JP2001225179A - Welding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding structure whose increase in weight by making the structure large is suppressed and its wall plates are not made to be thick and a large-sized vacuum container having a high degree of vacuum, to which the structure is applied. SOLUTION: The welding structure is characterized in that the structure has construction supporting an inside member 1 made of aluminum or an aluminum alloy by an outside member 3 having strength stronger than the inside member, the above inside member is welded 2 by friction-stir-welding and is metallurgically or mechanically welded to the above outside member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel joint structure capable of reducing the weight and thickness of a thin wall, and more preferably to a vacuum vessel to which the present invention is applied, which is easy to increase in size and suitable for obtaining a high degree of vacuum. About.

[0002]

2. Description of the Related Art In recent years, in the manufacturing process of the semiconductor field,
Due to the demand for higher degree of vacuum with the miniaturization of the circuit and the increase in the processing capacity, a larger processing chamber is required.

In order to realize a high degree of vacuum, there is a problem of leakage of a vacuum vessel and gas released from a material forming an inner surface of the vessel. Although the outgassing rate of aluminum and aluminum alloys is low, for example, stainless steel having a low outgassing rate as low as that of aluminum alloys has been invented as disclosed in Japanese Patent Application Laid-Open No. 7-60099. Further, in order to eliminate a joint which is a major source of leakage and released gas, Japanese Patent Application Laid-Open No. 6-315
As disclosed in JP-A-43-43, there is also considered a method of manufacturing an integrated container by cutting from a single metal lump, for example, casting as in JP-A-11-221660, or forging as in JP-A-9-57389. I have.

With an increase in the size of the processing chamber, the force applied to the vacuum vessel from the outside air pressure increases, and it is necessary to ensure the rigidity of the vessel. Conventionally, rigidity has been maintained by increasing the thickness of the container. The increase in weight due to this necessitates the reinforcement of the floor at the place where the device is installed, or hinders the layout change. Therefore, the weight of the device is required to be reduced. In contrast, Japanese Patent Application Laid-Open Nos. 5-103972 and 10-7
Japanese Patent No. 4827 discloses a method of reducing the weight of a vacuum vessel by forming a wall of a vacuum vessel between two plates with a corrugated rib or honeycomb material interposed therebetween.

Further, in the case of a welding structure, if the size is increased, the number of welds increases, and in a usual welding method, dimensional accuracy is deteriorated due to distortion due to welding heat, which hinders the manufacturing process of the apparatus. On the other hand, a method using brazing described in Japanese Patent Application Laid-Open No. 7-251058, a method using a brazing material described in Japanese Patent Application Laid-Open No. -29106
8, Japanese Patent Application Laid-Open No. 11-300480, Japanese Patent Application Laid-Open
A low heat input method such as a friction joining method described in JP-A No. 1-300481 and JP-A No. 11-300482 has been considered.

[0006]

In order to increase the size of the vacuum container, to manufacture an integrated container by cutting or forging, the processing cost is high and there are many wasteful materials, and the manufacturing cost is too high. Therefore, in order to manufacture at low cost, it is appropriate to use a welded structure. However, there is a problem in normal welding that dimensional accuracy is deteriorated due to thermal strain during welding. Although the effect of thermal strain can be avoided by using a joining method by brazing, there is a problem that a large heating furnace is required.

In order to obtain a high vacuum, it is preferable to use aluminum or an aluminum alloy. However, welding is difficult and the plate must be thick to maintain the rigidity of the vacuum vessel due to its low strength. Stainless steel with a low outgassing rate is relatively strong, but is expensive, and the pretreatment for obtaining a low outgassing rate is complicated.

[0008] The vacuum vessel wall structure using a rib material or a honeycomb material aiming at weight reduction also has a problem in that not only the number of members increases but also the number of manufacturing steps increases, so that the manufacturing cost increases.

An object of the present invention is to provide a joined structure having a high degree of vacuum and a vacuum container using the same.

[0010]

The present invention has a structure in which an internal member made of aluminum or an aluminum alloy is supported by an external member made of a material having a higher strength than aluminum or an aluminum alloy. The leg is joined by friction stir welding, and is characterized by a joint structure having a structure of metallurgical or mechanical joining with the external member at the joint portion, and the vacuum vessel having this structure has a high vacuum depending on the material of the internal member. In addition to the above, since the rigidity is maintained by the external member, the plate thickness can be reduced and the weight can be reduced.
Furthermore, since the standard width commercial product of aluminum or aluminum alloy has a narrow plate width of about 1 meter, it was necessary to use a specially processed one when enlarging the vacuum vessel. As a result, a commercially available product of a fixed standard can be used, and the cost can be reduced.

The internal member made of aluminum or an aluminum alloy is desirably manufactured by rolling, forging, or extrusion rather than casting, and a high degree of vacuum can be obtained because the amount of released gas is small.

[0012] In the friction stir welding, a metal rod made of a material harder than aluminum or an aluminum alloy used for the internal member is inserted into a joint between the two internal members and the external member. It is characterized by welding by frictional heat generated between the members and stirring by moving while rotating, there is no deformation due to thermal strain due to low heat input, and not only internal members but also external Since the members are joined at the same time, the manufacturing process can be made more efficient.

A cut is made in advance at the joint between the outer member and the inner member, and the material of the inner member fluidized by friction stir welding is caused to flow into the notch to mechanically cut the material. By joining the inner member and the outer member, the joining strength can be increased in addition to the metallurgical joining of the inner member and the outer member by alloying.

The efficiency of the manufacturing process can be improved by a manufacturing method in which the internal member and the external member are joined to form an integrated member by bending and forging to finish to a final shape.

[0015] The outer member is made of any one of a steel material, nickel and a nickel alloy, titanium and a titanium alloy, copper and a copper alloy, and is used for the inner member by the friction welding. By forming an intermetallic compound with aluminum or an aluminum alloy, the metallurgical bond can be made stronger.

[0016]

(Embodiment 1) FIG. 1 shows the structure of an internal member of a vacuum vessel according to the present invention. Each inner member is made of aluminum or aluminum alloy by casting, rolling,
It is manufactured by giving a shape by forging or extrusion. In order to reduce the emission gas, it is desirable to manufacture by rolling, forging, or extrusion instead of casting. The inner member 1 was aligned with an adjacent inner member 1 at an arbitrary angle, and an outer member 3 was applied to the outside of the joint 2 as shown in FIG. 2 to perform friction stir welding. In friction stir welding, a metal rod 4 made of tool steel harder than aluminum or an aluminum alloy is inserted into a joint formed by two internal members 1 and an external member 3 and moved while being rotated, whereby these members are moved. Welding was caused by frictional heat generated during stirring and stirring. As the outer member 3, stainless steel was used, and the cuts 5 were formed in advance as shown in FIG. Part of the internal member flowing into the cut portion 5 by plastic flow during friction stir welding mechanically joins the internal member and the external member, and the internal member and the external member are alloyed and metallurgically joined. By making the center of the notch 5 convex as shown in FIG. 3B, it is easy to come into contact with the metal bar 4.
Alloying was further promoted and bonding was firm.

As shown in FIG. 4 (a), rigidity is secured by the external member by a structure in which the internal member 1 is attached to the external member 3. As a result, the thickness of the internal member was reduced, the wall thickness of the vacuum vessel was reduced, and the weight was reduced. Further, since the internal member was made of aluminum or an aluminum alloy to suppress the amount of released gas, a high degree of vacuum could be realized.

(Embodiment 2) As shown in FIG. 4 (b), the rigidity of the inner member 1
And the external member 3. As a result, the weight of the outer member 3 can be reduced and the thickness of the inner member can be reduced as compared with the first embodiment, so that the weight of the vacuum vessel can be reduced.

(Embodiment 3) As shown in FIG. 5A, a flat inner member 1 is joined to a flat outer member 3 by friction stir welding, and the integrated member is formed into a cylindrical shape by bending. did. The ends were joined by welding from the outside and by friction stir welding from the inside, as shown in FIGS. 5 (b) and 5 (c). By such a manufacturing method, a vacuum vessel could be manufactured efficiently.

The aluminum or aluminum alloy is desirably manufactured by rolling, forging, or extruding, and the amount of gas emitted can be further suppressed.

The inner member is supported by an outer member made of a material having a higher strength than the inner member to maintain the rigidity of the vacuum container, thereby reducing the thickness of the inner member and reducing the weight of the vacuum container. it can. In addition, when a vacuum vessel is enlarged using a material having a narrow plate width and a welded structure as in the present invention is used, the size can be increased.

The friction stir welding of the outer member to the joint of the inner members at the same time not only suppresses deformation due to welding strain, but also eliminates the need to join the outer member again later. Can be more efficient.

A notch is formed in advance in a joint portion of the outer member, and the material of the inner member that has flowed plastically during friction stir welding is caused to flow into the notch, in addition to metallurgical joining by alloying the inner member and the outer member. Mechanical joining is enabled, and joining between the inner member and the outer member can be strengthened.

The efficiency of the manufacturing process can be improved by a manufacturing method in which an integrated member obtained by joining an inner member and an outer member is formed into a final shape by bending and forging.

The outer member is made of any one of steel material, nickel and nickel alloy, titanium and titanium alloy, copper and copper alloy, and is made of aluminum or aluminum used for the inner member by friction stir welding. By forming an aluminum alloy and an intermetallic compound, a metallurgical bond can be strengthened.

[0026]

According to the present invention, a joined structure having a high degree of vacuum can be obtained by using aluminum or an aluminum alloy joined by friction stir welding to the inner member of the vacuum vessel.

Furthermore, a large-sized vacuum vessel having a high degree of vacuum can be manufactured, and this can be applied to, for example, a large-sized high-performance semiconductor manufacturing apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of an internal member.

FIG. 2 is a cross-sectional view and a perspective view showing a joint.

FIGS. 3A and 3B are a cross-sectional view and a perspective view illustrating a cutout portion of an external member.

FIG. 4 is a perspective view in which an internal member and an external member are joined.

FIG. 5 is a perspective view showing a manufacturing process using bending.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal member, 2 ... Internal member joint part, 3 ... External member, 4
... metal rod, 5 ... cut part of joint part of external member, 6 ... bead by friction stir welding, 7 ... bead by welding.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Terunobu Abe 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi, Ltd. 4E067 AA05 BG00 EB06

Claims (6)

[Claims] An internal member made of aluminum or an aluminum alloy is supported by an external member having higher strength than the internal member. The internal member is joined by friction stir welding, and A bonded structure characterized by being metallurgically or mechanically bonded. 2. The method according to claim 1, wherein the friction stir welding includes:
By inserting a metal rod of a material harder than the internal member into the joint and moving the metal rod while rotating, the metal rod is joined by frictional heat generated between the member and stirring. Joint structure. 3. The outer member according to claim 2, wherein the outer member has a notch in advance in a portion corresponding to a joint of the inner member, and the inner member fluidized by friction stir welding flows into the notch. A joining structure, wherein the joining structure is mechanically joined to the internal member. 4. The joining method according to claim 2, wherein the member formed by joining the inner member and the outer member to form an integral member is formed by bending and forging. object. 5. The external member according to claim 1, wherein the external member is made of any one of an iron-based material, nickel and a nickel alloy, titanium and a titanium alloy, copper and a copper alloy. Joint structure. 6. The vacuum vessel according to claim 5, wherein the vacuum vessel comprises the joint structure.