WO2005110644A1

WO2005110644A1 - Method for preparing semi-solid metal slurry, molding method, and molded product

Info

Publication number: WO2005110644A1
Application number: PCT/JP2005/009150
Authority: WO
Inventors: Ayako Kikuchi; Kouichi Anzai; Masayuki Itamura; Masao Kikuchi; Eisuke Niiyama
Original assignee: Ayako Kikuchi; Kouichi Anzai; Masayuki Itamura; Masao Kikuchi; Eisuke Niiyama
Priority date: 2004-05-19
Filing date: 2005-05-19
Publication date: 2005-11-24
Also published as: JP3919810B2; JPWO2005110644A1; EP1767290A1; US20090095434A1; EP1767290A4

Abstract

A semi-solid slurry and a semi-solid molded product, which can be simply prepared in a short time without limitation of kind and composition of an object metal, is provided. Pouring is carried out so that, upon pouring of a molten metal into a vessel or a sleeve (hereinafter referred to as “vessel or the like”), the metal is brought to a supercooled state without forming an initial solidified layer and self-agitation takes place within the vessel. A molten metal is brought into contact with a cooling vessel or a cooling part from a given height to produce nuclei without forming any initial solidified layer utilizing a supercooling phenomenon, and, subsequently, agitation is carried out to bring the metal to a semi-solid state while eliminating a temperature gradient in the cooling vessel or the cooling part.

Description

Specification

Method for producing semi-solid metal slurry, molding method and molded article

Technical field

The present invention relates to a method for producing a semi-solid metal slurry, a molding method, and a molded product.

Background art

[0002] The metal slurry used in the semi-solid molding method (the rheocast method) maintains primary crystals separated from each other by a liquid matrix, and the primary crystal particles are as fine and uniform as possible in a non-branched state. And preferably spherical. By doing so, it is possible to mold (form) with a high solid fraction and a low-viscosity semi-solid state, thereby suppressing the occurrence of shrinkage cavities in the molded product and improving the mechanical strength of the molded product. Can be.

[0003] The following are known as techniques for producing metal slurries! /

Patent Document 1: JP-A-8-325652

Patent Document 2: JP-A-11-138248

Patent Document 3: Japanese Patent No. 3520991

[0005] The technique described in Patent Document 1 discloses a method for forming a semi-molten metal that can easily and easily obtain a compact having a fine and spherical thixostructure at low cost without using a mechanical stirring method or an electromagnetic stirring method. It is proposed to place an alloy in the liquid state with crystal nuclei above the liquidus temperature or in a solid-liquid coexisting state above the forming temperature with crystal nuclei in an insulated container with heat insulation effect. In addition, by holding for 5 seconds to 60 minutes while cooling to a molding temperature showing a predetermined liquidus rate, fine primary crystals are crystallized in the alloy liquid in the liquid, and the alloy is used for forming. It is supplied to a mold and pressure-formed.

[0006] However, when a slurry is actually prepared using the technique described in Patent Document 1 and then molded, a molded article having a fine and uniform structure is not necessarily obtained. In particular, the tendency is remarkable in alloys other than the JISAC4C alloy. That is, it is impossible to obtain a molded article having a fine and uniform structure in which the temperature range where solid-liquid coexistence is wide and the alloy system is not used. In addition, when pouring directly into an insulated container, a grain refining element must be added without fail! [0007] On the other hand, the technology described in Patent Document 2 is a semi-solid metal having fine and almost uniform non-dendritic (spherical) primary crystal particles with a simple apparatus and equipment that does not require a particularly complicated process. The semi-solid metal slurry can be easily and stably prepared to produce a semi-solid metal slurry, and the semi-solid metal slurry prepared above can be easily loaded into a press sleeve of a molding machine and press-formed. There is a configuration in which a movement is applied to the molten metal when the molten metal is being cooled and at least a part of the molten metal is below the liquidus temperature, and then the molten metal is cooled. In the method for producing a semi-solid metal slurry in which the molten metal is semi-solidified, the molten metal is poured into a slurry production container, so that at least a part of the molten metal is moved to a liquidus temperature or lower and the molten metal is moved. In addition It is obtained so as to load the pressure sleeve of the slurry one manufacturing containers each molding machine.

[0008] According to the technique described in Patent Document 2, even when a slurry is actually prepared and then molded, a molded article having a fine and uniform structure is not always obtained. . In particular, the tendency is remarkable in non-JISAC4C alloys.

[0009] Patent Document 3 discloses that an electromagnetic field that does not cause an initial solidification layer to be formed in a molten metal poured into a container is applied to the container at the same time as the molten metal is poured into the container, A pouring step of pouring the molten metal into the container in a state where the electromagnetic field is applied, and cooling the molten metal poured into the container to form a metal material in a solid-liquid coexisting state. A method for producing a metal material in a solid-liquid coexistence state, which comprises a cooling step as described below. However, the technology described in Patent Document 3 requires equipment for applying an electromagnetic field. This equipment is large and requires cost and space. In addition, a time for applying the electromagnetic field is required, and the processing time becomes longer.

Disclosure of the invention

Problems to be solved by the invention

[0010] The present invention has been made to eliminate the above problems.

An object of the present invention is to provide a method for producing a semi-solid metal slurry that does not require large-scale equipment, can be processed in a short time, and can form a molded product having a fine and homogeneous structure. With the goal.

Means for solving the problem [0011] In the method for producing a semi-solid metal slurry according to the present invention, the molten metal is placed in a container or a sleeve.

(Hereinafter referred to as “container etc.”) is characterized in that when the metal is poured into the inside of the container, the metal is supercooled and self-stirring occurs in the container.

[0012] In the method for producing a semi-solid metal slurry of the present invention, a predetermined kinetic energy is applied to the molten metal, the molten metal is poured into a cooling container or the like maintained at a low temperature, and the molten metal is brought into contact with the bottom of the container or the like at a high speed. The nucleus is generated without generating an initial solidification layer by the supercooling phenomenon that occurs, and then the molten metal itself is self-stirred to eliminate the temperature gradient of the molten metal in the container etc. and to a semi-solidified state. It is characterized by doing.

[0013] The energy for self-stirring is provided by mechanical energy or potential energy.

[0014] The mechanical energy is pressurizing energy. The pressurized energy is applied to the molten metal by applying pressure to the molten metal in a closed container, causing the molten metal to be ejected and poured into the container.

[0015] The kinetic energy is provided by dropping the molten metal from a predetermined height.

[0016] The difference (H) between the pouring position of the molten metal and the position of the bottom of the container or the like is defined as

It is characterized by pouring at least 3.5 times the diameter (D) such as m.

[0017] The difference between the height of the metal in the molten metal state and the bottom of the cooling vessel is more preferably 4 times or more the vessel diameter, and more preferably 5 times or more. 3. If it is less than 5 times, a dendrite-like structure may be formed depending on the conditions. By making it 4 times or more, a finer and more uniform structure can be obtained.

The upper limit is preferably 10 times. If it exceeds 10 times, depending on the pouring conditions, the hot water may flow, or air may be entrained, and the entrained air may suddenly expand, causing the hot water to dance. In addition, it becomes difficult to fill the molten metal without spilling.

[0018] The shape of the container and the like is set in consideration of thermal equilibrium and the like, and the inner diameter is preferably 10 mm to 200 mm, and more preferably 40111111 to 120111111. With such dimensions, a finer and more homogeneous structure can be obtained. When the inner diameter D is large, the poured hot water cannot move to the side, and it is difficult to perform sufficient thermal stirring. As a result, the particle size becomes finer or uniform. It is difficult to obtain oneness.

[0019] When the height (internal height) from the bottom to the head of a container or the like is h, for example, h = 3H

in

~ 10H may be designed. In this case, pouring can be performed near the head of the container,

Spills during hot water can be reduced. Conversely, for example, if you design h <H, hZ in

Since D can be reduced, gas entrapment during pouring can be reduced.

[0020] It is preferable that the container and the like are arranged vertically without tilting, and the molten metal is poured from the center without being along the side inner wall of the container and the like. In the past, pouring was carried out gently by tilting the container and the like so as to be along the inner wall. However, in the present invention, it is preferable that the molten metal is poured at a stretch without being along the side inner wall. Thereby, self-stirring tends to occur.

Further, it is preferable that the molten metal is poured directly into a container or the like without passing through a cooling member or the like.

[0021] Pouring time is also an important factor. The pouring time depends on the pouring amount, but is preferably 1 to: LO seconds. 3 to 8 seconds is more preferred. More preferably, 3 to 5 seconds. In consideration of mass productivity, the pouring time is shorter and more preferable, but if it is less than 1 second, it takes less time to stir in the container and the hot water is agitated! Cases arise. If it exceeds 10 seconds, the workability will deteriorate. In addition, when the time is 4 times, fresh hot water is poured into the entire semi-solidified state, and self-agitation is less likely to occur. The pouring amount is generally 200 cc to 3000 cc (for example, 540 to 8100 kg in the case of an aluminum alloy).

[0022] The bottom of the container or the like has a curved surface shape that is concave when viewed from the pouring side force.

[0023] It is preferable that the bottom of the cooling container has a concave curved shape when viewed from the side force at which the molten metal is poured. With a strong curved surface, the molten metal containing nuclei generated in contact with the bottom of the cooling vessel flows along the curved surface. That is, when the molten metal is poured into the center of the bottom of the container, the molten metal that has reached the bottom flows out of the container along the curved surface of the bottom. When the molten metal flows outside, it hits the wall of the container and flows again inside the container. Thereby, the convection of the molten metal is easily generated, so that the self-stirring is performed more quickly. As a result, a large number of the above nuclei are present inside, and a more uniform and fine crystal structure can be obtained.

As the curvature of the curved surface, if the inner diameter of the container is D, 0.5D to 3D is preferable.0.6D to 1 D is more preferred. Within this range, convection occurs more rapidly, vigorous self-stirring occurs, and the temperature becomes more uniform throughout the vessel.

[0024] It is characterized in that the molten metal is pressurized and poured.

As the temperature in the initial stage of pouring the molten metal, T (T + 100) is preferable.

And

T: Liquidus temperature of metal (° C)

And

τ: Initial temperature of molten metal (° c)

After the pouring, pouring is performed so as to satisfy the following equation.

Τ <Τ <Τ

S eq L

T: liquidus temperature of the metal

S

τ: solidus temperature of the metal

And

τ: Temperature when the temperature of the container etc. and the temperature of the metal become the same after pouring

eq

[0026] It is characterized in that the container and the like are kept in an insulated state.

Pouring is performed by setting the heat capacity of the container or the like to a predetermined value in accordance with the amount of heat of the metal in the molten state.

When the inside diameter, height, and material of the container and the like are constant, pouring is performed by setting the thickness to a predetermined value.

The container or the like is made of a non-magnetic material or a magnetic material. In the present invention, electromagnetic stirring is not performed. Therefore, the degree of freedom in selecting materials such as containers is widened. A method for producing a semi-solidified slurry according to any one of claims 1 to 20.

The container or the like is made of stainless steel or copper. In particular, a material having a higher thermal conductivity than stainless steel is preferred.

The filling time is preferably 1 to 10 seconds, which varies depending on the shape of the container and the amount of filling. 3-5 seconds is more preferred.と If the charging time is too short, self-stirring occurs. On the other hand, it is difficult for the flow to be uniform because the continuous flow is not too long.

The container or the like may be kept in a heat-insulated state.

[0027] The molding method of the present invention is characterized in that the semi-solid metal slurry produced by the method for producing a semi-solid metal slurry described in the above item 1 is molded.

[0028] A molded article of the present invention is formed by the molding method described above. [0029] The operation of the present invention will be described together with the knowledge obtained in making the present invention. The present inventor has searched for the reason why fine and uniform compositions are not always obtained in the techniques of Patent Documents 1 and 2.

[0030] In Patent Documents 1 and 2, generation of crystal nuclei due to the supercooling phenomenon is recognized. However, after the molten metal is poured into the container, the molten metal is not stirred in the container, so that the molten metal remains in a temperature gradient state. That is, the molten metal is poured into the container and the movement of the molten metal stops. As a result, even if the temperature on the container side is low and a large number of nuclei are generated, the slurry will be in a state where the temperature is high on the inside and the number of nuclei is small.

[0031] Particularly, in Patent Document 1, this tendency is remarkable because pouring is performed quietly for the purpose of preventing air from being entrained (and thus preventing the occurrence of gas cavities in molded products).

[0032] On the other hand, in the present invention, a fine and uniform (size of 100 to 150 m in which the variation in the particle size is small) is obtained by controlling the drop starting height.

Therefore, a predetermined kinetic energy is applied to the molten metal to generate nuclei without generating an initial solidified layer. Many nuclei generated at the bottom of the container by pouring are distributed to the entire container by self-stirring. In other words, the initial pouring metal having many nuclei moves in the container, so that the nuclei are uniformly distributed throughout.

[0033] Eventually, the molten metal is poured into the cooling vessel from a certain height and brought into contact with the bottom of the cooling vessel, thereby using a supercooling phenomenon to generate nuclei without generating an initial solidified layer. By dropping at a constant height force, potential energy is converted to kinetic energy. In a container, the kinetic energy of the molten metal is large! The molten metal moves around in the container until the kinetic energy disappears. Therefore, self-stirring occurs in the container. When the molten metal self-stirs, the temperature gradient of the molten metal in the container disappears, and the molten metal becomes a semi-solid state throughout. As a result, a slurry in which many nuclei are uniformly distributed is obtained.

[0034] However, in order to generate self-stirring by giving potential energy and converting it to kinetic energy, it is not only necessary to pour high potential force. The present inventor has found that there is a factor other than the height, and when exploring it, has found that the ratio to the diameter of the container is important. In other words, by setting the ratio of diameter to height to 3 or more, It has been found that stirring occurs favorably.

[0035] The temperature of the container or the like is generally preferably from room temperature to 100 ° C, but varies depending on the type of metal, the temperature of the molten metal, and the like. The temperature may be a temperature at which a cooling phenomenon occurs when the molten metal is poured. What is necessary is just to check in advance corresponding to the metal used by experiment etc.

[0036] In the present invention, for example, BN spray may be applied to the surface of the container to generate nuclei.

Conventionally, a BN spray is applied to a container to increase the releasability. In the present invention, the BN spray is applied to generate nuclei.

[0037] When the molten metal is poured into the container, nuclei are also generated on the surface of the hot water in the container. In this case, if new hot water is poured so as to pour onto the surface, the core of the surface is mixed into the entire container by the energy of the newly poured hot water (kinetic energy of the molten metal).

[0038] In the present invention, the molten metal temperature is kept substantially uniform by forced convection at the time of filling. In addition, since the inside surface of the cup is constantly washed with molten metal, many nuclei are generated and the force grows spherically.

In order to make the molten metal temperature uniform, it is important to control the temperature in the thermal equilibrium state after pouring. Hereinafter, this point will be described in detail with reference to FIG.

[0039] When the molten metal 1 is poured into a cup (container or the like) 2) (Fig. 1 (a)), the heat of the molten metal 1 starts to move to the cup 2 (Fig. L (b)). Accordingly, the initial temperature T of the molten metal decreases and the initial temperature T of the cup rises.

c m Ascend. It is thought that when the temperature of the molten metal and the cup become the same, heat transfer stops and the temperature does not change any more.) Fig. 1 (c)).

The temperature T at this time (hereinafter called the equilibrium temperature) is given by the following equation.

[0040] Here, T is the initial temperature of the molten metal, T is the initial temperature of the cup, and H 'is the solidification latent heat divided by the specific heat.

c m f

Where f is the solid fraction. Γ is the heat required to raise the cup temperature by 1K s

The amount is divided by the amount of heat required to raise the temperature of the molten metal by 1 K, and is given by the following equation. 7 = ^--(2) where p is density, c is specific heat, V is volume, subscript c is for molten metal, and subscript m is for cup.

As is clear from the equations (1) and (2), the equilibrium temperature T (or the obtained solid fraction) is determined by the cup eq

And the value of γ, which is the ratio between the initial temperature of the molten metal and the heat capacity of the cup and the molten metal. However, the relationship between the solid fraction and the temperature must be investigated in advance. Further, if the materials of the cup and the molten metal are specified from the equation (2), it is apparent that y is determined only by the volumes of the cup and the molten metal.

Now, when T satisfies the following equation,

eq

T <T <Τ 3)

s eq L

The molten metal in the cup is kept in a semi-solid state.

Actually, the cup surface and the surface power are directed to the atmosphere and the heat escapes, so the temperature should be lower than T obtained by Eq. (1). By insulating the outer surface of the cup (1) Where eq

A temperature close to the given T is reached.

eq

[0042] Heat insulation may be performed by covering the outside of the cup with a heat insulating material.

The actual temperature reached is expressed by the following equation.

α Τ (0 <α <1) 4)

eq

a is a correction coefficient obtained from an experiment, and may be obtained in advance by an experiment in accordance with actual implementation conditions.

For example, if the cup shape is a cylinder with inner diameter: D, inner height: H, and wall thickness: t (constant)

V = π (D / 2) ¾-(5)

V = π (D / 2 + t) ² (h + t) -V

_{1 +} + unit 1 1 (6)

V., D)

From Equations (1) and (6), if the inner diameter D and the inner height h of the cup are fixed, the equilibrium temperature T is given by Determined only by initial temperature of molten metal and cup eq

I will get over. From the above, given the initial temperature of the molten metal and the cup, the material, amount, solid phase ratio and the corresponding temperature T of the semi-solid to be produced, (1), (2), (3), (4), (6) The required thickness of the cup can be obtained from the formula.

From the above, it is possible to produce a semi-solid having a desired solid phase ratio. In order to crystallize fine primary crystals having a uniform solid phase ratio in a force cup, a sufficient pouring height is required. This is very important.

In other words, when the molten metal is sufficiently stirred in the S cup, nucleation occurs sufficiently on the cup wall and molten metal surface where the temperature difference between the cup wall and the center of the cup is small, and its growth is suppressed. The conditions can be fulfilled.

As a material for the container and the like, it is preferable to use a material having good thermal conductivity such as stainless steel or copper.

As described above, the shape of the container and the like is set in consideration of the thermal equilibrium and the like. With such dimensions, a finer and more homogeneous structure can be obtained.

Hereinafter, specific examples of changes in fs when the degree of superheat of the molten metal is constant and when the thickness t of the cup is constant are shown. Here, α in Eq. (4) was set to 1.

(Condition)

Melt: AC4C

T = 612 ° C

L

T = 555 ° C

.H, = H / C

f f

= 413 / K

Cup: stainless steel

Wall thickness t

Cylindrical shape Cup inner diameter D

Cup height h

C = 500J-kg-k

m

T = 25 ° C

= 7700 X 500/2710 X 963

= 1.48

One _

: Then, the relationship between temperature and solid fraction is evaluated by the following equation.

(7)

When the above result is substituted into equation (1), f is given by the following equation.

s

f = (587 · γ-δΤ) / (413+ (1+ γ)-57) — (8) where δΤ = Τ -Τ and the superheat.

And

A calculation example in which D, t, h, and the like are specified values is shown below.

場合 When overheating is constant

D = 60mm

h = 150mm

δΤ = 50 (Κ)

t (mm) fs (%)

13

2 17

3 31

4 45

5 60

6 74 [0049] 場合 When the wall thickness is constant

D = 60mm

t = 4mm

6 T (k) fs (%)

0 56

10 54

20 52

50 45

100 35

The invention's effect

According to the present invention, the following effects are achieved.

Does not require large equipment.

It is possible to make a semi-solid slurry in a short time.

A molded article having a fine and homogeneous structure can be formed.

A semi-solid metal slurry can be produced without being limited to the type of the target metal 'composition.

That is, material selectivity can be expanded. It can be applied to iron alloys, aluminum alloys, magne alloys and other alloys. Also, in the case of aluminum alloys, conventionally, only AC4C alloy can be used for semi-solid molding, but in the present invention, it is also applicable to ADC10 alloys which were conventionally considered to be practically inapplicable. . For example, semi-solid molding is possible even for an alloy having a composition near the eutectic point.

[0051] Semi-solid molding can be performed without being limited by the temperature of the molten metal. In the past, a precise temperature was required, which required a complicated control system. However, the present invention does not require the installation of a powerful and complicated control system, so that the system can be simplified.

[0052] Conventionally, in order to refine the crystal, a refiner (for example, Ti, B, etc.) is added, but the crystal is refined without using a powerful refiner. be able to. Needless to say, in the case of adding a finer material also in the present invention, further finerness is achieved. Furthermore, it is possible to easily control the solid fraction by performing heat balance. Become.

Brief Description of Drawings

FIG. 1 is a conceptual diagram showing a thermal equilibrium state.

FIG. 2 is a perspective view of a container used in Example 1.

FIG. 3 is a graph showing a temperature measurement result in Example 1.

FIG. 4 is a photomicrograph of a molded product using the semi-solid product produced in Example 1.

FIG. 5 is a side view showing a pouring method according to Embodiment 2.

FIG. 6 is a graph showing the relationship between the crystal grain size and HZD in Example 3.

m

FIG. 7 is a photomicrograph of Test No. 3 in Example 3.

FIG. 8 is a micrograph of Test No. 4 in Example 3.

Explanation of symbols

[0054] 1 Molten metal

2 containers (cups)

10 plunger

BEST MODE FOR CARRYING OUT THE INVENTION

[0055] In the embodiment of the present invention, the molten metal poured into the container or the like is agitated without applying an electromagnetic field from the outside so as not to form an initial solidified layer, and the molten metal is poured into the container or the like. It is to be poured. The molten metal poured into the container is cooled to form a solid-liquid coexisting metal material to produce a semi-solid metal slurry.

An embodiment of the present invention will be described below with reference to the drawings.

Example 1

Using the container shown in FIG. 2, pouring was performed under the following conditions.

Melt material: AC4CH

T = 610-612. C

s

T = 555 ° C

And

Initial temperature of molten metal: 670 ° C

Cup thickness t: 3mm Cup material: SUS304

Cup inner diameter D: 60mm

Cup height h: 150mm

Cup initial temperature: 5 ° C

Pouring height H: 550mm (Pouring from 400mm above cup top)

in

H / D = 9.1

in

Recording time: 8 seconds

Cup insulation: Yes (not shown)

Pouring time: 5 seconds

From the pouring straightness, the temperature change in each part was measured. Figure 3 shows the results. As can be seen from Fig. 3, the temperature attained by equilibrium is about 590 ° C, which is maintained between T and T.

And

FIG. 4 shows a micrograph of a molded product molded from the semi-solid obtained in this example. As can be seen from FIG. 4, the microstructure of the molded article obtained in this example has fine primary crystals uniformly present throughout.

Example 2

In FIG. 5, the bottom plunger tip 10 of the container 2 is arranged, and the tip of the plunger tip has a curved surface having a curvature. The curved surface has a concave shape when viewed from the pouring side.

The curved surface had a curvature of R = 70 mm.

The container was poured.

The pouring conditions were the same as in Example 1.

Molding was performed using the semi-solidified slurry obtained in this example, and the structure of the molded article was observed. As a result, a finer and more uniform structure was obtained than in Example 1.

In the above-described embodiment, the same effects as in the above-described embodiment can be obtained, even if the molten metal is the force shown in the example of the aluminum alloy.

Example 3

In the present example, pouring was performed by changing H ZD.

m

H: Pouring height

in

D: Inner diameter of container Other points were the same as in Example 1.

Test No. H / Ό

in Yui '

1 1 3

2 2 2.8

3 3 2.7

4 3.5.2.3

5 4 1.5

6 5 1.2

7 7 1. 1

8 8 1

9 9 1

10 10 0.9

11 11 Water

*: The crystal grain size (spherical primary crystal size) shows the relative value of the crystal grain size based on Test No. 9 (1).

*: Air entrainment occurred.

Figure 6 shows the relationship between the above crystal grain size and HZD. Test No. 4 and Test No. 5

m

The micrographs are shown in FIGS. 7 and 8, respectively.

As shown in the figure, if the H / D is 4 or more, show an excellent organization

m

Yes.

Example 4

In this example, the influence of the initial temperature of the molten metal was examined.

In this example, AC4CH was used. However, the liquidus temperature of the material of this example is 617 ° C.

Include temperatures of 610 (-7), 620 (+3), 640 (+23), 655 (+38), 670 (+53), 680 (+63), 700 (+83), 720 (+ The experiment was carried out by changing the temperature to 103) and 730 (+113) ° C. The value in parentheses is the difference from the liquidus temperature.

Other conditions were the same as in Example 1.

As the temperature was increased, the crystal grain size became smaller. However, it peaked at 700 ° C, and showed a tendency of saturation or a slight decrease at higher temperatures.

Example 5

[0062] In this example, the pouring time was changed.

Other points were the same as in Example 1.

No. Pouring time (sec) Crystal grain size

4- 1 0.5 0.20 △

4-2 1 1.3 〇

4-3 2 1 〇

4-4 3 1 ◎

4-5 4 1 ◎

4-6 5 1 ◎

4-7 6 1 ◎

4-8 7 1 〇

4-9 8 1 〇

4- 10 9 1 〇

4- 11 10 1.4 〇

4- 12 11 1.5 △

4- 13 12 1.6 △

*: The crystal grain size (spherical primary crystal size) indicates the relative value of the crystal grain size with reference to Sample No. 4-6 (1).

**: The uniformity of the structure is indicated by 〇 when the non-uniformity including segregation is large, and 力 when the strength is large, based on Sample No. 4-6 as the standard (（).

Example 6

In this example, the ratio (tZD) between the thickness of the container and the inner diameter D in Example 1 was changed.

When tZD was 0.01 to 0.08, a finer and more uniform crystal structure was obtained than in other cases.

In particular, the tendency was remarkable when the diameter D force of the container was 40 to 120 mm.

Claims

The scope of the claims

[I] When molten metal is poured into a container or a sleeve (hereinafter referred to as “container or the like” t), the metal is poured so that self-stirring occurs in the container or the like. A method for producing a semi-solid metal slurry.

[2] By applying a predetermined kinetic energy to the molten metal, pouring the molten metal into the container, etc., and contacting the inner wall of the container, etc. at high speed, without generating an initial solidified layer due to the supercooling phenomenon that occurs. A method for producing a semi-solid metal slurry, wherein nuclei are generated, and subsequently, the molten metal itself is self-stirred to eliminate a temperature gradient of the molten metal in the container or the like to be in a semi-solid state.

3. The method for producing a semi-solid metal slurry according to claim 1, wherein the energy for the self-stirring is given by mechanical energy or potential energy.

4. The method for producing a semi-solid metal slurry according to claim 3, wherein the mechanical energy is pressurizing energy.

5. The method for producing a semi-solid metal slurry according to claim 3, wherein the potential energy is given by dropping the molten metal from a predetermined height.

[6] The difference in height (H) between the metal in the molten state and the bottom of the container or the like is calculated as the diameter (D) of the container or the like.

m

3. The method for producing a semi-solid metal slurry according to claim 5, wherein the molten metal is poured five times or more.

[7] The method for producing a semi-solid metal slurry according to claim 6, wherein HZD is 4 to 11.

m

Law.

[8] The method for producing a semi-solid metal slurry according to claim 6, wherein HZD is 5 to 10.

m

Law.

[9] The method for producing a semi-solidified slurry according to any one of claims 1 to 8, wherein the diameter of the container or the like is 10 to 200 mm.

10. The method for producing a semi-solid slurry according to claim 9, wherein the diameter of the container or the like is 40 to 120 mm.

[II] The method for producing a semi-solidified slurry according to any one of claims 1 to 10, wherein the molten metal is directly poured into a container or the like.

[12] The method for producing a semi-solidified slurry according to any one of claims 1 to 11, wherein the filling time is 1 to 10 seconds.

13. The method for producing a semi-solidified slurry according to claim 12, wherein the filling time is 3 to 5 seconds.

14. The method for producing a semi-solid metal slurry according to claim 1, wherein a bottom of the container or the like has a concave curved shape when viewed from a pouring side.

15. The method for producing a semi-solid slurry according to claim 14, wherein the radius of curvature of the concave curved surface shape is 0.5D to 3D. Here, D is the inner diameter of the container or the like.

16. The method for producing a semi-solid slurry according to claim 15, wherein a radius of curvature of the concave curved surface shape is 0.6D to 1D.

[17] The molten metal according to any one of [1] to [16], wherein the molten metal is pressurized and poured.

2. The method for producing a semi-solid metal slurry according to claim 1.

[18] The semi-coagulant according to any one of claims 1 to 17, wherein T <(T + 100).

And

How to make a solid slurry.

Τ: Liquidus temperature of metal (° C)

And

τ: Initial temperature of molten metal (° c)

[19] The method for producing a semi-solidified slurry according to any one of claims 1 to 18, wherein pouring is performed after the pouring so as to satisfy the following equation.

Τ <Τ <Τ

S eq L

T: liquidus temperature of the metal

And

τ: solidus temperature of the metal

S

τ: Temperature when the temperature of the container etc. and the temperature of the metal become almost the same after pouring

eq

20. The semi-solidified slurry production according to claim 17, wherein the pouring is performed by setting a heat capacity of the container or the like to a predetermined value in accordance with a heat amount of the metal in the molten state. Method.

[21] When the inside diameter, height, material, and initial temperature of the container and the like are constant, pouring is performed by setting the wall thickness to a predetermined value so as to maintain a thermal equilibrium state. 21. The method for producing a semi-solidified slurry according to claim 20, wherein:

[22] The method for producing a semi-solidified slurry according to claim 21, wherein t / D is set to 0.01 to 0.08. t is the thickness of the container or the like.

23. The method for producing a semi-solid slurry according to claim 1, wherein the container or the like is made of a non-magnetic material or a magnetic material.

[24] The method for producing a semi-solidified slurry according to any one of claims 1 to 23, wherein the container or the like is made of stainless steel or copper.

[25] The method for producing a semi-solidified slurry according to any one of claims 18 to 24, wherein the container and the like are insulated from the outside.

[26] A molding method characterized by molding a semi-solid metal slurry produced by the method for producing a semi-solid metal slurry according to any one of claims 1 to 26.

[27] A molded article formed by the molding method according to claim 26.