JPS62137147A - Apparatus for producing bar-shaped ingot - Google Patents

Abstract

PURPOSE:To stabilize the outside diameter of a cast rod and to decrease the intrusion of foreign matter by providing a cylindrical skirt concentrical with a seed bar extending into a molten metal so that the molten metal is separated to a peripheral molten metal part of a solid phase to solidify and the molten metal part around the same. CONSTITUTION:The bottom end of the seed bar 2 of the same type as the molten metal 1 is allowed to contact the surface of the molten metal and the solid phase 3 solidified at the bottom end of the seed bar 2 is rotated and pulled up while said phase is cooled by a water cooling jacket 4 and a cooling gas blow nozzle 5. A cylindrical support 6 consisting of the refractory heat resistant material concentrical with the seed bar 2 is provided around the jacket 4 and the concentrical cylindrical skirt 7 extending into the molten metal 1 is likewise attached to the support 6. The molten metal 1 is thus separated to the peripheral molten metal part 1a of the solid phase 3 to solidify and the molten metal part 1b around the same. The outside diameter of the casting lot is thereby stabilized and the intrusion of the foreign matter is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a rod-shaped ingot manufacturing apparatus that directly pulls solid phase into a rod shape from molten metal without using a mold.
The present invention provides a casting device for obtaining ingots that are used as raw materials for ultra-fine wires.

Conventional technology Conventional ultra-fine wire ingots use water-cooled molds; vertical continuous casting method that pulls the ingot downwards against the molten metal surface; top-drawing continuous casting method that pulls the ingot upward; and horizontal casting method. Horizontal continuous casting method, belt and wheel continuous casting method,
Manufactured using twin belt continuous casting method. However, in recent years, due to the miniaturization and higher precision of electronic equipment, the diameter of
Ultra-fine wires of the 0μ class are now required, and there is a particular desire to develop a method for producing ingots with fewer internal defects.

With ultra-fine Cu and At wires, wire breakage during the wire drawing process is a major problem, and the majority of wire breaks are caused by defects in the material.

A known method for producing a perfect crystal is to pull semiconductors such as Si or GaAS without using a mold, but this method uses a single crystal ingot with extremely high internal quality. In order to ensure the highest quality, we pay attention to the cleanliness of not only the equipment that performs the lifting, but also the base material and the room where the equipment is installed. As a result, productivity is poor and lengthening is not possible. Recently, a method of pulling the ingot at a relatively high speed without using a mold is being considered by installing a device in a normal atmosphere to pull the ingot and forcing the ingot to cool as a small diameter and long rod. .

Problems to be Solved by the Invention In the method under consideration for pulling an ingot without using a mold, in order to keep the molten metal surface i constant, a rough drawing wire is fed and melted, and as a result, there are It is easy for foreign matter to get in, and it is also easy for slag to occur.

If slag or foreign matter floating on the molten metal adheres to the ingot, the outside diameter of the rod will change rapidly and the attached area will become defective. In addition, the temperature distribution around the solidification part changes depending on the insertion speed of the rough drawing wire, making it impossible to capture foreign substances convecting within the molten metal, and adding charcoal, etc. to reduce the amount of oxygen in the molten metal. There are drawbacks such as not being able to do so.

Means for Solving the Problems In view of this, the present invention has been developed as a result of various studies, and it is possible to stabilize the outer diameter of the ingot rod when pulling the ingot without using a mold and reduce the entrainment of foreign matter inside. We have developed a rod-shaped ingot manufacturing device that can be used in a variety of ways.

One of the manufacturing apparatuses of the present invention is to bring the lower end of a seed rod of the same type as the molten metal into contact with the surface of the molten metal, and rotate and pull up the seed rod and the solid phase solidified at the lower end of the seed rod while cooling. In this apparatus, a seed rod extending into the molten metal and a concentric skirt are provided, and the molten metal is separated into a molten area surrounding the solid phase that solidifies and a molten metal area surrounding the solid phase. It is something.

Another device of the present invention is to bring the lower end of a seed rod of the same type as the molten metal into contact with the surface of the molten metal, and rotate and pull up the seed rod and the solid phase solidified on the lower end of the seed rod while cooling. , the solid phase is made to grow into a rod shape, and an ilter is provided to separate the molten metal into a molten area around the solid phase that solidifies the molten metal, and a molten metal area surrounding it.

That is, one aspect of the present invention is to solidify the molten metal by bringing the lower end of a seed rod (2) of the same type as the molten metal (1) into contact with the surface of the molten metal (1), as shown by the solid line in FIG. A nozzle (5) is provided for spraying the inert gas, and the seed rod (2) and rod-shaped solid phase (3) to be pulled up are forcibly cooled. A cylindrical support (6) made of a refractory and heat-resistant material is provided around the cooling jacket (4) and is concentric with the seed rod (2). A concentric cylindrical skirt (7) is attached to (2), and the molten metal (1) is separated into a completely solidified solid phase (3) into a surrounding molten metal part (1a) and a surrounding molten metal part (1b). In the plan view, (8) shows a rough line inserted to replenish the molten metal (1).

Another aspect of the present invention is that the length of the skirt (7) extending into the molten metal (1) is lengthened as shown by the dotted line in the apparatus shown in Fig. 1, and the entire filter is attached to the lower end of the skirt (7). be.

By providing a working skirt, it is possible to effectively prevent foreign matter within a visible range generated due to melting of rough lines in the melting part of the enclosure for molten metal replenishment from entering the molten metal part around the solid phase where it solidifies. I can do it. Furthermore, even if deoxidizing charcoal is poured into the surrounding molten metal, its fragments will not impede castability. Furthermore, by attaching a filter to the lower end of the skirt, it is possible to effectively prevent invisible foreign matter from entering the molten metal surrounding the solid phase.

The material of the skirt is to minimize the influence of the temperature change required to completely melt the rough wire for the purpose of replenishing the surrounding molten metal on the molten metal surrounding the solid phase, and to prevent the influence of the water cooling jacket. Therefore, it is desirable to use an alumina-based refractory material with low thermal conductivity, and to further prevent the permeation of molten metal, the surface is coated with alumina cement. In addition, in devices with a filter attached to the lower end of the skirt, the diameter of the skirt should be at least twice the outer diameter of the rod-shaped solid phase, and the amount of molten metal in the area surrounded by the skirt and filter should be at least 5 times the amount of solid phase pulled up per minute. By doing so, fluctuations in the temperature of the molten metal area around the solid phase can be suppressed.

Example (1) Using the apparatus shown by the solid line in Fig. 1, pure Cu with a diameter of 2
A rod-shaped ingot of 0- was manufactured. The skirt has an outer diameter of 110 mm made of alumina-based high porosity refractory material with low thermal conductivity.
A cylindrical body with a diameter of 60 mm was used, and its surface was coated with alumina.

First, without using a skirt, the temperature of the molten metal was maintained at 1,100°C, and the ingot was pulled up without using all the charcoal for carbonation.The ingot was preheated at a position 150 mm away from the pulling part, and a rough drawing wire was inserted. Then melt and the molten metal surface? was held approximately constant. As a result, under stable casting conditions, the temperature of the molten metal in the melting part of the rough drawing wire decreased to below 1090°C, and the temperature of the molten metal in the ingot pulling part fluctuated by more than ±3°C in a short period of time, which was difficult to achieve.

Next, when the skirt was inserted into the molten metal for about 2 crn, the temperature fluctuation of the molten metal at the ingot pulling part was less than ±1°C.
The pulled ingot had a small variation in outer diameter, and a good quality ingot was obtained. Furthermore, deoxidizing charcoal was inserted outside the skirt, but no charcoal was observed to enter the ingot pulling part.
A rod-shaped ingot with a size of 0 was manufactured. A cylindrical body similar to that in (2) above was used as the skirt, and a ceramic filter having a thickness of 10 dew was attached to the lower end of the cylindrical body.

This skirt was inserted into the molten metal, and the insertion depth and ingot pulling speed were varied to investigate temperature fluctuations at the ingot pulling part. The typical results are shown in FIG.

In the figure, the horizontal axis shows the volume inside the skirt [the cross-sectional area of the skirt is 2
The distance from the molten metal surface to the filter is 8.3 cm (circle diameter 60 cm), so the distance from the molten metal surface to the filter is 90], and the vertical axis shows all the molten metal temperatures around 10 mm from the molten metal surface at the ingot pulling part, which can be understood from the figure. It can be seen that in order to obtain a good ingot, stable casting cannot be performed unless the volume inside the skirt is at least five times the amount of ingot pulled up per minute.

Next, the ingot in the stable state is hot-rolled, then cold-drawn and annealed repeatedly using a conventional method, and the wire drawability is evaluated by the conventional ingot-pulling method without using a skirt until the wire diameter reaches 50μ. Compared with ingot. As a result, the amount of wire drawing without permission increased by about 10%.

Effects of the Invention As described above, according to the present invention, ingot defects due to foreign matter are greatly reduced, outer diameter accuracy and pulling speed are stabilized, and in particular, it is possible to manufacture ultra-fine wires with a diameter of 10 μ class, etc. The noticeable effect is that it smells like gold.

[Brief explanation of drawings]

FIG. 2 is an explanatory diagram showing the relationship between quantities. ] Molten metal 1a Molten metal inside the skirt 1b Molten metal outside the skirt 2 Seed rod 3 Solid phase (ingot) 4 Water cooling jacket 5 Nozzle for cooling gas spray 6 Support 7 Skirt 8 Rough drawing line Fig. 2 0 (mm)

Claims (3)

[Claims] (1) The lower end of a seed rod of the same type as the molten metal is brought into contact with the surface of the molten metal, and the solid phase solidified on the seed rod and the lower end of the seed rod is rotated and pulled up while cooling, thereby growing the solid phase into a rod shape. 1. A rod-shaped ingot manufacturing device, characterized in that the device is provided with a seed rod extending into the molten metal and a concentric cylindrical skirt, separating the molten metal into a solid phase peripheral molten metal portion for solidifying the molten metal and a surrounding molten metal portion. (2) The lower end of a seed rod of the same type as the molten metal is brought into contact with the surface of the molten metal, and the solid phase solidified on the seed rod and the lower end of the seed rod is rotated and pulled up while cooling, thereby growing the solid phase into a rod shape. In the device, a cylindrical skirt is provided that is concentric with the seed rod that extends into the molten metal, and a filter is provided at the lower end of the skirt to allow the molten metal to pass through. A rod-shaped ingot manufacturing device characterized by being separated. (3) The skirt diameter is at least twice the outer diameter of the rod-shaped solid phase,
Claim 2 in which the amount of molten metal in the area surrounded by the skirt and filter is 5 times or more the amount of solid phase pulled per minute.
The rod-shaped ingot manufacturing apparatus described in 1.