JPWO2004001089A1 - Wear resistant composite wire for arc spraying and method for producing the same - Google Patents

Abstract

A powder 3 made of at least one material selected from the group consisting of metals, ceramics and combinations thereof, and an outer skin made of at least one material selected from the group consisting of nickel-base alloys, cobalt-base alloys and iron-base alloys. 2 is a wear resistant composite wire 1 for arc spraying covered with 2. The composite wire is characterized in that powder made of at least one material selected from the group consisting of boron or a boron compound, silicon or a silicon compound and phosphorus or a phosphorus compound is added to such a powder to be self-solubilized. Have.

Description

    The present invention relates to a wear resistant composite wire for arc spraying, specifically, a pump, a turbine, a member of a rotary machine such as a compressor, which is required to have sand erosion resistance or slurry erosion resistance, a casing, Abrasion resistant composite wire for arc spraying suitable for use for applying a wear resistant coating to the surface of metal members such as blades, bearings and seals, and a method for manufacturing the same, and a sprayed wear resistant composite wire for arc spraying. The present invention relates to an impeller and a fluid machine including the impeller.

In rotary machines such as pumps, water wheels, and compressors, along with the need for high speed and large capacity, damage to metal materials becomes a problem due to sand erosion due to mixing of particles and slurry erosion due to mixing of earth and sand into running water. Materials used for rotary machines are required to have high toughness as well as excellent sand erosion resistance and slurry erosion resistance, so that the thermal spraying technique has been widely used for metal substrates. Since sand erosion or slurry erosion partially occurs at a specific position of the site, it is possible to previously apply the wear resistant coating to the site where the damage is expected to occur in advance. In addition, after a certain period of operation, repairing the location damaged by sand erosion or slurry erosion by arc spraying can extend the life of the rotating machine.
As shown by 1 in FIG. 1, the wear-resistant composite wire used in the arc spraying process is a ceramic powder made of WC or W ₂ C inside the tubular metal outer shell 2. 3 is a wire that is filled with 3. Such a composite wire is generally manufactured by supplying ceramic powder into a concave portion formed by bending a strip-shaped metal plate so that the cross section becomes a trough shape or a U shape, and bending it to form an internal portion. It is manufactured by winding ceramic powder into a tube and forming it into a tubular shape, and then drawing it, or by filling the pre-made tubular body with ceramic powder while vibrating, and then drawing wire. Is done by.
The conceptual diagram of the arc spraying method using such a composite wire made of wear resistant material is shown in FIG. As can be seen from the figure, in the arc spraying method, two pairs of composite wires (diameter 1.5 to 3.2 mm) 1 are used, and the tips are crossed diagonally and continuously by a feed mechanism (not shown). While supplying, a predetermined voltage is applied to both composite wires 1, an arc is generated between the tips of the composite wires 1 to melt the composite wires, and the melted metal and ceramic particles are jetted from the nozzle 5 by an air jet, It is performed so that the base material B is sprayed to form a film of metal and ceramic particles. In this way, by causing an arc discharge between the pair of composite wires 1, both ends of the composite wire are melted, and the melt is welded to the sprayed area by the air, which is the carrier gas from the nozzle 5, to thereby form the sprayed area. A film 6 of wear resistant material is formed on.
Since arc spraying has a mechanism to blow off droplets of the composite wire and unmelted ceramic particles with an air jet, when the ceramic is tungsten carbide, if the particle diameter is 5 μm or less, the ceramic particles will be scattered around. Since the particles are scattered, the spraying efficiency of the tungsten carbide particles becomes extremely small, the content rate of the tungsten carbide particles in the sprayed coating layer becomes small, and there is a problem that a desired wear resistant coating cannot be obtained. FIG. 3 shows the relationship between the hard particles (W ₂ C) filled in the composite wire in the arc spraying and the spraying efficiency. As can be seen from this figure, although within a limited range, the spraying efficiency increases as the particle size of the hard particles increases. Further, in the conventional composite wire, a metal having a relatively high melting point, such as a Ni-based alloy, a Co-based alloy, or an Fe-based alloy, is used as a material for the hoop, that is, the outer skin, so that there are many voids in the sprayed layer and the dense spray Since no layer is obtained, there is a problem that the required slurry erosion resistance cannot be obtained when conventional arc spraying is applied to a pump member in which severe slurry erosion occurs.
As a result of repeated studies in view of the problems of the conventional composite wire for arc spraying as described above, the present inventor has found that the self-dissolving property of the composite wire can be obtained by adding a specific component to the powder or outer shell of the composite wire. It has been found that the slurry erosion resistance can be improved by performing thermal spraying treatment using such a self-fluidizing composite wire. It has also been found that by granulating the powder filled in the outer shell to a desired size, the scattering of hard particles during arc spraying can be suppressed and the spraying efficiency can be improved.
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wear resistant composite wire for arc spraying, which can improve slurry erosion resistance.
Another object of the present invention is to add a powder made of at least one material selected from the group consisting of boron or a boron compound, silicon or a silicon compound and phosphorus or a phosphorus compound to the powder constituting the composite wire, and arc spraying. Abrasion resistant composite wire for self-fluxing, thereby increasing the spraying efficiency of the composite wire and improving wear resistance.
Another object of the present invention is to add at least one element selected from the group consisting of boron, silicon and phosphorus to the material of the outer shell forming the composite wire to self-solubilize the wear resistant composite wire for arc spraying, Thereby, the spraying efficiency of the composite wire is increased and the wear resistance is improved.
Another object of the present invention is to increase the spraying efficiency of the composite wire and improve the wear resistance by granulating the powder filled in the outer shell into particles of a desired size.
Still another object of the present invention is to provide a method of manufacturing the wear resistant composite wire for arc spraying as described above, an impeller spray-treated using the composite wire, and a fluid machine including such an impeller. That is.
According to the present invention, a powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof comprises at least one selected from the group consisting of nickel-based alloys, cobalt-based alloys and iron-based alloys. In a wear-resistant composite wire for arc spray coating made of a material, the powder is made of at least one material selected from the group consisting of boron or a boron compound, silicon or a silicon compound and phosphorus or a phosphorus compound. Provided is a wear-resistant composite wire for arc spraying, which is made self-fluxing by adding a powder.
Powder made of at least one material selected from the group consisting of the above metals, ceramics and combinations thereof, and at least one material selected from the group consisting of the above boron or boron compound, silicon or silicon compound and phosphorus or phosphorus compound. You may granulate with the powder made in (2) so that the particle size may be 15 μm to 150 μm.
According to another invention of the present application, the powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof is selected from the group consisting of nickel-based alloys, cobalt-based alloys and iron-based alloys. A wear-resistant composite wire for arc spray coating made of at least one material, which is self-fluxable by adding at least one element selected from the group consisting of boron, silicon and phosphorus to the material of the outer coating. Abrasion resistant composite wire for arc spraying is provided.
In the wear resistant composite wire for arc spraying, the ceramic may be either a carbide or an oxide, and the ceramic may be WC or W ₂ C. Furthermore, the primary particle size of the powder containing WC or W ₂ C as a main component may be 5 μm or more and 150 μm or less.
According to another invention of the present application, there is provided an impeller provided with a hub and a plurality of blades circumferentially spaced around the hub, wherein at least a part of a surface of the impeller is provided. There is provided an impeller that has been surface-treated using the wear resistant composite wire for arc spraying.
According to still another invention of the present application, an impeller including a hub and a plurality of blades circumferentially spaced around the hub, and a chamber rotatably accommodating the impeller are defined. And a casing for performing at least a part of a surface of the impeller and/or at least a part of an inner surface of the casing are surface-treated with the wear resistant composite wire for arc spraying. A fluid machine is provided.

Hereinafter, embodiments of the present invention will be described.
Similarly to the conventional composite wire 1 shown in FIG. 1, the wear resistant composite wire for arc spraying according to the present embodiment (hereinafter simply referred to as composite wire) also has a tubular outer skin (hoop) and powder filled in the outer skin. It consists of and. In the present embodiment, the material of the outer skin and/or the material of the powder is improved. In a composite wire according to one embodiment, the outer skin is made of at least one alloy material selected from the group consisting of nickel-based alloys, cobalt-based alloys and iron-based alloys. The material of the powder filled in the outer shell is a powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof, boron (B) or a boron compound, silicon (Si) or a silicon compound, and It is made by adding and mixing powders made of at least one material selected from the group consisting of phosphorus (P) and phosphorus compounds. As in the conventional case, the outer shell is formed by forming a plate material or a stop material made of the alloy material into a gutter-shaped or U-shaped cross section, and filling the mixed powder therein, and then forming the outer shell into a tubular shape and drawing a wire. Then it is made into a composite wire. The present inventor reduces the melting point of the composite wire by adding the above-mentioned materials to the powder of metal and/or ceramics (tungsten carbide (WC, W ₂ C)) filled in the tubular outer skin, that is, It becomes possible to be self-fluxing (self-melting), and by lowering the melting point of the composite wire, scattering of particles made of a hard material such as ceramics (for example, W ₂ C) is reduced during arc spraying. I found that I can. Therefore, a large amount of wear-resistant hard material powder is contained in the coating layer sprayed on the substrate. It will effectively function as an abrasion resistant film. By making the composite wire self-fluxing, that is, by lowering the melting point, it is possible to reduce the scattering of powder of hard material such as ceramics because hard particles such as ceramics are easily trapped in the molten metal layer. I think that the.
In the above case, the ceramic powder may be WC or W ₂ C carbide powder, or may be an oxide of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), or the like. It may be a powder of the product. When WC or W ₂ C is used as the ceramic, the primary particle diameter of the powder containing WC or W ₂ C as a main component is preferably 5 μm or more and 150 μm or less, and most preferably 5 μm or more and 65 μm or less. The primary particle size of the oxide powder of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or the like is preferably 1 μm or more and 150 μm or less, and most preferably 1 μm or more and 50 μm or less.
Further, a powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof, and at least one material selected from the group consisting of boron or boron compounds, silicon or silicon compounds and phosphorus or phosphorus compounds. It may be prepared by mixing with the powder prepared in (1) and granulated to have a particle size of preferably 5 μm to 150 μm, most preferably 5 μm to 65 μm. Granulation may be performed by a known method.
In another embodiment of the present invention, the material of the skin is at least one selected from the group consisting of nickel-based alloys, cobalt-based alloys and iron-based alloys, and at least one selected from the group consisting of boron, silicon and phosphorus. It is made by adding the element of. The outer skin is made in the same manner as in the above embodiment using such a material, and the powder filled therein is made of at least one material selected from the group consisting of metals, ceramics and combinations thereof. ..
The present inventor also added a low melting point to the composite wire by adding at least one element selected from the group consisting of boron, silicon and phosphorus as described above into the material of the tubular outer shell as in this embodiment. In other words, it becomes possible to make the composite wire self-melting (self-melting), and by lowering the melting point of the composite wire, scattering of hard materials such as ceramics (for example, W ₂ C) is reduced during arc spraying, It has been found that the spraying efficiency can be improved. Therefore, a large amount of wear-resistant hard material powder is contained in the coating layer sprayed on the substrate. It will effectively function as an abrasion resistant film.
The wear resistant composite wire produced as described above is sprayed on the surface of the base material by the known arc spraying method shown in FIG. 2 to form a wear resistant film on the base material. Examples of the base material on which such an abrasion resistant film is formed include members of rotary machines such as pumps, turbines, and compressors, and more specifically, blades that require sand erosion resistance or slurry erosion resistance. Examples include cars, casings, blades, bearings and seals. By forming a wear resistant film on such a base material, the wear resistance of such a base material is improved, and the life of a machine using such a base material, for example, a pump, a turbine, a compressor, etc. Can be extended.

The outer shell is made of NiCr alloy as described above, and as the filling powder (powder to be filled in the outer shell), powder of hard particles of W ₂ C (particle diameter 44 μm to 65 μm) and NiB alloy powder (particle diameter 44 μm) are used. To 65 μm) and FeSi powder (particle size 44 μm to 65 μm) were added and mixed so that W ₂ C was 55% by weight, NiB was 20% by weight and FeSi was 25% by weight to form a composite wire. As a result, the composite wire as a whole can be made self-fluxable (lower in melting point). The chemical composition of the composite wire thus produced is as listed in Example 1 of Table 1. The inventors have found that when a NiB compound powder and a FeSi compound powder are added to a powder composed of W ₂ C hard particles to form a self-fluxing alloy of the composite wire, the sprayed layer itself has high hardness. .. By adding boron (B) and silicon (Si) to a composite wire made of a Ni-based alloy, W ₂ C particles that are hard particles can be efficiently dispersed in a coating film that is a sprayed layer, and an alloy matrix. Since the phase itself has a high hardness, the porosity in the coating is reduced, the denseness is improved, and it becomes possible to form a coating of high quality and excellent in abrasion resistance and the like.
The cross-sectional state and Vickers hardness measurement results of the coating of the wear-resistant material obtained by depositing the composite wire of Example 1 on the surface of the base material by the arc spraying method are shown in comparison with those of the coating of the conventional composite wire. As shown in 4. As is clear from the electron micrograph showing the cross section, the cross section of the sprayed layer of the conventional example has many relatively large voids (blackened portions) and has a multi-layered structure in which several deposited metals overlap each other. There is. On the other hand, the cross section of the sprayed layer of the present invention is a dense sprayed layer with few voids and few boundary layers. It can also be seen that the Vickers hardness is improved by adding boron and silicon.

The outer shell is made of NiCr alloy in the same manner as described above, and hard particles of WC (particle size 1 μm to 5 μm), chromium carbide CrC (particle size 1 μm to 5 μm) powder and Ni powder (particle size 1 μm) are used as filling powder. To 5 μm) were mixed in a weight ratio of 1:20:7, and the powder was granulated by a known method. The average particle size of the granulated particles was 65 μm. Using this granulated powder, a composite wire was prepared in the same manner as described above. The chemical composition of the composite wire thus produced is as set forth in Example 2 of Table 1.
In the composite wire of this Example 2, since the filling powder filled in the outer shell was granulated to form a granular body having a desired size, it is possible to suppress the scattering of hard particles during arc spraying and improve the spraying efficiency. It is possible. Further, the porosity in the coating is reduced to improve the denseness, and it becomes possible to form a coating of high quality and excellent in abrasion resistance.

The outer skin was made of NiCr alloy in the same manner as described above, and as the filling powder, the powder of chromium carbide CrC (particle size 1 μm to 5 μm) and the powder of Co (particle size 1 μm to 5 μm) were used, and the composition shown in Example 3 of Table 1 was used. The mixed powder was adjusted so that The average particle size of the granulated particles was 65 μm. Then, using this granulated powder, a composite wire was prepared in the same manner as described above. The chemical composition of the composite wire thus produced is as listed in Example 3 in Table 1.
In the composite wire of this Example 3 as well, as in the case of Example 2, the filling powder was granulated into a granular material having a desired size, so that the scattering of hard particles during arc spraying can be suppressed and the spraying efficiency can be improved. It is possible to improve. In addition, the porosity in the coating is reduced, the denseness is improved, and it becomes possible to form a coating of high quality and excellent in abrasion resistance.

The outer shell is made of stainless steel (SUS304) in the same manner as described above, and as filling powder, hard particles of WC (particle size 1 μm to 5 μm), titanium carbide (TiC) powder (particle size 1 μm to 5 μm), and NiB alloy The powder (particle size 44 μm to 65 μm) and the FeSi powder (particle size 44 μm to 65 μm) were adjusted to have the composition shown in Example 4 of Table 1 and mixed to form a composite wire. As a result, the composite wire as a whole can be self-fluxing (lowering the melting point) as in the first embodiment. The chemical composition of the composite wire thus produced is as set forth in Example 4 of Table 1.
By adding boron (B) and silicon (Si) also to the composite wire of this Example 4, the WC particles, which are hard particles, can be efficiently provided in the coating film that is the sprayed layer, similarly to the composite wire of Example 1. Since it becomes possible to disperse and the matrix phase of the alloy itself becomes harder, the porosity in the coating becomes smaller and the denseness is improved, and a coating of high quality and excellent in abrasion resistance etc. is formed. Will be possible.

The outer skin is made of NiCr alloy in the same manner as described above, and as powders, hard particles of WC (particle size 44 μm to 65 μm), Co powder (particle size 44 μm to 65 μm), Cr powder (particle size 44 μm to 65 μm) , NiB alloy powder (particle size 44 μm to 65 μm) and FeSi powder (particle size 44 μm to 65 μm) were adjusted to have the composition shown in Example 5 of Table 1 and mixed to form a composite wire. . As a result, the composite wire as a whole can be self-fluxing (lowering the melting point) as in the first embodiment. The chemical composition of the composite wire thus produced is as listed in Example 5 in Table 1.
Also in the composite wire of Example 5, by adding boron (B) and silicon (Si) to the composite wire made of the Ni-based alloy, as in the composite wire of Example 1, in the coating film which is the sprayed layer. WC particles, which are hard particles, can be efficiently dispersed and the matrix phase of the alloy itself becomes harder, which reduces the porosity in the coating and improves the compactness, resulting in high quality and wear resistance. Thus, it becomes possible to form a film excellent in the above.

The outer shell is made of NiCr alloy as described above, and as powder, granulated powder of CrC (particle size 15 μm to 125 μm), NiB alloy powder (particle size 44 μm to 65 μm) and FeSi powder (particle size 44 μm) are used. To 65 μm) were mixed and adjusted to have the composition shown in Example 6 of Table 1, and the mixed powder was granulated by a known method. The mixed powder was granulated by a known method. The average particle size of the granulated particles was 65 μm. Then, using this granulated powder, a composite wire was prepared in the same manner as described above. As a result, the composite wire as a whole can be self-fluxing (lowering the melting point) as in the first embodiment. The chemical composition of the composite wire thus produced is as set forth in Example 6 of Table 1.
Also in the composite wire of Example 6, by adding boron (B) and silicon (Si) to the composite wire made of the Ni-based alloy, as in the composite wire of Example 1, in the coating film which is the sprayed layer. It becomes possible to disperse CrC particles efficiently, and it becomes possible to form a film having excellent wear resistance and the like. Moreover, since the filling powder is granulated, it is possible to improve the thermal spraying efficiency.
In the above examples, the method of adding the additives such as B and Si to the ceramic powder has been described with respect to the case where the powders such as NiB and FeSi are added and mixed, but it is also possible to add them by the wet plating method. It is possible. For example, a method of electrolessly plating hard particles such as WC or W ₂ C in a plating solution containing B and Si, or electroless or electrolytic plating of an outer skin and a hoop in a plating solution containing B and Si continuously. That is also an effective method. In addition to the wet plating method, a physical vapor deposition method or a chemical vapor deposition method in which B and/or Si is vapor-deposited on the ceramic powder or the outer surface of the outer cover is also effective.

As a material for the outer skin, a material prepared by mixing so as to have a composition shown in Example 7 of Table 1 was used. An outer coat was made of such a material as in the above-mentioned example, and W ₂ C powder (particle size 44 μm to 65 μm) was filled therein to form a composite wire.
In the composite wire of Example 7, B and Si are added to the material of the outer cover to lower the melting point of the outer cover, thereby making the entire composite wire self-fluxing. Therefore, the composite wire of this embodiment can achieve the same effect as the composite wire of the first embodiment. In the case of this embodiment, since B, Si, etc. are mixed in the outer shell itself, it is not necessary to add these materials to the powder to be put in the tubular outer shell, and accordingly, WC, W ₂ C per unit length of the composite wire It is possible to increase the content of ceramics such as, and improve the thermal spraying efficiency of ceramics.

As a material for the outer skin, a material prepared by mixing so as to have the composition shown in Example 8 of Table 1 was used. An outer coat was made of such a material as in the above-mentioned example, and W ₂ C powder (particle size 44 μm to 65 μm) was filled therein to form a composite wire.
In the composite wire of this Example 8 as well as in Example 7, by adding B and Si to the material itself of the shell, the melting point of the shell is lowered and the composite wire as a whole is self-fluxing. It differs from Example 7 in that it is a self-fluxing alloy. The composite wire of this embodiment can also achieve the same effect as the composite wire of the first embodiment. In the case of this embodiment, since B, Si, etc. are mixed in the outer shell itself, it is not necessary to add these materials to the powder to be put in the tubular outer shell, and accordingly, WC, W ₂ C per unit length of the composite wire It is possible to increase the content of ceramics such as, and improve the thermal spraying efficiency of ceramics.

The outer coat is made of a Ni-based alloy as described above, and hard powder of W ₂ C (particle size 44 μm to 65 μm), BC powder and FeSi are used as filling powder (powder to be filled in the outer coat). Was added to prepare a composite wire. As a result, the composite wire as a whole can be made self-fluxing (having a low melting point). The chemical composition of the composite wire thus produced is as in Example 9 of Table 1. The inventors have found that when a BC compound powder and a FeSi compound powder are added to a powder composed of W ₂ C hard particles to make the composite wire a self-fluxing alloy, the sprayed layer itself has a high hardness. .. By adding boron and silicon to a composite wire made of a Ni-based alloy, it becomes possible to efficiently disperse W ₂ C, which is hard particles, in the sprayed layer, and the matrix phase of the alloy itself has a high hardness. The internal porosity is reduced, the denseness is improved, and it becomes possible to form a coating having excellent wear resistance.

The outer coat is made of a Co-based alloy as described above, and as the filling powder (the powder to be filled in the outer coat), the hard particles of W ₂ C (the particle size is 44 μm to 65 μm), the BC powder and the FeSi are used. Was added to prepare a composite wire. As a result, the composite wire as a whole can be made self-fluxing (having a low melting point). The chemical composition of the composite wire thus produced is as in Example 9 of Table 1. The inventors have found that when a BC compound powder and a FeSi compound powder are added to a powder composed of W ₂ C hard particles to make the composite wire a self-fluxing alloy, the sprayed layer itself has a high hardness. .. By adding boron and silicon to a composite wire made of a Co-based alloy, W ₂ C, which is hard particles, can be efficiently dispersed in the sprayed layer, and the matrix phase of the alloy itself has a high hardness. The internal porosity is reduced, the denseness is improved, and it becomes possible to form a coating having excellent wear resistance.
[Effect confirmation test]
The inventors carried out a slurry erosion test in which sand containing SiO ₂ as a main component was mixed in clear water in order to investigate the slurry erosion resistance of the base material and various arc sprayed materials. The experimental conditions were such that the average particle diameter of sand was 5 μm, the concentration of sand was 1 kg/m ² , the collision angle of sand was 15° or less, and the relative collision velocity of sand was 55 m/s. The relationship between the Vickers hardness and the slurry erosion damage rate in the base material and various arc sprayed materials is shown in FIG. It can be seen that the slurry erosion resistance improves as the Vickers hardness increases. Compared with a conventional W ₂ C hard particle-containing Ni-based alloy, the W ₂ C hard particle-containing Ni-based self-fluxing alloy (when the outer shell itself is a self-fluxing alloy) of Example 7 of the present invention is Vickers hard. It can be seen that the slurry erosion resistance is improved. In general, it is desirable that the hard particle diameter of the sprayed layer be equal to the particle diameter of sand contained in river water. On the other hand, in the arc spraying, since the mechanism is such that the droplets of the composite wire and the unmelted ceramic particles are blown off by the air jet, if the ceramic particle diameter is 150 μm or less, the ceramic particles scatter to the periphery, so The thermal spraying efficiency of the ceramic particles in the layer becomes low. Further, as described above, the thermal spraying efficiency becomes extremely small when the diameter of hard particles such as WC and W ₂ C that are filled in the composite wire is 5 μm or less. Furthermore, if the particle size of carbides and the like is reduced, the carbide particles themselves oxidize at high temperature during arc spraying. On the other hand, the present inventors have proposed a mechanism in which the droplets of the composite wire and the unmelted ceramic particles are blown off by a jet using a reducing gas, nitrogen, or an inert gas instead of an air jet, and the particle diameter of the carbide is 5 μm. It is believed that even the following can prevent oxidation during thermal spraying. The particle size of carbides such as WC and W ₂ C used for arc spraying using an ordinary air jet is preferably 5 μm or more and 150 μm or less.
It has already been described that when the diameter of the ceramic particles is 150 μm or less, the ceramic particles scatter to the periphery, so that the thermal spraying efficiency of the ceramic particles in the thermal spray layer becomes low and a desired abrasion resistant coating cannot be obtained. Even if the self-fluxing alloying method of the present invention is used, if the hard particle size is about several tens of μm, the thermal spraying efficiency will be low, so it is possible to granulate with a powder such as a metal or an alloy or a self-fluxing alloy. It is possible to improve the thermal spraying efficiency. It is desirable that the melting point of the self-fluxing alloy of the present invention is lowered and the secondary particle diameter is 40 μm or more by granulation. However, the oxide particle size is preferably such that the particle size is adjusted to the particle size of the sand of the river water, since the displacement of the oxide does not occur during arc spraying.
The blast erosion test by the Arata type thermal spray coating evaluation test was performed on the composite wires produced under various arc thermal spraying conditions under the following conditions. The results of examining the wear resistance of the various arc-sprayed materials obtained are shown in FIG. It can be seen that in the conventional composite wire, the wear resistance has a great influence depending on the spraying condition. It can be seen that the composite wire of the present invention exhibits substantially constant and good wear resistance even if the air pressure condition during spraying is changed. In consideration of application to an impeller such as a pump, it is a practically effective effect that even an object having a complicated shape exhibits a certain degree of wear resistance.
Blast erosion test conditions by Arata type thermal spray coating evaluation test propellant: Al ₂ O ₃ (particle size: 60 Mesh)
Injection angle: 30°
Injection distance: 90mm
Injection pressure B: 3.1 kg/cm ²
Injection nozzle: φ5.2mm
The wear resistant composite wire for arc spraying produced as described above is sprayed on the surface of the base material by the arc spraying method to form a wear resistant film on the base material. Examples of the base material on which such an abrasion resistant film is formed are members of rotary machines such as pumps, turbines and compressors, and more specifically, blades that require sand erosion resistance or slurry erosion resistance. Examples include cars, casings, blades, bearings and seals. By forming a wear-resistant film on such a base material, the wear resistance of such a base material is improved, and the life of a machine using such a base material, for example, a pump, a water turbine, a compressor, or the like. Can be extended.
More specifically, as shown in FIG. 7, the impeller 30 includes a hub 32 in which a shaft hole 31 for receiving a rotation shaft is formed, and a disk-shaped member that radiates radially outward from the hub 32. The main plate 33, an annular side plate 34 that is separated from the main plate 33 in the axial direction (vertical direction in FIG. 7), and a circumferential direction (circumferential line about the axis O-O of the shaft hole) between the main plate 33 and the side plate 34. Direction)) and a plurality of blades 35 which are arranged at equal intervals in a curved manner along a desired curved surface and are integrally formed with the side plate and the main plate. Defining a flow passage 36 of A radially inner portion 37 of the flow path 36 serves as an inlet portion, and a radially outer portion 38 serves as an outlet portion. Further, the annular side plate 34 has a portion 34a extending in the axial direction on the inner side in the circumferential direction and a portion 34b extending on the outer side in the radial direction, and defines the inlet 39 of the impeller 30 by the axially extending portion 34a. .. When the impeller 30 is rotated to deliver the fluid, for example, when the impeller is rotated in water containing earth and sand, the particles of the earth and sand in the water cause the surface of the impeller 30 to flow, particularly the flow passage 36 in the impeller 30. The inner surface 41 of the main plate 33, the inner surface 42 of the side plate 34, and the both surfaces of the blade 35, that is, the pressure surface 43 and the suction surface 44, are rubbed against the surfaces, and these surfaces are extremely worn due to friction.
Therefore, a desired surface among the inner surfaces 41 and 42, the pressure surface 43 and the negative pressure surface 44, the inner surface 45 of the inlet 39, the outer surface 46 of the side plate 34, and the back surface 47 of the main plate 33 that define the flow path 36 of the impeller 30. For example, the inner surfaces 41, 42, the pressure surface 43, and the negative pressure surface 44 that define the flow path are subjected to surface treatment using the above-mentioned arc-spraying wear resistant composite wire to form a coating.
The impeller 30 of the present invention, which has been surface-treated with the wear resistant composite wire for arc spraying as described above, is used for a fluid machine such as a water turbine or a pump. In FIG. 8, a vertical pump 50 is shown in cross section as an example of such a fluid machine. In the figure, a pump 50 includes a casing 51 that defines a pump chamber 52 that accommodates the impeller 30 according to the present invention, a main shaft 57 that is arranged with its axis vertical and has the impeller 30 fixed to the lower end, A main bearing 58 mounted above the casing and rotatably supporting the main shaft 57 with respect to the casing, and a seal device 59 for preventing fluid leakage from between the casing 51 and the main shaft 57 are provided. The casing 51 is fixed on the tubular support base 60 by a known method. The casing 51 includes an upper disk-shaped end plate 53, a casing main body 54 that defines a spiral outlet chamber 55, and a tubular cover 56. A cylindrical suction pipe 61 is connected to the lower end of the cover 56.
In the above pump, when the impeller 30 fixed to the lower end of the pump is rotated by rotating the main shaft 37, fluid is sucked into the inlet 39 of the impeller in the suction pipe 61 as indicated by the arrow X, and the impeller is rotated. It is extruded in the radial direction from the outlet 38 side through the flow path 36 of 30, and flows into the outlet chamber 55. The fluid in the outlet chamber is discharged from an outlet (not shown). At least a part of the inner surface of the casing may be surface-treated by using a wear resistant composite wire for arc spraying.

The invention's effect

According to the present invention, the following effects can be achieved.
(A) It is possible to suppress the scattering of hard particles during the thermal spraying treatment and increase the amount of such particles in the thermal spray coating to improve the wear resistance.
(B) The spraying efficiency can be increased by suppressing the scattering of hard particles.
(C) Hard particles can be efficiently dispersed in the coating that is the sprayed layer, and the matrix phase of the alloy itself becomes harder, so the porosity in the coating becomes smaller and the denseness is improved. It is possible to form a coating having excellent quality and abrasion resistance.
(D) It is possible to form a sprayed coating having excellent slurry erosion resistance.

FIG. 1 is an enlarged cross-sectional view showing the general structure of a composite wire.
FIG. 2 is a conceptual drawing of the arc spraying method for explaining the principle of the arc spraying.
FIG. 3 is a diagram illustrating the relationship between the hard particles filled in the composite wire and the thermal spray efficiency in arc spraying.
FIG. 4A is a diagram showing a comparison between cross-sectional properties and Vickers hardness of a coating formed by arc spraying using a composite wire according to an embodiment of the present invention and cross-sectional properties and Vickers hardness when a conventional composite wire is used.
FIG. 4B is a diagram showing a cross-sectional property of a coating formed by arc spraying using a composite wire according to another embodiment of the present invention.
FIG. 5 is a diagram showing a relationship between the Vickers hardness and the slurry erosion damage depth rate in the base material and various arc sprayed materials.
FIG. 6 is a diagram showing a relationship between arc spraying conditions and wear resistance.
FIG. 7 is a cross-sectional view showing an example of an impeller surface-treated with the wear resistant composite wire for arc spraying of the present invention.
FIG. 8 is a sectional view of a pump including the impeller of FIG. 7.

Claims (9)

A powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof is a skin made of at least one material selected from the group consisting of nickel base alloys, cobalt base alloys and iron base alloys. In the coated wear resistant composite wire for arc spraying, to the powder, a powder made of at least one material selected from the group consisting of boron or a boron compound, silicon or a silicon compound and phosphorus or a phosphorus compound is added. A wear resistant composite wire for arc spraying characterized by being made soluble. A powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof is a skin made of at least one material selected from the group consisting of nickel base alloys, cobalt base alloys and iron base alloys. In the coated wear resistant composite wire for arc spraying, at least one element selected from the group consisting of boron, silicon and phosphorus is added to the material of the outer shell to make it self-fluxable, for arc spraying. Wear resistant composite wire. In the wear resistant composite wire for arc spraying according to claim 1, a powder made of at least one material selected from the group consisting of metals, ceramics and combinations thereof, and boron or a boron compound, silicon or a silicon compound and phosphorus or phosphorus. An arc spray-sprayed wear-resistant material composite wire, characterized in that a powder made of at least one material selected from the group consisting of compounds is granulated to have a particle size of 15 μm to 150 μm. The wear resistant composite wire for arc spraying according to claim 3, wherein the powder made of the one kind of material has a particle size of 5 μm to 65 μm. The wear resistant composite wire for arc spraying according to any one of claims 1 to 4, wherein the ceramic is either a carbide or an oxide. The wear resistant composite wire for arc spraying according to any one of claims 1 to 4, wherein the ceramic is WC or W ₂ C. The abrasion-resistant composite wire for arc spraying according to claim 6, wherein the primary particle diameter of the powder containing WC or W ₂ C as a main component is 5 μm or more and 150 μm or less. .. In an impeller equipped with a hub and a plurality of blades circumferentially spaced around the hub,
An impeller in which at least a part of the surface of the impeller is surface-treated using the abrasion-resistant composite wire for arc spraying according to any one of claims 1 to 7. An impeller provided with a hub and a plurality of blades circumferentially spaced around the hub;
A casing defining a chamber rotatably housing the impeller;
Equipped with
A fluid machine in which at least a part of the surface of the impeller and/or at least a part of the inner surface of the casing are surface-treated with the wear resistant composite wire for arc spraying according to any one of claims 1 to 7.

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