JPH07314157A - Method for joining metallic pipe - Google Patents

Abstract

PURPOSE:To rapidly, easily and efficiently join metallic pipes and piping parts at a low temp. by heating a joint part inserted with an inert member at a specific temp. to melt the insert member while maintaining the internal pressure of the metallic pipes and the wiring parts at an atm. pressure or above by using an inert gas, thereby diffusion joining both. CONSTITUTION:The insert member 6 is held between the pipe 9 and the pipe 10 and is fixed to clamps 2 and 3; simultaneously, pressurizing force is acted on the joint surfaces by a pressurizing device 7. The gaseous argon commonly used for preventing oxidation and controlling the internal pressure of the pipes is thereafter admitted from gas nozzles of shielding gas nozzles 5 and a purging gas nozzles 8 and the joint part is heated to a temp. lower than the m.p. of the pipes 9, 10 and higher than the m.p. of the insert member 6 by a high-frequency induction heating coil 4, by which the pipes are joined. The joint part joined in such a manner is extremely smooth and the insert member 6 is diffused into the metallic pipes 9, 10. The state that the insert member is not detectable in terms of metal structure is thus attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a metal pipe and a metal pipe or a pipe component suitable for producing a pipe material for a semiconductor chip manufacturing apparatus.

[0002]

2. Description of the Related Art In recent years, with the demand for increased storage capacity, highly integrated semiconductor chips have been manufactured, and it has been required to further increase the degree of integration. In order to increase the degree of integration, it is necessary to use a technique for thinning a semiconductor chip element. In order to process fine lines, the etching process of the pattern on the chip and the subsequent etching process are extremely important. The etching process is roughly classified into a wet method and a dry method, and the dry method is now the mainstream. In this dry method, various gases are used in order to improve the reactivity including the subsequent thin film formation / diffusion step, but halogen-based gas, which is particularly corrosive, is often used. These corrosive gases are supplied to the semiconductor chip manufacturing apparatus through the gas supply system piping, but in particular, react with moisture, causing corrosion of parts and generation of particles, which results in defective semiconductor chip products. . By the way, to ensure the quality of semiconductor chips,
It is necessary not to contaminate these corrosive gases in the piping. Therefore, a high-cleaning process for completely removing unnecessary components and impurities in advance from high-purity source gas, high-purity water, chemical liquid, etc. is essential. In the high-purification process, high-purity internal fluid such as high-purity source gas is required, and the piping materials such as pipes and joints for supplying the same are also cleaned and the inner surface is smoothed.

Conventionally, pipelines in which parts such as pipes, valves and joints made of stainless steel are joined by welding have been used for gas supply system pipes for semiconductor chip manufacturing equipment or pipes for highly cleaning processes. Butt welding (TIG welding) is used for joining pipes and the like. In carrying out TIG welding, the following points are particularly important. 1. There are no external leaks,
2. No particles are generated, that is, various kinds of dust contained in the fluid supply (dust floating in the air, foreign matter generated from the human body or clothes, cosmetic powder,
2. No non-metallic inclusions or metal pieces are generated outside the fiber) or inside the pipe. There is no dead zone, that is, in the case of TIG welding, a backside bead is formed on the inner surface of the welded portion, but this formation is insufficient or excessive, and the joint becomes valley-shaped or mountain-shaped and the fluid It is required that there is no area that hinders smooth flow. If these requirements are not satisfied, for example, if particles are generated, they will be mixed in the fluid, causing a decline in the function of the semiconductor chip and a failure, leading to a deterioration in yield. In addition, when a dead zone occurs, the fluid accumulates in that portion, which not only hinders the cleaning but also causes corrosion due to the influence of the accumulated material.

In order to satisfy these requirements, it is essential to have a welding technique that smoothes the welded surface and manages the width and height of the back bead generated on the inner surface of the pipe during welding to be as small as possible. Welding methods have hitherto been generally adopted in order to satisfy these requirements to some extent. FIG. 2 is an explanatory diagram for explaining the TIG welding method. Positioning is performed so that the joints of the pipes 9 and 10 as the materials to be joined are on the extension line of the apex of the tungsten electrode 14, and the clamps 11 and 12 fix the positions. Next, when argon gas is made to flow into the pipe from the back shield gas nozzle 16 and the gas pressure in the pipe is adjusted by the seal cap 17 to complete the setting of the joint, and then the power is turned on, the electrode rotor 13 becomes Simultaneously with the start of rotation, argon gas is discharged from the shield gas nozzle 15 toward the joint surface, the base metal is melted by the heat of the arc discharged from the tungsten electrode, and welding is performed. The current value and the rotation speed of the rotor at this time are set in advance by a controller and are automatically controlled.

[0005]

However, the TIG
It has been pointed out that the welding method has the following problems. (1) Preparation of master sample, preparation of test piece, comparison with master sample before starting welding work,
It takes a great deal of time and effort to set and set welding conditions, and the work efficiency decreases.
(2) A skilled worker is required to set welding conditions and conditions. (3) It is necessary to change welding conditions frequently due to external factors such as temperature and temperature on the working day. Occurs, the number of constructions is limited, (4) because the welding conditions change due to the heat of the welder, multiple welders are required for replacement, and (5) the base metal contains manganese. In this case, the corrosion resistance around the weld deteriorates due to the generation and adhesion of manganese fumes, and particles are generated due to corrosion. (6) Due to the change in the molten metal flow in the weld due to the difference in the sulfur component content of the base metal There are problems such as frequent changes in welding conditions. Furthermore, the smoothness of the welded surface is still insufficient, and it is required to further reduce the width and height of the back bead.

The present invention has been made for the purpose of solving the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a method for joining a metal pipe and a metal pipe or a pipe component suitable for producing a pipe material for a semiconductor chip manufacturing apparatus without the above-mentioned problems in the TIG welding method. .

[0007]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention, unlike the TIG welding method, do not melt the base material, melt only an extremely thin insert material, and in the pipes to be joined together, By introducing an inert gas and controlling the internal pressure, the shape of the backside bead that accompanies the melting of the insert material can be controlled to be narrow and low, which makes it possible to smooth the welded part and to create a dead space. They found that they could be prevented, and completed the present invention. That is,
TECHNICAL FIELD The present invention relates to a method for joining a metal pipe and a metal pipe or a piping component, and when joining the metal pipe and the metal pipe or the piping component, an insert having a melting point lower than that of the metal pipe material and the piping component material. Insert the material between the joining surfaces, apply pressure to the joining surfaces for pressure welding, and insert the insert material while maintaining the internal pressure of the metal pipe and piping parts above the atmospheric pressure using an inert gas. The joined portion is heated to a temperature higher than the melting point of the insert material and lower than the melting points of the metal pipe material and the piping component material to melt the insert material and perform diffusion bonding.

Next, the present invention will be described in detail. In the present invention, the metal pipe and the metal pipe to be joined, or the pipe component such as the metal pipe and the joint, is used for the gas supply system pipe in the semiconductor chip manufacturing apparatus, and is made of any material such as stainless steel. It may be made,
It is preferable to adopt an iron alloy containing Cr and Ni as main components. In addition, its size is 7 m or less in length and 1 / outer diameter
Those having a thickness of 8 to 1 inch and a wall thickness of 0.7 to 1.7 mm are preferably welded. A thin film of an insert material is inserted between the joint surfaces of these materials to be joined. As the insert material, one made of an amorphous metal material having a melting point lower than that of the metal pipe material and the piping component material is used, and specifically, a nickel-based alloy or the like is preferably used. The thickness of the insert material is 20 to 50 μm.
A range of m is preferred. An adhesive may be applied to one side or both sides of the insert agent. As a result, the insert material can be attached to the joint surface of the materials to be joined prior to welding, and the positioning work becomes easy. After the thin film of the insert material is inserted between the welding surfaces of the materials to be joined, a pressure is applied to the joining surfaces for pressure welding. The applied pressure is generally 0.5 MPa to 10 MPa, preferably 3 MPa to 1
The range of 0 MPa is preferable. When the applied pressure is lower than 0.5 MPa, contact between the weld surface of the material to be welded and the insert material is insufficient, and when it is higher than 10 MPa, the material to be welded in the joint portion buckles and deforms.

In the present invention, upon welding by heating, an inert gas such as argon gas or nitrogen is further provided inside or inside and outside the pressure-welded metal pipe and metal pipe or the metal pipe and piping parts. Introduce gas etc.,
It is necessary to keep the internal pressure above the atmospheric pressure. By introducing an inert gas to increase the internal pressure, it is possible to prevent the melted insert material from being oxidized, and it is possible to control the back bead to be small. Next, the joint portion in which the insert material is inserted is heated to a temperature higher than the melting points of the insert material and lower than the melting points of the metal pipe material and the piping component material to melt the insert material and perform diffusion bonding. The heating is preferably carried out so that the heat-affected zone at the time of bonding is 1 mm or less, and as the heating means,
Although laser heating, high frequency heating, etc. can be adopted, it is preferable to use a high frequency induction heating coil arranged so as to surround the joint. At that time, it is preferable to heat the surface of the joint while protecting the surface of the joint with an inert gas such as argon. The joint portion welded as described above is extremely smooth, and the insert material is diffused into the metal pipe and cannot be detected metallically.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is an explanatory diagram for explaining the joining method of the present invention. The insert material 6 is sandwiched between the pipe 9 and the pipe 10 to be fixed to the clamps 2 and 3, and at the same time, a pressing device 7 applies a pressing force to the joint surface. After that, argon gas, which also functions as an antioxidant and an internal pressure control of the pipe, is introduced from the gas nozzles of the shield gas nozzle 5 and the purge gas nozzle 8, and the joint portion is lower than the melting point of the pipe by the high frequency induction heating coil 4 and the insert material 6 Heat to a temperature above the melting point and bond. This temperature is measured by the radiation thermometer 1 and is controlled by an automatic controller (not shown).

Next, a specific example of welding performed by the welding method shown in FIG. 1 will be described. Outer diameter 1 /
4-inch, 1 mm thick, 100 mm long SUS316
L pipe (C: 0.007, Si: 0.22, Mn:
0.26, P: 0.020, S: 0.002, Ni: 1
4.62, Cr: 16.81, balance Fe) was used. As the insert material, a Ni-based alloy (Si: 4.5%, B: 3%, balance: Ni) having a thickness of 40 μm was used. The following conditions were adopted as the joining conditions. Junction temperature:
1200 ° C, holding time: 60 sec, pressure: 3.9M
Pa, shield gas: (outside) Ar 30 L / min,
(Inside) Ar 15 L / min.

As a comparative example, regarding the above-mentioned materials to be joined,
Joining was performed by the TIG welding method shown in FIG. The joining conditions were as follows. Arc gas: 7% H ₂ / Ar
15 L / min, back seal gas: 100% Ar
5 L / min, electrode rotation speed: 7.5 rpm, front purge: 20 sec, rear purge: 20 sec, voltage: 15
V, current: 14A.

(Method for evaluating quality of welded portion after welding and evaluation result) A particle counter is attached to one end of the joined pipe, and high-purity argon gas is continuously fed from the end of the other pipe at 15 L / min. Time supply,
The generation status of particles was judged. Table 1 shows the quality evaluation results of the joining by the joining method of the present invention and the joining by the conventional TIG welding method.

[0014]

[Table 1]

From the results shown in Table 1 above, in the case of joining metal pipes by the conventional TIG welding method, the back bead width and height are larger than those of the present invention, and there are variations, and particles are also present. It can be seen that outbreaks are often observed. On the other hand, in the joining method of the present invention, welding can be carried out in a short time, the width and height of the back bead are small, and there is no variation, and no particles are generated.

[0016]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it is possible to easily and efficiently perform joining at a low temperature in a short time, and the welded joint portion is extremely smooth, and the insert material is Is diffused into the metal pipe and cannot be detected metallically, which is useful for producing a piping member used in a semiconductor chip manufacturing apparatus or the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a joining method of the present invention.

FIG. 2 is an explanatory diagram for explaining a TIG welding method.

[Explanation of symbols]

1 ... Radiation thermometer, 2, 3 ... Clamp, 4 ... High frequency induction heating coil, 5 ... Shield gas nozzle, 6 ... Insert material, 7 ... Pressurizing device, 8 ... Purge gas nozzle, 9, 10 ...
Pipe, 11, 12 ... Clamp, 13 ... Electrode rotor,
14 ... Tungsten electrode, 15 ... Shield gas nozzle,
16 ... Back shield gas nozzle, 17 ... Seal cap.

Claims (3)

[Claims] 1. When joining a metal pipe and a metal pipe or a piping component, an insert material having a melting point lower than that of the metal pipe material and the piping component material is inserted between the joining surfaces to apply a pressing force to the joining surfaces. And the internal pressure of the metal pipe and piping parts is maintained at atmospheric pressure or higher by using an inert gas, and the joint portion in which the insert material is inserted is higher than the melting point of the insert material, And a method for joining a metal pipe and a metal pipe or a pipe component, wherein the insert material is melted by heating to a temperature lower than the melting point of the pipe component material and diffusion bonding is performed. 2. The method for joining a metal pipe and a metal pipe or a piping component according to claim 1, wherein the joint is heated by using a high-frequency induction heating coil arranged so as to surround the joint. 3. The method for joining a metal pipe and a metal pipe or a piping component according to claim 1, wherein the surface of the joint is heated while being protected by an inert gas.