WO2001030519A1

WO2001030519A1 - Mg ALLOY PRECISION PRESSURE MOLDING METHOD AND MOLDING DEVICE THEREFOR AND Mg ALLOY MOLDING PRODUCED THEREBY

Info

Publication number: WO2001030519A1
Application number: PCT/JP2000/007227
Authority: WO
Inventors: Manabu Matsumoto; Shigefumi Matsumoto
Original assignee: Matsumoto Seisakusho Co., Ltd.
Priority date: 1999-10-22
Filing date: 2000-10-18
Publication date: 2001-05-03
Also published as: AU7947500A; TW527239B; JP2002059252A

Abstract

A Mg alloy precision pressure molding method and a molding device therefor and a Mg alloy molding produced thereby which can eliminate such conventional technique-based defects in Mg alloy die casting that compact thin-walled parts free from surface folds and cavities are difficult to cast and are cast with a very high fraction defective. In the case of thick-walled parts, moldings with reduced surface folds and cavities, increased strength and reduced surface roughness can be provided by compression. A method of producing a Mg alloy molding, wherein a primary mold clamping is performed, using the mold clamping force of a molding machine, at a low pressure up to a status where a thickness is set about 0.1% to 20% larger than a product thickness, Mg alloy molten metal is poured into a cavity, and then a secondary mold clamping is performed one or a plurality of times at a high pressure to compress or forge the parts of a product.

Description

Detail

Mg alloy precision pressure forming method and forming apparatus and Mg alloy molded product manufactured by the method

The present invention relates to a Mg alloy precision pressure forming method, a forming apparatus therefor, and a Mg alloy formed product produced by the method, and more particularly, to a formed product made of a Mg alloy having poor formability, particularly a thin-walled portion. It is intended to reduce molding defects in molded products (eg, notebook personal computer housings, mobile phone cases, etc.) and produce precise products. Background art

Mg alloys are known to have extremely poor workability because their crystal structure is made of hexagonal close-packed ceramics. Die-casting of Mg alloy requires advanced technology, and particularly in the case of thin-walled parts, the run of the molten metal is poor and many cavities are formed, which is a major cause of the failure. Also, in aluminum die-casting, a hydraulic cylinder is provided in the mold to eliminate the nest of thick-walled parts, and a part of the product or a part of the outside of the product, such as a pool, is compressed with a squeeze pin By doing so, there was a device to make the product denser and eliminate nests. However, the effect was good for thick parts, but it was difficult for thin parts. Even good products require post-processing such as hand finishing, padding of surface irregularities, polishing, etc., resulting in high product costs.

In general, it is known that a product made of a molten Mg alloy has a crystal grain size of about 200 to 500 m. However, it was generally recognized that there is no high-speed superplastic region in the Mg alloy die cast structure. Disclosure of the invention In the die-casting manufacturing, it is difficult to precisely manufacture thin-walled parts without hot water lines or nests by the conventional technology, and the defect rate is extremely high. The purpose of the present invention is to eliminate the above disadvantages. In other words, by improving the die-casting method and by reducing the crystal grain size of the Mg alloy, high-speed superplastic working is realized, and high workability and high strength are achieved. In addition, by compressing even thick-walled parts, it provides a molded article with reduced hot water wrinkles and nests, increased strength and reduced surface roughness.

The present invention solves the above-mentioned problems by increasing the thickness of the cavity in the cavity during primary clamping at low pressure to improve the flow of molten metal, reducing nests due to poor molten metal flow, and increasing the pressure of the secondary mold. Mg alloy precision pressure forming method and device capable of obtaining high-density molded products while crushing to a predetermined thickness by compressing at a predetermined pressure and eliminating defects caused by poor molten metal flow And a Mg alloy molded article produced thereby.

In other words, the Mg alloy precision pressure molding method of the present invention uses the mold clamp of the molding machine to perform primary mold clamping at a low pressure until it is set to be 0.1% to 20% thicker than the product wall thickness. Injecting molten Mg alloy into the cavity and then performing one or more secondary clamping at high pressure to compress or forge the product part to produce a Mg alloy molded product It is.

Here, the secondary mold clamping should be performed with the temperature of the Mg alloy in the cavity at 150 ° C to the melting temperature, and the temperature of the Mg alloy in the cavity should be 200 ° C to 3 ° C. It is more preferable to perform secondary mold clamping at a temperature of 50 ° C. Further, the present invention provides a Mg alloy precision pressure forming method in which a molten Mg alloy is injected into a cavity by a hot chamber die casting method, a cold chamber die casting method, or a thixo molding method. is there. In the present invention, the term “molding” is used as a concept including both molding by a die casting method and molding by a thixomolding method. The crystal grain size of the Mg alloy is reduced to the range of 0.5 to 10 μηι by the rapid solidification of the molten metal in the cavity and by the stress when passing through the runner gate. A molded product is produced by superplasticity.

And, the Mg alloy precision pressure forming apparatus of the present invention is configured such that the movable-side mold is Mold driving means for moving the mold, injection means for injecting the molten Mg alloy into the cavity formed by the fixed mold and the movable mold, and a temperature controller for adjusting the temperature of the mold. The primary mold clamping is performed at a low pressure to a state where the thickness is set to be about 0.1% to 20% thicker than the product thickness by using the knot means and the mold clamping means of the movable mold by the mold driving means. After the molten Mg alloy is injected into the mold, it is equipped with a mold gap adjusting means for performing secondary clamping at high pressure to compress or forge the product part.

More specifically, a direct pressure method is adopted in which at least two stages of mold clamps can be set as the mold driving means, and the movable mold is formed on the back plate that transmits the mold clamps to the surface of the product. A movable-side insert is fixed, and a movable-side base plate joined to the fixed-side mold is provided around the movable-side insert so as to be movable in a mold-clamping direction. 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. It is provided for. In addition, the first 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 metal of the Mg alloy, and the elastic force of the elastic body. And at least two stages of a second mold clamping force for squeezing the elastic body and advancing the movable side insert by the distance between the back plate and the movable base plate to apply a sufficient compressive force to the product portion. It is possible. Here, it is preferable that the elastic body is formed as a dish panel.

Alternatively, a toggle system is adopted as the mold driving means, and the movable mold is fixed to a movable side insert forming a surface of a product on a back plate transmitting a mold clamping force, and a fixed side is provided around the movable insert. The movable base plate to be joined to the 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. A gap maintaining wedge member is interposed in the groove, and the gap is adjusted by the degree of insertion of the wedge member into the tapered groove, and the mold gap adjusting means is provided.

In the above-mentioned Mg alloy precision pressure forming apparatus, it is preferable that the injection means for injecting the molten Mg alloy into the cavity is an injection machine using a hot chamber die casting method or a thixo molding method. Then, the crystal grain size of the Mg alloy is 0.5 to 1 The product is made into a Mg alloy molded product by superplasticity by refining it to the range of 0 m, and the present invention uses the above-mentioned Mg alloy precision pressure forming method or the Mg alloy precision pressure forming device Then, the Mg alloy is compressed to produce a Mg alloy molded product that covers the details, is dense, has good dimensional accuracy, and does not require a smooth surface finish.

Here, “superplasticity” means “in the tensile deformation of a polycrystalline material, the deformation stress shows a high strain rate dependence, and a huge 100% or more with no local contraction (necking). Phenomenon indicating elongation ”(from Japanese Industrial Standards · Metallic superplastic material terminology (JISH 707)). Mg alloys generally have poor ductility and very poor plastic workability due to their close-packed hexagonal lattice structure.However, refinement of crystal grains improves room temperature strength, ductility and workability due to superplasticity. It is known that a significant improvement in The strain rate of the Mg alloy material in the superplastic state increases with decreasing crystal grain size.If the crystal grain size is reduced by one order of magnitude, the superplastic strain rate increases from 100 to 100 times. To increase. The main deformation mechanism of the Mg alloy material in the superplastic state is the grain boundary torsion, and there is a liquid phase in addition to diffusion flow and dislocation as an auxiliary adjustment mechanism that plays a role in maintaining the superplastic flow. In other words, due to the sliding at the grain boundary, a huge elongation is exhibited without causing macroscopic fracture.However, the mechanism that relaxes the local stress concentration generated between the fine crystal grains due to the sliding of the grain boundary Is the associated adjustment mechanism described above.

In a tensile test at a laboratory level with good conditions, a large elongation of about 200% can be obtained even with Mg-based material having a coarse crystal grain size of 100 ^ m order. However, superplastic working of a commercially available Mg alloy material by die casting or thixo molding has not been put to practical use. Furthermore, in the case of Mg alloy, microstructure can be refined by dynamic recrystallization by performing warm extrusion and warm rolling as pre-processing, but in order to realize superplastic forming at lower temperature, It is also known that preliminary processing is required to control the boundary structure itself. This means that superplastic forming of Mg alloys at lower temperatures requires very well controlled preloading and special hydrostatic processing equipment.

The present invention provides a hot chamber die casting method or a cold chamber die casting method. Injects molten Mg alloy into cavities by thixomolding method. When the Mg alloy material passes through a channel such as a runner gate and the like and moves inside the cavity, stress is applied to the crystal grains, and the crystal grains are refined. After performing primary clamping at low pressure until the thickness is set to about 20% to 20% thick, perform single or multiple secondary clamping at high pressure to compress or forge the product part to produce a molded product. Thus, the crystal grains are further refined, and a high-speed superplastic state with a crystal grain size in the range of 0.5 to〗 0 / m is realized. BRIEF DESCRIPTION OF THE FIGURES

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

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

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

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

FIG. 5 is a schematic diagram of a molding apparatus using a hot chamber die casting injector.

FIG. 6 is a schematic diagram 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 has been clamped and a Mg alloy has been injected in a molding apparatus according to another embodiment of the present invention.

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

FIG. 9 is a total pole figure of the molded product at the time of high-pressure secondary mold clamping measured by an automatic X-ray diffractometer. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the precision pressure forming method of the Mg alloy of the present invention will be described in more detail. FIGS. 1 to 3 are views showing a molding apparatus for carrying out the precision pressure molding method of an Mg alloy according to the present invention. FIG. 1 shows a state in which the mold is opened, and FIG. 2 shows primary clamping by low pressure. Fig. 3 shows a state in which secondary clamping by high pressure has been performed. FIG. 4 (a) is a partially enlarged view of FIG. 2, and FIG. 4 (b) is a partially enlarged view of FIG. The Mg alloy precision pressure forming apparatus of the present invention includes a mold driving means (not shown) for moving the movable mold B with respect to the fixed mold A, and a fixed mold A and a movable mold B. Injecting means C for injecting the molten Mg alloy into the cavity formed by the above, temperature adjusting means (not shown) for adjusting the temperature of the mold, and a mold for the movable mold by the mold driving means. Using a clamp, perform primary clamping under low pressure until the product is set to a thickness of about 0.1% to 20%, more preferably about 2% to 5%, so that the molten Mg alloy is in the cavity. After injection, a mold gap adjusting means for performing secondary clamping at a high pressure to compress or forge the product part is provided.

As a result, using the mold clamp of the molding machine, primary clamping is performed at a low pressure until it is set to be 0.1% to 20% thicker than the product wall thickness, and the molten Mg alloy is poured into the cavity. After performing the above, the molded part of the Mg alloy can be manufactured by compressing or forging the product part by performing one or more times of secondary mold clamping at a high pressure. Here, the secondary mold clamping should be performed in a state where the temperature of the Mg alloy in the cavity is 150 ° C to the melting temperature, and more preferably, the secondary mold clamping should be performed in the state of 200 ° C to 350 ° C. It is. As the Mg alloy used in the present invention, AZ91D (Mg: 9% by weight, AI: 90% by weight, Zn:〗% by weight) was used. The melting point of this Mg alloy is between 620 ° C and 700 ° C. It is also preferable to add Ca to the Mg alloy by up to 2% by weight. In that case, the flash point of the Mg alloy is increased by about 200 ° C., which simplifies the apparatus configuration and is preferable. The temperature at which the molten Mg alloy is injected into the cavity may be in a completely molten state or a semi-solid semi-solid state (solid solution) at around 500 ° C. In addition, the mold temperature at this time is preferably as low as 150 ° C or higher because a quenching action utilizing the difference between the casting temperature and the mold temperature can be realized.In practice, the mold temperature is 200 ° C to 350 ° C. Set to 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. Can be forged, and the surface is more dense and flat A smooth molded product can be produced.

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

First, the movable die plate 12 is moved to the fixed side, and the mold is clamped at a low pressure while positioning with the guide pins 20 and the guide bush 19. At this time, the gap α is set between the back plate 7 and the movable base plate 5 having the movable insert 6 integrated with the disc spring 13. This gap α can be changed in the range of 0.1% to 20% of the thickness of the molded product. The operation shall be performed by the bolt 21. The countersunk panel 13 should be strong enough to maintain the gap α with the primary clamping force.

The molten Mg alloy is injected into the cavity from the sleeve 14 through the inlet 4 to make the product part 17. Figure 2 illustrates this situation. The product section 16 is thicker than the predetermined product thickness by α.

At that 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 dish panel 13 is moved by moving the molding machine plate 12 until the gap α becomes 0, so that the product section 16 becomes the product section. It is crushed by α to 17 If the molten metal is completely solidified, it will not be possible to crush the product 16 to the product 17 with the mold clamper of the molding machine, so high-pressure secondary clamping is performed in the molten or semi-molten state. It is desirable. However, the clamping force of the molding machine is large. In a severe case, even after the Mg alloy melt is solidified, compression can be performed at a temperature of at least 150 ° C or more, preferably from 200 ° C to 350 ° C. Adding supersonic waves to the Mg alloy may also be advantageous for densification.

More specifically, a direct pressure system is adopted in which at least two stages of mold clampers can be set as the mold driving means. The movable mold B is fixed to a back plate 7 for transmitting a mold clamp to the movable mold insert 15 forming the surface of the product, and the movable mold B is joined to the fixed mold A around the movable mold insert B. A plate 5 is provided so as to be movable in the mold clamping direction. An elastic body (dish panel 13) is interposed between the back plate 7 and the movable base plate 5 and the back plate 7 opened by the elastic body 13. A bolt 21 that defines the maximum distance a between the movable base plate 5 and the movable base plate 5 is attached to the back plate 7 through the movable base plate 5. In addition, as the elastic body, an appropriate spring such as a compression coil panel or a leaf spring can be used in addition to the disc spring 13 depending on the mold structure. And a first clamping force smaller than the elastic force of the elastic body 13 and sufficiently larger than the injection pressure of the molten Mg alloy; The elastic body 13 is larger than the elastic force 13 and the elastic body 13 is crushed to move the movable side insert 15 by a 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 to at least two steps with the mold clamping force.

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 thixomolding method can be used. As shown in Fig. 5, the hot chamber die cast injection machine has a gooseneck 31 and a built-in biston 32 inside a heating vessel 30 containing a molten Mg alloy. The molten metal taken in 31 is pressurized by the intake piston 32 and supplied from the nozzle 33 to the intake cavity 4. In addition, as shown in FIG. 6, the thixomolding injection machine uses the Mg alloy injected from the raw material hopper 40 to convert the frictional heat of rotation between the cylinder 41 and the screw 42 into an outer circumferential surface of the cylinder 41. A semi-molten and semi-solidified (solid solution) state is established with the heater 43 provided in the nozzle, and the liquid is injected from the nozzle 45 to the inlet 4 by the high injection system 44 provided behind. In addition, a cold-chamber die-casting injection machine is also conventionally known, and a description thereof will be omitted. Further, as another embodiment of the present invention, the Mg alloy precision pressure forming apparatus shown in FIG. 7 employs a toggle instead of using the above-described direct-pressure type mold driving means and a counter panel 13 (elastic body). The movable side mold B is changed as follows by adopting the mold driving means of the system, that is, the movable side mold B is provided on the back plate 7 for transmitting the mold clamp to the surface of the product. And a movable base plate 5 for joining to the fixed mold A is provided around the movable base insert 5 so as to be movable in the mold clamping direction. A tapered groove 22 is formed between the periphery of the tapered groove 5 and a wedge member 23 for maintaining an interval is interposed between the tapered groove 22 and the wedge member 23 is inserted into the tapered groove 22. The taper groove 22 and the wedge member 23 adjust the distance α depending on the condition. Than is configured the adjusting means.

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 (manufactured by Rigaku Corporation: RINT 2000) was used. The measurement conditions were as follows: X-ray (Mo / 50kVZ30mA), K3 filter, Sintellation counter, Schullz transmission method with concentric measurement mode, and FT scanning mode. The Schulz reflection method was used. The processing conditions were calculated and normalized using the actually measured linear absorption coefficient t (6.97335 cm- ¹ ).

In general, the texture allows the crystal orientation of a polycrystalline material and its strength to be known. Normally, the X-ray diffraction intensity of a specific crystal plane is determined by measuring the omnidirectional orientation of the sample, and the diffraction intensity is expressed as a so-called 'positive dot diagram' that is displayed two-dimensionally 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. FIG. 8 shows the state of the working texture of the molded product 16 at the time of the low-pressure primary mold clamping.

The processed assembly formed for the high-pressure secondary mold-formed product〗 7 produced by applying 8% compression deformation in the thickness direction at 300 ° C to the low-pressure primary mold-formed product 16 described above. As a result of measuring the structure on the (00002) plane, it was found that before the deformation, it was widely distributed from the plate surface (the center of the positive pole diagram) to the side surface rotated 90 degrees (around the positive pole diagram) (0 It was found that the (002) plane was concentrated on the plate surface after the deformation (see Fig. 8) (see Fig. 9). As described above, the Mg alloy molded article produced by the high-pressure secondary mold clamping of the present invention has a high-pressure It was shown that the mechanical and crystallographic properties changed compared to the molded product without secondary clamping. In addition, 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 1 μμηι or less, and it can be judged that superplastic working was realized. Industrial applicability

According to the Mg alloy precision pressure forming method of the present invention configured as described above, the primary mold clamping is performed at a low pressure during the formation of the Mg alloy, which has an effect of improving the flow of the molten metal when pouring the molten metal. By using a high-pressure secondary mold clamp to compress or forge the molded product, the molded product can be crushed, making it possible to produce a dense molded product without nests.

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 burrs, a low defect rate, and the like. Furthermore, if the primary mold clamping using a strong dish panel is performed and the movable insert is moved in the direction to increase the thickness of the cavity while the PL is in close contact, the device structure can be simplified. .

Claims

The scope of the claims

1. Using the mold clamping tool of the molding machine, perform primary clamping under low pressure until the thickness is set to 0.1% to 20% thicker than the product wall thickness, and inject molten Mg alloy into the cavity. An Mg alloy precision pressure forming method characterized by producing a Mg alloy molded product by performing secondary clamping one or more times at a high pressure and compressing or forging the product part.

2. The Mg alloy precision pressure forming method according to claim 1, wherein the secondary mold clamping is performed in a state where the temperature of the Mg alloy in the cavity is 150 ° C. to a melting temperature.

3. The Mg alloy precision pressure forming method according to claim 2, wherein the secondary mold clamping is performed in a state where the temperature of the Mg alloy in the cavity is 200 ° C. to 350 ° C.

4. The method according to any one of claims 1 to 3, 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 thixomolding method. Mg alloy precision pressure forming method.

5. The magnesium alloy according to any one of claims 1 to 4, wherein the crystal grain size of the Mg alloy is refined to a range of 0.5 to 10 m to produce a molded product by superplasticity. g Alloy precision pressure forming method.

6. Inject the molten Mg alloy into the mold formed by the fixed mold and the movable mold. The mold drive means moves the movable mold relative to the fixed mold. Means, a temperature adjusting means for adjusting the temperature of the mold, and a mold clamping means for the movable mold by the mold driving means, wherein the thickness is set to be 0.1% to 20% thicker than the product thickness. Primary mold clamping was performed at low pressure until the state was reached, and after the molten Mg alloy was injected into the cavity, mold spacing adjustment means was provided to perform secondary clamping at high pressure to compress or forge the product part. An Mg alloy precision pressure forming machine characterized by the following.

7. Adopt a direct pressure method that can set at least two stages of mold clamps as the mold driving means, and form the movable mold with a back plate that transmits the mold clamp to the surface of the product. The movable insert is fixed, and a movable base plate that is joined to the fixed mold is provided movably in the mold clamping direction around the movable insert, and an elastic body is provided between the back plate and the movable base plate. A back plate interposed and opened by the elastic body and a movable base 7. The Mg according to claim 6, wherein a bolt for defining the maximum interval between the plates is attached to a back plate by penetrating the movable base plate, and the mold gap adjusting means is provided. Alloy precision pressure forming equipment.

8. The first 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 metal of Mg alloy; At least the second mold clamping force that squeezes the elastic body and squeezes the elastic body to advance the movable side insert by the distance between the back plate and the movable side base plate to apply a sufficient compressive force to the product part. 8. The Mg alloy precision pressure forming apparatus according to claim 7, which can be set in two stages.

9. The Mg alloy precision pressure forming apparatus according to claim 7, wherein the elastic body is a disc spring.

10. Adopting the sliding method as the mold driving means, fixing the movable mold to the movable mold insert forming the surface of the product on the back plate that transmits the mold clamp, and surrounding the mold. 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 which expands laterally is formed between the back plate and the periphery of the movable base plate. 7. The structure according to claim 6, wherein a wedge member for maintaining an interval is interposed in the groove, the interval is adjusted by the degree of insertion of the wedge member into the tapered groove, and the mold interval adjusting means is provided. Mg alloy precision pressure forming equipment.

11. The injection means for injecting the molten Mg alloy into the cavity is an injection machine using a hot chamber die casting method, a cold chamber die casting method, or a thixo molding method. The Mg alloy precision pressure forming equipment described in (1).

12.A method according to any one of claims 6 to 1, wherein the crystal grain size of the Mg alloy is reduced to a range of 0.5 to 10 m to produce a molded product by superplasticity. Mg alloy precision pressure forming equipment.

13. Magnesium alloy precision pressure forming method according to any one of claims 1 to 5, or using the Mg alloy precision pressure forming apparatus according to any one of claims 6 to 12. An Mg alloy molded product characterized by being made.