JP2000317614A - Apparatus for continuously supplying semi-molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a apparatus for continuously supplying a semi-molten metal, by which the high quality semi-molten metal having the solid phase dispersed in granular state and, having high wear resistance can efficiently, stably, and continuously be supplied. SOLUTION: This apparatus is provided with a means 3 for supplying the molten metal 1 having the solid-liquid coexisting range into a cylinder 2, a temp. control means 4 arranged at the outer periphery of the cylinder 2 for cooling or heating the molten metal 1 supplied into the cylinder 2 in the temp. range of the semi-molten temp. or lower temp. by heating or cooling the outer peripheral wall of the cylinder 2 to adjust the cylinder temp., a stirring and transferring means 5 arranged in the cylinder 2 for continuously stirring and transferring the semi-molten metal in the cylinder 2, and a detecting means 6 arranged at the outlet part 2b of the cylinder 2 for detecting molten state of the semi-molten metal stirred and transferred to the outlet part 2b of the cylinder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously supplying a semi-molten metal used for die casting, metal injection molding and the like.

[0002]

2. Description of the Related Art In general, an injection molding machine is used to produce a product of a desired quality and shape from a solid metal material. This injection molding machine has a supply hopper that receives pellets of a suitable metal alloy at room temperature, an extruder that communicates with the supply hopper through a conduit in an inert gas atmosphere, and a cavity that communicates with the inside of the extruder. The extruder has a mold provided therein, and a rotatable screw is disposed inside the extruder. In order to manufacture a product using such an injection molding machine, first, pellets are supplied into the extruder from a supply hopper via a conduit, and then the screw of the extruder is rotationally driven to extrude the supplied pellets. While shearing. Along with this, the pellets have frictional contact and shearing action,
Further, the temperature rises due to the heat applied from the outside and the material is melted. In this state, an alloy product can be obtained by pressing the alloy raw material into the mold cavity from the tip of the extruder.

[0003]

However, in the above-mentioned conventional injection molding machine, if pellets of the alloy raw material are supplied to the inside of the extruder, the pellets may be sheared due to frictional contact with screws or frictional contact between metals. It has the advantage that the pellets can be maintained in a molten state only by heating from the outside of the extruder, but the screw for shearing the pellets is severely abraded and has a problem in durability. Was.

[0004] The present invention has been made in view of such circumstances, and an object thereof is to provide a high-quality semi-molten metal in which a solid phase is dispersed in a granular form, because of its high wear resistance, high efficiency and stability. It is an object of the present invention to provide a continuous supply device of semi-molten metal which can be supplied continuously by heating.

[0005]

The details are given in the claims. In order to solve the problems of the prior art, according to the present invention, there is provided a supply means for supplying molten metal into a cylinder, and a cylinder provided on an outer periphery of the cylinder for heating or cooling an outer peripheral wall of the cylinder. Temperature control means for cooling or heating the molten metal supplied into the cylinder to a semi-molten temperature or a temperature range lower than the temperature by adjusting the temperature, and provided in the cylinder, the semi-molten metal in the cylinder A stirring / transferring means for continuously stirring and transferring, and a detecting means provided at an outlet of the cylinder and detecting a molten state of the semi-molten metal stirred and transferred to the outlet of the cylinder are provided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. Here, FIG. 1 is a configuration diagram of a continuous supply device for semi-molten metal according to the first embodiment of the present invention,
FIG. 2 is an equilibrium diagram of the Al—Si alloy used in the continuous supply device, and FIG. 3 is a diagram of a temperature distribution in the cylinder by the temperature control means. In FIG. 2, a point a is a liquid phase, L is a liquidus line, S line is a solidus line, and a hatched line indicates a composition range of the alloy. Shown respectively. SC in FIG. 3 indicates the degree of supercooling. The degree of supercooling in this case refers to the difference between the solid phase temperature in the equilibrium diagram and the actual temperature lower than that. Point a in FIG. 2 corresponds to FIG.
Corresponds to the cylinder inlet.

As shown in FIG. 1, a continuous supply apparatus for semi-molten metal according to a first embodiment of the present invention is a molten metal 1 having a solid-liquid coexistence range, for example, an alloy of silicon (Si) and aluminum (Al). Supply means 3 for supplying the material into the inlet 2a of the cylinder 2, and heating or cooling of the outer peripheral wall of the cylinder 2 to adjust the cylinder temperature to semi-molten the molten metal 1 supplied into the cylinder 2. Temperature control means 4 as metal, stirring and transfer means 5 for continuously stirring and transferring the semi-molten metal in the cylinder 2, and melting state of the semi-molten metal stirred and transferred to the outlet 2b of the cylinder 2. And a molten state detecting means 6 for detecting the molten state.

[0008] The cylinder 2 is formed in a tapered bottomed cylindrical shape and is arranged substantially horizontally. An inlet 2a communicating with the supply means 3 is provided on the upper wall on the upstream side of the cylinder 2, and at the tip on the downstream side,
An outlet 2b communicating with the cooling device (forming device) 7 is provided. In addition, the cylinder 2 has an inner peripheral wall which is in contact with the molten metal 1 and the semi-molten metal is formed of low-reactivity ceramic such as silicon nitride, and an outer peripheral wall thereof is formed of heat-resistant steel to protect the inner peripheral wall. Thus, a reaction and melting damage by the high-temperature molten metal 1 to be stirred and transferred are suppressed to improve durability.

The supply means 3 includes a hopper-shaped holding furnace 8 for storing the molten metal 1 which has been melted and conveyed by a heating device (not shown) provided outside, and an outside of the holding furnace 8. The molten metal 1 in the holding furnace 8
And a conduit 8a provided integrally with the bottom of the holding furnace 8 and communicating with the holding furnace 8 and the cylinder 2. Therefore, the holding furnace 8
The molten metal 1 is supplied from the bottom of the holding furnace 8 to the inlet 2a of the cylinder 2 through the conduit 8a in order, so that air is not entrained in the molten metal 1.

Further, the temperature control means 4 is provided along the axial direction at the outer periphery of the cylinder 2 and at an intermediate portion between the inlet 2a and the outlet 2b, and is supplied into the cylinder 2. The molten metal 1 is once cooled to the temperature of the supercooling degree SC to a temperature below the solidus temperature. That is, the molten metal 1 in the molten state supplied from the holding furnace 8 is
The cylinder 2 is cooled to a semi-molten state by the temperature control means 4. By the way, when the molten metal is uniformly melted above the liquidus temperature, the solid phase begins to crystallize when cooled to the liquidus temperature, and between the solidus temperature and the liquidus temperature, the solid phase and the liquid phase begin to crystallize. Coexist, and when the temperature further decreases to a temperature below the solidus temperature, only the solid phase is formed, and the solidification is completed. This is shown in Figure 2.
This is shown in the state change process in the case of cooling a metal in a molten state having a constant composition indicated by point a. The temperature control means 4 is provided with a heater 10 and a cooling blower 11, starts cooling from a completely molten state from the inlet to the outlet of the cylinder, temporarily cools to a temperature region of a supercooling region, and then lowers the solidus temperature. Heat to a slightly higher temperature. Specifically, as shown in FIG. 3, the inside of the cylinder 2 has a molten portion or a semi-molten portion A which is located on the inlet portion 2a side and has a liquidus temperature or higher to a solidus temperature.
A partial solid phase generator B (solid phase supercooling section) below the solidus temperature located between the inlet / outlet sections 2a and 2b, and a liquidus higher than the solidus temperature located on the exit side It is configured to control the temperature to three temperature distribution regions including a solid-liquid phase mixing section C at a temperature lower than the temperature. It should be noted that the silicon content is 7% by weight of Al—S
For the i-alloy, the temperature range from the liquidus line L to the solidus line S is 45
The temperature range from the liquidus line L to the solidus line S is 25 to 30 ° C. for an Al—Si alloy having 9 ° C. and a silicon amount of 9% by weight. When the semi-solid alloy in the cylinder is cooled and supercooled by a temperature control means provided outside the cylinder, dendrites called dendrites grow from the wall surface of the cylinder 7 to the center.

On the other hand, the stirring and transferring means 5 has a screw 12 rotatably supported in the cylinder 2, and the screw 12 is rotatably driven by a rotation driving device 13 provided outside the cylinder 2. Have been. The screw 12 includes a cylindrical screw main body 12a, and a plurality of screw grooves 14 for stirring and transferring the semi-molten metal are arranged on the outer peripheral surface of the screw main body 12a at intervals in the axial direction. . The peak of the screw is stirred and mixed in the step of transferring the dendrites (dendrites) grown in the cylinder 2 through the crushing grooves in a granular manner, so that as the transfer step progresses, a fine solid phase alloy is formed in the molten alloy. A semi-molten alloy in a state of being uniformly diffused is selected. When this is further cooled, a high-quality solid alloy having a small solidification shrinkage and few shrinkage cavities is obtained. The screw 12 has a base material made of heat-resistant steel, and a film made of 10 to 30 wt% of NiCr and the remainder made of WC is formed on its surface by thermal spraying or the like. As a result, similarly to the cylinder 2, it is possible to suppress the reaction and erosion due to the high-temperature molten metal 1 to be stirred and transferred.

The base end of the screw 12 is
The cylinder 2 is connected to the rotary drive device 13 via a b, and a through hole 15 through which the screw shaft 12b is inserted is formed in the upstream end wall of the cylinder 2. Therefore, the rotation driving device (rotation driving unit) 13 provided outside the cylinder 2 and the screw 12 and the upstream end wall of the cylinder 2 are connected to the sealing means 1.
The sealing means 16 prevents the molten metal 1 from leaking out from the through hole 15 and preventing air from being trapped by the sealing means 16. The sealing means 16 includes a cooling means 17 provided on the outer periphery of the through hole 15 in the upstream end wall, and the cooling means 17 reduces the temperature of the molten metal 1 so that the temperature decreases from the inside toward the outside. The temperature of the molten metal 1 is controlled to be in a semi-molten state, and the viscosity of the liquid to be sealed is increased by the coexistence of the solid and liquid, thereby keeping the rotary drive device 13 and the upstream end wall of the cylinder 2 airtight. It is configured as follows.

On the other hand, the molten state detecting means 6 is provided at the outlet 2b of the cylinder 2 as shown in FIG.
As the detecting means 6, there are a temperature detecting means using a thermocouple or the like, and a solid-phase ratio detecting means for semi-molten metal using an ultrasonic sensor or an eddy current sensor. Further, the molten state detecting means 6
Is electrically connected to the temperature control means 4, monitors whether the semi-molten metal has a predetermined solid fraction, and feeds back a detection signal to the temperature control means 4 so that The semi-molten metal is extruded more stably and continuously. In addition, the predetermined solid phase ratio means that the ratio of the solid phase in the semi-molten metal is about 5 to 30 vol%, and the ingot 1 formed by the cooling device 7
8 according to the required quality.

Next, in order to continuously extrude a semi-molten metal such as an aluminum alloy into the cooling device 7 by the continuous supply device according to the first embodiment of the present invention, as shown in FIG. 8 and the molten metal 1 stored in the inlet portion 2a
While supplying it into the cylinder 2 via the conduit 8a,
The screw 1 of the stirring / transferring means 5 is rotated by the rotation driving device 13.
Rotate 2. Molten metal 1 supplied into cylinder 2
While being stirred by the screw 12 in the cylinder 2, is transferred through the above three temperature distribution areas set by the temperature control means 4 sequentially. That is, the supplied molten metal 1 is gradually cooled in the melting part A first, and then supercooled for a short time below the solidus temperature in the next partial solid phase generating part B to crystallize the solid phase. The solid-liquid phase kneading section C is maintained in the solidus to liquidus temperature range to form a predetermined solid fraction, and the solid and liquid phases are kneaded to form a semi-molten metal in which the solid phase is dispersed in a granular manner. Becomes At this time, a large number of crystal nuclei of the solid phase are finely crystallized at once by short-time supercooling in the partial solid phase generation part B, thereby preventing the dendrite from becoming coarse, and the subsequent dendrite in the solid-liquid phase kneading part C And the kneading of the solid phase and the liquid phase is facilitated, and the solid-phase granular dispersion structure of the extruded semi-molten metal can be reduced.

Thereafter, the semi-solid metal is screwed into the screw 1
2, it is continuously extruded from the outlet 2 b of the cylinder 2 to the cooling device 7 side, and is formed as an ingot 18 by the cooling device 7. At this time, the outlet 2 of the cylinder 2
If the temperature and solid phase ratio of the semi-molten metal extruded from b are detected by the molten state detection means 6 and the detection signal is fed back to the temperature control means 4 to adjust the cylinder temperature, more stable and high quality Can be obtained. The ingot 18 is again brought into a semi-molten state by reheating, transported to an injection molding machine (not shown), and manufactured into a desired alloy product.

As described above, in the continuous supply device according to the first embodiment of the present invention, the molten metal 1 is supplied from the holding furnace 8 of the supply means 3 into the cylinder 2 via the conduit 8a. While the molten metal 1 supplied to the inside is stirred by the screw 12 of the stirring and transferring means 5 in the cylinder 2, the melting part A and the partial solid phase forming part B set by the temperature control means 4
Since the three temperature distribution areas of the solid-liquid phase kneading section C are sequentially transferred, the supplied molten metal 1 is gradually cooled, and the solid phase is crystallized by short-time supercooling at a temperature below the solidus temperature. By maintaining the solidus temperature to the liquidus temperature range, a predetermined solid fraction is achieved, and the solid and liquid phases are kneaded to form a semi-molten metal in which the solid phase is dispersed in a granular manner. Therefore, according to the continuous supply apparatus of the present embodiment, it is possible to crystallize many crystal nuclei of the solid phase at once by short-time supercooling in the partial solid phase generation unit B, and prevent dendrite coarsening. In addition to this, the separation of dendrites and the kneading of the solid phase and the liquid phase in the solid-liquid phase kneading section C can be easily performed, and the solid-phase granular dispersion structure of the extruded semi-molten metal can be made fine.

FIG. 4 shows a second embodiment of the continuous feeder according to the present invention.
This embodiment is different from the first embodiment in that the cylinder 2 is arranged upward with respect to the direction of extrusion of the semi-molten metal. For this reason, the cylinder 2 is configured so as to be inclined upward so that the outlet 2b is higher than the inlet 2a. Along with this, the screw 12 of the stirring and transferring means 5 disposed in the cylinder 2 is also disposed with an upward inclination, similarly to the cylinder 2. Other configurations and operations are the same as those in the first embodiment.

In the continuous feeder according to the second embodiment of the present invention, since the cylinder 2 and the screw 12 are arranged upward with respect to the extrusion direction of the semi-molten metal, the molten metal 1 supplied from the holding furnace 8 Can be prevented from flowing out to the outlet 2b side through the gap between the cylinder 2 and the screw 12, and melted into the melting portion A and the partial solid phase generating portion B in the temperature distribution region in the cylinder 2 at the initial stage of the supply. The metal 1 can be filled, the temperature control can be effectively operated, the metal can be reliably made into a semi-molten metal, and a pushing force can be generated in the screw 12.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes may be made without departing from the gist of the present invention. What you get. For example, as shown in FIG. 4, instead of disposing the cylinder 2 and the screw 12 so as to be inclined upward with respect to the direction of extrusion of the semi-molten metal, the cylinder 2 and the screw 12 are disposed substantially horizontally, By forming only the outlet 2b high, the semi-molten metal in the cylinder 2 may be prevented from flowing toward the outlet 2b.

[0020]

As described above, the continuous supply apparatus for semi-molten metal according to the present invention is provided on the outer periphery of the cylinder and the supply means for supplying the molten metal into the cylinder, and heats the outer peripheral wall of the cylinder. Or temperature control means for cooling or heating the molten metal supplied into the cylinder to a semi-molten temperature or lower temperature range by cooling and adjusting the cylinder temperature, and provided in the cylinder, A stirring and transferring means for continuously stirring and transferring the semi-molten metal, and a detecting means provided at an outlet of the cylinder and detecting a molten state of the semi-molten metal stirred and transferred to the outlet of the cylinder. As a result, it is possible to efficiently and stably continuously supply high-quality semi-molten metal in which the solid phase is dispersed in a granular manner, thereby improving the quality of products using the obtained semi-molten metal. It is possible to improve the fine productivity.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration of a continuous supply device of a semi-molten metal according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an equilibrium state of an Al—Si alloy used in the continuous supply device of FIG. 1;

FIG. 3 is a diagram showing a cylinder temperature distribution by a temperature control means constituting the continuous supply device of FIG. 1;

FIG. 4 is a conceptual diagram illustrating a configuration of a continuous supply device of a semi-molten metal according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molten metal 2 Cylinder 2a Inlet part 2b Outlet part 3 Supply means 4 Temperature control means 5 Stirring transfer means 6 Melting state detecting means 8 Holding furnace 8a Conduit 9 Heat retaining heater 10 Heater 11 Cooling blower 12 Screw 13 Rotary drive device 14 Screw groove 15 through-hole 16 sealing means 17 cooling means

Claims (11)

[Claims] 1. A supply means for supplying molten metal into a cylinder, and a supply means provided on an outer periphery of the cylinder, wherein the outer peripheral wall of the cylinder is heated or cooled to adjust the cylinder temperature so as to be supplied into the cylinder. Temperature control means for cooling or heating the molten metal to a semi-molten temperature or lower temperature range, and stirring and transfer means provided in the cylinder, for continuously stirring and transferring the semi-molten metal in the cylinder, Detecting means provided at an outlet of the cylinder and detecting a molten state of the semi-molten metal stirred and transferred to the outlet of the cylinder. 2. The apparatus according to claim 1, wherein said temperature control means is configured to temporarily control the molten metal supplied into said cylinder to a temperature below the solidus temperature by supercooling. Continuous supply of semi-molten metal. 3. The temperature control means includes a heater and a cooling blower, and the inside of the cylinder has a melting portion having a liquidus temperature equal to or higher than a liquidus temperature located on the inlet side and a solidus temperature located in the middle of the inlet / outlet. It is characterized by being controlled to three temperature distribution regions consisting of the following supercooling section and a solid-liquid phase kneading section located above the solidus temperature and below the liquidus temperature located at the outlet side. The continuous supply apparatus of a semi-molten metal according to claim 1. 4. The stirring and transferring means includes a screw rotatably supported in a cylinder, the screw being configured to be rotationally driven by a rotary driving device, and the cylinder being driven in a direction in which the semi-molten metal is extruded. The continuous supply apparatus of a semi-molten metal according to claim 1, wherein the apparatus is arranged to face upward. 5. An apparatus according to claim 1, wherein said molten state detecting means is a temperature detecting means using a thermocouple. 6. The continuous supply apparatus for a semi-molten metal according to claim 1, wherein said molten state detecting means is a solid phase ratio detecting means for the semi-molten metal. 7. The continuous supply device for semi-molten metal according to claim 6, wherein the solid phase ratio detecting means is an ultrasonic sensor or an eddy current sensor. 8. The cylinder according to claim 1, wherein the cylinder is formed of a double tube in which the inside in contact with the molten metal and the semi-molten metal is made of a low-reactivity ceramic such as silicon nitride and the outside is protected by heat-resistant steel. The continuous supply apparatus of a semi-molten metal according to any one of claims 1 to 4, wherein: 9. The screw of the stirring and transferring means has a base material formed of heat-resistant steel and has a surface of NiCr10 to 30 wt.
5. The continuous supply apparatus for a semi-molten metal according to claim 1, wherein a coating consisting of the balance WC is formed in%. 5. 10. The semi-molten metal according to claim 4, wherein a rotary drive portion provided outside the screw of the stirring and transferring means and the cylinder end wall are air-tightly separated by a sealing means. Continuous feeder. 11. The sealing means includes a cooling means provided on an outer periphery of a screw shaft through hole in an end wall of the cylinder, and the temperature of the molten metal is controlled by the cooling means so that the temperature decreases from inside to outside. The continuation of the semi-molten metal according to claim 10, wherein the rotation driving unit and the cylinder end wall are configured to be kept airtight by an increase in viscosity based on a decrease in temperature of the molten metal. Feeding device.