JP2002059252A - Mg ALLOY PRECISION PRESSURE-FORMING METHOD AND ITS FORMING APPARATUS, AND Mg ALLOY FORMED PRODUCT PRODUCED BY THIS METHOD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Mg alloy precision pressure-forming method and its forming apparatus, and an Mg alloy formed product produced by using this method with which such defects are eliminated that the thin parts are difficult to densely cast without developing surface folds or cavities and thus, the strength defective is actually very high in the conventional technique, and to provide a formed product reducing the surface roughness, the cavities, etc., increasing the strength and having little surface roughness by compressing even in the thick parts in the casting of the Mg alloy with a die casting. SOLUTION: A primary die clamping is performed at low pressure into the state setting the thickness greater by about 0.1-20% than the thickness of the product by utilizing the clamping force of the forming machine. After pouring the molten Mg alloy into a cavity, single or more times of secondary die clampings are performed at high pressure and the product is compressed or forged to produce the formed product of the Mg alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of precision pressure forming of an Mg alloy, an apparatus for forming the same, and an M formed by the method.
Related to g-alloy molded products, more specifically Mg
This is intended to reduce molding defects of molded products made of an alloy, particularly molded products having a thin portion (eg, a case of a notebook computer, a case of a mobile phone, etc.), and to produce a dense product.

[0002]

2. Description of the Related Art It is known that the workability of an Mg alloy is extremely poor because its crystal structure is a hexagonal close-packed structure. Die-casting of Mg alloy requires advanced technology, especially in casting of thin-walled parts, the running of the molten metal is poor,
Many nests also occurred, which was a major cause of failure.
In addition, in aluminum die casting, in order to eliminate nests in thick parts, a hydraulic cylinder is provided in the mold to compress a part of the product or a part of the pool outside the product with a squeeze pin. By doing so, the product was made more elaborate and the nest was devised. However, although the effect was effective in the thick part, the effect was difficult in the thin part. In addition, even though it is a good product, post-processing such as hand finishing, padding of surface irregularities, polishing, etc. is required at present, and the product cost is high.

It is generally known that a casting made of a molten Mg alloy has a crystal grain size of about 200 to 500 μm, and a die casting of an Mg alloy also has a crystal grain size of 100 μm or more. It was common to recognize that there is no high-speed superplastic region in Mg alloy die casting.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention seeks to solve the problems described above. In the prior art, in the case of die casting of Mg alloy, thin parts are densely formed without hot lines or nests. Casting is difficult, the defect rate is extremely high, and the present situation is inconvenient. The present invention has been made to eliminate the above-mentioned disadvantages. That is, by devising the die-casting method to refine the crystal grain size of the Mg alloy, high-speed superplastic working is achieved and high workability and high strength are achieved. Further, the present invention also provides a molded article having reduced thickness, burrs, etc., increased strength, and reduced surface roughness by compressing even a thick-walled part.

[0005]

According to the present invention, in order to solve the above-mentioned problems, the thickness of the cavity is increased by thickening the cavity in the primary mold at a low pressure to improve the flow of molten metal, and the nest due to poor flow of molten metal. And pressurized by high-pressure secondary clamping to squeeze to a predetermined thickness and eliminate the problems caused by poor flow of the molten metal and obtain a molded product with high density.
An object of the present invention is to provide a g-alloy precision pressure forming method and a forming apparatus therefor, and a Mg alloy molded product produced thereby.

[0006] That is, the Mg alloy precision pressure forming method of the present invention utilizes the mold clamping force of the forming machine to reduce the product thickness by 0.1% or more.
After the primary mold clamping is performed at a low pressure until the thickness is set to about 20%, the molten Mg alloy is injected into the cavity.
The molded part of the Mg alloy is manufactured by compressing or forging a product part by performing secondary clamping one or more times at a high pressure.

Here, the secondary mold clamping is performed in a state where the temperature of the Mg alloy in the cavity is 150 ° C. to the melting temperature.
Further, the temperature of the Mg alloy in the cavity is 200 ° C. to 35 ° C.
It is more preferable to perform secondary mold clamping at 0 ° C. Further, the present invention is an Mg alloy precision pressure forming method in which a method of injecting a molten Mg alloy into a cavity is a hot chamber die casting method, a cold chamber die casting method, or a thixo molding method. In the present invention, “forming” is used as a concept including both casting by a die casting method and forming by a thixo molding method. Then, by the rapid solidification of the molten metal in the cavity and by receiving stress when passing through the runner gate or the like, the crystal grain size of the Mg alloy is reduced to 0.5 to 1 mm.
The molded product is produced by superplasticity with the fineness in the range of 0 μm.

The Mg alloy precision pressure forming apparatus of the present invention is formed by a mold driving means for moving the movable mold with respect to the fixed mold, and the fixed mold and the movable mold. Injection means for injecting a molten Mg alloy into the cavity;
A temperature adjusting means for adjusting the temperature of the mold and a primary pressure at a low pressure until the thickness is set to be about 0.1% to 20% thicker than the product thickness by utilizing the mold clamping force of the movable mold by the mold driving means. After clamping the mold and pouring the molten Mg alloy into the cavity,
Die spacing adjusting means for performing secondary clamping at a high pressure to compress or forge the product part.

More specifically, a direct pressure system capable of setting at least two stages of mold clamping force is adopted as the mold driving means, and the movable mold is attached to a back plate for transmitting the mold clamping force to the surface of the product. The movable side insert forming the fixed side mold is fixed, and a movable side base plate joined to the fixed side mold is provided around the periphery so as to be movable in the mold clamping direction, and an elastic body is interposed between the back plate and the movable side base plate. In addition, a bolt that defines the maximum distance between the back plate opened by the elastic body and the movable base plate is attached to the back plate by penetrating the movable base plate, and the mold distance adjusting means is provided. Things.

In addition, the first mold clamping force of the mold driving means is smaller than the elastic force of the elastic body and sufficiently larger than the injection pressure of the molten Mg alloy; The force is greater than the force and the elastic body is crushed to move the movable side insert by a distance between the back plate and the movable side base plate to set at least two stages of the second mold clamping force for applying a sufficient compressive force to the product portion. It is possible. Here, it is preferable that the elastic body is a disc spring.

Alternatively, a toggle system is adopted as the mold driving means, and the movable mold is fixed to a back plate for transmitting a mold clamping force by a movable insert forming a surface of a product.
A movable base plate to be joined to the fixed mold is provided movably in the mold clamping direction around the periphery thereof, and a tapered groove which expands laterally is formed between the back plate and the periphery of the movable base plate. And a mold spacing adjusting means provided with a spacing adjusting wedge member interposed therebetween and adjusting the spacing by the degree of insertion of the wedge member into the tapered groove.

In the above-described Mg alloy precision pressure forming apparatus, it is preferable that the injection means for injecting the molten metal of the Mg alloy into the cavity is an injection machine using a hot chamber die casting method or a thixo molding method. And M
The crystal grain size of the g alloy is refined to a range of 0.5 to 10 μm, and a molded product of the Mg alloy is produced by superplasticity.

Further, the present invention is manufactured using the above-mentioned Mg alloy precision pressure forming method or the Mg alloy precision pressure forming apparatus, and the Mg alloy is compressed so that the details are spread out.
M that is dense and has good dimensional accuracy and does not require a smooth surface finish
A g-alloy molded product is produced.

Here, the term "superplasticity" means "in the tensile deformation of a polycrystalline material, the deformation stress exhibits a high strain rate dependence, and does not cause local shrinkage (necking).
Phenomenon showing huge elongation of 0% or more "(from Japanese Industrial Standards, Metallic Superplastic Material Term (JISH 7007)). Mg alloy has a close-packed hexagonal lattice structure,
It is generally known that ductility is poor and plastic workability is very poor. However, it is known that, by making crystal grains fine, improvement in room temperature strength, ductility and workability due to superplasticity are significantly improved. The strain rate of the Mg alloy material in the superplastic state increases as the crystal grain size decreases, and
As the order of magnitude decreases, the superplastic strain rate increases by a factor of 100 to nearly 1000. Further, the main deformation mechanism of the Mg alloy material in the superplastic state is grain boundary sliding, and there is a liquid phase in addition to the diffusion flow and the dislocation as an accompanying adjustment mechanism that plays a role of continuing the superplastic flow. In other words, due to the sliding at the grain boundary, a large elongation is exhibited without causing macro-fracture.However, the mechanism for relaxing the local stress concentration generated between the fine crystal grains due to the sliding at the grain boundary is described above. It is an adjustment mechanism.

Further, in a tensile test at a laboratory level under good conditions, it has been found that a large elongation of about 200% can be obtained even with an Mg-based material having a coarse crystal grain size of the order of 100 μm. Superplastic working of a commercially available Mg alloy material by die casting or thixo molding has not been put to practical use. Further, in the case of Mg alloys, the structure can be refined by dynamic recrystallization by performing warm extrusion and warm rolling as preliminary processing. However, in order to realize superplastic forming at a lower temperature, the grain boundary structure is required. It is also known that pre-processing is required to control the processing itself. In other words, superplastic forming of a Mg alloy at a lower temperature requires very well-controlled preliminary processing and a special static pressure processing apparatus.

[0016] The present invention relates to a hot chamber die casting method or
Means cold chamber die casting or thixomolding
Injection of molten Mg alloy into the cavity
However, the rapid solidification of the molten metal in the cavity
The phenomenon of miniaturization and incidental high-speed irradiation of Mg alloy material
When it is discharged, the Mg alloy material passes through a flow path such as a runner gate.
When moving through a cavity through a cavity
Utilizing the phenomenon that crystal grains become finer,
0.1% to 20% thicker than at low pressure
After performing primary clamping, perform secondary clamping one or more times at high pressure.
Go to compress or forge the product part to make a molded product
By doing so, the crystal grains are further refined, and the crystal grain size is 0.5 to
A high-speed superplastic state in the range of 10 μm is realized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method of precision pressure forming of an Mg alloy according to the present invention will be described in more detail. 1 to 3 are views showing a forming apparatus for carrying out the precision pressure forming method of an Mg alloy according to the present invention. FIG. 1 shows a state in which the mold is opened, and FIG. FIG. 3 shows a state in which secondary clamping by high pressure has been performed. FIG. 4A is a partially enlarged view of FIG. 2, and FIG.
Is a partially enlarged view of FIG.

The Mg alloy precision pressure forming apparatus of the present invention comprises a mold driving means (not shown) for moving the movable mold B with respect to the fixed mold A, a fixed mold A and a movable mold. Injecting means C for injecting the molten Mg alloy into the cavity formed by the mold B, temperature adjusting means (not shown) for adjusting the temperature of the mold, and the movable mold by the mold driving means. The primary mold clamping is performed at a low pressure until the thickness is set to about 0.1% to 20%, more preferably about 2% to 5% thicker than the product thickness by using the mold clamping force, and the molten Mg alloy in the cavity. After injection of the mold, a mold gap adjusting means for performing secondary mold clamping at a high pressure in order to compress or forge the product part.

Thus, the primary clamping is performed at a low pressure to a state where the thickness is set to about 0.1% to 20% thicker than the product thickness by utilizing the clamping force of the molding machine, and the molten Mg alloy is injected into the cavity. After performing the secondary clamping one or more times at high pressure to compress or forge the product part, Mg
It becomes possible to produce a molded article of the alloy. Here, the secondary mold clamping is performed in a state where the temperature of the Mg alloy in the cavity is from 150 ° C. to the melting temperature, more preferably from 200 ° C. to
The secondary mold clamping is performed at 350 ° C.

The Mg alloy used in the present invention is AZ
91D (Mg: 9% by weight, Al: 90% by weight, Zn: 1)
% By weight). The melting point of this Mg alloy is 620 ° C.
700 ° C. It is also preferable to add 1 to 2% by weight of Ca to the Mg alloy. In this case, the flash point of the Mg alloy increases by about 200 ° C., which is preferable because the apparatus configuration is simplified. The temperature at which the molten Mg alloy is injected into the cavity may be in a completely molten state or a semi-molten semi-solid state (solid solution) at about 500 ° C. The mold temperature at that time is preferably as low as possible at 150 ° C. or higher because a quenching effect utilizing the difference between the casting temperature and the mold temperature can be realized. Actually, the temperature is set to 200 ° C. to 350 ° C. . When the secondary mold clamping is performed after the Mg alloy has solidified, it is also preferable to slightly open the mold at the time of mold clamping, and then to perform hot clamping by performing mold clamping one or more times. Thus, a molded article can be forged, and a denser and more smooth molded article can be produced.

Specifically, in the fixed mold A, a fixed cavity insert 3 is inserted into a fixed base plate 2,
The structure is such that the molten Mg alloy is injected through the casting hole 4. The fixing base plate 2 is attached to the die plate 1 of the molding machine. The movable die B has movable inserts 6 and 15 incorporated in a movable base plate 5. In addition, the shunt 8 is used to create a gap between the casting port 4 and the hot water, and to inject the gap. Backboard 7
Is a plate that supports the movable base plate 5 and the movable inserts 6 and 15 during molding. Movable base plate 5, back plate 7
Is mounted on the movable die plate 12 of the molding machine via the spacer 9. The push plates 10 and 11 are moved by the return pins 18 to take out products. The fixed mold A and the movable mold B are positioned by the guide pin 20 and the guide bush 19, are in close contact with each other when the mold is clamped, and have a gap formed by the fixed cavity insert 3 and the movable insert 15. Cavity) is filled with a molten Mg alloy to form a product.

First, the movable die plate 12 moves to the fixed side, and the mold is clamped at a low pressure while being positioned by the guide pins 20 and the guide bushes 19. At this time, a gap α is set between the movable side base plate 5 and the back plate 7 by the disc spring 13 and the movable side insert 6. The gap α can be changed between 0.1% and 20% of the thickness of the molded product. The operation is performed by the bolt 21. The disc spring 13 has such a strength that the gap α is maintained by the primary clamping force.

From the sleeve 14 through the casting port 4, Mg
The molten alloy is injected into the cavity to form the product part 17. FIG. 2 shows this state. Product Division 16
Is thicker than a predetermined product thickness by α.

At this time, a vacuum pump may be used to evacuate the air or a chill vent device may be used to prevent air or the like from being caught in the product.

After the molten metal is poured, the gap α secured by the disc spring 13 is moved until the gap α becomes zero by moving the molding machine die plate 12, so that the product section 16 is moved to the product section 17. Is crushed by α. Incidentally, if the molten metal is completely solidified, the product 16 becomes the product 1 by the mold clamping force of the molding machine.
Since it is impossible to crush up to 7, the high-pressure secondary mold clamping is desirably performed in a molten or semi-molten state. However, when the mold clamping force of the molding machine is large, even after the Mg alloy melt is solidified, compression can be performed at a temperature of at least 150 ° C., preferably 200 ° C. to 350 ° C. Adding ultrasonic waves to the Mg alloy may also be advantageous for densification.

More specifically, a direct pressure system capable of setting at least two stages of mold clamping force is employed as the mold driving means. The movable mold B is fixed to a back plate 7 for transmitting a mold clamping force, with a movable insert 15 forming the surface of the product, and a movable base plate 5 joined to the fixed mold A around the movable mold insert 15. The elastic member (disc spring 13) is interposed between the back plate 7 and the movable base plate 5, and the maximum distance between the back plate 7 and the movable base plate 5 opened by the elastic member 13. Bolt 21 that defines α
Is attached to the back plate 7 through the movable base plate 5. The elastic body is a disc spring 1.
In addition to 3, it is possible to use an appropriate spring such as a compression coil spring or a leaf spring according to the mold structure. The first mold clamping force of the mold driving means is smaller than the elastic force of the elastic body 13 and sufficiently larger than the injection pressure of the molten Mg alloy; The second mold clamping force which is larger than the force and squeezes the elastic body 13 to advance the movable insert 15 by the distance between the back plate 7 and the movable base plate 5 to apply a sufficient compressive force to the product portion. It can be set in two stages.

Further, as an injection means C for injecting the molten Mg alloy into the cavity, an injection machine using a hot chamber die casting method, a cold chamber die casting method or a thixo molding method can be used. As shown in FIG.
A gooseneck 31 and a casting piston 32 are arranged inside a heating vessel 30 in which a molten alloy is stored, and the molten metal taken into the gooseneck 31 is pressurized by the casting piston 32 and supplied from the nozzle 33 to the casting port 4. Is what you do. In addition, as shown in FIG. 6, the thixomolding injection machine transfers the Mg alloy supplied from the raw material hopper 40 to the cylinder 4.
The frictional heat of rotation between the screw 1 and the screw 42 and the cylinder 41
And a heater 43 provided on the outer periphery of the cylinder to form a semi-molten and semi-solidified (solid solution) state, and injects from a nozzle 45 to the casting port 4 by a high injection system 44 provided behind. Further, the cold chamber die casting injection machine is also conventionally known, and the description thereof will be omitted.

FIG. 7 shows another embodiment of the present invention.
The Mg alloy precision pressure forming apparatus shown in (1) employs a toggle-type mold driving means instead of the direct-pressure-type mold driving means and the disc spring 13 (elastic body) described above. B is changed as follows, that is, this movable-side mold B fixes the movable-side insert 15 forming the surface of the product to the back plate 7 that transmits the mold clamping force, and surrounds the periphery thereof. The movable base plate 5 to be joined to the fixed mold A is provided so as to be movable in the mold clamping direction, and a tapered groove 22 that expands laterally is formed between the back plate 7 and the periphery of the movable base plate 5. A wedge member 23 for maintaining a space is interposed in the tapered groove 22, and the space α is adjusted by the degree of insertion of the wedge member 23 into the tapered groove 22. Thus, the mold interval adjusting means is configured.

FIGS. 8 and 9 show the results of measuring the total pole figure of the molded product 16 at the time of the low pressure primary mold clamping and the molded product 17 at the time of the high pressure secondary mold clamping by the X-ray transmission method and the reflection method, respectively. For this measurement, an automatic X-ray diffractometer (RINT2 manufactured by Rigaku Denki) was used.
000) was used. The measurement conditions were X-ray (Mo / 50 kV
/ 30 mA), using a Kβ filter and a scintillation counter, a Schulz transmission method in which the measurement mode is concentric, and a Schulz reflection method in which the scanning mode is FT. The processing conditions are as follows: the measured linear absorption coefficient μ (6.9735c
m ^-1 ), and was performed by calculation normalization processing.

Generally, the crystal orientation and the strength of the polycrystalline material can be known from the texture. Normally, the X-ray diffraction intensity of a specific crystal plane is determined by a method of measuring all directions of the sample, and the diffraction intensity is expressed as a so-called “positive electrode spot diagram” that is two-dimensionally displayed on the sample coordinate system. It is known that the texture changes due to the rotation of the crystal generated during plastic working, forming a so-called processed texture. The state of the working texture of the molded product 16 at the time of the low-pressure primary mold clamping is as follows:
This is shown in FIG.

The above-described molded article 16 at the time of the low-pressure primary mold clamping has 30
As a result of measuring the formed texture of the (0002) plane of the molded article 17 at the time of high-pressure secondary clamping produced by giving 8% compression deformation in the thickness direction at 0 ° C. The (0002) plane that was widely distributed from the (center of the positive electrode dot diagram) to the side surface of the plate (around the positive electrode dot diagram) rotated 90 degrees (see FIG. 8), and that it was concentrated on the plate surface after deformation. It turned out (see FIG. 9). As described above, the molded product made of the Mg alloy manufactured by the high-pressure secondary mold clamping of the present invention has a change in mechanical properties and crystallographic properties as compared with the molded product without the high-pressure secondary mold clamping. It has been shown. Further, it can be confirmed from the micrograph of the structure that the crystal grain size of the molded product 17 at the time of the high-pressure secondary mold clamping is 10 μm or less, and it can be determined that superplastic working has been realized.

[0032]

According to the Mg alloy precision pressure forming method of the present invention as described above, the primary mold clamping is performed at a low pressure during the formation of the Mg alloy, thereby improving the flow of the molten metal when pouring the molten metal. This makes it easier to mold products without hot lines and burrs, and by crushing the molded product by compressing or forging with a high-pressure secondary mold clamp, a dense molded product with no nests can be obtained.

Further, according to the Mg alloy precision pressure forming apparatus of the present invention, it is possible to produce a high-density and high-precision die-casting product having a small number of hot spots and cavities, a low defect rate, and the like. Furthermore, primary clamping using a strong disc spring is performed,
If the movable insert is moved in the direction of increasing the thickness of the cavity in a state where L is in close contact, the device structure is simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a mold of the present invention is mounted and a mold is opened.

FIG. 2 is a cross-sectional view showing a state where low-pressure primary mold clamping has been performed and an Mg alloy has been injected.

FIG. 3 is a cross-sectional view showing a place where a high-pressure secondary mold is clamped and a Mg alloy molded product is crushed.

FIG. 4 is an enlarged view of a main part of the molding apparatus;
(A) is a partial enlarged sectional view of FIG. 2, and (b) is a partial enlarged sectional view of FIG.

FIG. 5 is a schematic view of a molding apparatus using a hot chamber die casting injecting machine.

FIG. 6 is a schematic view of a molding apparatus using an injection machine for thixomolding.

FIG. 7 is a cross-sectional view showing a state in which a low-pressure primary mold clamping is performed and a Mg alloy is injected in a molding apparatus according to another embodiment of the present invention.

FIG. 8 is a total pole figure obtained by measuring a molded product at the time of low-pressure primary mold clamping with an automatic X-ray diffractometer.

FIG. 9 is a total pole figure obtained by measuring a molded product at the time of high-pressure secondary mold clamping with an automatic X-ray diffractometer.

[Explanation of symbols]

 Reference Signs List A fixed-side mold B movable-side mold C Injector 1 Molding machine die plate fixation 2 Fixed-type base plate 3 Fixed-side cavity insert 4 Casting port 5 Moveable-side base plate 6 Moveable-side insert (1) 7 Back plate 8 Shunting Child 9 Spacer 10 Extruded plate (1) 11 Extruded plate (2) 12 Die plate for movable side molding machine 13 Disc spring 14 Sleeve 15 Movable side insert (2) 16 Molded product for low pressure primary mold clamping 17 For high pressure secondary mold clamping Molded product (compressed product) 18 Return pin 19 Guide push 20 Guide pin 21 Bolt 22 Tapered groove 23 Wedge member

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B22D 27/04 B22D 27/04 Z 27/09 27/09 A // H05K 5/02 H05K 5/02 J (72) Inventor Manabu Matsumoto 1-12-1 Shinya, Neyagawa-shi, Osaka Pref. Matsumoto Seisakusho Co., Ltd. (72) Inventor Shigefumi Matsumoto 2-48-10 Takayanagi, Neyagawa-shi, Osaka Pref. 326 F-term (reference) 4E360 EE15 GA52 GB46 GC04

Claims (13)

[Claims] 1. Using a mold-clamping force of a molding machine, perform primary mold-clamping at a low pressure until it is set to be 0.1% to 20% thicker than a product thickness, and inject a molten Mg alloy into a cavity. A Mg alloy precision pressure forming method characterized in that a single or plural times of secondary mold clamping is performed at a high pressure, and then a product part is compressed or forged to produce a Mg alloy molded product. 2. The temperature of the Mg alloy in the cavity is 15
The method according to claim 1, wherein the secondary mold clamping is performed at a temperature of 0 ° C. to a melting temperature. 3. The temperature of the Mg alloy in the cavity is 20 or less.
The Mg alloy precision pressure forming method according to claim 2, wherein the secondary mold clamping is performed at a temperature of 0C to 350C. 4. The Mg alloy precision pressure forming method according to claim 1, wherein the method of injecting the molten Mg alloy into the cavity is a hot chamber die casting method, a cold chamber die casting method, or a thixo molding method. 5. The Mg alloy has a crystal grain size of 0.5 to 10 μm.
The Mg alloy precision pressure forming method according to any one of claims 1 to 4, wherein a molded product is produced by superplasticity after being refined to the range described in (1). 6. A mold driving means for moving the movable mold relative to the fixed mold, and injection of molten Mg alloy into a cavity formed by the fixed mold and the movable mold. Injecting means, temperature adjusting means for adjusting the temperature of the mold, and a state in which the thickness is set to be about 0.1% to 20% thicker than the product thickness by utilizing the mold clamping force of the movable mold by the mold driving means. Primary mold clamping at a low pressure until then, and after injecting the molten Mg alloy into the cavity, the mold is equipped with mold spacing adjustment means for secondary clamping at a high pressure to compress or forge the product part. Mg alloy precision pressure forming equipment. 7. A direct pressure system in which at least two stages of mold clamping force can be set as the mold driving means, and the movable mold is formed on a back plate for transmitting the mold clamping force. The movable side insert to be fixed is fixed, and a movable side base plate joined to the fixed side mold is provided movably in the mold clamping direction around the movable side insert, and an elastic body is interposed between the back plate and the movable side base plate. A bolt, which defines the maximum distance between the back plate opened by the elastic body and the movable base plate, is attached to the back plate by penetrating the movable base plate, and the mold distance adjusting means is provided. 7. The Mg alloy precision pressure forming apparatus according to 6. 8. The first mold clamping force of the mold driving means is smaller than the elastic force of the elastic body and sufficiently larger than the injection pressure of the molten Mg alloy; The force is greater than the force and the elastic body is crushed to move the movable side insert by a distance between the back plate and the movable side base plate to set at least two stages of the second mold clamping force for applying a sufficient compressive force to the product portion. The Mg alloy precision pressure forming apparatus according to claim 7, which is capable of being used. 9. The spring according to claim 7, wherein the elastic body is a disc spring.
Or the Mg alloy precision pressure forming apparatus according to 8. 10. A toggle system is adopted as said mold driving means, and said movable mold is fixed to a movable insert for forming a surface of a product on a back plate transmitting a mold clamping force. A movable base plate to be joined to the fixed mold is provided so as to be movable in the mold clamping direction, and a tapered groove that expands laterally is formed between the back plate and the periphery of the movable base plate,
7. The mold gap adjusting means according to claim 6, wherein a wedge member for maintaining a gap is interposed in said tapered groove, and the gap is adjusted by the degree of insertion of said wedge member into said tapered groove. Mg alloy precision pressure forming equipment. 11. The Mg according to claim 6, wherein the injecting means for injecting the molten Mg alloy into the cavity is an injector using a hot chamber die casting method, a cold chamber die casting method, or a thixo molding method.
Alloy precision pressure forming equipment. 12. The Mg alloy has a crystal grain size of 0.5 to 10 μm.
The Mg alloy precision pressure forming apparatus according to any one of claims 6 to 11, wherein a molded product is produced by superplasticizing the product in a range of m. 13. The Mg according to claim 1, wherein
A Mg alloy molded product produced using an alloy precision pressure molding method or the Mg alloy precision pressure molding device according to any one of claims 6 to 12.