JP3027260B2 - Method for producing semi-solid slurry - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a semi-solid semi-solid slurry having thixotropic properties by stirring a molten metal by electromagnetic force generated by a rotating magnetic field.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Sho 55-117556 discloses a method of manufacturing a metal material having a high toughness by forming a metal composition densely, as shown in FIG. A cooling jacket B for cooling the mold A and a stator coil C corresponding to an induction motor for generating a rotating magnetic field are provided.
The molten metal D is agitated by electromagnetic force in the process of solidifying by applying a rotating magnetic field generated by the stator coil C to shear the dendrite (dendrites) generated from the molten metal D by the flow of the metal. A technique is disclosed in which a semi-molten metal slurry having good thixotropy is produced by spheroidization and the slurry is drawn out from the lower part of the mold to continuously cast the material E.

[0003]

According to the method for producing a semi-molten metal slurry described above, when the molten metal D is stirred, air is introduced into the molten metal or semi-molten metal slurry by the vortex generated by the stirring. May occur, making it difficult to obtain a high quality slurry. Also, mold A
Is cooled by the cooling jacket B, so that the molten metal is poured into the mold, and the preceding solidification of the molten metal occurs along the mold wall a, so that the solidified shell is not subjected to the above-mentioned stirring action. As a result of being formed on the surface of the material and being pulled out, the quality of the material is deteriorated due to non-uniform structure between the surface of the material and the inside of the material slurried by the stirring action. Furthermore, since the casting of the raw material E is performed while pouring a molten metal into the mold A and sequentially forming a slurry, it is difficult to cast the raw material by extracting the slurry at a desired solid phase ratio. However, the size of the solid phase particles of the metal in the slurry was limited, and the toughness of the raw material was lacking.

Accordingly, an object of the present invention is to provide a method for producing a semi-molten slurry in which a high-quality material having a uniform metal structure can be obtained.

[0005]

That is, the invention according to claim 1 of the present invention (hereinafter referred to as the first invention) is characterized in that a molten metal is agitated by a rotating magnetic field generated by a magnetic generating means to semi-molten. A method for producing a slurry, wherein the molten metal is poured into a mold, and the molten metal is stirred by the rotating magnetic field in a state where a closing member is in contact with the surface of the molten metal. The semi-solid slurry is extruded from the bottom of the mold by the closing member when the solid phase ratio reaches

Further, the invention according to claim 2 (hereinafter referred to as “second
The present invention is characterized in that an extrusion port having a diameter smaller than the inner diameter of the mold is provided at the bottom of the mold, and the semi-molten slurry is extruded from the extrusion port.

[0007] The invention according to claim 3 (hereinafter referred to as "third")
The invention is characterized in that stirring blades are provided on the lower surface of the closing member.

Further, the invention according to claim 4 (hereinafter referred to as the fourth invention)
The invention is characterized in that the closing member is rotated in a direction opposite to the stirring direction by the rotating magnetic field.

Further, the invention according to claim 5 (hereinafter referred to as a fifth invention) is characterized in that the semi-molten slurry is extruded from the mold by a closing member while stirring.

[0010]

According to the first aspect of the present invention, the molten metal in the mold is stirred while being held down by the closing member, so that the molten metal can be prevented from coming into contact with the air and the shrinkage due to the solidification of the molten metal can be reduced. Since the above-mentioned contact state can be maintained by lowering the closing member, the entrapment of air into the molten metal and the semi-molten mixed slurry can be eliminated.

Moreover, when the semi-molten slurry reaches a predetermined solid phase ratio, the semi-molten slurry is extruded from the mold by the closing member, so that the size of the solid phase particles can be adjusted by selecting the extrusion timing.

Further, since the raw material is cast from the semi-molten slurry by extrusion by the above-mentioned closing member, it is possible to manufacture a raw material having an irregular cross section.

According to the second aspect of the present invention, since the semi-molten slurry is extruded from the extrusion port having a diameter smaller than the inner diameter of the mold to form the material, the solidified shell formed on the inner wall of the mold at the time of pouring becomes less solid. It can be prevented from being formed on the surface.

Further, according to the third and fourth aspects of the present invention, the stirring blade provided on the closing member enters the inside of the molten metal or semi-molten slurry to be stirred to generate a turbulent flow. In particular, in the fourth invention, the stirring blade rotates in the direction opposite to the stirring direction by the electromagnetic stirring, so that the stirring effect is further increased.

According to the fifth aspect of the present invention, since the casting of the material by extrusion of the semi-molten slurry is performed while maintaining the stirring state, the metal composition of the semi-molten slurry obtained by shearing the dendrite may return to the original state. Disappears.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 illustrates a method for producing a semi-molten slurry according to a first embodiment of the present invention. A non-magnetic and cylindrical mold 2 having an inner lining material 1 made of a heat insulating material is used. A stator coil (e.g., equivalent to a stator coil of a four-pole three-phase induction motor) 3 that generates a rotating magnetic field outside the mold 2 is provided coaxially,
A container 4 is provided surrounding the stator coil 3.

In the above-mentioned mold 2, a die 5 is attached to a lower end opening of the mold 2, and an extruding opening 6 having a diameter smaller than the inner diameter of the mold 2 is formed at a position corresponding to the center of the die. At the same time, a lid member 7 for opening and closing the extrusion port 6 is provided. Further, a cooling water pipe 8 around which the cooling water flows to be wound around the casting mold 2 is provided on the outer surface of the casting mold 2, and a cooling water nozzle 9 is provided in the die 5 at an extruding opening 6. The cooling water is supplied to the cooling water nozzle 9 through a pipe 10.

Further, a lid-like closing member 12 which is raised and lowered by a hydraulic cylinder 11 is provided on the upper part of the mold 2, and when the closing member 112 is lowered,
Is injected into the mold and is removed from the mold 2 when it is raised, and the molten metal supply for pouring a molten metal such as aluminum or an alloy thereof into the mold 2 in the removed state. A gutter 13 is provided. FIG.
In the figure, the molten metal supply gutter 13 indicated by a dashed line is located on the closing member 12 in a state in which the upper end of the mold is closed, and is at a position where the closing member 12 is prevented from rising. In order to clarify the existence of the water, the pouring means 13 comes to the dashed line position in a state where the closing member 12 is actually raised.

In the production of the semi-molten metal slurry, cooling water is passed through a cooling water pipe 8 to cool the mold 2 to solidify the molten metal, and the extrusion port 6 of the die 5 is covered with a lid member 7. And the closing member 12 is pulled out of the mold 2 upward, and the molten metal 14 is poured into the mold 2 from the molten metal supply trough 13.

After completion of the pouring, the closing member 12 is lowered and set in contact with the top surface of the poured molten metal 14 as shown in FIG. In this state, while the molten metal 14 is solidified, the molten metal 14 is stirred by receiving an electromagnetic stirring force by the action of the rotating magnetic field of the motor stator 3, and is formed into a thixotropic semi-molten metal slurry by shearing of the dendrite. Then, when a slurry having a predetermined solid phase ratio (for example, an intrinsic ratio of 0.4 to 0.6) is obtained by the cooling and stirring, as shown in FIG. And the closing member 12 is lowered by the action of the hydraulic cylinder 11, and the semi-molten metal slurry is extruded from the extrusion port 6 by the extrusion force associated with the lowering, and the material 15 having a sectional shape determined by the shape of the extrusion port 6. Cast into Further, at the time of the extrusion, the cooling water is sprayed from the cooling water nozzle 9 on the surface of the raw material to promote cooling.

Thus, the molten metal 1 in the mold 2
The stirring of the four to semi-molten metal slurry is
This is performed in a state where the closing member 12 is in contact with the upper surface of the device, so that entrainment of air due to the stirring is prevented. Further, with respect to solidification shrinkage due to cooling of the molten metal 14, the hydraulic cylinder 11 can be controlled so that the closing member 12 always contacts the surface of the molten metal 14, and air contact can be eliminated. It can be controlled so that the closing member 12 is lowered by the amount of contraction caused by the solidification of the above and the above-mentioned contact state is maintained. Therefore, a high quality slurry or material 15 in which air bubbles are not mixed into the internal structure can be obtained. At the same time, the closing member 12
Works to prevent the molten metal 14 from overflowing from the upper part of the mold 2 and flowing away due to centrifugal force accompanying the stirring.

Further, since the semi-molten metal slurry in the mold 2 is forcibly extruded by the closing member 12,
The extrusion can be performed at any solid fraction of the slurry, thus allowing for adjustment of solid phase particle size,
The material 15 having high toughness can be cast by reducing the particle size.

As the molten metal 14 is poured into the mold 2, solidification occurs on the inner surface of the mold 2 cooled by the cooling water. When such solidification occurs, the solidification occurs. No electromagnetic stirring force acts on the shell, and the shell undergoes non-uniformity with the portion that is slurried under the stirring force, thereby deteriorating the quality of the obtained material. However, since the casting of the raw material 15 by extrusion of the semi-molten metal slurry is performed at the extrusion port 6 having a diameter smaller than the inner diameter of the mold formed in the die 5 at the center of the mold, the solidified shell formed along the inner surface of the mold is formed. Are not included in the material 15 extruded from the extrusion opening 6. Therefore, a high-quality material 15 having a uniform metal structure can be obtained.

Further, the closing member 12 is connected to the hydraulic cylinder 11
And the semi-molten metal slurry is forcibly extruded, so that the material 1 according to the shape of the extrusion port 6 is used.
5, which makes it possible to produce a profiled material.

FIG. 3 shows a manufacturing method according to a second embodiment of the present invention, in which a plurality of agitating blades 16 to 16 are radially provided on the lower surface of a closing member 112, and a rotation supporting the closing member 112 is performed. A gear 18 is attached to the shaft 17, and the rotational force of a motor 20 is input to a drive gear 19 meshing with the gear 18 via a speed reducer 21.
At the time of stirring of 4, the closing member 112 and the stirring blades 16 to 16 are rotated in the direction a opposite to the stirring direction by the electromagnetic force.

According to this, the molten metal 14 receives a relatively large stirring force between the rotation force of the electromagnetic force and the rotation force of the stirring blades 16 to 16, and the same stirring force as the stirring force is applied to the stator. The power consumption of the stator coil 3 can be significantly reduced as compared to the case where the magnetic field is generated only by the coil 3.

Also, without rotating the above-described stirring blades 16 to 16, it is possible to simply make the stirring blades 16 to 16 protrude into the molten metal 14.
Since the molten metal 14 collides with the stirring blades 16 to 16 and generates a turbulent flow as the molten metal 14 rotates by the electromagnetic force, the stirring force can be increased substantially similarly, and the power consumption can be reduced.
By the way, the rotating shaft 17 of the closing member 112 moves up and down together with the closing member 112 by the operation of the hydraulic motor 11 shown in FIG. It is preferable that the rotation shaft 17 is allowed to move up and down by spline fitting, and at the same time, the rotation force of the drive gear 19 is reliably transmitted to the rotation shaft 17 via the gear 18.

As the molten metal used in the method for producing a semi-molten metal slurry of the present invention, copper and its alloys, iron and its alloys are conceivable, in addition to aluminum described above, and are particularly limited. is not.

[0030]

As is apparent from the above description, according to the present invention, since the molten metal is electromagnetically stirred while being held down by the closing member, air contact of the molten metal can be eliminated and the molten metal can be eliminated. Since the amount of shrinkage due to solidification of the metal and the closing state can be maintained by lowering the closing member, entrainment of air into the molten metal or semi-molten slurry can be eliminated, and a high-quality semi-molten slurry can be obtained. The quality of the material cast by the slurry can be improved.

Further, when the semi-molten slurry reaches a predetermined solid phase ratio, the semi-molten slurry is forcibly extruded from the mold by the closing member, so that the size of the solid phase particles can be adjusted by selecting the extrusion timing. In particular, it is possible to increase the toughness of the material by reducing the size of the crystal grains.

Further, since the raw material is cast from the semi-molten slurry by the pressure extrusion by the closing member, it is possible to manufacture the raw material having the irregular cross section.

Also, since the semi-molten slurry is extruded from the extrusion port having a diameter smaller than the inner diameter of the mold to form the material, the solidified shell formed on the inner wall of the mold at the time of pouring is formed on the surface of the extruded material. Can be prevented, and a high-quality material having a uniform tissue can be obtained.

Further, the stirring blade provided on the closing member is caused to protrude into the interior of the molten metal or semi-molten slurry to generate a turbulent flow, thereby increasing the stirring effect, and moving the stirring blade in the stirring direction by electromagnetic force. By rotating in the opposite direction, the stirring effect can be increased. For this reason, the power consumption of the induction motor that generates the electromagnetic force can be reduced.

In addition, since the casting of the raw material by extrusion of the semi-molten slurry is performed while maintaining the stirring action, the metal composition of the semi-molten slurry obtained by shearing the dendrite does not return to the original state, and the slurry or the raw material is not recovered. Production can be stabilized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a slurry manufacturing apparatus for explaining a method for manufacturing a semi-molten slurry according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an operation state of the slurry manufacturing apparatus.

FIG. 3 is a schematic sectional view of a slurry manufacturing apparatus for explaining a method for manufacturing a semi-molten slurry according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view of a slurry manufacturing apparatus for explaining a conventional method.

[Explanation of symbols]

 Reference Signs List 2 mold 3 stator coil 5 die 6 extrusion port 12,112 closing member 14 molten metal 15 material 16 stirring blade

Continuation of the front page (56) References JP-A-3-248743 (JP, A) JP-A-2-274345 (JP, A) JP-A 1-166857 (JP, A) JP-A 1-138045 (JP) JP-A-1-309766 (JP, A) JP-A-63-68251 (JP, A) JP-A-58-157558 (JP, A) JP-A-55-40004 (JP, A) 55-117556 (JP, A) JP-A-54-95924 (JP, A) JP-A-55-117555 (JP, A) JP-A-58-9572 (JP, A) JP-A-57-184555 (JP, A A) JP-A-1-19247 (JP, A) JP-A-1-13844 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B22D 27/02 B22D 11/00 B22D 11 / 115

Claims (5)

(57) [Claims] 1. A method for producing a semi-molten slurry by stirring a molten metal by a rotating magnetic field generated by a magnetic generating means, wherein the molten metal is poured into a mold and closed on a surface of the molten metal. Agitating by the rotating magnetic field in a state where the members are in contact with each other, and when the semi-molten slurry reaches a predetermined solid fraction by the agitation, the semi-molten slurry is extruded from the bottom of the mold by the closing member. A method for producing a semi-molten slurry. 2. The method according to claim 1, wherein an extrusion port having a diameter smaller than the inner diameter of the mold is provided at the bottom of the mold, and the semi-molten slurry is extruded from the extrusion port. Method. 3. The method for producing a semi-molten slurry according to claim 1, wherein a stirring blade is provided on a lower surface of the closing member. 4. The method for producing a semi-molten slurry according to claim 3, wherein the closing member is rotated in a direction opposite to a stirring direction by the rotating magnetic field. 5. The method for producing a semi-molten slurry according to claim 1, wherein the semi-molten slurry is extruded from a mold by a closing member while stirring.