JP5058672B2 - Metal surface film sealing treatment method and metal surface film sealing treatment apparatus - Google Patents

Description

The present invention relates to a device for carrying out sealing treatment method of a metal surface film, a sealing treatment method of the metal surface film.

  The base material of the continuous casting mold for steel is made of copper, and if it is left as it is, the wear is severe against sliding of slab and powder. Therefore, Ni-based or Co-based plating is usually applied as a countermeasure against wear, but the hardness is lower and the wear resistance is insufficient as compared with the sprayed coating, and there has been a demand for improved life. In particular, since the lower part of the mold is severely worn, the application of Ni-based self-fluxing alloys has been studied as a countermeasure against wear. However, since self-fluxing alloys are generally subjected to remelting (fusing) at a high temperature after spraying, There is a problem that the thermal deformation of the material becomes large and it becomes impossible to assemble the processed copper plate as a mold. In the case of a slab continuous casting mold, it cannot be applied to the long side exceeding 400 mm, and only the short side is applied. Yes.

  The remelting treatment is usually carried out by heating the sprayed coating with a flame of a gas burner. However, in this method, oxidation degradation of the coating is also a problem in addition to the thermal deformation described above. In addition, when a film with a large area is heat-treated with a gas burner, the heating state is likely to be non-uniform, and the occurrence of a portion where the adhesion strength of the film is insufficient, and further the generation of pinholes are also problematic. Furthermore, since the film thickness after remelting tends to be non-uniform, a method of grinding after forming a sprayed film that is thicker than the required film thickness is generally used, resulting in poor yield of sprayed material and increased construction costs. There was also a problem.

  As a countermeasure for the above problem, as disclosed in Patent Document 1 and Patent Document 2, for example, a self-fluxing alloy is subjected to supersonic flame spraying (remelting process omitted), or WC / NiCr, WC / Co, CrC / NiCr. There is provided a method of treating the surface by supersonic flame spraying.

  As a means for preventing the oxidative deterioration of the sprayed coating during the remelting process, as disclosed in Patent Document 3, after the self-fluxing alloy spraying, a porous ceramic sprayed coating is formed on the surface of the coating as a top coat. Then, after remelting the sprayed coating by controlled atmosphere heating or high frequency induction heating, the ceramic sprayed coating is removed to expose the self-fluxing alloy. However, since this method heats the entire base material, there is a problem that the distortion of the base material becomes significant.

  In addition, as disclosed in Patent Document 4, a method of fusing by applying an electron beam to a self-fluxing alloy, a method of remelting a self-fluxing alloy as disclosed in Patent Document 5 with a laser beam, etc. Although it has been proposed, as in the case of remelting treatment with a gas burner, it is not possible to heat a large area at the same time, and the occurrence of parts where the adhesion strength of the film is insufficient, and also the occurrence of pinholes is a problem. Become.

JP-A-8-225917 JP-A-8-187554 JP-A-11-217664 JP 11-226700 A JP 2003-320441 A

The present invention has been made in view of such a point. For example, even a self-fluxing alloy sprayed coating having a large area is uniformly heated to a desired temperature and melt-heat treated to perform sealing treatment. An object of the present invention is to provide a sealing treatment method and apparatus capable of achieving densification of a film.

In order to achieve the above object, the inventors have extensively studied the melt heat treatment of the metal surface coating by microwave and have obtained the following knowledge.
(1) Even if a self-fluxing alloy film or a copper base material is irradiated with a microwave of 900 MHz to 2.45 GHz, almost no increase in temperature is observed.
(2) By depositing a susceptor powder having microwave absorption capability on the surface of the self-fluxing alloy spray coating, it is possible to raise the temperature of only the self-fluxing alloy spray coating through the susceptor powder by microwave irradiation. I found.

Accordingly, the inventors propose the following invention based on the above findings. That is, the present invention is a method for sealing a sprayed coating of a self-fluxing alloy on a metal surface, which has a microwave absorption capability for the surface to be sealed in the sprayed coating of the self-fluxing alloy on the metal surface. One or more susceptor powders selected from carbon powder, graphite powder, activated carbon powder, SiC powder, ZrB ₂ powder or TiC powder are deposited in a thickness of 2 mm to 20 mm , and then on the deposited layer of the susceptor powder In this case, a heat insulating material is provided, and then, at least a region including the deposited layer of the susceptor powder is irradiated with microwaves to melt-heat-treat the sealing target surface on the metal surface. An arbitrary frequency of the microwave can be used, but a frequency of 900 MHz to 2.45 GHz is preferable. Here, the self-fluxing alloy is JIS H8303.

  According to the present invention, while the susceptor powder having the ability to absorb microwaves generates heat by the energy of microwaves, since the heat insulating material is provided on the deposition layer of the susceptor powder, the generated heat is effectively It is thrown into the sealing target surface of the film, and only the sealing target surface can be efficiently heated. Therefore, it is possible to heat the surface to be sealed in the coating on the metal surface to a desired melting heat treatment temperature to realize a suitable melting heat treatment, and to make the coating firmly adhere to the metal surface, thereby densifying the coating. Can be achieved. Therefore, the problem of pinholes does not occur.

In addition, since the susceptor powder is deposited to a thickness of 2 mm to 20 mm on the surface to be sealed and a heat insulating material is provided thereon, the present invention can be implemented very easily. Further, according to the inventors' knowledge, since the coating can be heated even if the thickness of the deposited layer of the susceptor powder is somewhat uneven, the surface to be sealed has a large area. In addition, by depositing the susceptor powder almost uniformly on the target surface, the sealing target surface can be uniformly heated and melted. In addition, since the metal itself as the base material is not directly heated, the temperature rise of the metal itself is suppressed, and distortion due to heat hardly occurs.

  Furthermore, since only the region where the susceptor powder is deposited is heated, even if the surface to be sealed is a partial region in the coating on the metal surface or a region having various planar forms, If a susceptor powder is deposited on the region and irradiated with microwaves, only the film in the region can be melt-heat treated. In this case, it is preferable to provide a heat insulating material not only on the deposited layer of the susceptor powder but also in a region other than the region to be sealed in the coating on the metal surface. In view of the heating efficiency by heat generation of the susceptor powder, it is preferable to cover not only the upper surface of the deposited layer of the susceptor powder but also the entire structure having the sealing target surface with a heat insulating material.

The heat insulating material used in the present invention is selected from quartz glass powder having a particle size of 3 mm or less, river sand, silica stone, silica stone bricks after use, ground magnesia powder, magnesia powder, Si ₃ N ₄ powder, or h-BN powder 1 It is preferable to be a seed or more. In this way, by using a powdery or granular heat insulating material, the heat insulating material layer can be easily formed on the deposited layer of the susceptor powder. Further, even if the planar form is various, it is possible to perform heat insulation treatment. In addition, when providing a powdery and granular heat insulating material in this way, for example, it is further deposited on the deposition layer of the susceptor powder, and the thickness (deposition thickness) at that time is, for example, 10 mm from the surface to be insulated. That's all you need. The inventors also found that if the thickness of the heat insulating material is 10 mm or more, even if the thickness is not uniform, the heating uniformity is not affected. Of course, when using such a powdery and granular heat insulating material, the entire structure having the surface to be sealed may be buried in the heat insulating material.

The susceptor powder having a microwave absorbing capacity described above, carbon powder, graphite powder, activated carbon powder, SiC powder, although one or more powders selected from ZrB ₂ powder or TiC powder are used, powders, Those having a maximum particle size of 100 μm or less and an average particle size of 30 μm are preferred.

As shown in the examples described later, the microwave output used in the present invention is 40 kW / m ² or more per area to be sealed in consideration of shortening of the processing time and efficiency of input energy. It is preferable.

  The metal surface film sealing apparatus of the present invention is a metal surface film sealing apparatus particularly useful for sealing a spray coating of a self-fluxing alloy, and has a structure having a surface to be sealed. And a microwave irradiation apparatus for irradiating microwaves into the processing container.

  In such a case, examples of the structure include a copper mold member for continuous casting.

According to the present invention, there is almost no heat input to the metal itself (base material) having a film on the surface, and only the film is heated at a desired temperature, and a sealing treatment by a suitable melt heat treatment can be realized. Moreover, even if the surface to be processed is a large area, uniform heating is possible, and therefore, for example, it can be applied to the long side for continuous casting using a copper plate as a base material, and the copper plate surface is smooth and has no defects. Remelted spray coating can be formed. Furthermore, the mold using the copper plate coated with the self-fluxing alloy processed according to the present invention is highly wearable by utilizing the characteristics of the self-fluxing alloy, and the life as a mold for continuous casting is greatly improved. . Furthermore, according to the present invention, no matter what the planar shape of the surface to be treated of the metal surface film is, only the surface to be treated is heated and the sealing treatment by the melt heat treatment is performed. Easy.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment is an example of sealing a self-fluxing alloy film on the surface of a continuous casting copper plate base material for producing a continuous casting mold.

  First, in order to improve the adhesion of the self-fluxing alloy sprayed coating, the base material such as shot blasting, grinder processing, and brushing is applied to the copper plate base material for continuous casting in advance. This makes it possible to remove the oxide layer and the corrosive layer on the substrate surface.

  In addition, as a base treatment for improving the adhesion of the self-fluxing alloy to the copper plate as described above, a Ni, Co, Fe plating layer, or an alloy plating layer based on these, or Ni or By forming any one or two or more coating layers of a Cu-Ni alloy brazing material, oxidation of the copper plate surface can be prevented, and adhesion with a self-fluxing alloy is excellent, and a more preferable coating layer. Can be obtained.

  As the self-fluxing alloy forming the coating layer, a Ni-, Co- or Fe-based self-fluxing alloy is preferable. These are densified by a melting process and have good adhesion to the copper plate surface. These self-fluxing alloys include chromium carbide, tungsten carbide, vanadium carbide, niobium carbide, titanium carbide, zirconium carbide, chromium boride, tungsten boride, vanadium boride, niobium boride, titanium boride, zirconium boride. If one or two or more types are added, the hardness of the coating layer, that is, the abrasion resistance is improved, and a more preferable coating layer can be obtained. Furthermore, these additives themselves are present in the sprayed coating layer, thereby absorbing microwaves and contributing to an increase in the temperature of the coating.

  In addition to the self-fluxing alloy, chromium carbide, tungsten carbide, vanadium carbide, niobium carbide, titanium carbide, zirconium carbide, chromium boride, tungsten boride, vanadium boride, niobium boride, titanium boride, zirconium boride The thermal spray raw material which added 1 type, or 2 or more types of these can be used. The sealing treatment method of the present invention is suitable for a coating formed by any spraying method such as flame spraying, supersonic flame spraying, explosion spraying, plasma spraying, etc. A preferred thermal spraying method includes supersonic flame spraying.

  Next, the sealing processing apparatus for implementing the sealing processing method concerning this Embodiment is demonstrated. FIG. 1 schematically shows the configuration of this sealing processing apparatus 1, and an applicator 2 as a processing container is configured by, for example, a grounded metal panel, and a copper plate base material 3 for continuous casting is contained therein. It has a sufficient space for accommodation, and microwave leakage prevention processing is performed.

  The continuous casting copper plate base material 3 in the applicator 2 is irradiated with microwaves from the microwave oscillator 11. More specifically, the microwave oscillator 11 is configured to oscillate, for example, a microwave having a frequency of 2.45 GHz. The microwave oscillated from the microwave oscillator 11 is reflected by the reflected microwave. An isolator 12 that prevents the wave from entering the wave oscillator 11, a power monitor 13 that monitors the output of the incident and reflected microwaves into the applicator 2, and a waveguide 14 that introduces the microwaves into the applicator 2. Is applied to the copper plate base material 3 for continuous casting in the applicator 2 through the tuner 15 for adjusting the impedance and the waveguide 14.

  Next, the sealing processing method according to this embodiment will be described. First, the lower half of the continuous casting copper plate base material 3 on which the self-fluxing alloy spray coating 21 is formed on the surface by, for example, a supersonic flame spraying method, is buried in the heat insulating material powder 22 having almost no microwave absorption ability. Let In such a case, for example, as shown in FIG. 1, the heat insulating material powder 22 is put in a box body 23 having a bottom surface and four side surfaces surrounded by a heat insulating ceramic board in advance, and the copper plate base material 3 for continuous casting is placed thereon. It is good to place.

As the powder composition of the heat insulating material powder 22, powder mainly composed of SiO ₂ component such as silica and river sand is preferable because of its low dielectric constant. For example, crushed waste of silica brick after being used in a coke oven, a hot air oven, or even a glass kiln is mainly composed of SiO ₂ and can be used as the heat insulating material powder 22.

Next, a susceptor powder 24 is deposited on the self-fluxing alloy spray coating 21 by a predetermined thickness. As the susceptor powder 24, carbon powder, graphite powder, activated carbon powder, SiC powder, ZrB ₂ powder, and TiC powder having high microwave absorption ability are suitable.

  The thickness for depositing the susceptor powder 24, that is, the deposition thickness of the susceptor powder 24, is preferably in the range of 2 to 20 mm in view of energy efficiency. According to the knowledge of the inventors, when the deposited thickness of the susceptor powder 24 is less than 2 mm, the input microwave is not sufficiently absorbed to the extent that the self-fluxing alloy spray coating 21 is melt-heat treated, and the input microwave is Most of the energy becomes reflected waves and is absorbed by the isolator 12, and is not very efficient in terms of energy for the melt heat treatment of the self-fluxing alloy spray coating 21. However, this evaluation is in the case of the melt heat treatment of the self-fluxing alloy spray coating 21 formed on the surface of the continuous casting copper plate base material 3, and assuming the sealing treatment of the metal surface coating, Depending on the type, even if the deposited thickness of the susceptor powder 24 is less than 2 mm, the melt heat treatment may be performed with sufficient energy efficiency.

  On the other hand, when the deposition thickness of the susceptor powder 24 is 50 mm or more, for example, the microwave penetrates only up to about 20 mm from the surface layer of the susceptor powder 24, so that heat conduction is conducted to a portion below 20 mm from the surface of the susceptor powder 24. As a result, the heat conduction from the deposited layer of the susceptor powder 24 is 40% or more lower than the heat conduction inherent in the material, and the heat transfer to the self-fluxing alloy spray coating 21 is delayed, Similarly, in terms of energy, it is difficult to be an efficient heating means.

As described above, the susceptor powder 24 is preferably deposited on the self-fluxing alloy sprayed coating 21 with a thickness in the range of 2 to 20 mm, but of course with a uniform thickness. In such a case, as a specific deposition method, for example, the susceptor powder 24 is sprayed on the self-fluxing alloy sprayed coating 21, and then the leveling roller 31 is used as shown in FIG. Just level it up. The leveling roller 31 has a configuration in which a cylindrical shaft 34 is arranged at the center of the rollers 32 and 33, and the radius difference d between the rollers 32 and 33 and the shaft 34 is 2 to 20 mm. is there. Therefore, the rollers 32 and 33 are set on the self-fluxing alloy spray coating 21, the leveling roller 31 is moved, and the deposition surface of the susceptor powder 24 is leveled by the shaft 34, so that the self-fluxing alloy spray coating 21. A deposited layer of susceptor powder 24 having a thickness of 2 to 20 mm can be easily formed thereon.
Since the susceptor powder is not deposited on the traces of the rollers 32 and 33, the length of the rollers 32 and 33 is as small as possible, for example, 5 mm or less. Take action.

  As described above, after the deposition layer of the susceptor powder 24 is formed on the self-fluxing alloy sprayed coating 21 with a thickness of 2 to 20 mm, the heat insulating material powder 22 is deposited also on the surface of the susceptor powder 24. In the present embodiment, the heat insulating material powder 22 is put into a box body 23 having a bottom surface and four side surfaces surrounded by a heat insulating ceramic board, and the continuous casting copper plate base material 3 is disposed thereon. As the work, the heat insulating material powder 22 may be introduced from above the copper plate base material 3 for continuous casting until the inside of the box 23 is filled with the heat insulating material powder 22. Then, after the inside of the box body 23 is filled with the heat insulating material powder 22, a cover body 25 made of a heat insulating ceramic board is placed on the box body 23.

Thereafter, the microwave oscillator 11 is operated to irradiate the continuous casting copper plate base material 3 in the applicator 11 with microwaves, whereby the susceptor powder 24 generates heat, and the self-fluxing alloy sprayed coating 21 is melt-heat treated. Sealing is performed. In such a case, with respect to the microwave irradiation output, by outputting microwaves of 40 kW / m ² or more per unit area product of the sealing target surface of the self-fluxing alloy sprayed coating 21, that is, the surface to be heated, self-fluxing is achieved. The surface of the alloy sprayed coating 21 rapidly increases in temperature, while the continuous casting copper plate base material 3 hardly increases in temperature, and only the original coating surface can be melt-heat treated. As a result of investigations by the inventors, when the microwave irradiation output is less than 40 kW / m ^2, it takes a long time to increase the surface temperature of the coating, and as a result, the temperature of the copper plate base material 3 for continuous casting also increases. So energy loss is great. Therefore, in order to heat-treat only the self-fluxing alloy sprayed coating 21 in a short time, a microwave irradiation output of 40 kW / m ² or more is preferable.

  Using the sealing treatment apparatus of FIG. 1, a test piece was cut out from a continuous casting copper plate to a thickness of 200 × 200 × 40 mm, and a surface treatment was performed on the surface by shot blasting, and four kinds of Ni-based self-fluxing alloys were subjected to various conditions Thermal spraying was carried out at The four Ni-based self-fluxing alloys are composed of Ni, Cr, B, Si and the like.

  As shown in FIG. 1, K thermocouples 41 and 42 are respectively installed on the upper surface (namely, the surface of the self-fluxing alloy spray coating) and the lower surface (namely, the lower surface of the continuous casting copper plate) of the sprayed copper plate. A melt heat treatment was performed under the conditions. For comparison, treatment using a gas burner, an atmosphere firing furnace, and a laser was also performed. In order to evaluate the properties of the film after the melt heat treatment, the cross section of the film was polished, the Vickers hardness after the melt heat treatment was measured, and a ball-on-disk friction wear test (thermal) at 750 ° C. in a nitrogen atmosphere using SiC balls. BOD test) was performed, and a relative evaluation of the coating wear amount was performed based on the wear amount of the sprayed coating after the wear test.

  The following table compares the examples of the present invention with the comparative examples. In the table, “SFA” is an abbreviation for self-fluxing alloy.

  According to this, No. of an Example. 1 to 3, good thermal spray coating heat treatment could be achieved in a short time within 14 minutes. Also, in the example No. In No. 4, the microwave output was as low as 35 kW, and accordingly, it took time for the melt heat treatment of the sprayed coating, but the sprayed coating after the treatment was good.

No. which is a comparative example. In No. 5, since the susceptor thickness was as thick as 25 mm, the temperature could be raised up to 1100 ° C. where the film was melted, but the wear resistance was poor. In Comparative Example 6, since there was no heat insulating material, the activated carbon used as the susceptor powder burned in the air atmosphere, and the coating surface melt heat treatment could not be performed. Comparative Example No. Nos. 7 and 9 were partial melt heat treatments of the gas burner irradiation part and the laser irradiation part, and had large variations in hardness and slightly poor wear resistance. Comparative Example No. In No. 8, the continuous casting copper plate as a base material was also heat-treated, the warp was large, and the wear resistance was slightly poor.
In addition, No. described in the bottom column of the table as a reference example. No. 10 is a susceptor powder with a thickness of 1 mm. Under these conditions, although the microwave was irradiated for 240 minutes, the thickness of the susceptor powder was as thin as 1 mm, so that the reflection of the microwave was large. The surface temperature of the film was raised only to 800 ° C., and the melting treatment was not possible. This is because the metal used as a sample was a copper plate for continuous casting, as in the case of the examples and comparative examples, and the target of the melt heat treatment was also a self-fluxing alloy spray coating, which is considered to be the result. It is done. However, for example, when an anodic oxide film of aluminum is to be subjected to a melt heat treatment, the melt heat treatment is sufficiently possible if the surface temperature reaches 800 ° C. Therefore, the thickness of the susceptor powder may be 1 mm when the aluminum anodic oxide film is subjected to melt heat treatment.

  The present invention is particularly useful for melt heat treatment of a spray coating of a self-fluxing alloy in a continuous casting mold or the like.

It is explanatory drawing which showed typically the structure of the sealing processing apparatus for enforcing the sealing processing method concerning embodiment. It is a front view of a leveling roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seal processing apparatus 2 Applicator 3 Copper plate base material for continuous casting 11 Microwave oscillator 12 Isolator 13 Power monitor 14 Waveguide 15 Tuner 21 Self-fluxing thermal spray alloy 22 Thermal insulation material powder 24 Susceptor powder

Claims (5)

A method for sealing a sprayed coating of a self-fluxing alloy on a metal surface,
One type selected from carbon powder, graphite powder, activated carbon powder, SiC powder, ZrB ₂ powder or TiC powder having microwave absorption capability for the surface to be sealed in the sprayed coating of the self-fluxing alloy on the metal surface The above susceptor powder is deposited with a thickness of 2 mm to 20 mm ,
After that, a heat insulating material is provided on the deposited layer of the susceptor powder,
After that, at least the region including the deposited layer of the susceptor powder is irradiated with microwaves, and the metal surface or the surface to be sealed on the metal surface is melt-heat treated, Method. ^2. The metal surface coating sealing method according to claim 1, wherein an output of the microwave is 40 kW / m ² or more per area to be sealed. 3. The method for sealing a metal surface film according to claim 1 or 2, wherein the metal surface is a surface of a copper mold member for continuous casting. The heat insulating material is at least one selected from quartz glass powder having a particle size of 3 mm or less, river sand, silica stone, silica stone bricks after use, magnesia powder, Si ₃ N ₄ powder, or h-BN powder. The method for sealing a metal surface film according to any one of claims 1 to 3, wherein the metal surface film is sealed. An apparatus for carrying out the sealing treatment method according to any one of claims 1 to 4 ,
A processing container containing a structure having the sealing target surface;
A microwave irradiation device for irradiating the processing vessel with microwaves;
A metal surface coating sealing apparatus characterized by comprising:

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