JPH0499856A - Arc spraying method - Google Patents

Abstract

PURPOSE:To continuously and altogether carry out the pretreatment of a base material and the arc spraying of a metal and to efficiently form a film by heating the base material with a heating means so that at least the surface is heated to a prescribed pretreatment temp. and then carrying out arc spraying on the heated surface. CONSTITUTION:A base material 1 is put on a working table in a spraying booth, the surface of the base material is heated with a gas burner 2 as a heating means and the surface temp. is measured with a contact type thermometer 4. After the surface temp. drops to a prescribed pretreatment temp., arc spraying is carried out on the heated surface with an arc sprayer 3. The base material 1 is mainly a metal but may be ceramics.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an arc thermal spraying method characterized by a pretreatment method for the surface of a base material performed prior to metal thermal spraying.

(b) Conventional technology Metal spraying methods include arc spraying, gas spraying, plasma spraying, etc., but regardless of the type of spraying, it is essential to pre-treat the surface of the base material prior to thermal spraying. Commonly used pretreatments include mechanical pretreatment, typified by shot blasting and sandblasting, and chemical pretreatment, in which a chemical conversion treatment agent is applied to the surface of the base material.

(c) Problems to be solved by the invention As mentioned above, it is necessary to perform some kind of pretreatment to perform metal thermal spraying, but in conventional pretreatment methods, pretreatment and thermal spraying operations are performed separately and independently. This poses a problem in terms of improving productivity and the need to secure individual work areas.

In addition, with mechanical pretreatment, a reliable and sufficient pretreatment effect can be obtained, but large blasting equipment is essential, and metal spraying can be completed within a certain amount of time after blasting. The processing target is limited to small parts that can be carried into the blast tank, such as the end face of the coil part of a coil-wound metal sheet material.
There were limitations such as the fact that the blasting material was not suitable for pretreatment of thermal spraying targets because it left a residue between the eyebrows.

In chemical pretreatment, since a chemical conversion treatment agent is simply applied to the surface of the base material, there are no restrictions on application as in blasting treatment. However, if the applied pretreatment layer is damaged, film formation defects or peeling of the film surface will occur in that area, so careful handling of the base material after application is required, and the use of chemical conversion treatment agents as agents. It has disadvantages such as limited processing capacity and restrictions on applicable processing targets compared to blast processing.

The present invention is intended to solve the above-mentioned problems, and its main purpose is to provide an arc thermal spraying method with excellent productivity that allows pretreatment of the surface of a base material and metal thermal spraying to be performed simultaneously in parallel. .

Another object of the present invention is to provide an arc thermal spraying method that is simple and has excellent on-site workability, without restrictions on application such as size, form, or time, and restrictions on handling of base materials. .

Still another object of the present invention is to realize metal spraying on ceramics, which has conventionally been considered difficult to form a spray coating, and to expand the range of products made of ceramics.

(d) Means for Solving the Problems In the arc thermal spraying method of the present invention, the base material 1 to be thermally sprayed is heated by the heating means 2 to raise at least the surface portion thereof to a predetermined pretreatment temperature. Arc spraying is performed on the surface portion heated to a treatment temperature to form a sprayed coating.

Although most of the base material 1 to be thermally sprayed is metal, it may also be ceramic.

The pretreatment temperature varies depending on the purpose of film formation and the difference between the base material 1 and the welding material. For example, when performing simple rust prevention, when performing rust prevention or surface modification that can guarantee sufficient peel strength, etc. There is a difference in the minimum temperature when the deposited layer is plated. The predetermined pretreatment temperature means a temperature state in all such thermal spraying states.

As the heating means 2, various heat sources such as combustion heat, electric heat using electric energy as an energy source, or friction heat can be used.

(E) Effect The present inventor has not yet elucidated the reason why heating the base material allows film formation to be performed in the same manner as mechanical pretreatment or chemical pretreatment. Originally, when arc spraying is performed without pretreatment, most of the atomized metal droplets are repelled by the surface of the base material. Even a small portion of the adhering droplets will easily fall off if subjected to a slight external force. However, it is clear from many experiments conducted by the present inventor that film formation can be performed by the method of the present invention, and heating the base material is the biggest reason why film formation can be performed even on untreated base materials. There is no doubt about that. Examples thereof will be described below.

(f) First Example A large number of base materials 1 were formed by cutting a thin steel plate with a thickness of 1 mm into strips. The steel plates used were ones that had been stored at room temperature in an indoor material storage area.

As shown in FIGS. 1 and 2, the base material 1 is placed on a workbench in a thermal spraying booth, its surface is heated with a gas burner (heating means) 2, and the surface temperature is measured with a contact thermometer. 4, and after waiting for the surface temperature to drop to a predetermined pretreatment temperature, thermal spraying was performed on the heating surface side using an arc spraying machine 3. At this time, using zinc wire as the welding material, the base material 1 and the arc Thermal spray machine 3
The spacing was according to the usual method.

The above pretreatment temperature was adjusted to sample numbers A1 to A1 in Table 1 below.
As in No. 6, thermal spraying was performed under the same conditions except that the temperature was varied between 100°C and 550°C.

(G) Second Example A thick steel plate with a thickness of 5 mm is cut into a rectangular shape to serve as the base material 1, and as shown in FIG. Along with the movement, thermal spraying was performed using an arc spraying machine 3 using zinc wire as a melting material toward the heated surface. The moving speed of gas burner 2 is approximately 50 m
m/sec.

At this time, the surface temperature of the base material immediately before thermal spraying is estimated to be around 300°C.

The sample number of the sample obtained in this example was A17 and is shown in Table 2 below.

(H) Third Example The welding material was changed to aluminum wire, and the pretreatment temperature was set to 120°C to 450°C as shown in sample numbers B1 to B6 in Table 3 below.
Arc spraying was carried out under the same conditions as in the first example except that the temperature was varied between .

(W) Fourth Example The welding material was changed to stainless steel wire, and sample number C in Table 4 below was used.
1 to C8, the pretreatment temperature is 120°C to 500°C.
Arc spraying was carried out under the same conditions as in the first example, except that the conditions were changed between .

(J) Fifth Example The welded portion of the electric resistance welded pipe was heated with a gas burner, and when the surface temperature of the welded portion reached 400° C., arc spraying was applied to the surface using zinc wire as a welding material. The sample obtained in this example was designated as sample number D1 and is shown in Table 5 below.

(l) Sixth Example A rectangular sintered alumina ceramic plate is used as the base material, its surface is heated with a gas burner, and the pretreatment temperature is adjusted as shown in sample numbers El to E6 in Table 6 below. 120℃～
Arc spraying was performed while changing the temperature between 450°C. The thickness of the ceramic plate was 2 mm, and the welding material used was aluminum wire.

(E) Seventh Example An alumina-based ceramic plate sintered into a rectangular shape is used as a base material, and its surface is heated with a gas burner, and the pretreatment temperature is adjusted as shown in sample numbers Fl to F8 in Table 7 below. 1208C
Arc spraying was performed while changing the temperature between ~500°C. The thickness of the ceramic plate was 2 mm, and the welding material used was a nickel alloy wire.

(E) Evaluation test The film formation state and film strength were tested for the samples obtained in each of the above examples. Regarding the film formation state, the distribution of attached particles and film thickness were visually confirmed. Strongly hit the membrane surface,
A piece of steel was strongly pressed against the film surface to rub it, and the base material was bent 180 degrees to observe changes in the state of the film. Note that sample numbers A17, Dl, El to B6, and Fl to B8 were difficult to bend, so no bending tests were conducted.

The results of the above test were as shown in Tables 1 to 7 below. In the table, the O mark means good, the Δ mark means good, and the X mark means bad.

Table 1 (First Example) Base material: 1 mm thick thin steel plate Solvent material: Zinc wire Surface wrinkles Film formation state Film strength (°C) Particle distribution Film thickness Strong abrasion bending Al100 Δ × Δ × × A2120 Δ × △ ×
×A3130 △ ○ ○ Δ × A4150 Δ ○ ○ △ × A3180 000 Δ × A62000 000 △ A7220 000 Q Δ A3240 00 Q ○ △ A9250 00000 AIO2800000Q All 30 0 0 Q ○ ○ ○A12 350
00000 A13 400 0 0000 A14 450 0 △ ○ Q ○ A15 500 0 Δ Q ○ ○ , A16 550 0 Δ Q O0 Table 2 (Second Example) Base material: 5 mm thick steel plate Welding material: Zinc wire surface wrinkles Film formation Condition Film strength (°C) Particle distribution Film thickness Strong abrasion bending A17 300 0 0 00 (General) Table 3 (Third example) Base material: 1 m thick thin steel plate weld material Nialuminum wire Surface wrinkles Film formation state Film strength (℃) Particle distribution Film thickness Strong impact abrasion bending B1120 △ × △ ×
×B2130 △ ○ ○ △ × B52000000 △ B42500 0000 B5400 0 0 0 0 0 B6450 △ ○ ○ Q ○ Table 4 (4th example) Base material: 1 mm thick thin steel plate Weld metal stainless steel wire surface wrinkles Filming state Film Strength Degree (℃) Particle distribution Film thickness Strong abrasion bending C1120Δ ×××× C2130△ Δ △ × × C3150△ △ △ × × C4200Δ Δ △ × ×C52
500△ ○ ○ Δ C63000△ ○ ○ △ C74000Δ ○ ○ ○ C85000Δ ○ ○ ○ Table 6 (6th example) Base material: 2 mm thick alumina ceramic plate melt material Nialuminum wire surface wrinkles Film formation state Film Strength (°C) ) Particle distribution Film thickness Strong impact abrasion bending E1120 Δ × △ ×E21
30 △ ○ Q △ B32000000 B4250 00 Q ○ B5400 0000 B64500 Δ ○ ○ Table 5 (Fifth Example) Base material: Welding part of electric resistance welded pipe Welding material: Zinc wire surface wrinkles Film formation state Film Strength (°C) Grain distribution Film thickness Strong impact, scratching, bending D1400 0000 Table 7 (7th example) Base material: 2 mm thick alumina ceramic plate Melting material: Nickel alloy wire Surface wrinkles Film forming condition (°C) Grain film thickness 1120 △ × 2130 △ △ 3150 △ △ 4200 △ △ 52500 △ 6300 0 △ 7400 0 △ 85000 △ Strength As can be seen from Tables 1.2 and 3.5, the weld material is zinc,
In the case of low-temperature melting metals such as aluminum, the film formation condition and film strength reach a certain level when the pretreatment temperature of the base material surface is set at 130°C or higher, becomes even better when the temperature is set at 200°C or higher, and at 250°C. The above will make it complete. The film formation state and film strength at this time correspond to the film formation state and film strength when arc spraying is performed after performing blast treatment. In addition, when the pretreatment temperature is 450°C (
In A14), a part of the film surface became plating, and at temperatures above 500°C (A15 and A16), the entire film surface became plating, and the film thickness became thinner accordingly. If the pretreatment temperature is less than 200°C, the film formation state and film strength (especially flexibility) will not be sufficient, but this will be sufficient for rust prevention under stationary conditions such as during transportation and storage. It can be used as a simple rust preventive, even if the film surface peels off when the material is used or reprocessed. For example, it can be used to prevent rust on the end face of a coil-wound metal sheet material, or on the cut end face of a strip material.

Next, in the case of high-temperature melting metals such as stainless steel and nickel alloys, as can be seen from Table 4 above, the film formation state and film strength are determined by the pretreatment temperature of 130°C or higher on the surface of the base material, although some adhesion occurs. , unless the temperature is 250°C or higher, the adhesion strength will not be sufficient, and more preferably the temperature is 400°C or higher. Note that in the case of high-temperature melting metals such as stainless steel and nickel alloys, if the film thickness is 0.1 mm or more, problems arise in adhesion to the base material, making it easy to peel off.

Furthermore, in the case of plated metals, in the conventional method it was necessary to apply a chemical conversion treatment agent as a pretreatment for thermal spraying.
A chrome-plated steel plate was selected as an example of such a plated metal, and thermal spraying was performed in the same manner as in the first to fourth examples. It was similar.

As shown in the results of the sixth and seventh examples, good film-forming quality was obtained even with samples made of ceramic as a base material, and this enabled the range of ceramic products to be expanded. For example, it is being considered to use the heat resistance of ceramics to construct electrical parts with excellent high-temperature durability, but conventionally it has been impossible to solder to ceramics and connect lead terminals, so products development was prevented. Even in such a case, by forming a thermally sprayed coating on the surface of the ceramic, lead terminals can be easily soldered to the coating surface.

The present invention is applicable to rust prevention of members that require heat resistance, rust prevention of welded parts, repair of damaged areas on hot-dipped plating surfaces, rust prevention of base metals exposed by processing after plating, bridges, etc. It can be used in a wide range of applications, including rust prevention for outdoor structures such as industrial complex piping, or as a base treatment for painting, or for surface modification of base materials.

Note that for heating the base material, a heating tank, a heating furnace, or the like can be used, so there are no limitations on the type of heat source or the heating form.

(iv) As described in detail, according to the arc thermal spraying method of the present invention, a base material is heated, at least the surface portion thereof is raised to a predetermined pretreatment temperature, and an arc is applied to the heated surface portion. Since a thermal spray coating can be formed by thermal spraying, pretreatment and metal thermal spraying can be performed continuously and at once, and the film forming process can be performed efficiently and its productivity can be significantly improved.

In addition, since thermal spraying can be performed by heating the base material, arc thermal spraying can be easily performed without being restricted by the size or shape of the target to be sprayed or the handling of the base material, making it easier to perform arc spraying than conventional methods. Because it has excellent workability on site,
For example, film formation on existing structures such as bridges can be performed easily and efficiently.

For ceramics, which have traditionally been considered difficult to form,
Since it is possible to reliably form a thermally sprayed coating with sufficient film condition and film strength, the range of products to which ceramics are applied can be expanded, and for example, the use of ceramics in electrical parts can be realized.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, FIGS. 1 and 2 are explanatory diagrams showing the principle of the first embodiment of the arc spraying method, and FIG. 3 is a diagram showing the principle of the first embodiment of the arc spraying method. It is a principle explanatory diagram showing a second embodiment. 1...Base material 2...Heating means 3...Arc spraying machine

Claims (4)

[Claims] (1) Heating the base material 1 to be sprayed with the heating means 2,
An arc thermal spraying method comprising: raising at least a surface portion thereof to a predetermined pretreatment temperature; and performing arc spraying on the surface portion heated to the pretreatment temperature to form a thermal spray coating. (2) The arc spraying method according to claim 1, wherein the melt material to be arc sprayed is a low melting metal such as zinc or aluminum, and the base material 1 is heated to a pretreatment temperature of 250° C. or higher. (3) The welding material used for arc spraying is a high-temperature melting metal such as stainless steel or alloy nickel, and the base material 1 is
The arc thermal spraying method according to claim 1, wherein the method is heated to a pretreatment temperature of .degree. C. or higher. (4) The arc thermal spraying method according to any one of claims 1 to 3, wherein the base material 1 is ceramic.