JPH01172562A - Method and apparatus for continuously supplying raw material bar - Google Patents

Abstract

PURPOSE:To join both metals with excellent adhering force by making the specific ratio of recessed part diameter in rear face of the preceding metal bar to projecting part diameter in front end face of the following metal bar at the time of connecting the rear end of preceding metal bar with the front end of the following metal bar for supplying into a vacuum melting furnace. CONSTITUTION:The metal bar 9a for vacuum deposition is inserted in the vacuum melting furnace 1 for executing vacuum deposition, etc., and melted with the heat source 3 of electron gun, etc., and stored into a crucible 5 as molten metal and used for the evaporation. When the preceding metal bar 9a is made to short length by melting, it is connected with the following metal bar 9b. Therefore, the recessed part 28 having the diameter d1 is formed at the rear end face of the preceding metal bar 9a and the projecting part 29 having the diameter d2 is formed at the front of the following metal bar, and the projecting part 29 is fitted to the recessed part 28. In this case, by deciding so as to have the relation between d1 and d2 satisfying the inequality I, when the following metal bar 9a advances and approaches to the vacuum melting chamber 1, it is heated and expanded, and the projecting part 29 is strong stuck and joined into the recessed part 28 under fitting condition, and the remained part of the shortened preceding metal bar 9a is dropped into the molten 4 and splash is developed and the temp. of molten metal 4 is not developed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for continuously supplying a rod-shaped raw material to a vacuum melting furnace, and a supply device used in the method.

A method of continuously supplying a finite length rod-shaped raw material (hereinafter referred to as a raw material rod) from the atmosphere to a melting furnace in a vacuum is applied, for example, to vacuum evaporation, ion blating, etc.

(Conventional technology) Conventionally, a raw material rod is replaced with a new one after a certain length has been used, but the usage yield of the raw material rod is low and it is uneconomical, and there is no need to replenish the raw material during replacement, making it difficult to stabilize melting. There are problems such as damage to sexuality.

On the other hand, there is also a method of pushing the raw material rod as it is with the next raw material rod and dropping the remaining part into the molten water, but since a fairly short insoluble lump enters the molten metal, you may notice the occurrence of splash or the temperature of the hot water. Non-uniformity in quality is likely to occur due to changes.

There is also a method that uses male and female screws to connect the leading raw material rod and the trailing raw material rod, but this method is expensive to process, causes large material loss, is difficult to automate, and requires detailed equipment. A problem remains.

(Problems to be Solved by the Invention) Therefore, it is an object of the present invention to propose a method for seamlessly supplying raw material rods and a device advantageously adapted to the method.

(Means for Solving the Problems) This invention provides a method for sending a raw material rod introduced into an airtight chamber to a vacuum melting furnace communicating with this airtight chamber at a speed corresponding to the amount of melting, while a new raw material rod is transferred to the airtight chamber. In order to seamlessly supply raw material rods by repeating the process of introducing a raw material rod to follow the preceding raw material rod and connecting the rear end of the preceding raw material rod to the tip of the following raw material rod, it is necessary to A cylindrical concave portion with a diameter d opening on the end face is provided at the rear end of the raw material rod, and a cylindrical convex portion with a diameter d2 is provided at the tip end of the trailing raw material rod, each satisfying the following formula, A method for continuously supplying a raw material rod, characterized in that it is formed on the central axis of the raw material rod, and the cylindrical convex portion of the following raw material rod is fitted into the cylindrical concave portion of the preceding raw material rod to connect the two. (1+α・ΔTz)>dl(1+α・ΔTl)
>dz where dl: Diameter d2 of the concave part of the leading rod at room temperature
: Diameter of the convex part of the trailing rod at room temperature α : Linear expansion coefficient ΔT, : Difference between the temperature of the leading rod at the time of melting and room temperature ΔT2: Difference between the temperature of the trailing rod and room temperature after introduction into the airtight chamber be.

The equipment directly used to carry out the method includes an airtight chamber that communicates with the vacuum melting furnace, and a waiting room that faces the vacuum melting furnace across this airtight chamber and communicates with the airtight chamber through a barrier that can be opened and closed. The airtight chamber is equipped with a transport device that sends the raw material rods introduced from the waiting room to the vacuum melting furnace, and the waiting room is equipped with a transport device that sends the raw material rods into the airtight chamber at a faster speed than the transport device in the airtight chamber. This is a continuous feeding device for raw material rods.

Now, in order to continuously supply raw material rods of finite length to the vacuum melting furnace, it is necessary to connect the raw material rods one after another and send them out, but at this time, the joints between the raw material rods are It must have the strength to withstand the transmission of rotational force, etc. and the force due to its own weight such as cantilever protrusion, the joint part must be able to be constantly and uniformly melted like other parts, and there is little loss of raw materials when manufacturing the joint part. It is advantageous to satisfy the following conditions: low manufacturing cost and automatic, simple and reliable jointing.

By the way, the leading raw material rod sent to the vacuum melting furnace (hereinafter referred to as the preceding rod) is at a high temperature due to the heat of melting, while the trailing raw material rod (hereinafter referred to as the trailing rod) remains at a low temperature around room temperature. .

Therefore, when fitting the raw material rods to each other with concavities and convexities, firstly, they fit together when there is a large temperature difference between the raw material rods, and then the temperature of the trailing rod that comes into contact with the leading rod increases after fitting, and the temperature difference between the two rods increases. When this becomes small, the convex portion of the trailing rod is expanded to perform so-called shrink fitting, resulting in a joint that satisfies the above-mentioned conditions.

Further, an apparatus applied to supplying raw material rods is shown in FIG.

In the figure, reference numeral 1 denotes a vacuum melting furnace, which is equipped with a melting heat source 3 such as an electron gun and a crucible 5 for receiving molten metal 4 in a melting chamber 2 . An airtight chamber 6 provided adjacent to the vacuum melting furnace 1
has an airtight structure, with a standby chamber 7 communicating with the airtight chamber 6 sandwiched between the airtight chamber 6 and facing the vacuum melting furnace. It is separated by Note that 9a and 9b are raw material rods, 9a is a leading rod, and 9b is a trailing rod.

The airtight chamber 6 is equipped with a conveying device 10 for feeding the raw material rod into the vacuum melting furnace 1. As shown in FIG. 2, the transport device 10 includes a fixed base 11 fixed to the floor of an airtight chamber, and a movable base 14 guided by a guide 12 rising vertically from the fixed base 11 and supported by a spring 13. A mount 16 is rotatably attached to each base via a pivot 15, and a drum roll 17a,
17b is rotatably provided.

Therefore, the upper and lower drum rolls 17a that support the raw material rod,
Since the spring 13 is interposed between 17b, it is possible to cope with changes in the diameter of the raw material rod. Note that the drum roll 17a is driven by a motor 18.

Further, as shown in FIG. 3, the pedestal 16 is rotated by operating a tie rod 19b that is engaged with a pin 19a fixed to the end of the pedestal 16, and thus the drum roll 17a is rotated.

The angle θ of 17b with respect to the moving direction of the raw material rod is adjusted simultaneously for each drum roll 17a, 17b.

Angle θ of drum rolls 17a and 17b and drum roll 17
By changing the rotational speed of a, the rotational speed and feeding speed of the raw material rod at the time of feeding the raw material rod are adjusted.

That is, when the angle θ=0° shown in FIG. 3(a), the raw material rod moves straight without rotating, and the angle θ shown in FIG. 3(b)
When the angle is 0°, the raw material rod moves forward while rotating at a rotational speed corresponding to θ. Note that the angle θ between the drum rolls 17a and 17b is in opposite phase.

On the other hand, the standby chamber 7 has an intake port 20 and its 1I21 for supplying raw material rods from outside, and an airtight chamber 6 for storing the stored raw material rods.
It is equipped with a conveying device 22 for sending out to.

The conveying device 22 is constructed in the same way as the drum roll on the lower side of the conveying device 10 in the airtight chamber 6, namely, a fixed base 23 fixed to the floor of the chamber, a pedestal 25 attached to the fixed base 23 via a pivot 24, and this pedestal. Drum roll 2 rotatably provided at 25
6 and a motor 27, and the upper drum roll does not have to take into account falling of the raw material rod or rear-end collision with the trailing rod.
Not necessary.

The transport device 10 in the airtight room 6 and the transport device 2 in the waiting room 7
Apart from the feed rate control with 2, the advance feeder 9a in the airtight chamber 6
is fed at a constant speed to melt it, and the trailing rod 9b in the waiting chamber 7 is rapidly moved to fit them together.

(for production) Next, the procedure for supplying the raw material rod will be explained.

The leading rod 9a in the airtight chamber 6 is rotated and advanced by the conveying device 10, and is melted in the vacuum melting furnace 1 sequentially from its tip.

When the remaining length of the leading rod 9a becomes equal to or less than a predetermined length, the blocking wall 8 is closed, the lid 21 of the intake port 20 of the waiting chamber 7 is opened, a new raw material rod is supplied into the chamber, and the lid 21 is closed. After closing, the inside of the waiting chamber 7 is evacuated.

When the pressure in the waiting chamber 7 becomes the same as that in the airtight chamber 6, the blocking wall 8 is opened, and the trailing rod 9b in the waiting chamber 7 is fast-forwarded by the conveying device 22 (see FIG. 4(a)), and the leading rod 9a is moved quickly. The tip of the trailing rod 9b is brought into contact with the rear end, and the cylindrical convex portion (hereinafter referred to as the convex portion) 29 of the trailing rod 9b is inserted into the cylindrical concave portion (hereinafter referred to as the concave portion) 28 of the leading rod 9a. (See figure (b)).

At this time, the temperature of the leading rod 9a has increased due to the heat of dissolution, while the trailing rod 9b is almost at room temperature, and due to contact between the two, the temperature of the trailing rod 9b increases as it receives heat from the leading rod 9a.
The convex portion 29 of the trailing rod 9b thermally expands within the concave portion 28 of the leading rod 9a, and the concave portion 28 and the convex portion 29 fit tightly together (the fourth
(See figure (c)).

Here, the diameters of the concave and convex portions at room temperature are determined according to the following formula so that the necessary interference for joining the raw material rods is obtained.

d2(1+α・ΔT2) >a+(1+α・ΔT,)
>d2 where d: Diameter at room temperature of the concave part of the leading rod (body) d2: Diameter at room temperature of the convex part of the trailing rod (mm) α: Linear expansion coefficient ΔT1: Temperature of the leading rod at the time of melting Difference from room temperature ΔT2: Difference between the temperature of the trailing rod after introduction into the airtight chamber and room temperature.

(Example) Using the supply device shown in FIG. 1, the composition of Ti is obtained.
40rrnφX 19 at the tip of the 1200mm raw material rod
．． A convex part with a length of 18 mm and a 20 mm diameter on the rear end.
．． When recesses each having a diameter of 0.00 mm and a depth of 20 mm were formed in advance, and the raw material rods were continuously supplied to the vacuum melting furnace using the procedure according to the method of this invention, the joints between the raw material rods did not separate and there was no interruption. A stable supply was achieved, and no splash was observed during melting.

(Effects of the Invention) According to this invention, the joint between the raw material rods is shrink-fitted using a large temperature difference, so that the joint can be ensured, and therefore, when the raw material rods are transmitted with rotational force and cantilevered, It has the strength to withstand its own weight, making it possible to achieve stable continuous feeding.

Furthermore, the joints between the raw material rods are solid, and splash generation during melting can be avoided. In addition, since the joint part can have a large interference margin, the length of the uneven part can be reduced, and there is less material loss due to machining, and the machining can be done by machining the cylindrical hole and shaft, so it is possible to reduce costs.

In addition, since the device utilizes the temperature difference generated during the supply process by the joint, no special power or equipment is required, and automation is easy.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the feeding device according to the present invention, Fig. 2 is a sectional view taken along the line
) to (c) are explanatory diagrams of joints of raw material rods. 1... Vacuum melting furnace 2... Melting chamber 3
... Heat source for melting 4 ... Molten metal 5 ... Crucible 6 ... Airtight chamber 7 ... Waiting room
8...Blocking wall 9a...Leading rod 9
b... Trailing rods 10, 22... Conveyance device LL
23...Fixed base 12...Guide 1
3... Spring 14... Moving base 15.24
... Pivot 16, 25 - ... Frame 17a
, 17b, 26-Drum roll 18, 27...Motor 19a...Bin 19b...Tie rod
20...Intake port 21...M 2
8... Concave portion 29... Convex portion Fig. 2 Fig. 3

Claims (1)

[Claims] 1. The raw material rod introduced into the airtight chamber is sent to the vacuum melting furnace connected to this airtight chamber at a speed corresponding to the amount of melting, while a new raw material rod is introduced into the airtight chamber and preceded. In seamlessly supplying the raw material rod by repeating the process of following the raw material rod and connecting the rear end of the preceding raw material rod with the tip of the trailing raw material rod, the rear end of the preceding raw material rod is A cylindrical recess with a diameter d_1 opening at the end face of the rod and a cylindrical convex portion with a diameter d_2 at the tip of the trailing raw material rod are formed on the central axis of the raw material rod by satisfying the following formulas. A method for continuously supplying raw material rods, characterized in that a cylindrical convex portion of a trailing raw material rod is fitted into a cylindrical concave portion of a preceding raw material rod to connect the two. Note d_2(1+α・ΔT_2)>d_1(1+α・ΔT_
1)>d_2 where d_1: Diameter of the concave part of the leading rod at room temperature d_2: Diameter of the convex part of the trailing rod at room temperature α: Linear expansion coefficient ΔT_1: Difference between the temperature of the leading rod and room temperature at the time of melting ΔT_2 : Difference between the temperature of the trailing rod and room temperature after introduction into the airtight chamber. 2. It consists of an airtight chamber that communicates with the vacuum melting furnace, and a waiting room that faces the vacuum melting furnace across this airtight chamber and communicates with the airtight chamber through a barrier that can be opened and closed.The airtight room is introduced from the waiting room. A continuous feeding device for raw material rods, which is equipped with a conveyance device that sends the raw material rods to a vacuum melting furnace, and a waiting chamber is equipped with a conveyance device that sends the raw material rods into the airtight chamber at a faster speed than the conveyance device in the airtight chamber.