JPH04107227A - Device for continuously producing cast ingot by electron beam melting - Google Patents

Abstract

PURPOSE:To enable the taking-out of a cast ingot during producing into the atmospheric air and to continuously produce the cast ingot by providing a cast ingot taking-out hole an a furnace bottom wall in an electron beam melting furnace and a dummy bar, which in hermetically contact with an annular sealing means and extends to a mold at the upper end part thereof. CONSTITUTION:In the condition of charging the upper end part 30A of dummy bar 30 into the mold 9, melting material 3A is irradiated with the electron beam 2 from an electron gun 1 and melted, and by driving the cast ingot drawing-out shaft 28 downward, the cast ingot 10 is taken out to the atmospheric air from a seal bearing 12. The cast ingot 10 taken out into the atmospheric air is cooled till coming to a black ingot by spouting the cooling water 17 from water cooling nozzle group 16. Then, after shutting off the cooling water 17 with draining rolls 18, the cast ingot can be cut off at the prescribed length with the flame of torch 19 for cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for continuously producing ingots by an electronic heat melting method.

[Prior art] Electron beam melting furnaces are a means of producing ingots of active metals such as T1 and Zr, high alloy steels, and superalloy steels by utilizing the characteristics of electron beams, such as melting and solidification under high temperature and high vacuum conditions. It has been widely used in recent years as A conventional electron beam melting furnace produces ingots using a hatch type, and an example thereof is shown in FIG.

As shown in FIG. 3, the conventional electron beam melting furnace is equipped with a vacuum evacuation device 22 so as to maintain the ingot manufacturing chamber 26 at the same degree of vacuum. The ingot is produced by irradiating the molten material 3A with an electron beam 2 generated from an electron gun 1 to form a droplet 7.
is dropped into the mold 9, and the electron beam 2 is also irradiated into the mold 9 to form a molten boule 6 on the upper surface of the ingot 10.The ingot 10 is then pulled out in the direction F and placed in the ingot manufacturing chamber 26. The whole is cooled down to below the solidification temperature. Note that the ingot 10 is pulled out via the ingot base plate 27 via the ingot pulling shaft 28.
This is carried out by a drive device (not shown) attached to the lower end of the ingot production chamber 26, which is not separated from the ingot production chamber 26 by the seal hair ring 12 and is placed under an atmospheric atmosphere. After melting the melted material 3A, the vacuum valve 5 is closed, the melted material is replaced with a new melted material, and the inside of the material supply device 4A is evacuated. During this time, the melted material 3B is melted, and when the evacuation is completed, the vacuum valve 5 is opened and a new melted material is melted. An example of such a melting furnace is shown in, for example, Japanese Unexamined Patent Publication No. 01-79328.

In such a melting furnace, the length of the ingot 10 to be manufactured or the length of the ingot production chamber 26 is limited, and the length of the ingot 1
When taking the 0 out of the melting furnace, it was necessary to cut off the vacuum system and take it out, and when restarting melting, it was necessary to evacuate again, resulting in extremely low production efficiency.

[Problem to be solved by the invention] It is impossible to continuously produce ingots using conventional electron beam melting furnaces, and the production efficiency is extremely low.

The present invention enables the ingot to be taken out into the atmosphere during production, cools the taken out ingot with water as necessary, and cuts it with a cutting torch, thereby continuously cutting the ingot. The purpose is to manufacture.

[Means for Solving the Problems] Claim 1 of the present invention provides an ingot outlet 25 on the bottom wall 23 of an electron beam melting furnace, and an annular sealing means 12 on the inner circumference of the ingot outlet 25. An apparatus for continuously manufacturing ingots by electron beam melting, characterized in that a tummy bar 30 is provided, which is in airtight contact with an annular sealing means 12 and whose upper end extends to a mold 9.

In addition, claim 2 of the present invention provides that the melting chamber 8 and the ingot chamber 11 are formed by airtightly providing a partition wall 14 between the mold 9 and the side wall 24 of the melting furnace. 2. An apparatus for continuously producing ingots by electron beam melting according to claim 1, characterized in that a vacuum evacuation device fi22.21 is connected thereto.

Hereinafter, a specific example of claim 1 of the present invention will be explained in detail with reference to the embodiment shown in FIG. In FIG. 1, members similar to those in the example of the conventional device shown in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted.

25 is an ingot outlet provided in the bottom wall 23 of the ingot chamber;
is provided at the ingot outlet 25 and is in airtight contact with the ingot lO.
For example, a sealing hair ring is used as an annular sealing means. 15 is an ingot pulling roll for pulling the ingot 10 downward; 16 is a group of water-cooled nozzles for cooling the ingot 10 with cooling water 17; and 18 is for removing water on the surface of the cooled ingot 10. The draining roll 19 is a cutting torch for cutting the ingot 10 to a required length after removing the cooling water. Reference numeral 30 indicates a tammy i<- which can be in airtight contact with the sealing hair link 12, the -1 end extends to the mold 9, the lower part is held between the drawing rolls 15, and the ingot l
It supports the ingot O and seals the ingot outlet 25 until the ingot 10 reaches the part t of the sealing hair ring 12 after melting has started.

The inner wall of the mold 9 should be inversely tapered (widening upward), as shown in FIG. 4, in order to make airtight contact with the ingot 10 and block ventilation between the melting chamber 8 and the ingot chamber 11. Or preferable.

That is, in FIG. 4, D represents the width of the F end of the mold, D2 represents the width of the lower end of the mold, and L represents the length from the upper end to the lower end of the mold. The amount of reverse taper is determined by formula (1).

Reverse taper amount (%)=”-D2xlOO... (1)
As shown in Fig. 5, a partition wall 14 is airtightly provided between the melting chamber 8 and the ingot chamber 1, and the melting chamber 8 and the ingot chamber 11 are evacuated using separate evacuation devices 2 and 22. and the lysis chamber I
The relationship between the inverse taper ratio of the mold and the degree of vacuum in the melting chamber 8 is shown when melting is started and an ingot is manufactured with the ingot chamber at 0-' Torr and the ingot chamber at 1.times.IQ-2 Torr.

As shown in the figure, when the reverse taper ratio is on the negative side, the degree of vacuum in the melting chamber 8 becomes poor, and the electron beam irradiation becomes unstable. On the other hand, when the reverse taper ratio is 0% or more, the degree of vacuum in the melting chamber is stable at a high level.

FIG. 6 shows the relationship between the reverse taper ratio of the mold and the amount of surface defects on the ingot. The amount of surface defects on the ingot is 1% on the entire surface of the ingot.
The length and number of cracks of mm or more are measured to determine the total length of the cracks, and this is the value converted per unit area of the ingot.

As shown in the figure, when the reverse taper ratio of the mold is 10% or less, the amount of surface defects is stable at a low level.

Next, a specific example of claim 2 of the present invention will be explained in detail with reference to an embodiment shown in FIG. In FIG. 2, members similar to those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

A partition wall 14 is airtightly provided to connect the mold 9 and the melting furnace side wall 24, and the melting chamber 8 and the ingot chamber 11 are partitioned off by the partition wall 14. A vacuum evacuation device 21.22 is connected to each of the ingot chamber 11 and the melting chamber 8 via an evacuation vibrator I3.29.

5A and 5B are vacuum valves provided on the outlet side of the material supply devices 4A and 4B for airtightly opening and closing between the melting chamber 8 and the material supply devices 48 and 4B; 31A and 31B are the material supply devices 4;
This is a vacuum evacuation device for reducing the pressure inside A and 4B, and exhaust pipes 32A and 32B are connected between the material supply devices 4A and 4B.
connected by. Thereby, the melting materials 3A and 3B can be alternately supplied from both the material supply devices 4A and 4B during electron beam melting.

Although the above description has given an example of a lot melting furnace among electron beam melting furnaces, the present invention can also be applied to a hearth melting furnace.

[Function] In the invention of claim 1 shown in FIG. 1, during continuous production of ingots, the upper end portion 30A of the dummy bar 30 is inserted into the mold 9, and the electron beam 2 is ejected from the electron gun 1 to the melted material 3.
A is irradiated to melt the melted material 3A, and the ingot pulling shaft 28 is driven downward to take out the ingot 10 from the seal hair link 12 into the atmosphere.

The ingot 10 taken out into the atmosphere is cooled until it becomes black pieces by discharging cooling water 17 from the water cooling nozzle group 16 using the same method as in the vertical continuous manufacturing apparatus for steel. Thereafter, after cutting off the cooling water 17 with the draining roll 18, a flame 20 is emitted from the cutting torch 19 to cut into a predetermined length.

In order to continuously produce ingots, it is also necessary to continuously supply molten material. This is after the melting of the melting material coarse boundary is completed.
Close vacuum valve 5. Next, the melted material 3B is poured into the melted material 3B to continue melting. During this time, after loading a new melted material into the material supply device 4A, the inside of the material supply device 4A is evacuated, and after the evacuation is completed, the vacuum valve 5 is opened to retreat the melted material 3B and remove the melted material 3A. advance,
Thereafter, the same operation is repeated over and over again to continue dissolving.

In the invention of claim 2 shown in FIG. 2, the melting chamber 8 and the ingot chamber 11 are airtightly separated by a partition wall 14, and vacuum evacuation is performed by independent evacuation devices 21 and 22. For example, the melting chamber 8 has a pressure of 1O-5 to 1O-3Tor.
The ingot chamber 11 is maintained at a vacuum level of 10-3 to 10-' Torr. The ingot 10 solidified in the mold 9 is placed in the ingot chamber 1.
1, the ingot is pulled out through the sealing hair links 14 by driving the ingot drawing rolls 15.

In the apparatus of the present invention, even if some outside air enters the ingot chamber 11 through the sealed bear link 12, a partition wall 14 is provided between the ingot chamber 11 and the melting chamber 8, and the ingot chamber 11 is depressurized. Therefore, the high degree of vacuum in the melting chamber 8 is maintained by the intrusion of outside air into the ingot chamber 11 and by the ventilation blocking effect of the partition wall 14. For this reason, the dissolution chamber 8
There are no problems such as destabilization or interruption of melting due to a decrease in the degree of vacuum.

It is preferable that the volume of the ingot chamber 11 is increased in order to increase the effect of reducing intrusion of outside air [Example] Using the apparatus of the present invention shown in FIG. We will explain the implementation when manufacturing.

Table 1 shows the average degree of vacuum in the melting chamber and the ingot chamber, the reverse Dever ratio of the mold, the amount of continuous melting, the amount of production per unit time, the amount of surface defects on the ingot, and the maintenance yield of the ingot.

Note that conventional apparatus examples No. 5 and No. 6 were melted using an electron beam melting furnace shown in FIG. In addition, the treatment yield of the ingot is the result of surface grinding the ingot using a lathe until it becomes defect-free.

The apparatus of the present invention maintains a stable vacuum level in the melting chamber and the ingot chamber, can melt up to 5000 kg, has few surface defects on the ingot, and achieves a treatment yield of 97.5% or more. ing.

In contrast, conventional device example No. 5. In No. 6, the ingot maintenance yield is high or the ingot cannot be continuously produced, so the productivity is very poor.

[Effects of the Invention] As described above, the apparatus of the present invention enables continuous production of ingots, and also stabilizes surface defects of the ingots to a low level.

As a result, the productivity of the electron beam melting furnace, which had been an issue in the past, has been significantly improved, and operation in three shifts has become possible. Further, even in an electron beam melting furnace with a small capacity electron gun, it becomes possible to manufacture long ingots, and equipment costs can be reduced.

[Brief explanation of the drawing]

1 and 2 are diagrams (partially sectional view) showing an example of the device of the present invention, FIG. 3 is a diagram (partially sectional view) showing an example of a conventional device, and FIG. 4 is a diagram showing an example of the device of the present invention (partially sectional view). A cross-sectional view showing an example of a mold, Figure 5 is a diagram showing the relationship between the reverse taper ratio of the mold and the degree of vacuum in the melting chamber, and Figure 6 is a diagram showing the relationship between the reverse taper ratio of the mold and the amount of surface defects on the ingot. It is a diagram.

Claims (1)

[Claims] 1. An ingot outlet (25) is provided on the bottom wall (23) of the electron beam melting furnace, and an annular sealing means (12) is provided on the inner circumference of the ingot outlet (25). , annular sealing means (12)
An apparatus for continuous production of ingots by electron beam melting, characterized in that a dummy bar (30) is provided which is in airtight contact with the dummy bar (30) and whose upper end extends to the mold (9). 2. By airtightly providing a partition wall (14) between the mold (9) and the melting furnace side wall (24), a melting chamber (8) and an ingot chamber (11) are formed, and the melting chamber (8) and ingot chamber (1
2. An apparatus for continuously manufacturing ingots by electron beam melting according to claim 1, characterized in that vacuum evacuation devices (22) and (21) are connected to and provided in each of step 1).