JPS6399000A - Plasma jet flame-coater - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a plasma jet thermal spraying apparatus for spraying a thermal spraying material onto a workpiece placed in the atmosphere.

[Conventional technology]

As is well known, thermal spraying provides a high degree of heat resistance to the object being treated.

This is done to give properties such as wear resistance and corrosion resistance. Therefore, it can be said that what is required of a thermal spray coating is strong adhesion between the object to be treated and the thermal spray coating, strong adhesion between the spray particles that form the thermal spray coating, and a high degree of homogeneity and density. . In addition, these thermal sprayed products have excellent properties such as heat resistance, abrasion resistance, and tactility. There is a growing demand for thermal spray products that are both superior and inexpensive. In order to meet such social demands, plasma jet thermal spraying apparatuses with various innovations have been developed, and thermal sprayed products are produced by spraying various thermal spraying materials using these thermal spraying apparatuses. Among these devices, the plasma jet thermal spraying device shown in FIG. 5 will be described below.

Details of the thermal spraying apparatus shown in FIG. 5 will be explained below. That is, the outer cylinder (10t) and the nuclear outer cylinder (401)
The inner cylinder (102) has a nozzle A/(103) at its tip and a through hole (104) at its other end. Tomo K,
A plasma generation chamber (105) is formed between the nozzle (103) and the through hole (104), and the plasma generation chamber (
1 o s) has a plasma gas supply port (105) connected to the plasma generation chamber (105) for supplying plasma gas.
6) is provided, and the plasma generation chamber (1o s
) through the through hole (104) to the same town hole (lO4
) and the cathode electrode (tO7) insulated with N1 air are connected to the tip of the same electrode (108) and the plasma generation chamber (tOS).
The outer cylinder (101) and the inner cylinder (t O
The space defined by the cooling chamber (1) and
10), and on the outside of the cooling chamber (110) there are a cooling water supply port (1t t) and a cooling water outlet (t 12) that communicate with the inside of the cooling chamber (110) for supplying and discharging cooling water, as well as energization. The nozzle A/(103) has an m-inch material supply port (114) for supplying thermal spray material at the front of the nozzle A/(103), and a cylinder whose tip is open. The shaped body (1t 5) is the nozzle/! /(
Although not shown in the plasma jet thermal spraying equipment installed concentrically with 103), atmospheric exhaust means, a non-oxidizing gas supply element, means for maintaining the internal pressure at a constant pressure lower than atmospheric pressure, '$ An airtight chamber (10
0) is provided, and the cylindrical body (115), which is the tip side of the thermal spraying device, is inserted from the outside of the airtight chamber (10) toward the inside of the airtight chamber (100), and the airtight chamber (lOO) is The airtight chamber (1o o
A supply means for the isotropic material supply port (114) etc. housed in ) is provided so as to penetrate the wall of the airtight room (LOO) so as to be airtight.

The iso-spraying apparatus with such a configuration is used to spray the object to be treated (15o), but at that time, first the airtight chamber (100) is
The object to be treated (XSO) is installed at a fixed distance from the thermal spraying device and movable at a constant speed perpendicular to the center of the thermal spraying device. In order to prevent oxidation of the melt, the atmosphere filling the airtight chamber (+oo) is replaced with non-oxidizing gas at a low pressure of several tens to hundreds of torr. Then, the object to be processed (150
) of the thermal spraying material along with a plasma jet generated by a known method! There is a plasma jet thermal spraying apparatus in which the J melt is injected from the tip opening of the cylindrical body (115) to form a thermally sprayed coating with less oxides.

[Problem that the invention seeks to solve]

The amount of oxides present in a thermal sprayed coating is considered to be one of the causes that have the most negative effect on the adhesion between the thermal sprayed coating and the object to be treated, which evaluates the quality of thermal sprayed products, and on the adhesion between the sprayed particles that form the thermal sprayed coating. In order to reduce the amount of heat generated by plasma jet spraying, measures have been taken to eliminate the oxygen-containing atmosphere around the object to be treated, and even with the plasma jet thermal spraying equipment described in the previous section, there are still a number of problems as explained below. It is.

In other words, since this is a device that performs thermal spraying with the object to be treated inside an airtight chamber, there are no strict restrictions on the size of the object to be treated; Since it requires replacement work and the simultaneous exchange of air and non-oxidizing gas in an airtight chamber, it is not suitable for mass production, and at the same time increases the cost of thermal sprayed products and increases the size and complexity of the entire thermal spraying equipment, making it difficult to handle. At the same time, strict restrictions are placed on the material of the object to be treated because the temperature of the object to be treated becomes extremely high due to the high temperature of the plasma jet, and there is also the problem of distortion of the product during thermal spraying. This is because the fR molten material injected during thermal spraying can reach 30 to 50% of the fR molten material, which is molten on the outside but inside, depending on the difference in the thermal spray material. is mixed with a semi-molten material that is in a solid state, and therefore a part of this semi-molten material is attached to the thermal spray coating. When formed, the thermal spray coating may peel off from the object to be treated, or become porous (11), so it must be removed as much as possible, but it cannot always be removed sufficiently with the force of the defsma jet alone. Therefore, the plasma jet thermal spraying apparatus cannot produce a sufficiently homogeneous and dense thermal spray coating.Therefore, the present invention addresses the unsolved problems faced by the conventional plasma jet thermal spraying apparatus as explained in FIG. By solving these problems, there are fewer restrictions on the size of the object to be treated, making it suitable for mass production and at low cost. A thermal sprayed product with strong adhesion is obtained,
The object (11) is a rod for a plasma jet thermal spraying device which is designed to be smaller, have a single FF, and be easier to handle.

[Means for solving problems]

The plasma jet thermal spraying device invented by Ichiki solved the problems described in the previous section by providing a means for injecting non-oxidizing gas while spraying the ejection material onto the object to be treated. A feature of the present invention is that it has an outer cylinder (1) and an inner cylinder (2) that is loosely fitted inside the outer cylinder (1), and that the inner cylinder (2) has a has a nozzle (8) at its tip and a through hole (4) at the other end, and a plasma generation chamber (5) between the nozzle (81 and the through hole (4)), The plasma generation chamber (5) is provided with a plasma gas supply port (6) communicating with the plasma generation chamber (5) for supplying plasma gas, and furthermore, the plasma gas main chamber (5) is provided with a plasma gas supply port (6) for supplying plasma gas. Through the through hole (4), the cathode electric rod (γ), which is electrically connected to the through hole (4), connects the electrode rod tip (8) and the nozzle opening (9) inside the plasma generation chamber (5). ), the space defined by the outer cylinder (1) and the inner cylinder (2) is sealed to form the cooling chamber shaft, is the cooling chamber 00 for supplying and discharging cooling water.
A cooling water supply port 011, a cooling water discharge port 0, and an anode N pole (13) for energization are provided, respectively.
Furthermore, the nozzle (3) has a thermal spray material supply port Q4) for supplying each spray material in the front part, and a cylindrical body α9 whose tip is open is provided concentrically with the nozzle (8). In the Pfusmajet screen projection device, the cylindrical body α9
A protective cylinder αη having a non-oxidizing gas supply port qG for supplying non-oxidizing gas and having an inner diameter larger than the outer diameter of the protective cylinder αη and having an open end is provided concentrically with the cylindrical body aF9,
A non-oxidizing gas passage (19), which is a cylindrical space, is formed between the outer circumferential surface of the cylindrical body a9 and the inner circumferential surface of the protective cylinder α. /rα is located at the point where the diameter of the opening side of both cylinders is gradually expanded outward at the same angle to form a trumpet-shaped injection port (11) having an opening angle of 80 to tone.

[For production]

In the plasma jet thermal spraying apparatus according to the present invention, a molten body of thermal spraying material is sprayed together with a plasma jet by a known method toward an object to be treated in the atmosphere, which is movably provided at a fixed distance from the thermal spraying apparatus. At the same time, the non-oxidizing gas is supplied from the non-oxidizing gas supply port aO, and the non-oxidizing gas passage (to) is passed through a trumpet-shaped cylindrical body with an opening angle between 80 and 100 degrees. a9 and protection tube α
η Injection port at the tip of both cylinders is 0! l to high speed, and 80 to 10
Injecting a skirt-shaped non-oxidizing gas with a spread between 0 degrees effectively blocks and eliminates the oxygen-containing atmosphere that exists in the infusion site between the objects to be treated and its surrounding zone. Therefore, it works to minimize the formation of oxides contained in sprayed skin. The value of the trumpet-shaped opening angle of 80 to 100 degrees at the tip of both the cylindrical body os and the maintenance tube aη of the present invention is determined by each investigation described below. That is, the cylindrical body (17) and the protective tube a'? The opening angles on the opening side of both cylinders are set to θ degrees, 60 degrees, 90 degrees, 120 degrees, and 140 degrees, and for each of them, the cylindrical body a9 and the protective tube are connected in the atmosphere. With a distance of l Q rnm between the tips of both M cylinders,
A plasma jet is generated by a known method toward the object to be treated ω, which is moving at a constant speed of 1000 m/s at a right angle to the thermal spraying device, and is disguised as a thermal spray material from the rumored thermal spray material supply port q. Fe-13cr material of 3115
Supply the plasma jet at a ratio of 0 to the cylindrical body.
1, while the non-oxidizing gas supply port q0
Argon gas, which is a non-oxidizing gas, was added at 50e/
The non-oxidizing gas is supplied through the non-oxidizing gas passage for n seconds from the non-oxidizing gas injection port at high speed until the opening angle on the opening side of the cylindrical body q9 and the protective cylinder α is 0 degrees. In some cases, cylindrical,
Please note that the opening angle is 60 degrees, 90 degrees, 120 degrees and 14 degrees.
In the case of 0 degrees, a skirt-shaped argon gas having the above-mentioned angle spread is injected, and the object to be processed FflKF is
A thermal spray coating of s-13cr type material was formed. Then, the weight of oxygen contained in each thermal sprayed coating was determined by chemical analysis, and further converted to weight percent to determine the resistance welding percentage of oxygen contained in the thermal sprayed coating corresponding to the opening. Figure 3 shows the plot. According to FIG. 3, it can be seen that when the aperture angle is 90 degrees, the 1 beak% of oxygen contained in the sprayed coating is the lowest, and if the aperture angle is in the range of 80 to 100 degrees, It can also be seen that it is equivalent to the Soviet Union. In this way, the opening angles of both the cylindrical body (17) and the protective cylindrical surface on the opening side are set in the range of 80 to 100 degrees.

However, this cylindrical body a9 with an opening angle of 80 to 100 degrees and the maintenance tube α have a trumpet-shaped injection port l'I9 at the tip of the opening part of the tube.
The argon gas, which is injected with a skirt-like spread, is mixed with the completely molten material of the thermal spraying material and is injected from the AV opening of the m-shaped body together with the plasma jet, and it adheres to the thermal spraying site of the object to be treated. The semi-molten material is removed from the sprayed area to form a thermal sprayed coating with very little intervening semi-molten material. Furthermore, the argon gas effectively cools down the temperature of the sprayed area of the object to be treated and its surrounding zone, which are exposed to the high temperature of the plasma jet and become very high in temperature.

〔Example〕

Embodiments of the invention will be described below with reference to the drawings.

First Embodiment An embodiment of the present invention is shown in Fig. 1 showing a cross section of the Butsuma Jet thermal spraying device, and a thermal spray coating for changes in the trumpet-shaped opening angle at the opening side tip of the cylindrical body and the first protective cylinder. This will be explained with reference to FIG. 3, which shows the relationship between the weight percent of oxygen contained therein.

That is, the Bwozma Jet welding device of the present invention has an outer cylinder (1
), and an inner cylinder (1) loosely spaced concentrically with the center of the outer cylinder (1).
2), and the inner cylinder (2) has a nozzle (2) at its tip.
3), and a through hole (4) is formed at the other end.
and a cylindrical part with an inner diameter larger than the inner diameter of both, and the cylindrical part forms the nozzle/L' (inner opening of 81).
9), the diameter of which is gradually reduced toward the nozzle (s
) is formed with a truncated conical portion connected to the inner opening (9) of the plasma generating chamber (5). A plasma gas supply port (6) is provided for supplying plasma gas to the plasma generation chamber (5), and a plasma gas supply port (6) is provided in the plasma generation chamber (5) through the through hole (4). (4) and an electrically insulated cathode (γ) with a space between the tip (8) of the electrode rod (A) and the inner opening (9) of the nozzle (8). , and a space defined by the outer cylinder (1) and the inner cylinder (2), which is inserted through the plasma generation chamber (6) and occupies the center thereof, has a through hole in the center at both ends of the two cylinders. The inner periphery of the outer cylinder (1) and the inner cylinder (2) are connected by a front plate (to) and a rear plate having
The outer periphery of the outer cylinder (1) is fitted in an airtight manner to form a cooling chamber 0[ffl, and the outer wall of the outer cylinder (1) is passed through the outer wall to provide a cooling chamber surface for supplying and discharging cooling water. A cooling water supply port aI) and a cooling water discharge port 0■ which lead to the
is provided, and further has a ninth thermal spraying material supply port 04 on the outer surface of the front plate for supplying thermal spraying material that communicates with the inside thereof,
The cylindrical body α9 whose tip is open is the nozzle IV (
8) In the plasma jet thermal spraying apparatus installed concentrically with the cylindrical body, the cylindrical body has a non-oxidizing gas supply port 00 with an inner diameter larger than the outer diameter of the non-oxidizing gas supply port 00 for supplying non-oxidizing gas, and a tip of the non-oxidizing gas supply port 00. A first protection tube 0η having an opening is provided concentrically with the cylindrical body α9, so that the outer circumferential surface of the cylindrical body a9 and the first
A non-oxidizing gas passage (toward), which is a cylindrical space, is formed between the inner peripheral surface of the protective cylinder αη, and the cylindrical body α9
and @1 Protective cylinder αη Both cylinders have a trumpet-shaped opening side that gradually expands in diameter outward at the same angle and has an opening angle of 90 degrees. ) Injection port 01 where a skirt-shaped non-oxidizing gas is injected at high speed toward
was formed.

In a plasma jet thermal spraying apparatus having such a structure, the thermal spraying apparatus has a cylindrical body α9 and a first protective cylinder αη with an interval of 1Q mm between the tips of the cylinders, and at right angles to the center of the thermal spraying apparatus. A plasma jet is generated by a known method toward the object to be processed ω moving at a speed of 1000 m/sec, and powdered Fe-13Cr material is supplied from the thermal spray material supply 0114) at a rate of 30+-15+. At the same time, argon gas, which is a non-oxidizing gas, is supplied from the non-oxidizing gas supply port O13 at a ratio of 511 e/15+, and the non-oxidizing gas is injected through the non-oxidizing gas passage. While injecting a skirt-shaped argon gas jet with a 90 degree spread at a high speed of z2om/sec at the injection port i'l from the injection port (17), Fe is injected onto the object to be processed (to). −
A thermally sprayed skin burr of 13Cr-based material is formed. Here, Fe-
Table 1 shows the component analysis values of the 13Cr-based material, and Table 2 summarizes the irradiation conditions.

Table 1 Powdered Fe-13cr component analysis value (wt%)
Second surface thermal spraying conditions In this example, a powdered Fe-13cr material having the components shown in Table 1 was used as the thermal spraying material.
The plasma jet spraying apparatus of the present invention can be applied to nonmetallic materials that dislike oxygen, such as WC-Co, regardless of the form of the thermal spraying material, such as powder or wire. .

It can also be applied to carbides and nitrides such as Cr5Cz and TiN. Furthermore, the thermal spraying conditions shown in Table 2 are conditions applied to the Fe-13cr material and thermal spraying equipment used in this example, and depend on the type of thermal spraying material used and the capacity of the thermal spraying equipment. Since the optimal conditions are set, these conditions do not have to be fixed. In addition, in this example, in order to confirm the performance of the plasma jet thermal spraying apparatus according to the present invention, we also attempted the following. That is, in the n-ray explained so far, the cylindrical body 05
A plasma jet thermal spraying device having a trumpet-shaped nozzle (11) with an opening angle of 90 degrees and whose diameter gradually expands outward on the opening side of the tip of the cylinder and the No. 1 Kobo cylindrical surface was used. However, furthermore, the opening angle is set to 0 degrees, 60?, 12
We investigated how the weight percent of oxygen contained in the sprayed skin changes when Fe-13Cr-based materials are thermally sprayed under the above conditions at 0 degrees and 140 degrees, respectively. It is something that FIG. 3 shows these investigation results together with the investigation results for the aperture angle of 90 degrees. According to this figure, the cylindrical body 05 and the first protection tube 0
η By setting the opening angle of both cylinders to 90 degrees, powder-like powder is injected onto the object to be processed while injecting argon gas in the shape of a skirt at a higher speed than that of a non-oxidizing gas injection port and with a spread of 90 degrees. It has been shown that when Fe-13Cr-based materials are thermally sprayed, the amount of oxygen contained in the thermally sprayed coating is minimized.
This also indicates that the opening angle is equivalent if it is within the range of 80 to 100 degrees.

On the other hand, if the opening angle is outside the range of 80 to 10 degrees, oxygen contained in the sprayed coating may increase rapidly, so the opening angle is within the range of 80 to 100 degrees. I concluded that it must be done.

Second Embodiment Regarding the embodiment of the present invention, see Plasma Jet.) Figure 2 showing a cross-sectional view of the M injection device, the relationship between the number of injection ports through which argon gas is injected and the weight percent of oxygen contained in the molasses. This will be explained below with reference to FIG. 4, which shows the adhesion strength of the thermally sprayed coating to the object to be treated, and the tensile strength of the thermally sprayed coating itself, which are thermally sprayed under various thermal spraying conditions.

In the plasma jet thermal spraying apparatus described in the first embodiment, a non-oxidizing gas supply wire having a larger inner diameter than the outer diameter of the first protection tube α is provided on the end face on the side where the first protection tube αη is provided. At the same time, a second protection tube slope with an open tip is provided concentrically with the first protection tube (+71), and between the outer circumferential surface of the first protection tube αη and the inner circumference surface of the second protection tube (2). A non-oxidizing gas passage is formed in the outer diameter of the second protective tube (21), and a second protective tube (c) is provided on each end face of the second protective tube (21), which has a larger inner diameter than the outer diameter. At the same time, a third protection tube C4 having an open tip is provided concentrically with the second protection tube (to), so that the outer peripheral surface of the second protection tube (goods) and the third protection tube (c)
A non-oxidizing gas passage (to) is formed between the inner peripheral surface of (17) and the non-oxidizing gas passage (17). (2) and (to) three layers, and a cylindrical body (17). The opening sides of the first protection tube αη, the second protection tube e21) and the third protection tube ■4 have an opening angle of 90 degrees, with the diameters gradually expanding outward at the same angle of 45 degrees. A trumpet-shaped nozzle 01 was formed from which non-oxidizing gas was injected in a three-layered skirt with a 90-degree spread toward the object to be treated (a) placed in the atmosphere. be. In a plasma jet thermal spraying apparatus having such a structure, first, a beam of 100 Cnl/ A plasma jet is generated by a known method between the objects to be treated that are moving at a constant speed of 1 second, and the spray material supply port a is
Powdered Fe-13Cr material is supplied at a ratio of 4 to 30g100 for thermal spraying, while the same amount of argon gas is supplied from the non-oxidizing gas supply port ae at a ratio of 50e79F to complete the non-oxidizing gas passage. 220 m from the non-oxidizing gas injection port al (g) via α8) (2) at the injection port.
The object to be treated (
(to) to avoid problems with thermal spraying of Fe-13Cr material.

Next, argon gas is supplied from the non-oxidizing gas supply ports aeeznrzs at the same rate of 50 e/min, and is passed through the non-oxidizing gas passages (A) and (A) to the non-oxidizing gas injection port ( A sprayed coating of Fs-13Cr-based material was formed on the object to be treated by spraying three layers of argon gas in the form of a skirt, each extending 90 degrees, at a high speed.

The difference between the thermal spraying conditions of the second embodiment and the first embodiment is that the non-oxidizing gas supply 0 and 1 was added to the plasma jet used in the first embodiment. Exactly the same amount of each! The only difference is that argon gas was supplied at a ratio of 17%, and high-speed argon gas was injected from the non-oxidizing gas injection ports H@ in a skirt shape with a 90 degree spread. Regarding the Fe-13Cr-based thermal spray coating formed in this way, the respective strengths relative to the weight percent of oxygen contained in the spray coating, that is, the adhesion strength between the object to be treated and the thermal spray coating and the tensile strength of the thermal spray coating itself, were determined by J
The test was conducted in accordance with the "Testing method for overlay (steel) products" stipulated in IS H8664. Then, Fe-
The data obtained by thermal spraying 13cr type materials under the conditions shown in Table 3 below are shown in Figure 4 and Table 4, respectively. Compare with conventional technology.

Table 3: Thermal spray conditions Note: The difference in conditions between the Niki table and Table 2 is that in the Ki table, the airtight chamber was filled with argon gas of 45 tomμ, whereas in Table 2, non-oxidizing gas injection was used. (F) Argon gas was injected at a rate of 50 e/min, and the experiments were conducted under the same thermal spraying conditions.

Figure 4 shows the high speed of the present invention, where the number of injection ports for injecting skirt-shaped argon gas with a width of 90 degrees is O (when no argon gas is injected), 1.2 and 3, respectively. F of the components shown in Table 1 under the conditions shown in the table.
When e-13Cr material is thermally sprayed, the weight percent of oxygen contained in the sprayed film is shown by the white circle, and as explained in Fig. The percentage of oxygen contained in the thermal spray coating obtained by thermal spraying the Fe-13Cr material having the components shown in Table 1 under the conditions shown in Table 3 is shown by black circles.

Therefore, if the number of nozzles for injecting argon gas is one, the weight percent of oxygen contained in the thermal spray coating will be slightly higher than in the conventional technology explained in Fig. The number of injection ports is 2.

This shows that when there are three, they are almost the same.

The Pg4 table shows the amount of Fe-
13Cr material was melted under the conditions shown in Table 2 Table 4 Oxygen content in the sprayed coating and strength of the sprayed coating The sprayed coating obtained by spraying (
The samples were obtained by spraying Fe-13Cr material having the composition shown in Table 1 under the conditions shown in Table 3 using a conventional plasma jet thermal spraying apparatus having sample heights of 1 to 8) and an airtight chamber as explained in FIG. The weight percent of oxygen contained in each thermal sprayed coating (sample height q), the adhesion strength between each thermal sprayed coating and the object to be treated, and the tensile strength of each thermal sprayed coating itself are as follows. . Therefore, since the opening angle of the injection port for injecting the non-oxidizing gas of the present invention is 90 degrees,
This applies to sample heights 4.7 and 8, and when these are compared with sample height 9 obtained using the prior art, the following can be said. That is, (wt% of oxygen contained in the thermal spray coating) If the number of injection ports is one, the present invention has a slightly larger amount of oxygen contained in the thermal spray coating than in the case of the prior art, but the number of injection ports is 1. The number of
When the number of particles reaches three, the amount of oxygen contained in the sprayed coating becomes the same.

(Adhesion strength between the cut object and the thermal sprayed coating When the number of injection ports is one, the adhesion strength between the object to be treated and the thermal sprayed coating is slightly weaker in the present invention than in the case of the prior art, but
When the number of injection ports is two or three, the adhesion strength between the object to be treated and the thermal spray coating becomes the same.

(c) Tensile strength of the thermal sprayed coating itself If the number of injection ports is one, the tensile strength of the thermal sprayed coating itself is slightly lower in the present invention than in the case of the prior art, but if the number of injection ports is 2 or 3. The tensile strength of the sprayed coating itself becomes the same.

Therefore, in the present invention, if the Fe-13cr material shown in Table 1 is thermally sprayed under the conditions shown in Table 2, compared to the prior art,
This can be said to indicate that the thermal spraying apparatus is capable of obtaining substantially the same strength as mentioned above in terms of the strength of the thermal sprayed product.

〔Effect of the invention〕

As explained in Fig. 5, in the conventional plasma jet fermentation equipment having an airtight chamber, non-oxidizing gas is By placing the object to be treated in an airtight chamber filled with air, the atmosphere around and around the sprayed area of the object is excluded. On the other hand, at high speed from the injection nozzle,
By injecting a skirt-shaped non-oxidizing gas with a 100 degree spread, it is possible to cut off and eliminate the oxygen-containing atmosphere present in the sprayed area of the object to be treated and its surrounding zone. There is no need to provide a very large and complicated airtight chamber like in a plasma jet thermal spraying device, and the generation of oxides interposed in the sprayed coating can be minimized. Therefore, not only the restrictions on the size of the object to be treated are relaxed to a large extent, but also mass production can be fully accommodated. Not only was it possible to produce thermal sprayed products that were equally strong in terms of strength but also cheaper, the thermal spraying equipment itself was smaller and simpler, and not to mention easier to handle. As a result of the object to be treated being exposed to the high temperature of the plasma jet, the sprayed area of the object and its surroundings become extremely hot. The temperature at the isotropic part is 100 to 200 degrees Celsius lower than in the case of the prior art, as explained in Figure 5, due to the effective cooling by the gas. This also has the effect of expanding the range of usable target materials and reducing the occurrence of distortion in thermal sprayed products. In addition, even if semi-molten material mixed with complete bath molten material and injected together with the plasma jet adheres to the thermal spraying part of the object to be treated, the non-oxidizing gas injected from the non-oxidizing gas injection port will The force easily removes the adhered semi-molten material from the sprayed area and scatters it into the atmosphere. Therefore, it is an extremely useful plasma jet thermal spraying apparatus that has the effect of being able to obtain a thermal sprayed product with a homogeneous and dense sprayed skin with very little amount of semi-molten material mixed in.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the plasma jet device of the first embodiment,
FIG. 2 is a sectional view of the plasma jet device of the second embodiment,
Figure 3 shows the percentage by weight of oxygen contained in the thermal spray coating when the opening angles of the cylindrical body and the first protective tube are changed.
Figure 4 shows the relationship between the weight percent of oxygen contained in the sprayed coating with respect to the change in the number of nozzles of the present invention and the weight percent of oxygen contained in the sprayed coating obtained with the prior art plasma jet thermal spraying apparatus having an airtight chamber. FIG. 5 is a sectional view of a prior art plasma jet thermal spraying apparatus having an airtight chamber. (1)...Outer cylinder, (2)...Inner cylinder, (3)...Nozzle, (4)...Through hole, (5)...Plasma generation chamber, (6)...・Plasma gas supply port, (A)...electrode rod, (101...cooling chamber, Qll-...cooling water supply port, 0...cooling water outlet, 03...electrode, a4)・
... Thermal spray material supply port, (17) ... Cylindrical body, 00 wire (
Support)...Non-oxidizing gas supply port, αη...First protection tube, (To) (A) (To)...Non-oxidizing gas passage. 01Ken (5)...Injection port, al)...Second protection tube,
(c)...Third protective cylinder patent applicant Kobe Steel Works Co., Ltd. Agent (patent attorney) Yoshiyuki Kaji Figure 1 Figure 2 Injection port (4) mouth ^4 cJ)

Claims (1)

[Claims] (1) It has an outer cylinder (1) and an inner cylinder (2) that is loosely fitted inside the outer cylinder (1), and the inner cylinder (2) has a nozzle (3) at its tip. A through hole (4) is formed at the other end of the nozzle (3) and a plasma generation chamber (5) is formed between the nozzle (3) and the through hole (4). A plasma gas supply port (6) communicating with the plasma generation chamber (5) for supplying plasma gas is provided, and the plasma generation chamber (6) is further provided with the through hole (
A cathode electrode (7), which is electrically insulated from the through hole (4) through the through hole (4), is fixed between the tip of the electrode (8) and the nozzle opening (9) inside the plasma generation chamber (5). The space defined by the outer cylinder (1) and the inner cylinder (2) is sealed to form a cooling chamber (10),
Outside the cooling chamber (10) are a cooling water supply port (11) and a cooling water discharge port (12) communicating with the cooling chamber (10) for supplying and discharging cooling water, and an anode electrode (13) for supplying and discharging the cooling water. ), and further has a thermal spraying material supply port (14) for supplying thermal spraying material at the front part of the nozzle (3), and a cylindrical body (15) with an open end is connected to the nozzle (3). In the plasma jet thermal spraying device installed concentrically with the cylindrical body (15), the non-oxidizing gas supply port (16) has an inner diameter larger than the outer diameter of the cylindrical body (15) and is for supplying non-oxidizing gas.
) and has an open end (17).
) is provided concentrically with the cylindrical body (15), and the cylindrical body (
A non-oxidizing gas passage (18), which is a cylindrical space, is formed between the outer circumferential surface of the cylindrical body (15) and the inner circumferential surface of the protective tube (17). ) The diameter of the opening side of both cylinders is gradually expanded outward at the same angle, and the injection port has an opening angle of 80 to 100 degrees.
19) A plasma jet thermal spraying apparatus characterized by forming: