JPH05237612A - Production of partially solidified slurry - Google Patents

Abstract

PURPOSE:To improve the quality of a partially solidified slurry and stock formed with the partially solidified slurry, in a method for producing the partially solidified slurry by stirring the molten metal with electromagnetic force in a rotating magnetic field. CONSTITUTION:The molten metal 14 is poured into a mold 2 and stirred by the electromagnetic force of a stator coil 5 in the condition of contacting with a closing member 12 on the surface of the molten metal 14 to form the partially solidified slurry. Further, when the solid phase ratio of the slurry becomes a prescribed value, the closing member 12 is lowered to push out the slurry from a push-out hole 6.

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 thixotropic semi-molten slurry by stirring molten metal with an electromagnetic force by a rotating magnetic field.

[0002]

2. Description of the Related Art As a method for producing a metal material having an increased toughness by densely forming a metal composition, for example, Japanese Patent Application Laid-Open No. 55-117556 discloses that a metal material is formed outside a mold A 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, and a molten metal D poured into the mold A.
By applying a rotating magnetic field by the stator coil C to the molten metal D, the molten metal D is agitated by electromagnetic force in the course of solidification, and dendrites (dendritic crystals) generated from the molten metal D are sheared by the flow of the metal. A technique is disclosed in which a semi-molten metal slurry having good thixotropy by spheroidizing is manufactured, and the slurry E is drawn from the lower part of a mold to continuously cast a raw material E.

[0003]

By the way, according to the above-mentioned method for producing the semi-molten metal slurry, when the molten metal D is stirred, the air flowing into the molten metal or the semi-molten metal slurry is generated by the vortex flow generated by the stirring. There is a risk that entrainment will occur and it will be difficult to obtain a good quality slurry. Also, mold A
Is cooled by the cooling jacket B, the preceding solidification of the molten metal occurs along the mold wall a in the process of pouring the molten metal into the mold, and the solidified shell by this is not subjected to the above stirring action. As a result of being formed on the surface of the material and pulled out, the quality of the material surface is deteriorated due to the non-uniformity of the structure between the material surface and the inside of the material slurried by the stirring action. Furthermore, since the casting of the material E is performed while pouring the molten metal into the mold A and sequentially forming the slurry, it is difficult to cast the material by extracting the slurry at a desired solid fraction. However, the solid phase particle size of the metal in the slurry is limited, and the toughness of the material tends to be poor.

Therefore, an object of the present invention is to provide a method for producing a semi-molten slurry capable of obtaining a high-quality material having a uniform metal structure.

[0005]

That is, the invention according to claim 1 of the present invention (hereinafter referred to as the first invention) is a method of stirring a molten metal by a rotating magnetic field generated by a magnetism generating means to semi-melt it. A method for producing a slurry, comprising pouring the molten metal into a mold and stirring the molten metal with the rotating magnetic field in a state where a blocking member is in contact with the surface of the molten metal, whereby the semi-molten slurry has a predetermined size. The semi-molten slurry is extruded from the bottom of the mold by the closing member when the solid phase ratio is reached.

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

The invention according to claim 3 (hereinafter, referred to as the third
(Referred to as an invention), a stirring blade is provided on the lower surface of the closing member.

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

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

[0010]

According to the first aspect of the present invention, since the molten metal in the mold is agitated while being held by the closing member, air contact with the molten metal can be eliminated, and the contraction amount due to solidification of the molten metal can be eliminated. Since the blocking member can be lowered to maintain the above contact state, entrapment of air in the molten metal and the semi-molten combined slurry can be eliminated.

Moreover, since the semi-molten slurry is extruded from the mold by the closing member when the semi-molten slurry reaches a predetermined solid phase rate, the solid phase particle size can be adjusted by selecting the extrusion time.

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

Further, according to the second aspect of the present invention, the semi-molten slurry is extruded from the extrusion port having a diameter smaller than the inner diameter of the mold to mold the raw material, so that the solidified shell generated on the inner wall of the mold during pouring is of the raw material. 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 rushes into the agitated molten metal or semi-molten slurry to generate a turbulent flow, so that an agitating effect is obtained. In particular, in the fourth aspect of the invention, the stirring effect is further increased by rotating the stirring blade in the direction opposite to the stirring direction by the electromagnetic stirring.

According to the fifth aspect of the invention, since the material is cast by extruding the semi-molten slurry while maintaining the stirring state, the metal composition of the semi-molten slurry obtained by shearing the dendrite can be restored. Disappear.

[0016]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 illustrates a method of manufacturing a semi-molten slurry according to a first embodiment of the present invention. A cylindrical mold 2 made of a non-magnetic material and provided with a lining material 1 made of a heat insulating material is used. A stator coil (for example, one equivalent to a stator coil of a four-pole three-phase induction motor) 3 for generating a rotating magnetic field is coaxially arranged on the outside of the mold 2.
A container 4 is provided so as to surround the stator coil 3.

Further, in the above-mentioned mold 2, a die 5 is attached to the lower end opening of the mold 2, and an extrusion port 6 having a diameter smaller than the inner diameter of the mold 2 is formed at a position corresponding to the center of the mold of the die 5. 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 is provided around the outer surface of the casting mold 2, and a cooling water nozzle 9 that opens at a portion of the extrusion port 6 is provided on the die 5. The cooling water is supplied to the cooling water nozzle 9 through the pipe 10.

Further, a lid-shaped closing member 12 which is moved up and down by a hydraulic cylinder 11 is provided on the upper portion of the casting mold 2, and the closing member 112 is lowered when the closing member 112 is lowered.
Is configured so as to rush into the mold and be removed from the mold 2 when the mold is raised, and a molten metal supply for pouring a molten metal such as aluminum or its alloy into the mold 2 in the removed state. A gutter 13 is provided. Note that FIG.
In FIG. 1, the molten metal supply gutter 13 is located on the closing member 12 in a state where the upper end of the mold is closed and is located at a position that hinders the rise of the closing member 12. In order to clarify the existence of the above, the pouring means 13 actually comes to the chain line position in a state where the closing member 12 is raised.

In the production of the semi-molten metal slurry, cooling water is passed through the cooling water pipe 8 to cool the mold 2 for solidifying the molten metal, and the extrusion port 6 of the die 5 is covered with the lid member 7. The molten metal 14 is poured into the mold 2 from the melt supply gutter 13 in a state in which it is closed and the closing member 12 is pulled out upward from the mold 2.

After completion of the pouring, the closing member 12 descends and is set in contact with the top surface of the molten metal 14 poured as shown in FIG. While the molten metal 14 solidifies in this state, the molten metal 14 is agitated by the electromagnetic stirring force of the rotating magnetic field of the motor stator 3, and is generated by the shearing of the dendrites into a semi-molten metal slurry having a thixotropic property. 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 above cooling and stirring, as shown in FIG. 2, from the extrusion port 6 of the die 5 to the lid member 7. And the closing member 12 is moved down by the action of the hydraulic cylinder 11, the semi-molten metal slurry is extruded from the extrusion port 6 by the extrusion force accompanying the downward movement, and the material 15 having a cross-sectional shape determined by the shape of the extrusion port 6 is removed. Is cast into. Further, at the time of the extrusion, the cooling water is sprayed from the cooling water nozzle 9 onto the surface of the material to promote cooling.

Thus, the molten metal 1 in the mold 2
Agitation of 4 to semi-molten metal slurry results in
Since it is performed with the closing member 12 in contact with the upper surface of the, the 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 is always in contact with the surface of the molten metal 14 to eliminate air contact. It is possible to control so as to maintain the above contact state by lowering the closing member 12 by the amount of contraction due to the solidification. Therefore, a good quality slurry or material 15 in which air bubbles are not mixed in the internal structure can be obtained. At the same time, the closing member 12
Will serve to prevent the molten metal 14 from overflowing from the upper portion of the mold 2 and being washed away by the centrifugal force caused by stirring.

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

By the way, 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. The electromagnetic stirring force does not act on the shell, and the texture becomes nonuniform with respect to the portion that receives the stirring force and is slurried, and the quality of the obtained material deteriorates. However, since the casting of the material 15 by the extrusion of the semi-molten metal slurry is performed by 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 generated along the inner surface of the mold is formed. Is not included in the material 15 extruded from the extrusion port 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.
The semi-molten metal slurry is forcibly extruded by being driven by, so the material 1 according to the shape of the extrusion port 6
5 can be molded, which makes it possible to manufacture a modified cross-section material.

FIG. 3 shows a manufacturing method according to the second embodiment of the present invention, in which a plurality of stirring blades 16 to 16 are radially provided on the lower surface of the closing member 112, and a rotation for supporting the closing member 112. A gear 18 is attached to the shaft 17, and a rotational force of a motor 20 is input to a drive gear 19 meshing with the gear 18 via a speed reducer 21.
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 of the rotating force of the electromagnetic force and the rotating force of the stirring blades 16 to 16, and the stirring force equivalent to the stirring force is applied to the stator. Compared to the case where the magnetic field is generated only by the coil 3, the power consumption of the stator coil 3 can be significantly reduced.

Further, even if the stirring blades 16 to 16 are not rotated, but they are simply thrust into the molten metal 14,
Since the molten metal 14 collides with the stirring blades 16 to 16 and a turbulent flow is generated as the molten metal 14 is rotated by the electromagnetic force, the stirring force can be increased almost in the same manner 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. 1 as described above. It is desirable that the rotary shaft 17 is allowed to move up and down by spline fitting so that the rotational force of the drive gear 19 is surely transmitted to the rotary shaft 17 via the gear 18.

As the molten metal used in the method for producing the semi-molten metal slurry of the present invention, copper and its alloys, iron and its alloys are considered in addition to the above-mentioned aluminum, 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 by the closing member, it is possible to eliminate air contact of the molten metal and to melt the molten metal. Since the amount of contraction due to solidification of the metal can be lowered to maintain the contact state by lowering the blocking member, entrapment of air into the molten metal or the 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.

Moreover, when the semi-molten slurry reaches a predetermined solid phase rate, the semi-molten slurry is forced out of the mold by the closing member, so that the solid phase particle size can be adjusted by selecting the extrusion time. In particular, it is possible to improve the toughness of the above material by making the crystal grains finer.

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

Further, since the semi-molten slurry is extruded from the extrusion port having a diameter smaller than the inner diameter of the mold to mold the material, the solidified shell formed on the inner wall of the mold during pouring should be formed on the surface of the material to be extruded. And a high quality material with a uniform structure can be obtained.

Further, the stirring blade provided on the closing member is rushed into the molten metal or the semi-molten slurry to generate a turbulent flow to increase the stirring effect, and the stirring blade is stirred in the stirring direction by electromagnetic force. By rotating in the opposite direction, the stirring effect can be increased. Therefore, the power consumption of the induction motor that produces the electromagnetic force can be reduced.

In addition, since the material is cast by extruding the semi-molten slurry 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 material. The production of can be stabilized.

[Brief description of 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 cross-sectional view showing an operating state of the slurry manufacturing apparatus.

FIG. 3 is a schematic sectional view of a slurry manufacturing apparatus for explaining a method of 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]

 2 Mold 3 Stator Coil 5 Die 6 Extrusion Port 12, 112 Closing Member 14 Molten Metal 15 Material 16 Stirring Blade

Claims (5)

[Claims] 1. A method for producing a semi-molten slurry by stirring molten metal with a rotating magnetic field generated by a magnetic generating means, comprising pouring the molten metal into a mold and closing the surface of the molten metal. It is characterized in that the members are agitated by the rotating magnetic field in a state of being in contact with each other, and the semi-molten slurry is extruded from the bottom of the mold by the closing member when the semi-molten slurry reaches a predetermined solid phase ratio by the agitation. Method for producing semi-molten slurry. 2. The production of a semi-molten slurry 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 to extrude the semi-molten slurry 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 the 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 the 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 the mold by a closing member while stirring the semi-molten slurry.