JPH09176822A - Thermal spraying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten thermal spraying time and to improve the yield of thermal spraying material and the adhesion of a sprayed coating by performing thermal spraying while applying electrostatic field or electromagnetic field to a thermal spraying material. SOLUTION: By applying electrostatic field or electromagnetic field to the thermal spraying material which is projected from a thermal spray gun and comes flying, a Lorentz's force is generated and the thermal spraying material is accelerated in the direction of projection and also the directivity to the direction of projection is made correct. Accordingly, the broadening of the thermal spraying material during projection and flying between the tip of the gun and the object to be sprayed can be reduced and projection onto the part to be sprayed can be performed with high precision. Further, the time necessary to obtain a sprayed coating of prescribed thickness can be shortened because the velocity of projection is accelerated and final velocity is increased. Moreover, because of high velocity of projection, the colliding force of the thermal spraying material against the object to be sprayed is increased and, as a result, the occurrence of pores in the sprayed coating is reduced and the adhesion of the coating is improved. It is preferable to regulate the electrostatic field to be applied to 10-300KV and also the electromagnetic field to (10 to 1000)KA/m.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermal spraying method.

[0002]

2. Description of the Related Art It is known that a thermal spraying powder material of cermet, ceramics or metal is semi-melted to obtain a thermal spraying material, which is projected onto a thermal spraying object for thermal spraying. Further, it is disclosed in Japanese Patent Laid-Open No. 2-225653 that the sprayed portion of the sprayed object is heated and sprayed to improve the adhesion of the sprayed film. Further, it is possible to increase the adhesion of the sprayed film by heating the sprayed powder material to the melting point temperature in advance and then spraying the melted sprayed material by supplying it to the spray gun.
No. 5 discloses this.

[0003]

In the above-mentioned thermal spraying, the thermal spray material scatters when it is projected onto the object to be sprayed, and the yield of the thermal spray material is remarkably reduced. In particular, if the thermal sprayed portion of the sprayed object is a curved surface, the sprayed material that has collided with the thermal sprayed portion will be scattered in large amounts, resulting in a lower yield and a significant increase in cost. The method of the present invention has been made in order to advantageously solve such a problem,
An object of the present invention is to provide a thermal spraying method capable of improving the yield of the thermal spraying material to be projected, accelerating the projection speed, shortening the thermal spraying time to improve the productivity, and further improving the adhesion of the thermal sprayed film. To do.

[0004]

The feature of the method of the present invention resides in that when the thermal spraying powder material is projected onto the object to be sprayed and sprayed, the thermal spraying material is projected onto the thermal spray material between the tip of the thermal spray gun and the object to be sprayed. The thermal spraying method is characterized in that the thermal spraying is performed on the sprayed object while applying an electric field or an electromagnetic field.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the thermal spray material ejected from the tip of the thermal spray gun gradually spreads (scatters) during the projection flight between the objects to be sprayed, and when it reaches the object to be sprayed, it goes to other parts than the sprayed part. There are those that reach, and those that collide with the sprayed part and bounce off and scatter. By applying an electrostatic or electromagnetic field to the spray material that is projected and thus flying, a Lorentz force is generated to accelerate the spray material that is projected and fly in the electrostatic or electromagnetic field in the projection direction, as well as directivity in the projection direction. Will be accurate. That is, by applying an electrostatic field or the like, the spraying material to be projected and projected is guided by the electrostatic field or the like and is further accelerated, so that the spread of the spraying material between the tip of the spray gun and the sprayed object is narrowed, It can be accurately projected onto the sprayed part, and since the projection speed is accelerated from the initial speed and the final speed is increased, it also bites into the sprayed part and rebounds and scattering are reduced, resulting in a dramatic improvement in yield. Further, by accelerating the projection speed, the spraying time for obtaining a sprayed film having a predetermined film thickness can be shortened, the productivity can be improved, and the projection speed becomes high, so that the sprayed material collides with the sprayed object. The force is increased, the generation of pores in the sprayed film is reduced, and the adhesion of the sprayed film can be improved. For this reason, it is extremely advantageous when the sprayed portion of the sprayed object has a curved surface shape or the like and the spraying range is narrow.

As described above, the electrostatic field applied to the thermal spray material projected onto the thermal spraying object is 10 to 300 KV, which can surely prevent the spraying of the thermal spray material and accelerate the projection speed, and is less than 10 KV. It becomes difficult to obtain a sufficient effect, and if it exceeds 300 KV, it is not preferable for safety. Next, when applying an electromagnetic field, 10 to 1000K
It is possible to prevent the spraying of the sprayed material at A / m and to accelerate the projection speed, and if it is out of this range, it can be explained in the same manner as the application of the electrostatic field.

As a thermal spray material (spray powder material),
Used in, for example, Ti, Ni, Ni-Cr system,
Metals such as Ni-Al series, Fe-Cr series, and Al. Or A
l_TwoO_ThreeSystem, TiO_TwoSystem, ZrO_Two-Y_TwoO_ThreeSystem, Y_Two
O_ThreeSystem, SiO_TwoCeramics such as series. Furthermore, like this
Made of various ceramics and metals, eg WC, Cr _Three
C_Two, TiC, ZnC, etc. cermets are generally
By gas flame spraying, plasma spraying, etc.
When spraying onto the object to be sprayed,
When an electrostatic or electromagnetic field is applied to the sprayed material projected onto
It is.

Next, an example of the method of the present invention will be described with reference to the drawings. In FIG. 1, fuel and supporting gas are supplied to a combustion chamber 2 of a thermal spray gun 1 from a fuel gas supply pipe 3 and a supporting gas supply pipe 4 for combustion, while a thermal spray powder material is supplied from a material supply port 5. It is heated and semi-melted to form a thermal spray material 6, which is projected onto the thermal spraying target 7 and sprayed. Then, the charging material 8 sprays between the tip of the spray gun 1 and the body 7 to be sprayed while applying an electrostatic field by the charging electrode 8. To generate such an electrostatic field stably,
It is preferable to arrange the high-voltage power supply 9 and the ground 10.
When an electromagnetic field is applied, an induction coil is arranged in place of the charging electrode 8 to apply a Lorentz force to the spray material 6 which is projected and fly, and is sprayed onto the sprayed material 7.

[0009]

EXAMPLES Next, examples of the method of the present invention will be given together with comparative examples.

[Table 1]

[0010]

[Table 2]

Note 1: Thermal spraying is carried out by gas flame spraying. Note 2: Thermal spray powder material (spray material) is A: Ti, B: N
i, C: Ni-Cr system, D: Ni-Al system, E: Fe-
Cr type, F: Al, G: Al ₂ O ₃ type, H: TiO
₂ system, I: ZrO ₂ —Y ₂ O ₃ system, J: Y ₂ O ₃ system,
K: SiO ₂ system, L: WC system, M: Cr ₃ O ₂ system, N:
Materials generally used in TiC type and O: ZnC type were used. A to F are metals, G to K are ceramics,
L to O are cermets. Note 3: The object to be sprayed was sprayed onto the surface of a roll (steel for general structure) having a diameter of 800 mm.

[0012]

According to the method of the present invention, the spraying time can be shortened and the productivity can be improved. Further, the yield of the thermal spray material can be remarkably increased and the thermal spray cost can be significantly reduced. In addition, the porosity in the sprayed film can be reduced, the adhesion of the sprayed film can be improved, and the quality can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of the method of the present invention.

[Explanation of symbols]

 1 Thermal Spray Gun 2 Combustion Chamber 3 Fuel Gas Supply Pipe 4 Combustion Gas Supply Pipe 5 Material Supply Port 6 Thermal Spray Material 7 Thermal Spray Object 8 Charging Electrode 9 High Voltage Power Supply 10 Earth

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Tsumura 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Stock Company Nagoya Works

Claims (1)

[Claims] 1. When projecting and spraying a sprayed powder material onto a sprayed object, an electrostatic field or an electromagnetic field is applied to the sprayed material that is projected and fly between the tip of the spray gun and the sprayed object, and the sprayed material is sprayed onto the sprayed object. A thermal spraying method characterized in that