JPS62267062A - Centrifugal precision casting apparatus for titanium and its alloy - Google Patents

Abstract

PURPOSE:To improve the material yield and the operational efficiency by charging melting material into a copper-made crucible with cooling vessel and melting while shifting an electrode toward front and back, right and left and vertical direction by an electrode position shifting device. CONSTITUTION:The crucible 3 arranges the flow-out hole 3' on its bottom and the cooling vessel on its side, and by circulation of coolant, thin film is formed between the crucible 3 and the melting material, to prevent the whole crucible wall from sticking. In the upper part of a vacuum chamber 15, an electrode holder 4 is inserted as slidable through sealed flange 5, etc. The electrode holder 4 has a electrode supporting rod fitted by a spherical seat 7, and at the time of melting, the position of the electrode 2 is adjusted according to the material to be melted. By this constituent apparatus, the product yield is improved and also the operation is efficiently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a centrifugal casting apparatus, and more particularly to a centrifugal precision casting apparatus for titanium and titanium alloys.

(Prior art and problems to be solved) In centrifugal precision casting of titanium and titanium alloys, arc melting is performed in an argon gas atmosphere because the material is easily oxidized and needs to be melted at high temperatures. However, various proposals regarding melting, casting, etc. have been made in the past.

For example, the crucible is made of copper and has a heat insulating groove cut into the concave surface that receives the material (Utility Model Publication No. 57-15008), or the crucible is made of magnesium oxide with a purity of 95% or more,
One with a (+) side electrode buried in the bottom (Utility Model No. 60-28
00) etc. There is also a structure in which the electrode part is surrounded by a cover to prevent argon gas from escaping to the outside of the crucible (Utility Model Publication No. 57-16569), and 4! for controlling the position of the electrode (-) from outside the container. There is also one (Utility Model Application Publication No. 105109/1983) that has a structure in place. There is also a locking mechanism (if!) which divides the container into a melting chamber and a mold chamber and allows one door to close the lid at the same time (Japanese Utility Model Publication No. 57-1016).

These proposals are measures against oxidation, high temperature melting, etc. inherent in arc melting of titanium and titanium alloys, or are aimed at improving workability.

However, all of them are based on the conventional centrifugal U-adic system, and although they are effective to that extent, they dissolve as a 1-1 system.

It is not intended to fundamentally improve casting work, etc. In particular, since titanium and titanium alloys are used as materials for relatively small cast products such as dental and decorative products, there is a need for the development of a technology that can centrifugally precision cast these products with a high material yield and that also has easy-to-operate equipment. ing.

The present invention was made in response to such demands, and includes the development and operation of a centrifugal precision casting method that prevents oxidation of titanium and titanium alloys and enables casting within the time required after high-temperature melting. The purpose is to provide a device that can be implemented easily.

(Means for Solving the Problems) In order to achieve the above object, the present inventor discovered that although the conventional centrifugal precision casting method for titanium materials involves arc melting in an argon gas atmosphere, the melting process is performed under atmospheric pressure. Afterwards, the mold was evacuated and centrifugal force was applied for the first time, but it was discovered that this could not cope with the temperature drop within a short time due to the arc stopping after high-temperature molten M (approximately 1720°C), and new measures were taken. We have conducted repeated research on As a result, the vacuum vessel is made to reach a predetermined degree of vacuum in advance, argon gas pressure is filled only during arc melting, and after melting, the molten material is dropped into a mold that has been rotated at a constant speed in advance. It has been found that this enables prevention of oxidation and casting within a short time. The present invention has been made by devising a device that can effectively carry out this method, with particular emphasis on operability.

That is, the centrifugal precision casting apparatus for titanium and titanium alloys according to the present invention evacuates the inside of the container containing the electrodes, crucible, and mold, then fills it with argon gas, and casts titanium or titanium alloys in this atmosphere. In a centrifugal precision casting device in which melting is carried out in a crucible and then cast into a mold that is rotating at a constant speed, the crucible is made of copper with a cooling seed, and the electrode is placed on the top of the container with a rocking bed and a spherical seat. The device is characterized in that it is provided with an electrode position variable device that can be moved forward, backward, left, right, and up and down by attaching the device through the device, and is also provided with a mold exchange door equipped with a one-touch locking mechanism.

The present invention will be explained in detail below based on examples.

(Embodiment) FIGS. 1 and 2 show a centrifugal precision casting apparatus according to an embodiment of the present invention.

In the figure, 1 is an electrode support rod that holds the electrode (-) 2;
It is connected to one terminal of an arc generator (1 to lance 34 are shown). 3 is a copper crucible,
As described below, it has a flow hole 3' on the bottom and a cooling tank on the side, so that when the material contained in the crucible is melted, a cooling medium (e.g., water) can be circulated through a conduit to cool it. It has become.

Reference numeral 31 denotes a mold provided on a turntable 32 attached to a drive shaft 36 of a drive motor 33, and a mold chamber is formed, for example, in a circular mold frame with a porous investment medium.

These electrodes 2, crucible 3, mold 31, etc. are placed in a vacuum container 15.
A vacuum pump (not shown) is connected to the vacuum chamber 15 through piping to the vacuum hole 28, and an argon gas cylinder is connected to the argon gas supply hole 28' through piping. (not shown) is connected. Reference numeral 37 denotes a pedestal in which the arc generator one-rotation drive unit and the like are housed, and supports the vacuum container 15.

In the above device, titanium or titanium alloy is centrifuged using precision g
To do this, first, a vacuum pump is used to reach a predetermined degree of vacuum in the vacuum container 15 (I X I O'' Torr), and air that obstructs the flow of the molten material during casting is eliminated in advance. The mold 31 is rotated in advance at a constant speed (600 to 900 rpm) by the drive motor 33. Next, the arc generator is turned on and an arc is generated between the electrode 2 and the material to cause arc melting of the material. conduct.

Arc generation is stopped by visually confirming the melting of the material through the viewing window 30 or by detecting the natural fall of the melt from the crucible 3. The melt naturally falls from the flow hole 3' of the crucible 3,
It is fed into a rotating mold and pushed into the mold chamber by centrifugal force.

In this way, since the melting, casting, and cooling solidification of the material is performed in a vacuum, oxidation can be prevented. In addition, the material is cast immediately after melting, there is no drop in viscosity due to temperature drop, and the material is cast with sufficient pressure due to centrifugal force.
There is no need for special mold design such as providing exhaust vent holes, and material yield is improved.

In the present invention, in order to realize a centrifugal precision manufacturing equipment with good operability, the following adjustment mechanism is provided.

First, the mechanism of the crucible, crucible, and crucible holder will be explained.

As shown in FIG. 4, the crucible 3 has a flow hole 3' on the bottom surface, a cooling tank is provided on the side, and a cooling medium is circulated through a conduit. Due to this cooling mechanism, the molten titanium or titanium alloy is coated with a thin film (
form a skull).

It is possible to prevent the crucible from sticking to the entire crucible 3, and it is possible to melt a large amount of material with a high material yield.

The crucible 3 is attached to the crucible pedestal 17 by a crucible holder 18 having a built-in spring 19, and the other end of the crucible pedestal 17 is provided with a screw guide 2o via a hinge pin 24 so as to be rotatable upward. The screw guide 20 is rotatable by the screw handle 21 (see FIG. 5). 22, 23 are screw seats, 26 is crucible holder 1
This is an electrical terminal (+) to be connected to 7.

With such a mechanism, the position of the crucible 3 can be adjusted up and down with the screw handle 21 according to the size of the mold, and when installing or removing the mold, the hinge pin 24 is used as a fulcrum and is lifted upward and retracted, and the stopper pin 35 is Easy to insert and operate.

Next, the positioning of the electrode part! The mechanism will be explained.

As shown in FIG. 4, an electrode holder 4 is slidably inserted into the upper part of the vacuum chamber 15 via a seal flange 5 and an insulating plate 6.
An electrode support rod 1 is attached to the holder, and a vertical operating handle 11 is attached to the upper part of the holder, which rotates around a shaft seat 12 fixed to the outside of the upper part of the vacuum container 15 as a fulcrum. 13 is a vertical guide, and 14 is a handle. A swing piece 9 having a plurality of swing handles 10 is attached to the upper part of the electrode support rod 1, and a conduit for cooling the electrode is also attached. 8 is an electrical terminal.

According to such a mechanism, during arc melting, the position of the electrode (e.g. tungsten material) 2 in the vacuum container can be adjusted according to the shape and size of the material to be melted, and its vertical movement is Loosen the handle 14 and turn the vertical operation handle 11
After moving up and down, it can be fixed by tightening the screw, and the movement back and forth and left and right can be done by grasping the two swing handles 10 (see Figure 7) with both hands.

For example, by lowering the right side and lowering the swinging piece 9, the electrode 2 can be moved to the left and right of the executive, as seen from the viewing window 3o, and the electrode 2 can be positioned at the desired position, making the operation easier. It's easy.

Next, the door mechanism provided in the vacuum container will be explained. As shown in FIG. 4, a container lid (door) 16 is provided on one side of the vacuum container 15. As shown in FIG. This container 'M16 is
When the inside is evacuated, no force is required for tightening, but it is necessary to set the contact surfaces with the vacuum container parallel and tighten with a predetermined force. Therefore, as shown in Fig. 8, a square thread is cut at the tip of the lid handle 25 so that it can be opened and closed with one touch, and this threaded part is machined as shown in the figure.
On the other hand, drill a hole in the vacuum container flange on the female thread side (see Figure 4) so that the threaded end of the lid handle can fit therein without resistance. Therefore, the lid handle 25 is
``By rotating, the door can be locked with a predetermined force.

It goes without saying that the apparatus of this embodiment having one or more configurations can automate the arc melting and casting of titanium and titanium alloys.

(Effects of the Invention) As detailed above, according to the present invention, the air in the mold is removed by vacuuming before melting, the mold is rotated in advance, and an atmosphere filled with argon pressure is created. Since titanium and titanium alloys are arc-melted in the mold and cast within a complex melting time, titanium and titanium alloys are forced into the mold chamber at high temperatures and with sufficient pressure without oxidation, making it possible to manufacture high-quality products with a high material yield. Furthermore, operations such as positioning the electrode and attaching and detaching the mold can be performed easily, and the operability of the entire apparatus is excellent.

[Brief explanation of drawings]

1 to 3 are diagrams showing a centrifugal ejector casting apparatus according to an embodiment of the present invention, in which FIG. 1 is a side sectional view, FIG. 2 is a front view, and FIG. 3 is a plan view. Fig. 4 is a sectional view showing the electrode part in the above device, Figs. 5 and 6 are explanatory views showing the mechanism of the crucible and crucible holder in the above device, respectively, and Fig. 7 is an enlarged explanatory view of the above device seen from above. , FIG. 8 is a perspective view illustrating the door mechanism in the above device. 1... Electrode support rod, 2... Electrode, 3... Crucible,
3'... Flow hole, 4... Electrode holder, 5... Seal flange, 6... Insulating plate, 7... Spherical seat, 8...
...Electrical terminal (-). 9... Swinging floor, 10... Swinging handle, 11...
Vertical operation handle, 12... Shaft piece, 13... Vertical guide, 14... Handle, 15... Vacuum container, 16.
... Container lid (door), 17... Crucible holder, 18...
Crucible holder, 19... Spring, 20... Screw guide, 2
1...Screw handle, 22.23...Screw seat, 24
...Hinge pin, 25...Lid handle, 26...
Electrical terminal (+), 27... Destruction plate, 28... Vacuum hole, 28 Electricity... Argon gas supply hole, 29... Internal lighting window, 30... Viewing window, 31... Mold , 32...
Turntable, 33... Drive motor, 34... Transformer, 35... Stopper pin, 36... Drive shaft,
37... mount. Patent applicant Takashi Nakamura, Patent attorney representing Kobe Steel, Ltd. Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] After evacuating the inside of the container containing the electrode, crucible, and mold, argon gas is filled in, and titanium or titanium alloy is arc melted in the crucible in this atmosphere, and the mold is rotated at a constant speed in advance. In a centrifugal precision casting device for casting into a metal, the crucible is made of copper with a cooling tank, and the electrode is attached to the upper part of the container via a rocking seat and a spherical seat so as to be movable in the front, back, left and right, and up and down directions. A centrifugal precision casting machine for titanium and titanium alloys, characterized in that it is equipped with a variable device and a mold exchange door with a one-touch lock mechanism.