JPH08319576A - Electroless plating method and plating device for long-sized pipe - Google Patents

Abstract

PURPOSE: To apply electroless plating on the inside or outside surface of a heavy-weight long-sized pipe with simple equipment and operation in a horizontal posture. CONSTITUTION: The long-sized pipe 10 is horizontally placed on a supporting and rotating mechanism 20. A degreasing liquid, pickling liquid and electroless plating liquid are successively and forcibly fed to the inside of the long-sized pipe 10. The long-sized pipe is rotated during the plating, by which the inside surface of the long-sized pipe is electroless plated. The long-sized pipe 10 is concentrically housed into a sheath pipe of a large diameter and this sheath pipe is placed on the supporting and rotating mechanism 20 in the case of outside surface plating. The respective treating liquids are then forcibly fed into the annular space between the sheath pipe and the long-sized pipe and the sheath pipe is rotated together with the long-sized pipe during the plating. The pretreating to the plating are executable without moving the long-sized pipe with the smaller amts. of the plating liquids to be used. The high-quality plating film which has the thickness uniform in a longitudinal direction and a peripheral direction and is free from defects is thus formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for plating a long pipe suitable for plating the inner and outer surfaces of a long and heavy metal pipe such as an oil well pipe or a line pipe by electroless plating. Regarding plating equipment.

[0002]

2. Description of the Related Art Steel pipes may be surface-treated on their inner and outer surfaces depending on the environment of use. For example, oil coating or thin film coating may be applied for the purpose of rust prevention. In addition, the inner surface or the outer surface is plated for stronger rust prevention or as a surface hardening treatment to withstand sliding and abrasion. Examples of this type of plating include zinc or zinc alloy plating, chromium plating, nickel plating, cobalt plating and the like. Of these platings, zinc or zinc alloy plating is usually performed by hot dipping or electrolytic plating, but other platings are electrolytic or electroless plating (chemical plating).
Plating is generally performed by the method.

Generally, the plating of a steel pipe is carried out by housing the steel pipe horizontally, vertically, or inclined in a plating tank larger than the steel pipe to be plated. In electroless plating,
In this method, the inner and outer surfaces of the steel pipe are plated at the same time. In the case of inner surface plating, it is also known that both ends of a steel pipe are sealed, the steel pipe is used as a plating tank, and an electroless plating solution is supplied to the inside of the steel pipe to plate the inner surface.
However, a method of plating only the outer surface of the steel pipe by electroless plating has not been established.

In recent years, the technology for manufacturing steel pipes has improved, and it has become possible to manufacture long steel pipes having a length of more than 10 m even for seamless steel pipes, and as a result, the plating tank becomes larger and the steel pipe moves between plating processes. Is a problem. Further, conventionally, a bath for plating pretreatment was used in addition to the plating bath, and a wide space was required to arrange many types of baths. Further, if the plating bath is large, a large amount of plating solution and each pretreatment solution are required, and the electroless plating method, which requires more expensive plating solution than the electroplating method, has a cost disadvantage. Furthermore, since washing is performed between each process, a large amount of contaminated water that requires waste liquid treatment is generated.

In the electroplating method, the electric current (I = V / R) sent from both ends at the center of the pipe is lowered by the electric resistance of the pipe. The decrease of the current in the central part is remarkable compared to the part,
The plating thickness, which depends on the current, is significantly smaller at the center than at the tube end. Therefore, there is a limit to the length of the tube in order to form a plating film having a uniform thickness.

[0006] However, in the electroless plating method, a plating film is formed by a chemical reaction in which metal ions are deposited on a metal by a reducing agent in a plating solution. Therefore, if the reaction conditions, especially the temperature, can be kept uniform in the steel pipe, Regardless of the length of the steel pipe, a plating film of uniform thickness can be formed over the entire length. Therefore, since the length of the steel pipe is not limited, the electroless plating method is suitable as a plating method for a long pipe.

As an electroless plating method for the inner surface of a long tube, Japanese Patent Laid-Open Nos. 54-121239 and 57-169097 disclose that an electroless plating solution is pumped into an upright tube. A method of plating is described. The long tube is made to stand upright in order to ensure uniform plating. However, if the length of a long pipe exceeds 10 m, the weight will be 100 to 10
It reaches 00 kg, and it becomes difficult to plate upright. That is, in such an ultra-long and heavy metal tube, it is indispensable to perform plating in a stable horizontal posture in terms of equipment and handling.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electroless plating method and apparatus for a long tube, which is capable of uniformly and satisfactorily plating the inner surface and the outer surface of the long tube in a stable horizontal posture. is there. Another object of the present invention is to plate the inner surface and the outer surface of a long tube by a simple operation by an electroless plating method without using a large space and without using a large amount of expensive electroless plating solution. It is to provide a plating method and apparatus capable of performing plating.

[0009]

[Means for Solving the Problems] According to the present invention, the following (1)
The plating method and apparatus of (4) are provided. (1) An electroless plating method for the inner surface of a long tube, in which the plating pretreatment liquid is first supplied to the inner space of the horizontally supported long tube to perform the pretreatment of the inner surface of the long tube. After that, the electroless plating solution is sent under pressure to plate the inner surface of the long tube,
A method for electroless plating the inner surface of a long tube, which comprises rotating the long tube in the circumferential direction at least during plating.

(2) A method for electroless plating the outer surface of a long tube, wherein the long tube is concentrically arranged inside a horizontally supported larger diameter outer tube, and the long tube and the outer tube are The plating pretreatment liquid is first supplied to the annular space formed between and to perform the plating pretreatment on the outer surface of the long tube, and then the electroless plating solution is pumped to plate the outer surface of the long tube. And rotating the long tube in the circumferential direction at least during plating, the electroless plating method for the outer surface of the long tube.

(3) A pair of sealing lids attached to both ends of the long pipe to be plated for sealing the internal space of the long pipe, supporting the long pipe horizontally and rotating in the circumferential direction. An electroless plating apparatus for an inner surface of a long tube, comprising: a supporting / rotating mechanism for allowing the inner space of the long tube; and a liquid supply mechanism for supplying a processing liquid to the internal space of the long tube via the sealing lid.

(4) An outer tube in which the long tube to be plated is housed, the long tube is concentrically supported in the outer tube, and an annular space formed between the long tube and the outer tube is formed. To seal,
A pair of sealing lids attached to both tube ends of the outer tube, a supporting and rotating mechanism for horizontally supporting the outer tube and rotating the outer tube in the circumferential direction together with the long tube housed therein, and the ring. An electroless plating apparatus for an outer surface of a long tube, comprising a liquid supply mechanism for supplying a processing liquid to a space through the sealing lid.

[0013]

In the electroless plating method and plating apparatus for the inner surface of a long pipe according to the present invention, the horizontally supported long pipe itself is used as a plating tank, and the internal space of the long pipe is used as a plating chamber. And Then, the electroless plating solution is supplied to the plating chamber to plate the inner surface of the long tube. In order to further reduce the volume of the plating chamber and save the amount of plating solution used, a rod or tube may be inserted inside the long tube, preferably concentrically with the long tube. In that case, the annular space between the rod or tube and the long tube becomes the plating chamber.

In the electroless plating method and the plating apparatus for the outer surface of the long tube according to the present invention, the outer tube in which the long tube is concentrically housed is used as a plating tank, and the outer tube and the long tube are used. The annular space between and becomes the plating chamber. Then, the plating solution is supplied to the annular plating chamber to plate the outer surface of the long tube.

In both the case of the inner surface plating and the case of the outer surface plating, the electroless plating solution is pressure-fed in the plating chamber to flow in one direction, that is, the plating solution sent from the plating solution storage tank is treated with a long pipe ( Alternatively, it is preferable to circulate in the plating chamber by pumping from one end of the outer tube) into the plating chamber and returning the plating solution discharged from the other end to the storage tank. As a result, most of the gas such as hydrogen generated during plating is discharged outside the tube. Further, since the plating solution flows in the long tube, the temperature in the plating chamber is kept uniform, and the chemical reaction for depositing the plating occurs uniformly in the longitudinal direction in the plating chamber. Therefore, a plating film having a uniform thickness is formed over the entire length, and thin plating at the central portion as seen in the electrolytic plating method can be avoided.

Further, by rotating the long tube in the circumferential direction during plating, it is possible to avoid the gas remaining in the tube from accumulating in the upper part and locally causing non-plating or bubble damage. This rotation also contributes to the improvement of plating uniformity.

Although the long pipe is plated in a horizontal position by the circulating feeding of the plating solution and the rotation of the long pipe as described above, there is little non-plating or bubble scratches, and the thickness and composition are small.
(In the case of alloy plating), a plating film of good quality, which is uniform in both the circumferential direction and the longitudinal direction, is formed on the inner surface or the outer surface of the long tube.

According to the present invention, since the plating chamber is also used for pretreatment, it is not necessary to separately install a treatment tank for pretreatment. As a pretreatment for electroless plating, degreasing and pickling are performed on metal pipes such as steel pipes, and in the case of resin pipes such as FRP pipes made of ABS or epoxy resin and glass fiber, reduction with precious metal compound Activation treatment using the agent is performed. The pretreatment (degreasing, pickling, etc.) is performed by sequentially supplying the treatment liquid from the storage tank for each pretreatment liquid to the plating chamber by switching the valve provided in the piping system. During each treatment, water is supplied from the piping system into the plating chamber to wash with water to prevent liquid mixing. Even during the pretreatment of plating, if necessary, the treatment liquid may be circulated under pressure to the plating chamber in the same manner as the plating liquid, or may simply be retained. Further, it is preferable to rotate the long tube in the circumferential direction as in the case of plating.

Therefore, the space is sufficient if the long pipe to be plated can be installed horizontally and the storage tank for the plating solution and the pretreatment solution for plating and the attached piping and the supporting / rotating mechanism can be installed. But you can do it. Further, since the plating chamber is small, the amount of expensive electroless plating solution used can be small. Furthermore, all plating steps (e.g., degreasing → washing with water → pickling → washing with water → plating → washing with water) can be performed without changing the long pipe to be plated, simply by switching the type of liquid supplied to the plating chamber. It is also suitable for long heavy tubes that are difficult to move.

The material of the long tube which can be electroless plated by the method and apparatus of the present invention is not particularly limited. Not only metal tubes made of various metals or alloys such as steel tubes, but also F
It can also be applied to resin pipes such as RP pipes (preferably epoxy resin and ABS resin are used as the resin type). However, depending on the material of the long tube, the type of treatment liquid used for the pretreatment for plating may change. For example, in the case of a resin tube, the pretreatment is not degreasing and pickling, but, for example, a sensitization treatment with a solution containing a reducing agent (eg Sn ²⁺ ion) and a precious metal (eg Pd ) An activation treatment with a solution containing ions is performed to form a noble metal nucleus having catalytic activity in advance on the plated surface of the resin tube.

Further, there is no limitation on the kind of plating metal, and it can be applied to any metal or alloy plating that can be electrolessly plated. As the plating species, for example, nickel alloy
(Eg, Ni-B, Ni-P, etc.), copper, etc.

The present invention is particularly suitable for the inner and outer surface plating of a long metal tube having a length of 10 m and a weight of more than 100 kg, which is difficult to plate upright, but There are no particular restrictions on length and weight.

The case of applying the plating method and apparatus of the present invention to a long metal tube will be specifically described below with reference to the accompanying drawings. FIG. 1 shows an inner surface electroless plating apparatus of the present invention. The long pipe 10 to be plated is placed on the support rotation mechanism 20 in a horizontal posture. The rotation mechanism 20
A plurality of rotating rollers 22 arranged in the tube axis direction of the long tube 10 are provided, and the long tube 10 is supported horizontally by this. The rotary roller 22 at each position is rotated in one direction by an attached motor M or is synchronously driven in both forward and reverse directions to rotate the long tube 10 in the circumferential direction.

At both ends of the long tube 10, screw-in type sealing lids are provided.
The (flange) 40 is mounted via an annular seal ring (O-ring) 42, and the internal space A of the long tube is sealed. A liquid passage hole 44 is provided in the sealing lid 40 to allow a processing liquid such as a plating liquid to flow from one end to the other end of the internal space A of the long tube.

The material of the sealing lid 40 is preferably one that is less susceptible to electroless plating (the surface is inactive) and has excellent corrosion resistance. For example, a synthetic resin, stainless steel that easily forms a passive oxide film on the surface, or a metal material having an oxide film formed on the surface by heat treatment can be used, but a synthetic resin is particularly preferable.

Each liquid passage hole 44 of the sealing lid 40 on both sides is connected to the liquid supply mechanism 60 by a flexible hose. Liquid supply mechanism 60
Includes a degreasing solution 62, a pickling solution 64, and an electroless plating solution 66, and by switching between the pump P and the valves V _{1 to} V ₈ , the degreasing solution, the pickling solution, The plating solution and the cleaning water can be independently pumped. The degreasing liquid 62 and the electroless plating liquid are kept at a predetermined temperature by the steam heating device 68 provided in the storage tank.

To carry out the electroless plating of the inner surface of the present invention using the apparatus shown in FIG. 1, first, the degreasing liquid 62 is circulated under pressure in one direction from one end to the other end in the internal space A of the long pipe 10, Degrease the inner surface of the long tube. After the degreasing is completed and the degreasing liquid is completely discharged from the long tube, cleaning water is pressure-fed to the space A to wash the inside of the long tube. Then, similarly, the pickling solution 64 is circulated and pressure-fed to pickle the inner surface of the long tube and then to wash with water.
During each of these processes, the motor of the support rotation mechanism 20 is operated to rotate the long tube in one direction or repeatedly in both forward and reverse directions. In addition, a pause period is inserted between the pumping of each liquid and the washing water.

After that, while rotating the long tube by the supporting and rotating mechanism 20, the electroless plating solution 66 is circulated under pressure in one direction into the internal space A of the long tube 10 so that the inner surface of the long tube has a predetermined thickness. To form a plating film. After the plating is completed, washing water is pumped into the internal space of the long tube 10 to wash it, and a series of plating operations are completed. Table 1 shows the operation program of the plating apparatus at this time.

[0029]

[Table 1]

FIG. 2 shows a partial view of the external electroless plating apparatus of the present invention. This outer plating apparatus is different from the inner plating apparatus shown in FIG. 1 in that the long tube 10 is inserted into the outer tube 70 and the outer outer tube 70 is horizontally placed on the support rotation mechanism 20. is there. Since the outer surface of the long tube 10 is plated over the entire length, the outer tube 70 is preferably made slightly longer than the long tube.

The long tube 10 inserted into the outer tube 70 is
It is supported in a horizontal posture concentrically with the outer tube 70 by screw-in type sealing lids 40 attached to both ends of the outer tube 70. Sealing lid
An annular seal ring 42 is interposed between 40 and the outer tube 70 and the end surface of the long tube 10 to seal the annular space B formed between the outer tube 70 and the long tube 10. The sealing lid 40 has a liquid passage hole 44 for allowing the processing liquid to flow in the annular space B. The materials of the sealing lid 40 and the outer tube 70 may be the same as those described for the sealing lid of FIG.

The outer electroless plating of the present invention using the apparatus shown in FIG. 2 is carried out essentially in the same manner as the inner electroless plating described above. That is, each processing solution is pressure-fed to the annular space B between the long tube 10 and the outer tube 70, not the inner space of the long tube 10, and the outer tube 70 is concentrically housed therein. Ten
The operation is the same, except that it is rotated with. As a result, it becomes possible to easily perform the electroless plating on the outer surface of the long tube, which has been difficult in the past, in a narrow place.

In both electroless plating on the inner surface and the outer surface described above, non-plating due to generated gas and generation of bubble defects are caused by unidirectional circulating pressure feeding of the plating solution and rotation of the long tube.
Non-uniform plating in the pipe circumferential direction is prevented. Further, the switching of the liquid type and the rotating operation of the long tube 10 can be automatically controlled by an external program controller. When the hose is not twisted due to the use of a rotary joint or the like, the hose can be rotated in one direction instead of both the forward and reverse directions.

The amount of the plating solution pumped is preferably 0.1 V / min (V is the volume of the plating chamber, that is, the space A or B) or more. If this amount of pumping is small, a sufficient gas discharging effect may not be obtained, and the temperature of the long tube may not be maintained. If the pumping amount is too large, the load on the pump increases and a large pump is required, so 3 V or less is usually sufficient. The rotation speed of the long tube is preferably 1 rpm or more. If the rotation speed is too high, the rotation will be unstable, so 10 rpm or less, usually 5
Below rpm is sufficient.

[0035]

【Example】

(Example 1) Using the inner surface plating apparatus according to the present invention shown in FIG. 1, electroless nickel plating was applied to the inner surface of a long steel pipe under the following conditions. A rotary joint was used to connect the hose to the liquid passage, and the steel pipe was rotated in one direction during pretreatment and plating.

Steel pipe for plating Dimensions: outer diameter 168 mm, inner diameter 152 mm, length 12.0 m (internal space volume = 218 L) Material: carbon steel sealing lid Material: polyvinyl chloride resin Degreasing condition Degreasing liquid: 3% Aqueous sodium orthosilicate solution Conditions: Temperature 60-70 ° C, time 5 minutes Pickling conditions Pickling solution: 10% hydrochloric acid (room temperature, 2 minutes) Plating conditions Plating solution: Commercial electroless nickel plating solution (Kamimura Kogyo,
Nimden Super) Temperature: 90 ± 2 ℃ Time: 30 minutes Pumping amount Each treatment liquid: 50 L / min (0.23 V / min) Plating liquid: 400 L / min (1.83 V / min) Rinse water: 80 L / min (0.37 V / min) Steel pipe rotation speed : 2 rpm (one direction rotation) A nickel plating layer was formed on the entire length of the inner surface of a long steel pipe having a length of 12.0 m. The thickness of the plating layer was uniform in the longitudinal direction and the circumferential direction, and was 18 ± 0.5 μm in the entire circumference of the tube end portion and the central portion. When the plating appearance was visually inspected, no plating or bubble defects were found.

(Example 2) Using the external plating apparatus according to the present invention shown in FIG. 2, electroless plating copper plating was applied to the external surface of a long steel pipe under the following conditions. A rotary joint was used to connect the hose to the liquid passage, and the steel pipe and the outer pipe were rotated in one direction during pretreatment and plating.

Steel pipe for plating Dimensions: outer diameter 168 mm, inner diameter 152 mm, length 4.0 m Material: carbon steel jacket tube dimensions: outer diameter 267 mm, inner diameter 240 mm, length 4.01 m Material: polyvinyl chloride resin (with steel pipe) Volume of the annular space between them = 92 L) Material of sealing lid : Degreasing / pickling conditions same as in Example 1: Plating conditions same as in Example 1 Plating solution: Commercial electroless copper plating solution (Uemura Kogyo, Sulcup ELC) -SR) Temperature: 55 ± 1.5 ° C Time: 25 minutes Pressure feed Each processing solution: 30 L / min (0.32 V / min) Plating solution: 200 L / min (2.18 V / min) Rinse water: 80 L / min ( 0.87 V / min) Steel pipe / jacket rotation speed : A copper plating layer was formed on the entire length of the outer surface of a long steel pipe having the same length as in Example 1 and having a length of 4.0 m. The thickness of the plating layer was uniform in the longitudinal direction and the circumferential direction, and was 1 ± 0.2 μm in the entire circumference of the tube end portion and the central portion. When the plating appearance was visually inspected, no plating or bubble defects were found.

Comparative Example 1 A length of 1 mm was obtained in the same manner as in Example 1 except that the rotation of the long steel pipe during the pretreatment and during plating was stopped.
Electroless plating nickel plating was applied to the inner surface of a 2.0 m long steel pipe. As a result, the plating thickness was almost uniform over the entire length of the steel pipe having a length of 12.0 m, but a linear unplated portion was generated in the ceiling portion of the steel pipe.

Comparative Example 2 Using the same apparatus as that shown in FIG. 1, the inner surface of the long steel pipe was nickel-plated by electrolytic plating. However, in order to apply the current required for electrolytic plating,
In the above apparatus, a tubular electrode thinner and longer than the long tube was concentrically inserted inside the long steel tube 10, and an annular space between the steel tube and the inner tubular electrode was used as a plating chamber. In the degreasing step and the plating step, electricity was supplied from an external power source so that the inner tubular electrode served as the anode and the long steel tube served as the cathode. The conditions of each process are shown below.

Steel pipe for plating Dimensions: outer diameter 168 mm, inner diameter 152 mm, length 7.5 m Material: carbon steel inner tubular electrode Dimensions: outer diameter 70 mm, inner diameter 46 mm, length 8.0 m Material: SUS 304 stainless steel ( Volume of annular space between steel pipe and electrode = 107 L) Material of sealing lid : same degreasing condition as in Example 1 degreasing liquid: 3% sodium orthosilicate aqueous solution condition: temperature 60 to 70 ° C., current density 4 A / dm ² , Time 2 minutes Pickling condition Pickling solution: 10% hydrochloric acid (room temperature, 1 minute) Plating condition Plating solution: Watt bath (pH 3.5) Nickel sulfate 250 g / l Nickel chloride 70 g / l Boric acid 40 g / l Temperature : 40 to 50 ° C Current density: 5 A / dm ² hours: 25 minutes Pumping amount Each processing solution: 50 L / min (0.47 V / min) Plating solution: 107 L / min (1.0 V / min) Rinse water: 80 L / Min (0.75V / min) Steel pipe rotation speed : 4 rpm (during plating and degreasing, reciprocal reciprocating rotation) A nickel plating layer was formed on the entire inner surface of a 7.5 m long steel pipe. However, the maximum thickness of the plating layer is 26 μm
(Tube end), minimum 18 μm (center), and fluctuation width in the longitudinal direction reached 8 μm. The fluctuation range of the plating thickness in the longitudinal direction is 2μ when the length of the long steel pipe becomes as short as 3.5 m.
It decreased to m. Therefore, when the length of the long steel pipe becomes as long as 12.0 m as in Example 1, the variation range of the plating thickness in the longitudinal direction becomes much larger than 8 μm. On the other hand, in the electroless plating method of Example 1, in the long steel pipe having a length of 12.0 m, the fluctuation range of the plating thickness in the longitudinal direction is 1 μm
Therefore, it is much smaller than the electrolytic plating method.

Since the long steel pipe was rotated during the plating, the fluctuation range of the plating thickness in the circumferential direction was 26 ± 0.6 at the pipe end.
μm and 18 ± 0.5 μm in the central part.

[0043]

The effects of the present invention are as follows. Both inner surface plating and outer surface plating of long tubes can be performed. By pumping and circulating the plating solution, even when plating a long pipe of more than 10 m, the variation of the plating thickness in the longitudinal direction of the pipe is extremely small. In the electrolysis method, even if the plating solution is pumped, thin plating in the central part cannot be avoided. Further, by rotating the long tube during plating, the plating thickness becomes uniform in the circumferential direction of the long tube.
Therefore, a plating film having a uniform thickness is formed in both the longitudinal direction and the circumferential direction.

By pumping the plating solution and rotating the long tube,
The discharge of bubbles and gas to the outside of the tube is promoted, and the local retention thereof is prevented, so that a plating film with less plating and less bubble defects is formed.

With the heavy long pipes arranged horizontally without moving, the pre-plating process to the electroless plating can be performed almost automatically by operating the external pump and the valves provided in each storage tank. Can be carried out.

Since the inside of the long tube to be plated (in the case of inner surface plating) or the annular space between the outer tube and the long tube containing the long tube (in the case of outer surface plating) is used as a plating chamber, The volume of the chamber is relatively small, the amount of each processing solution including an expensive electroless plating solution used is small, and the amount of contaminated cleaning water discharged is also small. Since degreasing and pickling are performed in the same processing equipment as plating, it can be performed in a relatively narrow space.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an inner surface electroless plating apparatus for a long tube according to the present invention.

FIG. 2 is an explanatory view showing a portion of an outer surface electroless plating apparatus for a long tube according to the present invention.

[Explanation of symbols]

10: Long tube, 20: Support rotation mechanism, 22: Rotating rollers 22, 4
0: Sealing lid, 42: Annular seal ring, 44: Liquid passage holes 44, 6
0: Liquid supply mechanism, 62: Degreasing solution, 64: Pickling solution, 66: Electroless plating solution, 68: Steam heating device, 70: Outer tube, A: Long tube inner space, B: Annular space, M: Motor, P: Pump,
V ₁ ~V _8: valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Sato No. 1 Nishinomachi, Higashimukaijima, Amagasaki City Sumitomo Metal Industries, Ltd. Kansai Works Special Pipe Works

Claims (4)

[Claims] 1. A method for electroless plating the inner surface of a long tube, wherein a plating pretreatment liquid is first supplied to the inner space of the horizontally supported long tube to perform the pretreatment of the inner surface of the long tube. After that, the electroless plating solution is pressure-fed to perform plating on the inner surface of the long tube, and at least during plating, the long tube is rotated in the circumferential direction. Electrolytic plating method. 2. A method for electroless plating an outer surface of a long tube, wherein the long tube is concentrically arranged inside a horizontally supported outer tube having a larger diameter, and the long tube and the outer tube are provided. In the annular space formed between the two, the plating pretreatment liquid is first supplied to perform the plating pretreatment on the outer surface of the long tube, and then the electroless plating solution is pumped to perform the outer surface plating of the long tube. And rotating the long tube in the circumferential direction at least during plating,
Electroless plating method for outer surface of long tube. 3. A pair of sealing lids, which are attached to both ends of the long pipe to be plated, for sealing the internal space of the long pipe, horizontally supporting the long pipe and rotating in the circumferential direction. An electroless plating apparatus for an inner surface of a long tube, comprising: a supporting / rotating mechanism; and a liquid supply mechanism for supplying a processing liquid to the internal space of the long tube via the sealing lid. 4. An outer tube in which a long tube to be plated is housed, a long tube is concentrically supported in the outer tube, and an annular space formed between the long tube and the outer tube is sealed. A pair of sealing lids attached to both ends of the outer tube, a supporting and rotating mechanism for horizontally supporting the outer tube and rotating the outer tube in the circumferential direction together with the long tube housed therein, and An electroless plating apparatus for an outer surface of a long pipe, comprising a liquid supply mechanism for supplying a processing liquid to the annular space via the sealing lid.