JPH07106380B2 - Manufacturing method of aluminum hollow extrusion for vacuum - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrahigh vacuum chamber used for an accelerator such as a synchrotron, a particle acceleration pipe, a thin film manufacturing apparatus, a surface analysis apparatus, a nuclear fusion apparatus, The present invention relates to a method for manufacturing a hollow aluminum extrusion product for vacuum used in a high vacuum device such as a small synchrotron orbital radiation (SOR) used as an X-ray source for semiconductor lithography.

In this specification, aluminum shall include pure aluminum and its alloys. In addition, in this specification, the inert gas includes not only inert gas of the periodic table such as argon gas, xenon gas and helium gas but also gas such as nitrogen gas which is inert to aluminum.

2. Description of the Related Art Conventional hollow extrusion molds made of aluminum for vacuum used in particle acceleration pipes, for example, have mechanically crushed the tip of a slightly extruded mold to mechanically crush the tip of the hollow extruded mold to prevent oxygen mixing. It is manufactured by supplying an active gas and forming a thin oxide film with honey on the inner surface of the hollow portion by the oxygen contained in this inert gas (see Japanese Patent Publication No. 59-19769).

However, in the conventional method, since the tip of the slightly extruded mold material is mechanically crushed, it is unavoidable that a minute gap exists, and moreover the moisture content in the mold material is inevitable. Since the pressure is lower than the partial pressure of the water in the atmosphere, the water in the air penetrates into the mold material through the minute gaps existing in the crushed portion. Therefore, a small amount of hydrated oxide is formed on the inner surface of the mold material, and the vacuum degree lowering substance may be adsorbed and stored therein. By the way, the released gas coefficient of the inner surface of the hollow part of the hollow profile manufactured by the conventional method is 10 ^-13 T.
The order is orr · l / s · cm ² . This is not yet a satisfactory value as a mold material used for products requiring ultra-high vacuum such as particle acceleration pipes.

An object of the present invention is to solve the above problems and to provide a method for producing an aluminum hollow extrusion mold material for vacuum suitable for applications such as a particle acceleration pipe.

Means for Solving the Problems A method for manufacturing a hollow aluminum extruded mold material for vacuum according to the present invention is a method of slightly extruding an aluminum hollow mold material, crushing the tip of the slightly extruded mold material and welding the tip opening. The inside of the mold with a slight extrusion and a sealed tip opening, and to keep the inside of the hollow part of the hollow part in an atmosphere that does not come into contact with the moisture-containing atmosphere, continue extrusion molding. Then, a hollow extruded material having an oxide film formed on the inner surface of the hollow portion is obtained.

In the above, as the billet for manufacturing the extrusion mold material,
High-purity aluminum and JIS used for normal extrusion
A 1000-based or JIS A 6000-based alloy is used, but from the viewpoint of extrudability and mechanical strength, an Al-Mg-Si-based alloy such as JIS A 6061 or JIS A 6063 is preferred. It is more preferable to use, as the billet, a billet made of a high-purity aluminum core material and the Al-Mg-Si alloy skin material.

The following method can be applied as a method for maintaining the inside of the hollow portion of the extruded hollow member in an atmosphere that does not come into contact with the air containing water.

The first is 0.5 to 30% by volume of oxygen after evacuating, especially 1 to 1 when extruding an aluminum hollow extrusion.
This is a method in which a mixed gas consisting of 0% by volume and the balance inert gas is supplied into the hollow portion of the mold material being extruded. And. After extruding for a predetermined length, the mold material is cut and the cut end is also sealed in the same manner as the above-mentioned tip. In this case, both the sealed ends may be cut and opened after being sent to the place of use of the hollow extrusion mold material after extrusion molding, or may be cut and opened at a stage before sending.

The second method is a method of using the inert gas containing oxygen as an impurity instead of the mixed gas in the first method. Currently, the purity of inert gas obtained industrially is almost 99.99%, and a trace amount of oxygen is always contained as an impurity.

The third method is a method of using dry air or pure oxygen instead of the mixed gas in the above-mentioned first method. Dry air is obtained, for example, by compressing the atmosphere with a compressor and passing it through a dehumidifier containing a desiccant. In this method, known drying agents can be used, and among them, synthetic zeolite is preferably used. The dew point of dry air is -30 ° C.
It is preferably below, and more preferably below -50 ° C. Pure oxygen is 100% pure oxygen, which contains no water.

The fourth method is a method according to the first method, in which the inside of the hollow portion of the mold material that is being extruded even after the evacuation is evacuated. In this case, there are a method of supplying nothing into the hollow portion during extrusion molding and a method of evacuating the hollow portion. In the latter case, the hollow portion of the mold material is evacuated at least only at the beginning of extrusion, the tip opening portion of the mold material immediately after extrusion is sealed, and after extruding for a predetermined length, the mold material is cut and the cut end is sealed.
The evacuation may be performed not only at the beginning of extrusion but also continuously during the extrusion process. In this method, the oxide film is formed by the oxygen remaining in the hollow portion.

By any of the above methods, the thickness of the inner surface of the hollow part of the mold material
A thin oxide film can be obtained with honey of 20 to 30Å.

In the above, the extrusion temperature is preferably 300 to 450 ° C. If the temperature is lower than 300 ° C., aluminum cannot be extruded, and if the temperature exceeds 450 ° C., a crystallized oxide is formed and a substance having a reduced vacuum degree is easily adsorbed and stored.

The hollow extruded mold material obtained by the method of the present invention can be used not only for particle accelerating pipes but also for devices that need to maintain a high vacuum.

Function Moisture in the atmosphere that has penetrated into the mold material until the tip opening of the slightly extruded mold material is sealed is removed by vacuuming after sealing the tip opening. In addition, if the tip end of the mold material after being slightly extruded is crushed and welded to seal the tip opening, moisture in the atmosphere is prevented from entering the inside of the mold material during the subsequent extrusion operation. Therefore, the formation of hydrated oxides caused by the invading water is prevented.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of an extrusion processing apparatus for producing a hollow aluminum extrusion material for vacuum. In the figure, the extrusion processing apparatus includes a container (1) for containing an aluminum billet (2), a dummy block (3) for pressing the aluminum billet (2) contained in the container (1), and a stem (4). ), A porthole die male mold (5) and a female mold (7) having a gas injection port (6) in the center, and a die holder (8) having an oxygen-mixed inert gas supply port (9) on the outer peripheral surface. , A bolster (9) and an oxygen-mixed inert gas supply device.

Porthole Dies Male (5) and Die Holder (8)
Gas passages (11) and (12) are formed in each of them, and the gas injection port (6) and the oxygen-mixed inert gas supply port (9) are connected to each other by both passages (11) and (12).

The oxygen-mixed inert gas supply device includes an oxygen-mixed inert gas container (14) connected to the oxygen-mixed inert gas supply port (9) via a conduit (15). In the middle of the conduit (15), a plurality of, for example, two dehydration columns (16) containing molecular sieves, synthetic zeolite, etc. inside are arranged in parallel. A vacuum gauge (17) and a dew point meter (18) are respectively provided from the supply port (9) side in a portion of the conduit (15) between the oxygen-mixed inert gas supply port (9) and the dehydration column (16). It is connected via two-way valves (19) (20). Further, in the portion of the conduit (15) between the oxygen-mixed inert gas container (14) and the dehydration column (16),
A regulator (22) and a flow meter (23) are provided from the container (14) side. A rotary pump (24) for vacuuming is connected to a portion of the conduit (15) between the dehydration column (16) and the flow meter (23) via a two-way valve (25). Also, a bypass pipe (26) for evacuation so that both sides of the dehydration column (16) in the conduit (15) communicate with each other.
Is provided. Both ends of the bypass pipe (26) are connected to the conduit (15) via the three-way valve (27).

In FIG. 2, the connecting portion of the conduit (15) to the oxygen-mixed inert gas supply port (9) is shown enlarged. In FIG. 2, a stainless steel sleeve (28) is inserted into the oxygen-mixed inert gas supply port (9) and welded to the die holder (8). A male screw (28a) is formed on the outer peripheral surface of the outwardly projecting portion of the sleeve (28), and the outwardly projecting portion serves as a male joint member (29). A silver brazing layer (30) is formed on the entire surface of the male screw (28a) of the male joint member (29). A through hole (31a) is formed in the top wall of the conduit (15), and a stainless steel cap nut (31) having an internal thread (31b) is fitted on the conduit (15). The tip of the conduit (15) has a tapered shape, and the diameter of the large end is the through hole (31) of the cap nut (31).
larger than the diameter of a) and the diameter of the small end is sleeve (2
An engaging portion (15a) smaller than the inner diameter of 8) is formed. Then, insert the tip of the engaging portion (15a) into the sleeve (28), and then insert the female screw (31b) of the cap nut (31).
The conduit (15) is detachably and fluid-tightly connected to the oxygen-mixed inert gas supply port (9) by screwing together the male thread (28a) of the male joint member (29) with the male thread (28a). Due to the function of the silver brazing layer (30) formed on the entire surface of the male screw (28a), the female screw (31b) of the cap nut (31) and the male screw of the male joint member (29) are heated by the heat during extrusion. (28a) is prevented from being seized, and the work of removing the conduit (15) can be easily performed after the end of extrusion. As shown in FIG. 3, the conduit (15) is connected to the oxygen-mixed inert gas supply port (9) by inserting the tip end of the engaging part (15a) into the sleeve (28) and previously connecting the conduit (15). ) By turning the cap nut (31) with a wrench (32) having a predetermined length, and fitting the female screw (31b) to the male screw (28a). The reason for using the wrench (32) as described above is to allow the worker to turn the cap nut (31) without approaching the extrusion processing device for the safety of attaching and detaching the conduit (15). is there.

The apparatus shown in FIG. 1 extrudes hollow extrusion molds (35) (36) used for a particle acceleration pipe having a cross section as shown in FIGS. 4 and 5, for example. As a matter of course, a die for molding both is used in a shape that matches each of the mold materials (35) (36) to be molded. An endless particle accelerating pipe (not shown) in which both extruded mold members (35, 36) of a predetermined length are alternately connected.
Are assembled. In both figures, the hollow extruded shape materials (35) (36) are hollow particles having an elliptical cross section (when incorporated in a particle acceleration pipe-the same applies below) (37) (38)
have. The hollow part (37) of the mold member (35) shown in FIG. 4 is provided with a hollow part (39) for vacuum evacuation which has a rectangular cross section adjacent to the hollow part (37). )
Communication holes are opened at predetermined intervals in the partition wall (40). A cooling water flow hollow portion (41) (42) having a small circular cross section is provided on one side of the particle flow hollow portion (37) (38), and the particle flow hollow portion (37) (38) and the vacuum hollow portion (39) are provided. ) Is provided with a groove (43) (44) and (45) for attaching a sheath wire for heating degassing treatment on each side.

Specific examples for producing the hollow extruded mold material (35) will be described below.

Example First, a die was caustic washed and then a billet (2) made of high-purity aluminum having a purity of 99.99 wt% was extruded at a temperature of 300 ° C.
It was extruded at an extrusion speed of 7 m / min. No lubricating oil was used at this time. Then, for example, after extruding for 1 to 2 m, the extrusion is temporarily stopped, and the tip end opening of the mold material (35) is crushed by a press and welded and hermetically sealed to one side as shown in FIG. The edge (47) was formed. Next, switch the 3-way valve (27) to the vacuum exhaust bypass pipe (26) side, open the 2-way valve (25), and further regulator (22).
In the closed state, the inside of the conduit (15) and the inside of the mold (35) were evacuated by the rotary pump (24), and the extrusion was restarted. Then, switch the 3-way valve (27) to the dehydration column (16) side and close the 2-way valve (25).
Further, with the regulator (22) open, a mixed gas (46) consisting of 7% by volume of oxygen and the balance argon from the mixed gas container (14) is passed through the dehydration column (16) to lower its dew point, and then the conduit. (15) Through the passages (12) and (11), it was jetted from the jet port (6) at a pressure of 1.1 to 1.5 kg / cm ² and was supplied into the hollow portion of the mold material (35) being extruded. After that, continue supplying the mixed gas (46), and after extruding for a predetermined length,
Simultaneously with cutting the template (35) with the chassis, the cut end was sealed in the same manner as above to form the other sealed end (48) (see FIG. 5). After that, the mold material (35) in which the mixed gas (46) was sealed was naturally cooled and then stretch-corrected. Finally, both sealed ends (47) and (48) of the mold material (35) were cut without using oil and without air blow to manufacture a hollow extruded mold material having a predetermined size.

A honey and thin oxide film was formed on the inner surface of the extruded mold material. Then, this was degassed at 140 ° C. for 24 hours, and the degree of vacuum after 20 hours was measured. As a result, the released gas coefficient was 1 × 10 ⁻¹⁴ Torr · l / s · cm ² .

For comparison, only slightly crushing the tip opening of the mold material (35) after being extruded by welding is not welded, and a hollow extruded mold material is manufactured by the same method as in the above-mentioned Examples, and When the degree of vacuum was measured in the same manner, the released gas coefficient was 1
It was × 10 ⁻¹³ Torr · l / s · cm ² .

EFFECTS OF THE INVENTION According to the method for producing a hollow aluminum extruded profile for vacuum of the present invention, as described above, moisture in the atmosphere that has penetrated into the profile at the beginning of extrusion is removed, and the subsequent extrusion is performed. During the work, moisture in the atmosphere is prevented from invading the inside of the mold material, so that formation of hydrated oxides caused by the invading moisture is prevented. Therefore, the amount of hydrated oxide present in the oxide film formed on the inner surface of the hollow portion of the manufactured aluminum hollow extrusion-molded material is extremely small, and the adsorption and occlusion of the vacuum degree-reducing substance is significantly reduced, and it is adsorbed and occluded. Also, it becomes possible to easily remove this by degassing treatment. As a result, the amount of the vacuum degree-reducing substance released into the mold material becomes extremely small, and it is possible to maintain a high degree of vacuum, and to omit or reduce the troublesome work for increasing the degree of vacuum as in the past. You can

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing the process of extrusion molding, FIG. 2 is a partially enlarged view of FIG.
FIG. 3 is a sectional view showing a method for connecting a conduit to an oxygen-mixed inert gas supply port of a die holder, and FIG. 4 is a IV-IV of FIG.
A cross-sectional view taken along the line, and FIG. 5 shows another mold used in combination with the mold shown in FIG. 4 when making a particle acceleration pipe.
FIG. 6 is a vertical cross-sectional view of the mold material in a mixed gas sealed state. (35) (36) …… Hollow extrusion mold material.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Teruo Kitamura 6-224 Kaiyama-cho, Sakai City, Osaka Prefecture Showa Aluminum Co., Ltd. (56) Reference JP-A-59-137113 (JP, A) JP-A-63 -313612 (JP, A)

Claims (1)

[Claims] 1. A method of slightly extruding an aluminum hollow mold member, sealing a tip opening by crushing and welding the tip of the slightly extruded mold member, and inside a mold member slightly extruded and having a sealed tip opening. While vacuuming, and maintaining the inside of the hollow part of the hollow part in an atmosphere that does not come into contact with the atmosphere containing water, continue extrusion molding to obtain a hollow extruded part with an oxide film formed on the inner surface of the hollow part. A method for producing a hollow extruded aluminum material for vacuum consisting of the following.