JP2957322B2 - Electric wire and electrode for electrolytic treatment of metal pipe inner surface and electrolytic polishing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic treatment method for an inner surface of a metal pipe, mainly a coiled pipe or a bent pipe, and more particularly to an optimal electrolytic treatment method for performing an inner surface electrolytic polishing.

[0002]

2. Description of the Related Art Metal pipes, mainly stainless steel pipes, have high pressure resistance, heat resistance, corrosion resistance and cleanliness (low generation of impurities) under special conditions, and special demands have been increasing in recent years. . For example, the outer diameter is 6.35 to 216.3.
light annealing with stainless steel pipe in the range of mm
Annealing tubes (hereinafter referred to as "BA tubes") have been useful as gas supply lines for semiconductor manufacturing.

[0003] Furthermore, with the increase in the degree of integration of semiconductors in the last three to four years, these BA tubes have been subjected to internal electropolishing and electropolishing.
shing or electropolishing)
It has been used as a pipe (hereinafter referred to as “EP pipe”). However, the length of these EP pipes is 4 m in Japan and 6 m overseas.
Straight pipe is used as the longest one.

On the other hand, a stainless steel pipe required by a semiconductor factory as a semiconductor production gas transfer line is usually 6.
Total length of 8,000 ~ with outer diameter of 35 ~ 216.3mm
16,000m, 2000m for 4m pipe
Although ４4000 pieces will be used, most of them are occupied by small pipes with a diameter of 6.35 to 12.7 mm. These 2000-4 used in one factory
The connection of 000 pipes is performed by joints or automatic welding, but this work requires enormous cost and time, and the periodic inspection of these joints to prevent leakage of toxic gas for semiconductor production is a serious and difficult task. Has become.

EP tubes manufactured in Japan have an outer diameter of 6.35 to
It is extremely common that the length is 216.3 mm and the length is 4 m, but the diameter and the length are not limited to the conventional size as the electropolishing technique. Especially if the pipe is straight in length
0 m is also possible. However, long straight pipes have problems in handling and have not been commercialized. This is because it involves problems such as enlargement of the polishing processing equipment, pipe transportation, distribution, and workability.

[0006] Under such circumstances, connection by welding or joints is avoided as much as possible, workability at the time of construction is greatly improved, and the number of inspection points can be drastically reduced even in a later gas leakage periodic inspection. A so-called coil tube in which a long pipe is wound in a coil shape has attracted attention and has been used. These tubes have a diameter of 6.35 m
m, 9.53 mm, 12.7 mm BA tube with a normal length of 30 to 50 m wound into a coil with a diameter of 0.8 to 1.0 m. It is returned to a straight pipe using.

As mentioned above, special gases for semiconductor manufacturing are often highly toxic, and there must be no gas leakage from pipe connections especially indoors. The demand for coil tubes of several tens of meters is increasing in terms of reducing the number of inspection points or promptly making corrections.

[0008]

However, since the coil tube is currently commercialized only as a BA tube, it is used for manufacturing semiconductors with a low degree of integration, but 4 mega (1) which requires extremely high cleanliness. The manufacture of semiconductors larger than mega-million-bit dynamic RAMs (random write / read memories that require a memory retention operation) required electropolished coil tubes.

[0009] On the other hand, a semiconductor production gas transfer line branches and bends at many points in a manufacturing plant, and these branches and bends are formed by welding or bending pipes or by fitting joints. However, electrolytic polishing of the prefabricated branch pipe 1 as shown in FIG. 1 or the bent pipe 2 shown in FIG. 2 was not possible with the prior art.

[0010]

As a result of various studies to solve the above-mentioned problems, the present inventors have invented an electrode inserted into the inner surface of a metal pipe to have a spring property. The electrode and the electric wire have a spring property, and the inside of the coil tube 3a as shown in FIG. 3 or the electrode has a spring property, so that the pole and the inside of the branch pipe or the bent pipe as shown in FIGS. Free insertion is now possible. That is, if the pole is an electric conductor and is made of a material having a spring property, the above-described problem can be solved.

Here, in the case of a relatively short pipe such as a branch pipe or a bent pipe, all the products of the present invention inserted into the pipe can be used as poles, but when inserted into a long pipe such as a coil tube. In the meantime, the configuration of the product of the present invention is a pole and an electric wire (lead wire) connecting the pole, and both of them are inserted into a coil tube for maintaining the spring property. That is, since the diameter of the pole inserted into the tube or the electric wire (lead wire) connected thereto is limited to 50 to 80% of the inside diameter of the tube, the area of the pole is limited according to the maximum value of the amount of electricity passing through the tube. That is because

Examples of materials that can be used as these poles or electric wires include phosphor bronze wires, silicon chrome oil wires, stainless steel wires for springs, straight stainless steel wires, oil-tempered wires, piano wires, carbon wires, copper wires, and the like. A wire having a spring property such as a stainless clad wire, a band, or a rod-like material, or a material in which these are combined with an electric conductor such as a copper wire or a silver wire as an electric wire is also convenient.

A more specific example of a material obtained by combining a wire having a spring property such as a silicon chrome oil wire, a stainless steel wire for a spring, and a copper wire will be described. In FIGS. 4 and 5, reference numeral 4 denotes a shaft having a spring property (extensibility), which corresponds to the above-described stainless steel wire for a silicon chrome oil wire spring, etc., but retains electric conductivity but does not become a good electric conductor. For this reason, a structure is adopted in which electric good conductors 5 such as copper wires and silver wires are combined. Reference numeral 6 denotes a heat-resistant and chemical-resistant polymer material for preventing contact with an object to be processed, which is coated with a fluororesin or the like. At the time of electrolytic treatment, a shaft 4 having a spring property by peeling off a fluororesin or the like which is a coating material at the tip of these wires
Is in the state of being exposed, and used as an electrode.

The structure of the shaft 4 and the electric conductor 5 is such that if the electric conductor 5 is too large compared to the shaft 4, the spring property is impaired, the spring property (extensibility) is insufficient, and the poles on the inner surface of the metal pipe are Insertion becomes difficult. For this reason, in order to perform efficient processing, appropriate spring properties (extensibility) and good electrical conductivity must be provided, and the balance between the shaft 4 and the electric conductor 5 is a key point. It is appropriate that the balance between the shaft 4 and the electric conductor 5 is about 4: 2 to 6 in terms of the area ratio of the cross-sectional area of the wire. For example, in FIG. 4, a description will be given of a material made of a combination of a stranded wire of a stainless steel wire for a spring and a stranded wire of a copper wire. A stainless steel wire for spring (hereinafter referred to as SUS7 / 0.1), in which seven strands of 0.1 mm of wire are twisted, is surrounded by six bundles of copper wires in which 22 strands of 0.08 mm of wire are twisted. (Hereinafter referred to as + AC6 / 22 / 0.08), and further covered with a fluororesin PFA having a thickness of 0.4 mm, that is, SUS7 / 0.1 + AC6 / 22 / 0.08.
PFA coating 0.4mm or SUS7 / 0.2 + A
C6 / 60 / 0.08PFA coating 0.4mm etc. or S
US19 / 0.36 + AC6 / 37 / 0.26 PFA coated 0.6 mm. Although the configuration of the shaft 4 and the electric conductor 5 can be reversed, the balance when the shaft 4 and the electric conductor 5 are reversed as described above needs to be adjusted as described above.

The electrode having the above conditions is used in the electrolytic treatment as follows. Outer diameter 6.35φ ~ 12.7φ
In the case of a coil tube of mm, for the length Lm, a pole of 2 to 3 m that can be added to Lm is prepared, and a tip of about 0.2 m of the pole is used as a bare wire (pole). The pole and the coil tube to be processed are provided with an O-ring-shaped insulator or the like in order to prevent an electrical short circuit.

After inserting the thus-formed electrode into the coil tube and filling the coil tube with an electrolytic solution, the electrode is moved at a constant speed while energizing between the electrode and the coil tube so that the entire length L is electrolyzed. To process. The use of the pole according to the present invention enables the electrolytic treatment of the inner surface of a metal pipe other than a straight tube such as a coil tube, a branch tube, and a bent tube. There are electrolytic polishing (2) electrolytic degreasing (3) electrification releasing rust (4) electrolytic plating, and it goes without saying that the present invention is applied to any of these.

That is, the present invention is a method of performing an electrolytic treatment by inserting a characteristic pole into the inner surface of a metal pipe, and general electrolytic conditions such as an electrolytic solution, a current density, a processing temperature and a processing time are the same as the conventional conditions. It is applicable. Examples are shown below, but the present invention is not limited thereto.

[0018]

【Example】

Example 1 Stainless steel SUS 316L BA pipe (pipe inner surface roughness Rm
ax2-3μm) outer diameter 6.35φmm, inner diameter 4.35φ
mm, bending angle 90 degrees, bending radius R
= 3D (bending radius is 3 times the pipe diameter) Also, a bent tube having a length of 20 cm as the straight portion 7 after bending and having a total of four bent portions 8 as shown in FIG. 2 is prepared. The cathode of the present invention was inserted into the inside, and an electrolytic solution (phosphoric acid, sulfuric acid and additives) heated to 60 ° C. was circulated to perform an electrolytic polishing treatment. As a comparison, insertion of a commonly used copper electrode was also attempted. However, at the time of use, the portions other than the electrode portions are coated with fluororesin PFA. Table 1 shows the conditions and evaluation.

[0019]

[Table 1]

Example 2 SUS 3 having an outer diameter of 6.35 mm and an inner diameter of 4.35 mm
16L stainless steel tube with inner surface roughness of 2-3μmRmax
Commercially available 30m coil tube (winding diameter 650mm)
, The cathode described in the present invention is inserted into the inside of the coil tube, and the electropolishing process is performed by circulating the electropolishing solution, which is a mixture of phosphoric acid, sulfuric acid and additives, by a pump while maintaining the temperature at 60 ° C. Was. As a comparison, an attempt was made to use a commonly used copper electrode. The poles used were all coated with fluororesin PFA except for the electrodes.
3b shows the central side 9 of the winding and the outer side 10 of the winding of FIG. 3b. Detailed conditions and evaluation are shown on the next page.

[0021]

[Table 2]

[0022]

According to the present invention, a phosphor bronze wire, a silicon chrome oil wire, a stainless steel wire for a spring, a straight stainless steel wire, an oil tempered wire, a piano wire, a carbon wire, a copper-stainless steel wire having strong spring properties are provided. Use electrodes made of synthetic resin other than those that are used as electrodes of wires or strips with a breakability, such as clad wires, or those coated with synthetic resin in combination with electrical conductors such as copper wires and silver wires. The inner surface of a long metal pipe or bent tube can be easily subjected to electrolytic polishing, electrolytic degreasing, rust release, and electroplating.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a branch pipe.

FIG. 2 is an explanatory view of a bent tube.

FIG. 3 is an explanatory view of a coil tube; FIG.

FIG. 4 is a partial perspective view of an electrode according to the present invention.

FIG. 5 is a partial perspective view of an electrode according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 branch pipe 2 bent pipe 3 coil pipe 4 shaft with spring property 5 electric conductor 6 polymer coating material 7 bent part 8 straight part

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Akio Nagasawa 5-22-5 Higashioi, Shinagawa-ku, Tokyo Sanaiishi Oil Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) C25F 3 / 16 C25F 7/00

Claims (6)

(57) [Claims] In an internal electrolytic treatment of a coiled pipe or a bent pipe, an electrode inserted inside the pipe and an electric wire connected to the electrode are connected to the electric wire when the pipe to be processed exceeds the length of the pole. The electrodes have spring properties,
Alternatively, when the pipe to be processed does not exceed the length of the pole, only the electrode is made of a material having a spring property. 2. In the internal electrolytic treatment of a coiled pipe or a bent pipe, regarding an electrode inserted inside the pipe and an electric wire connected to the electrode, when the pipe to be processed exceeds the length of the pole, the electric wire is not used. The electrodes have spring properties,
Alternatively, when the pipe to be processed does not exceed the length of the pole, the electrode-treated electric wire and the electrode on the inner surface of the metal pipe, wherein the electrode is formed of a combination of a material having a spring property and an electric conductor only. 3. An electrode inserted into the pipe and an electric wire connected to the electrode when the electrolytic treatment liquid is circulated inside the pipe to fix or move the electrode to perform electropolishing in the pipe. When the pipe to be processed exceeds the length of the pole, both the wire and the electrode have spring properties. When the pipe to be processed does not exceed the length of the pole, only the electrodes are made of a material having spring properties. An electrolytic polishing method for an inner surface of a pipe, characterized in that: 4. An electrode inserted into a pipe and an electric wire connected to the electrode when electrolytically polishing the inside of the pipe by fixing or moving an electrode by circulating an electrolytic treatment solution inside the pipe, When the pipe to be processed exceeds the length of the pole, the wire and the electrode have spring properties, or when the pipe to be processed does not exceed the length of the pole, only the electrode has a spring property and a good electric conductor. An internal electrolytic polishing method for a pipe, characterized by comprising a combination of: 5. In an internal electrolytic treatment of a coiled pipe or a bent pipe, regarding an electrode inserted inside the pipe and an electric wire connected to the electrode, when the pipe to be processed exceeds the length of the pole, the electrode is connected to the electrode. The electric wire connected to this is made of stainless steel or a combination of stainless steel and copper. If the pipe to be processed does not exceed the length of the pole, only the electrode is made of stainless steel or a combination of stainless steel and copper, or An electrolytic treatment electric wire and electrode comprising a combination of bronze or phosphor bronze and copper. 6. An electrode inserted into a pipe and an electric wire connected to the electrode when electrolytically polishing the inside of the pipe by circulating an electrolytic solution inside the pipe and fixing or moving the electrode, When the pipe to be processed exceeds the length of the pole, the electrode and the electric wire connected to it are made of stainless steel or a combination of stainless steel and copper or a combination of phosphor bronze or phosphor bronze and steel and processed. If the pipe does not exceed the length of the pole, only the electrodes are made of stainless steel or a combination of stainless steel and copper, or phosphor bronze or a combination of phosphor bronze and steel, electrolytic polishing of the inner surface of the pipe Method.