JP3356960B2 - Spraying method of cast iron tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for spraying a cast iron tube, and more particularly to an improvement in a method for spraying a cast iron tube when performing metal spray coating on the outer periphery of the cast iron tube.

[0002]

2. Description of the Related Art Conventionally, in order to improve the corrosion resistance of the outer periphery of a cast iron pipe, a metal powder having excellent corrosion resistance is sprayed by flame spraying to ultra-high-speed flame spraying to form a metal film.

When forming a metal spray coating, it is necessary to remove the oxide scale on the cast iron base in order to improve the adhesion of the spray coating. In general, as a removing means, after the surface of the cast iron pipe is shot blasted and the surface is sufficiently polished, necessary preheating is performed, and the metal powder is sprayed and adhered by an ultra-high-speed flame spray gun.

[0004]

However, conventionally, the step of performing the shot blast and the step of spraying the metal powder are separate facilities, so that the water, oil, or dust during the transfer process to the spraying step after the shot blasting. There is a problem that the particles adhere and cause defects in the sprayed coating.

[0005] Further, it is necessary to provide two facilities for shot blasting and metal spraying, and the equipment including the transporting equipment between them becomes large-scale, and a preliminary heating device is sometimes required. There was a problem.

In view of the above problems, the present invention makes use of the features of a flame spray gun that performs metal spraying, enables shot blasting and flame spraying with one facility, and can eliminate the facility and improve the quality of the coating. The object of the present invention is to provide a method for spraying a cast iron tube.

[0007]

That is, according to the method of the present invention for spraying a cast iron tube, a plurality of frame spray guns are arranged on the side surface along the tube axis direction of the cast iron tube, and the cast iron tube is rotated around the tube axis. While moving the plurality of flame spraying guns in the axial direction, in this moving process, spraying ferrosilicon alloy powder from one or more flame spraying guns on the moving tip side, and following the moving tip side frame spraying gun. The thermal spray material is sprayed from the end frame thermal spray gun.

[0008] The flame spray gun sprays a metal powder with a high-temperature flame, and melts the metal powder in the flame, and sprays the metal powder at high pressure on the outer periphery of the cast iron pipe. Therefore, if metal powder that does not adhere to the outer periphery of the cast iron tube even when sprayed with a thermal spray gun, for example, ferrosilicon powder, is sprayed, the same effect as shot blast can be obtained, and the outer periphery of the cast iron tube is heated by the spray metal. Thus, it can be used as a base under favorable conditions for subsequent metal spraying.

Further, if a metal serving as a metal film material is sprayed from the spray gun continuously arranged after the above-mentioned spray gun, a metal film can be spray-formed immediately on a perfect base, and the film performance is very high. Get better.

If an ultra-high-speed flame spray gun is used as the above-mentioned flame spray gun, the polishing effect and the preheating effect can be more excellently obtained.

[0011]

Next, an embodiment of the present invention will be described. FIG. 1 is a sectional view of an embodiment of the present invention.

On a side surface of a supporting device 2 for rotating a cast iron tube 1 around a tube axis, a carriage 5 on which two spray guns 3 and 4 are installed is installed. Next, while rotating the cast iron tube 1, ferro silicon powder having a particle size of about 50 to 150 μ is supplied from the flame spraying gun 3 on the front side in the moving direction, and Al-Si alloy powder is supplied from the frame spraying gun 4 on the rear side in the moving direction. The trolley 5 was moved from one end to the other end of the cast iron tube 1 while performing thermal spraying, and metal spraying was performed.

The above-mentioned ferrosilicon powder has an extremely small adhesion to the cast iron tube, hardly adheres thereto, and the outer peripheral surface of the cast iron tube 1 is sufficiently polished by metal spraying from the flame spray gun 3.

Al sprayed from the flame spray gun 4
The -Si alloy powder had good adhesion and uniformly adhered to the outer peripheral surface of the cast iron tube 1. As a result, it was confirmed that a metal film having almost no pinholes was formed.

[0015] In the above, three or more metal spray guns are provided, ferrosilicon powder having no adhesion is sprayed from the first and second frame spray guns, and the adhesive Al-Si powder is sprayed from the last frame spray gun. The alloy powder may be sprayed.

Further, if an ultra-high-speed flame spray gun is used as the flame spray gun, a polishing effect and a preheating effect can be more advantageously obtained.

[0017]

As described above, according to the present invention, a plurality of flame spraying guns are prepared without using a shot blasting device at all, and a metal having no or very low adhesion is sprayed with a front spraying gun. At the same time as polishing the surface of the cast iron tube, heating is performed with the metal sprayed, and then the highly sprayed metal is sprayed with the rear spray gun, so the time from polishing to metal spraying is extremely short, and the moisture, oil and It is possible to form a metal film on a very good base surface without any adhesion of dust, and to form a metal film without defects.

Furthermore, since a shot blasting device, a transporting device, a preheating device, and the like are not required, there is an effect that the equipment can be largely omitted and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cast iron tube 2 ... Rotation support device 3 ... Thermal spray gun 4 ... Thermal spray gun 5 ... Dolly

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-76265 (JP, A) JP-A-51-214631 (JP, A) JP-A-9-25558 (JP, A) JP-A-60-1985 262952 (JP, A) JP-A-7-243792 (JP, A) JP-A-61-35873 (JP, A) JP-A-57-101662 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) C23C 4/00-4/18

Claims (1)

(57) [Claims] 1. A plurality of frame spraying guns are arranged on a side surface along a tube axis direction of a cast iron tube, and the plurality of frame spraying guns are moved in an axial direction while rotating the cast iron tube around the tube axis. In the process, the ferrosilicon alloy powder is sprayed from one or more flame spray guns on the moving tip side, and the spray material is sprayed from the rear frame spray gun following the moving tip frame spray gun. Spraying method of cast iron pipe.