi-solid particles, which are further cooled and solidified.

JP 2001-303150 A

  However, the metal particles for casting disclosed in Patent Document 1 are formed into pellets having a particle diameter of 1 to 5 mm, so that they are too small and cumbersome to handle, and when heated, they immediately become oxides. Can not be molded. Thus, in thixo molding, the pellets (1 to 5 mm) are immediately oxidized when dissolved. Therefore, it is necessary to form the metal particles for casting in the form of pellets in an atmosphere that does not oxidize when they are put into the heating tower, but the pellets themselves are very small as 1 to 5 mm as described above. Sometimes it quickly solidifies and oxidizes and turns black. Moreover, accurate weighing is not possible.

  Therefore, the present invention was created in view of the existing circumstances as described above. A uniform semi-solid slurry with a refined semi-solid structure is formed into a spherical shape, and this is injected, so that at the time of injection molding Provided is a casting metal lump that enables accurate metering, prevents oxidation by heating, prevents burrs after injection molding, etc., and eliminates the need for strict and troublesome temperature control of semi-solid slurry. For the purpose.

In order to solve the above-mentioned problems, in the present invention, a spherical ingot 1 having a desired diameter and weight is formed from a uniform semi-solid slurry by a refined semi-solid structure made of an alloy containing at least two elements. It is characterized by being formed and solidified.
The ingot 1 has a spherical shape with an average sphere diameter R of 36 to 58 mm, and is formed of nuclei 2 that are the basis of a metal structure including a uniform and fine primary crystal structure (dendrites) as a whole. can do.
The alloy may be any one of an aluminum alloy, a magnesium alloy, a zinc alloy, and an iron alloy.
More specifically, a casting metal formed by solidifying a uniform semi-solid slurry made of a refined semi-solid structure made of an alloy containing at least two or more elements into a spherical ingot 1 having a desired diameter and weight. In the lump, the ingot 1 has a spherical shape with an average sphere diameter of 36 to 58 mm, and is formed by the core 2 that is the base of the metal structure including the uniform and fine primary crystal structure as a whole. It is heated to a temperature at which the semi-solidified microstructure just before the liquid phase is maintained, so that it can be used in a semi-molten state where the semi-solid microstructure is maintained. And

In the casting metal lump according to the present invention configured as described above, a semi-solid slurry is formed into a desired ingot and diameter, for example, an ingot 1 having an average sphere diameter R of 36 to 58 mm. Since it is solidified and the distance from the center of the sphere to the surface of the ingot 1 is constant in all directions, the outer wall side of the ingot 1 and the inside of the ingot 1 are the same during the heating process. Then, it softens substantially uniformly, and the entire sphere becomes a uniform semi-solid structure, so it is not oxidized. This enables optimum casting management when performing die casting, hot chamber and thixo molding.
On the other hand, if the shape is other than spherical, the distance from the center to the surface varies depending on the direction. In particular, ingots such as columnar and stick shapes have different thicknesses and distances depending on the direction, and are crushed from the peripheral surface toward the inside due to differences in heat conduction due to heating, resulting in an uneven stick shape. Even if such an ingot is mass-produced, each becomes a distorted shape, and an optimum cast product cannot be obtained.
Further, if the ingot 1 is a sphere, the number of grams can be accurately maintained, so the injection conditions are constant. That is, since each ingot 1 is formed into a sphere having a desired diameter, the weight of each ingot 1 becomes constant, so that accurate weighing can be performed only by counting the number of ingots 1. As a result, at the time of heat forming using the ingot 1, it is only necessary to use the number of ingots 1 corresponding to the entire weight of the product to be molded, and since no extra amount is generated, no burrs are generated.

  According to the present invention, it is formed into a spherical shape by a uniform semi-solid slurry with a refined semi-solid structure, and an appropriate number of predetermined amounts can be introduced to enable accurate measurement during injection molding, and also by heating. This makes it possible to prevent oxidation, prevent burrs from occurring after injection molding, and eliminate the need for strict and troublesome temperature control of semi-solid slurry.

  That is, this is because the casting metal block according to the present invention forms a uniform semi-solid slurry with a refined semi-solid structure made of an alloy containing at least two or more elements into a spherical ingot 1 having a desired diameter and weight. This is because it is formed and solidified. For example, when a molded product that is a cast product made of an aluminum alloy is manufactured by a die casting machine, an amount corresponding to the total weight of the molded product in the input injection sleeve. If the ingots 1 of the number of aluminum alloys are heated and charged, the ingot 1 itself is in a state in which a semi-solid microstructure is maintained, so that the aluminum alloy itself is not oxidized and burrs are not generated. In this state, an aluminum casting having a fine metal structure and excellent mechanical properties can be easily manufactured.

  Further, the ingot 1 according to the present invention can be forged by making a sphere having a size substantially corresponding to the weight of the molded product, for example, and the temperature control of the specific heat can be easily performed. Further, when the cast product is manufactured, it is only necessary to heat the ingot 1 and there is no need to control the temperature by melting the hot water in a large furnace as in the prior art, thus saving energy. Moreover, in conventional water heaters, the temperature, flow speed, etc. always change, so that a nest is formed by entraining hot water or air, whereas in the present invention, casting is not performed with molten metal. There is no hot water or air inside.

  Moreover, in this invention, aluminum casting becomes possible with the system of an injection molding machine. That is, since the flow of the semi-solid slurry is a continuous flow at a constant speed similar to the flow of plastic, no nest can be formed because air is not involved. Therefore, in the ingot 1 according to the present invention, the semi-solid fine particles immediately before becoming the liquid phase (580 ° C.) in the equilibrium curve representing the solid-liquid phase separation of the aluminum alloy, that is, the phase diagram showing the correlation between the concentration and the temperature. If it is heated up to a temperature of 570 ° C. in a state where the chemical structure is maintained, a quantitative amount such as a resin is supplied and flows like a resin. It can be used. In addition, it is possible to realize a composite material of iron and aluminum, for example, an extremely thin laminated structure material laminated on each other, an engine mechanism of a vehicle or the like.

  Since the ingot 1 has a spherical shape with an average sphere diameter R of 36 to 58 mm, the entire ingot 1 is formed by nuclei 2 that are the basis of a metal structure including a uniform and fine primary crystal structure (dendrites). Aluminum that excels in mechanical properties from small precision products such as camera parts to large automobile parts, for example, by simply adjusting the number and combination of ingots 1 with different average sphere diameters R and heating them. A cast product can be easily manufactured.

  Since the alloy is any one of aluminum alloy, magnesium alloy, zinc alloy, and iron alloy, cast any of aluminum alloy, magnesium alloy, zinc alloy, and iron alloy that has a fine metal structure and excellent mechanical properties. It can be manufactured easily.

  Note that the reference numerals added in the means for solving the above-described problems and the effects of the invention are given for easy reference to the parts showing the components shown in the drawings. The present invention is not limited to the structure / shape indicated by the reference numeral.

It is a front view including the expanded sectional view of a part of ingot in one form for carrying out the present invention. It is a process block diagram for demonstrating the shaping | molding process of an ingot similarly.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 shown in the drawing is an ingot constituting a metal lump for casting according to the present invention. Then, a meltable alloy of aluminum alloy / magnesium alloy / zinc alloy is electromagnetically stirred to form a uniform semi-solid slurry with a refined semi-solid structure, and the semi-solid slurry is formed and solidified into a spherical shape with a desired diameter and weight. (Solidified).

  As shown in FIG. 1, the ingot 1 is formed of nuclei 2 that are the basis of a metal structure including a spherical structure having an average sphere diameter R of 36 to 58 mm and a uniform and fine primary crystal structure (dendrites). In addition, a predetermined molded product can be casted by heating and charging a number of ingots 1 corresponding to the total weight of the molded product into a charging injection sleeve of a die casting machine (not shown). The ingot 1 has a sphere diameter R smaller than these when the opening diameter of the input port of the input injection sleeve and the inner diameter of the input path are, for example, 40 mm, 50 mm, and 60 mm. For example, when the opening diameter of the charging / injecting sleeve and the inner diameter of the charging path are 40 mm, the spherical diameter R = 36 mm (minimum value), and when the opening diameter of the charging / injecting sleeve and the inner diameter of the charging path are 60 mm, the spherical diameter As a guide, the diameter R = 36 mm (minimum value) to the spherical diameter R = about 58 mm. Further, even if the sphere diameter R is 36 mm (minimum value) or less, it may be of a size that does not oxidize. However, if the sphere diameter R is 58 mm or more and is too large, the nucleus 2 varies. Therefore, the average spherical diameter R of the ingot 1 is preferably 36 to 58 mm. In addition to making the ingot 1 spherical, for example, a polyhedral structure in which the distance from the center to each surface is substantially the same may be used.

  When the ingot 1 is heated, for example, in the case of an aluminum alloy, the ingot 1 is shown as a liquid phase in an equilibrium curve representing solid-liquid phase separation of the aluminum alloy, that is, a phase diagram showing a correlation between concentration and temperature. What is necessary is just to heat to 570 degreeC just before becoming (580 degreeC), and to throw in in the injection | emission injection sleeve of a die-casting machine. Since the ingot 1 itself maintains a semi-solid microstructure, the semi-solid slurry is charged into the injection sleeve of the die casting machine without oxidizing the aluminum alloy itself and generating burrs. Thus, a cast product having a fine metal structure and excellent mechanical properties similar to that produced by pressure casting is produced. In the case of a magnesium alloy or zinc alloy, a cast product is manufactured by the same heating method of the ingot 1.

  The electromagnetic stirring when the ingot 1 according to the present invention is manufactured is, for example, a rotating magnetic field and an axial moving magnetic field that are non-contacted by the rotation of a permanent magnet, etc., and the molten metal is uniformly and strongly stirred throughout. To do. Although a description by illustration is omitted, as a specific electromagnetic stirring device, a rotating magnetic field generating coil provided along the outer peripheral surface of a container that accommodates a cup for generating a rotating motion in the molten metal, and an axial movement in the molten metal. The axial movement magnetic field generating coil provided along the axial direction of the outer peripheral surface of the container that accommodates the cup for generating the gas can be used in combination. As a result, a strong flow velocity motion in which the rotational motion and the axial motion are superimposed is generated in the molten metal, and the molten metal is strongly and uniformly stirred. In particular, the electromagnetic stirrer can form a large velocity gradient in the molten metal, and therefore can promote and control the aggregation and enlargement of inclusion particles in the molten metal. As a result, the ratio between the liquid phase and the solid phase can be freely changed depending on the energization time of the magnetic field generating coil, the frequency of the magnetic field, the electric power to be applied, etc., for example, the molten metal is fragmented with a low-viscosity semi-solidified by nano-sized spherical crystals It can be organized. As disclosed in Japanese Patent Application Laid-Open No. 2000-152600, a coil that applies a rotating magnetic field to the molten metal in the cup is arranged obliquely on the iron core so as to be twisted with respect to the axis of the cup. An inductive electromagnetic driving device that applies a torsional magnetic field by energization of the magnetic field and applies a traveling magnetic field in the axial direction simultaneously with the rotating magnetic field may be used.

  The alloy component forming the ingot 1 may be an iron alloy or the like in addition to a non-ferrous metal such as an aluminum alloy, a magnesium alloy, or a zinc alloy, and any alloy can be used as long as it is a component capable of electromagnetic stirring.

  Next, the molding procedure of the ingot 1 configured as described above will be described in detail based on a process block diagram also serving as a flowchart shown in FIG. A melt holding furnace (not shown) is held as a molten metal having a melting temperature of, for example, 640 ° C., such as an aluminum alloy. Further, for example, a heat-resistant SUS cup having a half-elliptical shell shape can be accommodated inside the accommodating portion of the electromagnetic stirring device.

  First, in the molten metal charging process A (step S1), a molten aluminum alloy is charged into the SUS cup from the melting holding furnace with a ladle. At this time, the nuclei 2 that cause crystal growth are adsorbed on the inner wall of the SUS cup, and dendrites begin to grow.

  In the microstructuring step B (step S2) by electromagnetic stirring, the molten metal is formed into a semi-solid slurry by putting the SUS cup into the accommodating portion of the electromagnetic stirring device and performing electromagnetic stirring. As described above, this electromagnetic stirring operation is performed by a rotating magnetic field generating coil provided along the outer peripheral surface of the container that accommodates the SUS cup in order to generate a rotational motion in the molten metal, and an axial motion in the molten metal. This is executed in combination with an axially moving magnetic field generating coil provided along the axial direction of the outer peripheral surface of the container that accommodates the SUS cup. At this time, the nucleus 2 is easily peeled off from the inner wall of the SUS cup, and many nuclei 2 are accumulated on the center side of the SUS cup, and a semi-solid slurry having a uniform fine structure as a whole is formed. In addition, even if a dendritic primary crystal structure (dendrite) grows from the nucleus 2, the dendritic primary crystal structure (dendrite) is crushed by the shearing force by forcibly stirring the semi-solid slurry with an electromagnetic stirrer, A non-dendritic (substantially spherical) primary crystal structure is easily formed, and a fine and uniform structure can be obtained.

  In the spherical molding process C (step S3), the semi-solid slurry in the SUS cup is put into a spherical mold and solidified by cooling, so that a spherical ingot in which nuclei 2 are uniformly accumulated from the central portion to the surface. 1 is formed. In addition, the spherical mold is configured by, for example, a half-shaped mold frame, and the average spherical diameter R is 36 to 58 mm by matching one mold frame with the other mold frame. A spherical concave portion is formed at the center, and an upper side of the spherical concave portion is formed with a generally trumpet-shaped inlet opening for feeding a semi-solid slurry into the spherical concave portion, and a spherical shape is formed on the lower side. A gas vent for discarding and escaping the gas generated from the semi-solid slurry put into the recess is formed.

  In the extraction step D after solidification (step S4), the ball molding die is cooled to solidify (solidify) the inner semi-solid slurry, and then the ball molding die is split into half to ingot 1 Take out. And the spherical ingot 1 is formed by cutting the unnecessary site | part solidified and formed by each of an upper inlet and a lower gas vent part, and scraping an excess burr | flash. At this time, an oxide film is formed only on the surface of the ingot 1, and the entire interior is uniformly dispersed by the nuclei 2 (see FIG. 1). Thus, the ingot 1 according to the present invention is completed, and this flow ends.

  Hereinafter, the casting molding procedure of the molded article by the die casting machine using the ingot 1 according to the present invention will be described. In addition, although description by illustration is abbreviate | omitted by a die-casting machine, for example, it is provided with the fixed die plate which has a fixed mold, and the movable die plate which has a movable mold, and these fixed molds and movable molds are united. The ingot 1 is clamped in a form according to the shape in both molds.

  First, the ingot 1 in a solidified state is heated with, for example, a heater. In this heating, the ingot 1 is heated to a temperature of 570 ° C. just before becoming a liquid phase (580 ° C.). At this time, the ingot 1 is in a semi-molten state in which the semi-solidified microstructure that is in a solid-liquid coexistence state is maintained.

  Next, the heated ingot 1 is charged from the charging port of the charging injection sleeve that has penetrated into the fixed mold from the fixed die plate side of the die casting machine. At the time of charging, only the number of ingots 1 corresponding to the weight of the product to be molded may be charged. That is, it becomes the same principle as forging using only a predetermined amount. As described above, the minimum value is 36 mm (when the opening diameter of the charging injection sleeve and the inner diameter of the charging path is 40 mm) to 58 mm (when the opening diameter of the charging injection sleeve and the inner diameter of the charging path are 60 mm) The standard is up to. When an appropriate number of ingots 1 having the same weight as the weight of the product to be molded are inserted, there is no excess amount, and therefore no burrs are generated during product molding.

  Next, the heated ingot 1 is pressure-extruded by an injection tip that slides back and forth in the injection sleeve, and is supplied into each of a fixed die and a movable die that are abutted against each other. The ingot 1 is mold-clamped in a form corresponding to the internal shape of the. Thereafter, the fixed mold and the movable mold may be opened to take out the cast product after molding.

A ... Molten metal charging process B ... Micro-texturing process C ... Ball molding process D ... Extraction process after solidification R ... Ball diameter 1 ... Ingot 2 ... Core

Claims (1)

In a casting metal mass formed by solidifying a uniform semi-solid slurry with a refined semi-solid structure made of an alloy containing at least two kinds of elements into a spherical ingot of a desired diameter and weight , the ingot is Semi-solidified immediately before it becomes a liquid phase at the time of casting, the average sphere diameter of which is a sphere with a diameter of 36 to 58 mm, is formed by the cores of the metal structure including the uniform and fine primary crystal structure. A casting metal block characterized by being heated to a temperature at which a refined structure is maintained and used in a semi-molten state of a mold in which a semi- solid microstructure is maintained .

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