JPH03199318A - Rapid melting device for aluminum ingot - Google Patents

Abstract

PURPOSE:To allow the adjustment of the induction coil of a melting furnace to the optimum height for the material quality and size of an ingot by constituting the induction coil of the melting furnace in such a manner that the coil can be elevated in the method for melting the ingots by a coolant insertion melting method. CONSTITUTION:The Al ingot (coolant) is inserted into an insertion guide 11 and is further inserted into the melting furnace 12. The induction coil 13 for melting on the outer periphery of the furnace 12 is adjusted to the optimum height by a lifting device 20 in such a manner that the optimum melting interlinkage point corresponding to the material quality and size of the coolant is obtd. The timing to insert the next ingot when there is the already inserted ingot in the furnace 12 is so adjusted that the interlinkage line with the magnetic flux from the coil 13 attains the state optimum for the ingot of this type when the height of the ingot in the furnace 12 lowers successively and the next ingot is inserted. The coolant is inductively heated to form liquid drops which are admitted into a heating up furnace 14. The liquid drops are heated up by the induction coil 15 for heating up and are admitted into a tapping pipe 16.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a rapid melting device for ingots of aluminum or aluminum alloys (hereinafter referred to as aluminum-based metals), and more specifically, for die-casting molten aluminum-based metals. When casting parts for machinery, electrical equipment, etc., aluminum-based metal ingots (hereinafter abbreviated as aluminum ingots) are placed immediately before the pouring slot of the die of the die-casting machine or the pouring port of other casting equipment. The two pieces are directly melted by induction heating, which is the so-called cold material insertion melting method, and the molten metal is made to flow down to a temperature rising area, where it is heated to a predetermined temperature and poured into the die of a die casting machine, etc. This article relates to a rapid melting device for aluminum ingots.

[Prior Art] Aluminum has a low specific gravity and a low melting point, making it a structural member for general machinery, special machinery, vehicles, electrical equipment, etc., and it can be made into an alloy with considerable strength. It is widely used as wrought materials and cast products because of its ability to

In addition to regular molds and sand castings, die castings, shell castings, and centrifugal castings are also used for casting products. Among these, the die casting method uses a die casting machine (also called a die casting machine) to cast molten metal. Demand for this product has been increasing in recent years as it meets the demands for improved dimensional accuracy and productivity, as it is possible to repeatedly inject water under high pressure and at high speed into a mold called a die to create a precision cast product. are doing.

However, in general, in order to supply molten metal to a die-casting machine, as shown in Figure 2, a large amount of concentrated melting is performed using a melting F31 using gas or heavy oil as a heat source, and the molten metal heated to 570 to 600°C is heated to 570 to 600°C. A holding furnace 32 whose heat source is
It is then transferred to a hand furnace 34 by means of transportation such as a cart 33, heated to a temperature suitable for pouring, for example approximately 720 degrees Celsius, and then heated manually or by a robot into the die throwers 1 to 1 of the die casting machine 35. The method follows the method of supplying the product inside.

[Problem to be solved by the invention 1 However, the method shown in Figure 2 is large-scale and uses a work process that passes through multiple furnaces, so it requires a large factory space and requires multiple furnaces. Since the material is kept in a molten state for a long time during use and transported between multiple furnaces, there is a disadvantage of low material yield due to losses such as combustion, oxidation, and scattering of the material, as well as energy loss due to waste heat and heat radiation. In particular, the melting furnaces and holding furnaces that supply the molten metal used in the many casting machines in the foundry are kept in high-temperature operating conditions for long periods of time. There was a need.

In addition, there are many processes such as transporting, storing, and pumping out the molten metal, which lowers work efficiency. In addition, there are many man-hours for maintenance, and there are concerns about safety. There were also problems with working conditions, such as the need for melting workers to arrive early or work after hours due to the long start-up time, and a solution was requested.

The inventor of the present invention aimed to solve many problems with the above-mentioned molten metal supply methods and devices that use large-capacity melting furnaces, holding furnaces, hand furnaces, etc. We developed the concept of using a cold material insertion melting method, in which the molten metal is melted directly in front of the pouring slot or other casting machine pouring ports, heated to a predetermined pouring temperature, and then poured into the die. However, it was necessary to solve the following problems.

(1) Structure of the heating means and melting chamber for inserting and melting cold material into the aluminum ingot, (2) Structure of the heating means and heating chamber for storing molten aluminum and raising the temperature to a predetermined pouring temperature, <3 〉Method of pouring molten metal from the heating chamber to the pouring slot of the die, etc. Items (1), (2) and (3) above apply to the melting chamber, heating chamber,
This is a problem related to the structure of the rapid melting device itself, such as heating means and pouring method, and for these problems, it is necessary to use a melting furnace of an appropriate shape,
We have developed a series of melting furnaces and heating furnaces that are connected in combination with warming chambers and equipped with appropriate heating means.

[Means for Solving the Problems] In the present invention, the order of metallurgical processes in the conventional method such as melting, temperature raising, and pouring, which was performed using multiple furnaces such as a melting furnace, a heating furnace, and a hand furnace, is unchanged. However, the following points are different in the present invention.

(b) Instead of the conventional method, which uses a large-capacity melting furnace to melt a large number of aluminum ingots and/or scraps, in the present invention, in principle, two aluminum ingots are melted as a pair using a cold material insertion rapid melting device. The aluminum ingot is transported to a melting furnace, and is melted from the surface of the aluminum ingot using the cold material insertion melting method, which uses induction heating to melt the aluminum ingot.The aluminum ingot is then flowed down through an opening in the bottom of the melting furnace into a heating furnace located directly below it. When the aluminum ingot in the melting furnace is melted by the melting induction coil, the optimal melting linkage point between the aluminum ingot as a conductor and the magnetic flux passing through the melting induction coil changes depending on the material and dimensions of the aluminum ingot. The melting induction coil is adapted to adjust the optimum melting linkage point to accommodate aluminum ingots of different materials and/or dimensions.

(Also, an opening is provided at the bottom of the heating furnace, and a tapping pipe is provided coaxially with this opening and continuing downward to form an extension of the heating furnace. Near the bottom of the tapping pipe, An opening for tapping is provided.This allows the heating furnace and tapping pipe to communicate vertically through the opening to accommodate the molten metal, resulting in a molten metal container with an open top end and an opening for tapping near the bottom. Further, a heating induction coil for raising the temperature of the molten metal to a predetermined tapping temperature is provided on the outer periphery of the heating furnace, while a tapping device such as an electromagnetic pump for pouring the molten metal to the outside is placed around the outer periphery of the tapping pipe. Using a heating furnace and tapping device having such a configuration, the molten metal flowing down into the heating furnace is heated to a predetermined temperature and tapped from the tapping pipe by the pouring device.

In this way, in the present invention, separate furnaces are used for melting and temperature raising, induction coils for heating and temperature raising are also arranged in each furnace, and for tapping the hot water, an electromagnetic pump etc. is installed in the tapping pipe. We adopted the traditional method of arranging the hot water tap equipment.

[Example 1] In order to explain an example of the rapid melting apparatus for aluminum ingots of the present invention, first, Fig. 1 (
Preferred embodiments of the apparatus of the present invention will be described with reference to A) to (C).

Figure 1 (A) is a side sectional view showing the structure of the main parts of the cold material insertion rapid melting apparatus for aluminum ingots of the present invention, and Figure 1 (B) shows the structure of the melting furnace in Figure 1 (A). A side cross-sectional view, drawing (C) is a side view showing the arrangement of the aluminum ingot rapid melting apparatus of drawing (A) and its related devices.

In the figure, reference numeral 1 indicates a cold material for aluminum ingots, 10 indicates the entire cold material insertion rapid melting apparatus for aluminum ingots of the present invention, and 11 indicates a cold material insertion guide serving as a guide section for inserting the cold material,
It guides the cold material 1 of the aluminum ingot sent by the cold material supply device f19 into the melting furnace 12, and also prevents the droplets of aluminum metal melted in the melting furnace 12 from scattering outside the furnace. To prevent.

Aluminum ingots are unstandardized and have unspecified shapes and dimensions; however, they usually have a nearly flat bottom and two to three trapezoidal protrusions separated by V- or U-shaped grooves on the top. . In the present invention, two aluminum ingots are paired with their flat bottom surfaces facing each other and used as a unit for transportation and melting.

The melting furnace 12 is an upright hollow cylindrical furnace with a garden made of refractory material, and a cold material 1 of an aluminum ingot is accommodated in the space inside the cylinder, and an induction coil 1 for melting is provided around the outer periphery of the melting furnace 12.
3, the aluminum ingot L is heated from the surface and melted to form droplets.

At the bottom of the melting furnace 12, there is an outflow hole 12 that penetrates downward in the axial direction.
' is opened, and the aluminum droplets flow downward from this outlet hole 12'.

In the present invention, a melting induction coil elevating device 20 is attached to the melting induction coil 13, and the elevating device 20 has an adjusting screw rod 22 attached to a support fitting 21 fixed to the melting induction coil 13, for example. The lower end thereof is inserted into the center hole of the pedestal 23, and an adjustment nut 24 with a handle is placed on the upper surface of the pedestal 23 in a state where it is screwed into the adjustment threaded rod 22. By turning the melting induction coil 13, the height can be adjusted by raising and lowering the melting induction coil 13 in the axial direction of the melting furnace 12.

Although not shown, the melting induction coil elevating device can also be configured such that the melting induction coil 13 is suspended by a wire and the hanging length of the wire is adjusted.

14 is a heating furnace coaxially arranged below the melting furnace 12;
It is an upright hollow cylindrical furnace with a garden, made of refractory material and having almost the same shape as the melting furnace 12. Like the melting furnace 12, the bottom is provided with an outflow hole 14' penetrating downward, and the temperature rising furnace 14 is A heating induction coil 15 provided on the outer periphery heats the molten metal to a temperature of 720° C., which is the temperature at which the molten metal is tapped into a die of a casting device such as a die-casting machine.

A hollow tubular tapping pipe 16 is provided at the bottom of the heating furnace 14, surrounding the outflow hole 14' from the outside, extending downward and communicating with the heating furnace to serve as an extension thereof.

The hot water tapping pipe 16 is a long and narrow hollow tube with a bottom closed at the lower end, and a hot water tap 16 is located near the bottom of the side wall for tapping hot water into the die of a die casting machine 18 or the like.
' is opened, and an electromagnetic pump 17 is attached to the side wall of the tapping pipe 16 above the tapping port 16' for applying thrust to the molten metal during tapping.

This electromagnetic pump 17 not only applies thrust and force to the molten metal during tapping, but also allows aluminum droplets generated in the melting furnace 12 to flow downward from the outlet hole 12' and into the heating furnace 14, where they become molten metal. Furthermore, the tap water pipe 16 passing through the outflow hole 14' and below the outflow hole 14'
When the molten metal flows into the molten metal, it applies a thrust in the direction opposite to that of the molten metal to prevent it from flowing out from the molten metal outlet 16'.

Next, the operation of the rapid melting device using cold material insertion according to the present invention will be described.

As shown in Figure 1 (C), two aluminum ingots)
A plurality of pairs of aluminum ingots 1 placed back to back are transported by a cold material supply device 19 to the vicinity of the cold material insertion guide 11 of the rapid melting device 10 of the present invention. The aluminum ingots 1 are inserted one pair at a time into the cold material insertion guide 11 using a combination of vertical and horizontal movements using an air cylinder or the like, and further into the melting furnace 12.

The melting induction coil of the melting furnace 12 is operated by the melting induction coil lifting device 2 so as to obtain the optimum melting linkage point according to the material dimensions of the aluminum ingot to be rapidly melted.
The height is adjusted to the optimum height by setting 0.

Furthermore, when the already inserted ingots are in the melting furnace 12, the timing for inserting the next pair of ingots 1 to 1 is such that the height of the already inserted ingots in the melting furnace 12 gradually decreases as the melting progresses. When the next pair of ingots is inserted, the point where the line of linkage with the magnetic flux from the melting induction coil 13 becomes optimal for melting that type of aluminum ingot, that is, the optimum melting linkage point. Adjust accordingly.

The aluminum ingot inserted into the melting furnace 12 in such an adjusted state is heated by induction by the melting induction coil 13, and melting proceeds from the surface of the aluminum ingot. hole 12 at the bottom of
′, flows into the heating furnace 14, and further passes through the opening 14′.
and flows into the outlet pipe 16.

In this state, the temperature raising induction coil 15 is energized, and the electromagnetic pump 17 applies an upward thrust to the molten metal in the opposite direction to the tapping direction, that is, to prevent the molten metal from flowing out from the tapping port 16' due to the action of gravity.

As the melting of the aluminum ingot in the melting furnace 12 progresses, the molten metal that flows into the heating furnace 14 and the tapping pipe 16,
If the temperature is suitable for tapping, the temperature remains the same; if the temperature has not reached the tapping temperature, the temperature is raised to a predetermined temperature by the heating induction coil 15, and the electromagnetic pump 17 is operated in the tapping direction, that is, to apply a downward thrust to the molten metal. and pour the molten metal into the outlet 16'
Then pour the molten metal into the die slot of the die-casting machine.

[Effects of the Invention] As can be understood from the above explanation, when the apparatus of the present invention is used to perform so-called cold material insertion rapid melting, in which aluminum ingots 1 to 1 are inserted and melted immediately before the die slot of a die-casting machine, Since melting and temperature raising are performed using independent melting furnaces and heating furnaces, which are placed close to each other above and below, and induction coils placed in each, accurate temperature control is possible.

In addition, the heating furnace and the tapping pipe communicate with each other through the outflow hole, and the molten metal inside them is heated to the optimum temperature by the heating induction coil as a whole, and is tapped by the electromagnetic pump on the outer periphery of the tapping pipe. So.

The amount and speed of hot water can be precisely controlled.

Furthermore, since the melting induction coil can be moved up and down along the outer periphery of the melting furnace, it is possible to adjust the height to the optimum height that matches the material dimensions of the aluminum ingot.

[Brief explanation of drawings]

Figure 1 (A) shows the aluminum ingot of the present invention.
Figure 1 is a side sectional view showing the structure of the main parts of the rapid melting device.
B) is a side cross-sectional view showing the structure of the melting furnace of the aluminum ingot rapid melting equipment shown in Figure 1(A), and Figure 1(C) is a side sectional view showing the structure of the melting furnace of the aluminum ingot rapid melting equipment shown in Figure 1(A). FIG. 2 is a side view showing the arrangement of related equipment. FIG. 2 is a side view showing a conventional melting and pouring method using multiple furnaces. 1 2 3 4 5 6 7 8 9 0 Cold material insertion guide Melting furnace Melting induction coil Temperature raising furnace Temperature raising induction coil Tapping pipe Electromagnetic pump Die casting machine Cold material supply device Melting induction coil Lifting device

Claims (1)

[Scope of Claims] A rapid melting device for aluminum ingots that receives a supply of aluminum ingot cold material to form molten metal to be poured into a casting machine such as a die-casting machine, rapidly melts it to form molten metal, raises the temperature, and pours the molten metal. At least one of the aluminum ingots supplied as a cold material
As a container for accommodating the aluminum ingots and sequentially melting them into droplets from the outer periphery, the opening for inserting the aluminum ingot is provided at the top, and the melting induction coil for melting the aluminum ingot is provided at the outer periphery. , an upright hollow cylindrical melting furnace having an opening at the bottom through which the droplets generated by melting flow down; It has an opening at the top, a heating induction coil for raising the temperature of the molten metal formed by the accumulation of the droplets to a predetermined temperature on the outer periphery, and an opening at the bottom that allows the molten metal inside to flow further downward. an upright hollow cylindrical temperature raising furnace, which surrounds the opening of the temperature raising furnace, extends further downward in close contact with the bottom, and has an opening for communication with the temperature raising furnace at the upper end; A tap hole for tapping molten metal is placed at the bottom of the side wall.
and an upright hollow cylindrical tapping pipe having a thrust imparting device on the outer periphery for tapping the heated molten metal, and the heating furnace and the tapping pipe constitute an integral molten metal storage container that communicates with each other. . A rapid melting apparatus for aluminum ingots, characterized in that a melting induction coil of the melting furnace is provided so as to be movable up and down along the outer periphery of the melting furnace.