JPS6277469A - Coating device for inside and outside surfaces of pipe - Google Patents

Abstract

PURPOSE:To improve the speed of forming films on the inside and outside surfaces of a pipe with a coating device by activating a reaction gas by high-frequency discharge or glow discharge and irradiating laser light to the activated gas. CONSTITUTION:A metallic pipe 1 is attached to a holding part 4 and after the pipe is hermetically closed, the inside of the pipe 1 is evacuated to expel the atmospheric air therefrom by a vacuum pump 11. While the reaction gas is supplied into a gas introducing pipe 8, the high-frequency discharge or glow discharge is generated between the pipe 8 and the inside surface of the pipe 1 by a discharge generator 14. The reaction gas flowing out of a nozzle 9 of the pipe 8 is activated by such discharge. The laser light 21 is irradiated from a window 12 to the activated reaction gas in parallel with the inside surface of the pipe 1 to induce the thermal cracking and synthesizing reaction of the reactive gas, thus sticking the resultant reaction product to the inside surface of the pipe 1. The pipe 1 is rotated by driving rollers 16 during this time to stick the resultant reaction product over the entire inside surface. The speed of forming the resultant reaction product is thereby increased and the density of the product sticking to the pipe is increased.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention provides a method for applying ceramics or T to the surface of a metal tube.
This invention relates to a coating device for the inner and outer surfaces of a metal tube, which improves the functionality of the surface of a metal tube by coating the surface of the tube.

[Conventional technology]

For example, oil country tubular goods are required to coat the inner and outer surfaces of metal tubes with ceramics, carbide, tungsten, etc. to improve the corrosion resistance, abrasion resistance, etc. of the tube surface.

Conventionally, typical methods for coating the inner and outer surfaces of a metal tube to make the surface highly functional include plasma spraying and overlay welding.

Plasma spraying is a method that uses an ultra-high temperature plasma jet to melt powder of a high-melting point material such as tungsten and sprays it onto the pipe surface at high speed to form a high-density and high-strength coating. The arc build-up welding method is a method in which corrosion-resistant weld metal is piled up and coated on the pipe surface.

[Problem that the invention seeks to solve]

In the above-mentioned conventional plasma spraying method, air is injected by a high-temperature, high-speed plasma jet to oxidize the particle surface of the sprayed material. As a result, the adhesion force between the grains weakened, and at the same time, minute pores were formed between the grains, making it impossible to achieve the desired performance in terms of corrosion resistance. After applying a vacuum, inert gas such as argon is heated to 30 to 40 Torr for metallic thermal spraying materials.
A low-pressure plasma spraying method has also been developed in which plasma spraying is performed by feeding at a low pressure of . When this low-pressure plasma spraying method is used, oxides are reduced and the porosity is reduced, but these do not become zero, and there is a problem that the above disadvantages have not been completely solved. The overlay welding method had problems such as poor work efficiency (and thermal distortion).

The present invention has been made to solve these problems, and it is an object of the present invention to provide a coating device for the inner and outer surfaces of a tube that can easily form a good coating without pores.

[Means for solving problems]

The apparatus for coating the inner and outer surfaces of a tube according to the present invention includes a sealing means, a vacuum evacuation means, a gas introducing means, a discharge generating means, a laser beam oscillation irradiation means, and a driving means.

The sealing means places the surface of the metal tube to be coated in a tightly closed space.The vacuum evacuation means evacuates the sealed space by means of the sealing means.The gas introduction means includes one or more nozzles and is evacuated. A reaction gas is introduced into the sealed space.The discharge generating means generates a high frequency discharge or glow discharge between the gas introducing means and the metal tube surface within the sealed space.The laser beam irradiation means generates a reaction gas introduced into the sealed space. Laser light is irradiated onto the gas to cause a photochemical vapor phase deposition reaction to coat the surface of the metal tube with a deposition material.The driving means relatively moves the nozzle of the gas introduction means and the metal tube to coat the surface of the metal tube. .

[Effect]

In this invention, the reaction gas is excited and activated by high-frequency discharge or glow discharge, and the activated gas is irradiated with laser light to improve the film formation rate.

〔Example〕

Fig. 81 is a partially cutaway schematic configuration diagram showing an embodiment of the present invention. In Fig. 1, 1 is a metal tube whose inner surface is coated, and 2 is an end of the metal tube 1 for sealing one end of the metal tube 1. 4 is a metal tube holding portion fixed to a base 5, which holds the other end of the metal tube 1 through a bearing 6 and a sealing material 7. There is. Reference numeral 8 denotes a gas introduction tube attached to the metal tube holding section 4, which is inserted into the metal tube 1 and is provided with a plurality of nozzles 9 in one radial direction of the insertion section. Reference numeral 10 represents a gas cylinder connected to the gas introduction pipe 8 via a valve or the like for supplying a reaction gas to the gas introduction pipe 8, and reference numeral 11 represents a vacuum pump that evacuates the inside of the metal tube 1.

12 is a laser beam irradiation window provided in the metal tube holding part 4, and is connected to the laser oscillator 13; &14 is a discharge window for generating high frequency discharge or glow discharge between the gas introduction tube 8 and the metal tube 1. The generator, 15 is a control device.

Reference numeral 16 denotes a plurality of drive rollers attached to the base 5, and the drive rollers 16 are rotated from rE, @ sota 18# via a pulley 17. Reference numeral 19 denotes a plurality of driven rollers also attached to the base 5#.

Next, the operation of the coating apparatus configured as described above will be explained.

First, after installing the metal tube 1 and sealing the inside, the inside of the metal tube 1 is evacuated using the vacuum pump 11 to exclude the atmosphere. Next, while supplying the reaction gas to the gas introduction pipe 8, the discharge generator 1
4, a high frequency discharge or glow discharge is generated between the inner surfaces of the gas introduction tube 8 and the metal tube 1, as shown in FIG. The reactive gas flowed between the inner surfaces is activated.

The activated reaction gas is irradiated with a laser beam 21 parallel to the inner surface of the metal tube 1 from the laser irradiation window 12 to cause thermal decomposition and synthesis reaction of the activated reaction gas, and a reaction product is transferred to the metal tube 1. Attach it to the inner surface of the

At this time, the metal tube 1 is rotated by the drive motor 18 and the drive roller 16, and the metal tube 1 is rotated by the drive motor 18 and the drive roller 16. The reaction product is deposited on the entire inner surface of the A-tube 1.

As mentioned above, the reactive gas activated by the discharge turns into gas plasma and absorbs the laser beam 21 well, so the gas temperature becomes high and the rate of reaction product generation increases, and at the same time, the reaction product adheres to the inner surface of the metal tube 1. The degree can be increased.

A specific example of coating the inner surface of a metal tube 1 using the coating apparatus of this embodiment will be described below.

[Specific Example 1] As the metal tube 1, the outer diameter of stainless steel 5US304 is 15Qm
, use a tube with a wall thickness of 100 mm and a length of 300 mm, and the inside of the tube is
After evacuation to xi O"Thrr, a mixed gas of 5α and sugar was supplied as a reaction gas at a gas pressure of 5 Torr, and a high frequency discharge of 13.5 MHz was generated between the inner surface of the tube and the gas introduction tube 8. However, the inner surface of the metal tube was coated by irradiating a CO laser with a laser output of 1000 W and a wavelength of 104 μm parallel to the inner surface of the tube.

In this case, the reaction gas advances the next reaction, and a TiN film is formed on the inner surface of the metal tube.

TiC44 + Nagi → TiN + HCt During this reaction, the reaction gas is activated by high-frequency discharge, so the film formation rate is 1μψ, and the film formation rate is 0.08 with only laser light irradiation without high-frequency discharge.
9 on the inner surface of the metal tube 1.
After forming a 0 μm film, the adhesion between the metal tube 1 and the film and the adhesion of the film were examined. As a result, the adhesion was 7kyf, 4 or more, and a good film was obtained with no pores observed in the film. It was done.

[Specific Example 2] A mixed gas of TiCl2 and CH4 was used as a reaction gas at 1 (r
The inner surface of the metal tube 1 was coated under the same conditions as in Example 1, with the other conditions being the same as in Example 1.

When the above reaction gas was irradiated only with laser light, the gas temperature did not rise and the reaction did not proceed, but by exciting the reaction gas by generating high frequency discharge or DC glow discharge, and irradiating it with laser light, the reaction occurred progressed easily.

In this case, the reaction gas undergoes the following reaction to form a TIC defect.

TiCl2 + CH4 → TiC + HCt After forming a 90 μm film on the entire inner surface of the tube by this reaction, the adhesion and adhesion of the film were examined. As a result, the adhesion force was still more than 7 to 17 *, and there were no holes in the film. was not well recognized.

〔Effect of the invention〕

As explained above, in this invention, a reactive gas is excited and activated by high-frequency discharge or glow discharge, and the activated gas is irradiated with laser light to coat the inner and outer surfaces of the metal tube. As the production rate becomes faster, the degree of adhesion also becomes higher, making it possible to form a good film without pores.

Furthermore, since the reactive gas is excited, it is possible to form a good film using a reactive gas that does not react with laser light alone.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the above embodiment. 1: metal tube, 2: sealing difference, 4: metal tube holding part, 8: gas introduction tube, 9: nozzle, 11; vacuum bond 12; laser irradiation window, 13; laser oscillator, 14; discharge generator, 16;
Drive roller, 18; Drive motor, 21; Laser light.

Claims (1)

[Claims] A coating device that forms a coating layer on one or both of the inner and outer surfaces of a metal tube by a photochemical vapor deposition reaction, which includes a sealing means for placing the surface of the metal tube in a sealed space, and a vacuum pump for evacuating the sealed space. a gas introducing means comprising one or more nozzles for introducing a reactive gas into a space sealed by the evacuation means; and a discharge generating means for generating a high frequency discharge or a glow discharge on the gas introducing means and a metal surface. and a laser beam oscillation irradiation means for irradiating the reaction gas introduced into the closed space by the gas introduction means with laser light to cause a photochemical vapor deposition reaction, and a nozzle of the gas introduction means and a metal tube are placed relative to each other. A coating device for the inner and outer surfaces of a tube, characterized in that it is equipped with a drive means for moving the tube.