JPH02280946A - Apparatus for producing semi-solidified metal - Google Patents

Abstract

PURPOSE:To stably and continuously operate an apparatus for producing the semi-solidified metal by applying refractory lining to the whole face of outer circumference of water cooling box for molten metal cooling stirrer in the apparatus for producing semi-solidified metal. CONSTITUTION:The cooling stirrer 2 is composed of a main metallic structure 25 having tubular casing, water supplying pipe 26 and copper-made water cooling box 2e as frame, and high heat resistant ceramics tile 2f is fitted on the outer surface of the water cooling box 2e to make a stirring head 2b. Further, the outer circumference of the tubular casing in the main metallic structure 25 has the structure covered with protecting sleeve 27 made of the refractory. This cooling stirrer is inserted and submerged into molten metal received in a stirring vessel 1 under cooling condition with flowing of the cooling water and started to rotate. Then, by receiving intensive cooling action at annular conical gap 2a between the cooling stirrer 2 and stirring vessel bottom and the stirring effect with rotation of the cooling stirrer 2, the molten metal is made into a semi-solidified state, and this can be taken out from a discharge nozzle 5.

Description

[Detailed Description of the Invention] (Industrial Application Field) Semi-solid metal, that is, a mixture of solid and liquid temperature states in which non-dendritic primary crystals are dispersed in a molten metal or alloy (also called rheometal). It has been reported that the so-called semi-solid processing process, in which the material is directly shaped into the final shape of the product through processing such as casting, forging, or rolling, has made a significant contribution to the improvement of the quality and functionality of metal materials. and its practical application is
It is strongly requested.

This invention proposes the results of research and development regarding a semi-solid metal manufacturing apparatus that aims to provide a stable supply of rheometal, which is the basis for application of semi-solid processing processes.

(Prior art) Japanese Patent Publication No. 56-20944 discloses that while molten metal supplied into a heat insulating tank is maintained at a constant temperature, the gap between the molten metal and a stirrer rotating at high speed in a cylindrical cooling stirring tank is It is disclosed that the liquid is introduced into a semi-solidified state by applying strong stirring force under appropriate cooling action, and then continuously taken out from the bottom of the cooling stirring tank through a discharge nozzle. Since it is impossible to adjust the stirring gap that applies stirring action to the raw molten metal,
It has not been put to practical use because it is difficult to perform the necessary control to stably achieve an appropriate semi-solid state regardless of the type of raw material molten metal.

(Problem to be Solved by the Invention) Semi-solid metals are produced by vigorously stirring a molten metal or alloy while cooling it, so that the branches of the resinous crystals that are forming in the molten metal disappear or shrink to become rounded. It is formed by converting it into a form with a . The finer the particles of non-dendritic primary crystals in semi-solid metals, the better their properties, and therefore, strong cooling effects and strong stirring effects are essential conditions for semi-solid metal manufacturing equipment.

In order to achieve these conditions, the inventor first developed a semi-solid metal manufacturing device that uses a water-cooled stirrer with a conical stirring surface, and confirmed its usefulness. It has been learned that it is difficult to obtain satisfactory results with so-called high-melting point materials having a melting point of about 1500°C or higher.

The problems with this type of semi-solid metal manufacturing equipment are (1) the refractory material needs to have high high-temperature strength in order to stir the raw material molten metal, which is as high as 1500°C while it is being cooled; Common ceramics have drawbacks such as being vulnerable to thermal shock and having limited mechanical structure.
It is difficult to implement the equipment, especially the stirrer, which requires strong cooling at the same time.
It is difficult to implement equipment because it requires high-speed rotation to provide strong stirring action.

(2) Due to the high temperature, there is always significant heat loss, which tends to cause undesirable solidification and condensation, making operation difficult.Especially in continuous processes, the biggest problem is the start of operation; However, it is necessary to establish appropriate equipment and a method for starting operations.

(3) As a practical device, it is necessary to consider the possibility that the system may be forced to stop due to an accident occurring during the process, and accident handling, maintenance, inspection, and preparation work are simple.

It also needs to be easy to do.

It is therefore an object of the present invention to provide a particularly advantageous solution to this problem.

(Means for Solving the Problems) The present invention has a molten metal reservoir for receiving raw molten metal, and has a conical opening expanding upward at the bottom of the inflow chamber communicating with the molten metal reservoir, and an insulating chamber directly below the conical opening. A conical cooling stirrer facing the conical opening of the stirring tank equipped with the above-mentioned conical opening and capable of being driven to rotate at high speed is combined with the stirring tank so that the clearance between the stirring tank and the conical opening can be adjusted. A cooling stirrer equipped with a discharge nozzle that can be closed by a slide valve at the bottom, characterized in that the cooling stirrer is made of a water-cooled box made of highly heat-conducting metal, and a refractory lining is applied to the entire outer periphery of the water-cooled box. This is a semi-solid metal manufacturing equipment.

Here, the refractory lining is made of a highly heat-resistant ceramic style, the cooling stirrer is movable by an elevating frame equipped with its rotational drive system, and the stirring tank is
It is particularly advantageous that it is movable by means of a carriage on which it is mounted.

As described above, the conical cooling stirrer has a structure in which the entire outer circumference of the cone of the internal water-cooled cooling box is made of a highly heat conductive metal, such as pure copper, and is lined with a refractory material, preferably a highly heat-resistant ceramic style. The temperature of the cooling box can be maintained at about 300°C or less, and sufficient cooling strength can be obtained.

The conical cooling stirrer is movable by an elevating frame equipped with a rotating drive system, making it possible to adjust the clearance.In addition, in the case of accident handling, maintenance inspection, preparation, or repair, it can be moved to a retreat position by raising the elevating frame. The work was made easier and simpler by moving the stirring tank from the stirring position to the maintenance position using a trolley.

Now, referring to FIG. 1 together with FIG. 2, 1 is a stirring tank, 2 is a cooling stirrer, and the stirring tank 1 has a molten metal reservoir 1a that receives raw molten metal poured into it, and this molten metal reservoir 1a and a sink weir 1b. an inflow chamber 1c communicating with the inflow chamber 1c and a conical opening 1d widening at the bottom of the inflow chamber 1c;
The cooling stirrer 2 is equipped with a conical stirring head 2b that faces the conical opening 1d and forms a conical annular stirring gap 2a, and has a main shaft 2c above the stirring head 2b. Similarly, a mixing screw 2d that occupies the inside of the insulating chamber 1d is provided below.

The stirring tank 1 and the cooling stirrer 2 are provided with a refractory lining on their outer surfaces that come into contact with the raw molten metal, and in particular, the induction heating coil 3 is arranged to surround the refractory peripheral wall of the insulating chamber 1e. The inside of the insulating chamber le is maintained at a constant temperature by being supplied with electricity from a power source 4, and the stirring rod 2b of the cooling stirrer 2 is made of a highly heat conductive metal such as copper, as shown in detail in cross section in Figure 3. The entire outer periphery of the water-cooled box 2e is provided with a refractory lining, such as a highly heat-resistant ceramic tile 2f (for example, silicon nitride porcelain) as shown.

A drainage nozzle 5 is provided at the bottom of the greenhouse 1e, and a slide valve 6 is installed.
This allows it to be opened and closed. In the figure, 7 is a lid that closes the upper opening of the inflow chamber 1c, 8 is a driving vertical shaft connected by a flange to the main shaft 2c of the cooling stirrer 2, and 9 is a rotary joint.

The vertical drive shaft 8 is a bracket extending from the lifting frame 10!
A bearing is supported at the front end of the bracket 1-11 (on the left side of the figure), and a motor 12 installed at the top of the bracket 1-11 transmits driving torque to the cooling stirrer 2 through a torque meter 13 and a reducer 14.
shall be communicated to.

The elevating frame 1O is made vertically movable by a hydraulic cylinder 15 under the guidance of a guide roller 17 disposed on a fixed column 16, thereby creating a conical annular stirring gap 2.
a and evacuation to an evacuation position for maintenance, inspection, maintenance, etc. of the cooling stirrer 2.

Further, the rotary joint 9 is connected to a pressurized source 19 of cooling water and drainage through a cooling hose 18, and is connected to the drive shaft 8 and the main shaft 2c.
The circulating flow of the cooling water flowing through the hollow hole piping (see FIG. 3) and filling the water passage groove 20 formed inside the water cooling box 2e is guided.

On the other hand, the stirring tank 1 is entirely supported on a cart 21 and is movable, for example, along a rail 22 laid in advance in the horizontal direction. Note that 23 is a wheel of the truck 21.

In this example, the rotation center of the cooling stirrer 2 is fixed, and when actually producing semi-solid metal, the cart 21 is moved to align the center position of the stirring tank 1 with the rotation center of the cooling stirrer 2. For example, this is fixed with the positioning pin 24 (see Fig. 2) during operation, and when the operation is finished, the positioning pin 24 is removed and moved, and maintenance 9 inspection, maintenance, accident handling, etc. can be easily performed at the preparation position 25. It can be done easily.

(Function) Before starting the actual operation, the cooling stirrer 2 is raised to the standby position, the slide valve 5 is fully closed, and the molten raw material is poured into the stirring tank 1 through the molten metal reservoir 1a. At the same time, the induction heating coil 3 is energized to heat the mixing chamber le.
Preheat the refractory lining sufficiently to maintain a constant temperature inside.

Next, the cooling stirrer 2 is lowered to fit into the conical opening 1d of the stirring tank 1, and rotational driving is started, and then the slide valve 5
is opened to start flowing out from the discharge nozzle 6 and to start continuously supplying the raw material molten metal.

The raw material molten metal is supplied to the molten metal reservoir 1a, enters the inflow chamber 1c of the stirring tank 1 from the sink weir 1b, and in the conical annular stirring gap 2a, there is a gap between the inner periphery of the conical opening 1d and the outer periphery of the cooling stirrer 2. In addition to being strongly cooled, the metal is intensely stirred by the cooling stirrer 2 rotating at high speed to become a semi-solid metal, which sequentially flows out into the insulating chamber 1e.

In the insulating chamber le, the temperature of the semi-solid metal is controlled by the induction heating coil 3, and the mixture is made uniform by the mixing screw 2d formed at the lower end of the cooling stirrer 2, and the temperature is maintained at a predetermined temperature through the opening of the discharge nozzle 5 and the slide valve 6. A uniform semi-solid metal with a controlled temperature is obtained.

(Example) The cooling stirrer 2 has a main metal body 25 having a tubular casing as shown in FIG. Style 2f is applied to constitute the stirring paddle 2b, and the outer periphery of the tubular casing of the main metal part 25 is covered with a protective sleeve 27 made of a refractory material.

Here, the main metal part 25 has an inverted truncated cone shape at its lower end,
A group of water holes 2 in the radial direction on the small diameter side and large diameter side, respectively.
B. A water-cooled box made of a body shell also in the shape of an inverted truncated cone, which is fitted with the outer surface of the lower end of the metal shell 25 in the shape of an inverted truncated cone, by opening the holes 29 and providing a water passage groove 30 that connects them on the conical surface. The lower end of the water supply pipe 26 is tightly fitted into the bottom hole of the metal shell 25 so that the water supply pipe 26 is cooled by the flowing water in the water passage hole groups 2B, 29 and the water passage groove 30. It has a double pipe structure, with the water supply pipe 26 separated from the inside and outside as water supply and drainage passages.

Note that a metal fitting 31 is fixedly attached to the lower end surface of the main metal object 25 to connect the mixing screw 2d. In the figure, 32 is a refractory sleeve that protects the mixing screw.

In this example, water-cooled N2e made of pure copper forms the cooling surface, but if the molten metal is directly cooled and stirred on such a cooling surface, the surface temperature of the cooling surface will increase rapidly due to its strong stirring action. The temperature reaches over 800°C, making it completely unusable, and even if other high heat conductive metals were used instead of pure copper, there would be little difference.

However, in the present invention, a highly heat-resistant ceramic tile of an appropriate thickness is adhered or joined to the entire outer periphery of the water-cooled box 2e, and the tile is made as small as possible in order to more effectively alleviate thermal stress. For example, 1
The outer surface of a pure copper water cooling box with a thickness of 0 mm is nickel plated, and then 5iJ4 with a thickness of 10 mm (
By diffusion bonding ceramic styles made of silicon nitride, we were able to obtain sufficient strength, durability, and cooling effect.

When this cooling stirrer is cooled by flowing cooling water and inserted into the molten metal received in the stirring tank 1, immersed and starts rotating, the molten metal flows between the cooling stirrer and the annular conical gap at the bottom of the stirring tank. At No. 2a, the metal became semi-solid due to the strong cooling effect and intense stirring effect caused by the rotation of the cooling stirrer, and this semi-solid metal could be taken out from the discharge nozzle.

In this case, the stirring effect depends on the rotational speed of the cooling stirrer.2 In this example, when the stirrer with an average diameter of 200M is set to a maximum of 100Or, p, and m, it can be used in practical use with arbitrary adjustment of the gap. The effect was confirmed.

(Effect of the invention) There is no continuous semi-solid metal production equipment for high melting point metals with a melting point of around 1500°C anywhere in the world, and this is due to the equipment materials for processing such high melting point metals. In addition to selection problems, it was difficult to implement the device due to the difficulty of the device structure, and it was also difficult to operate because the heat loss was large and solidification was likely to occur. It is possible to realize a continuous semi-solid metal manufacturing apparatus for melting point metals, and it is very useful industrially in that stable operation and operation can be realized.

[Brief explanation of drawings]

FIG. 1 is an overall cross-sectional view of the main parts of the apparatus of the present invention, FIG. 2 is a plan view, and FIG. 3 is a detailed view of the cooling stirrer. l... Stirring tank 2... Cooling stirrer 1a.
... Molten metal reservoir 1d... Conical opening 1e...
Warming room 2e...Water cooling box 2f...Refractory lining 5...Discharge nozzle 6...Slide valve patent applicant Rheotech Co., Ltd.

Claims (1)

[Scope of Claims] 1. A stirring tank that has a molten metal reservoir that receives raw molten metal poured into it, has an upwardly expanding conical opening at the bottom of the inflow chamber that communicates with the molten metal reservoir, and has an insulating chamber directly below the conical opening. A conical cooling stirrer that faces the conical opening and can be driven to rotate at high speed is combined with a stirring tank so that the clearance between the conical opening and the conical opening can be adjusted, and a slide valve is installed at the bottom of the insulating chamber. A cooling stirring device equipped with a discharge nozzle that can be closed by a semi-solid cooling stirrer, characterized in that the cooling stirring element is a water-cooled box made of highly heat conductive metal, and a refractory lining is applied to the entire outer periphery of the water cooling box. Metal manufacturing equipment. 2. The apparatus of claim 1, wherein the refractory lining is a high temperature ceramic style. 3. The apparatus according to claim 1 or 2, wherein the cooling stirrer is movable by an elevating frame on which the rotational drive system is mounted. 4. The stirring tank is movable by a trolley on which it is mounted.
A device as claimed in claim 1, 2 or 3.