CN1671878A - Self-fluxing Alloy Spraying Material Containing Ceramic Particles - Google Patents

Abstract

A ceramic particle-containing self-fluxing alloy thermal spraying material of the present invention is characterized in that at least one ceramic powder 11 selected from the group consisting of carbides, oxides, nitrides and borides and at least one self-fluxing alloy powder 12 selected from the group consisting of nickel-based self-fluxing alloys, cobalt-based self-fluxing alloys and iron-based self-fluxing alloy powders are mixed and aggregated to produce a granular body 10 having an average secondary particle size larger than the average primary particle size of the powders, wherein the average secondary particle size of the granular body is 15 to 250 [ mu ] m.

Description

Self-fluxing Alloy Spraying Material Containing Ceramic Particles

technical field

The invention relates to a self-fluxing alloy spraying material containing ceramic particles. Specifically, it is suitable for turbomachinery such as pumps, water turbines, and steam turbines, and especially requires gas erosion resistance and mud erosion resistance on the surface of metal substrates. Such impellers, bushings, blades and bearings, etc. require wear-resistant parts and other metal substrates to implement wear-resistant coatings on the surface of metal substrates such as self-fluxing alloy spraying materials containing ceramic particles, spraying with such spraying materials Plated impellers and fluid machines with impellers.

Background technique

In turbomachinery such as pumps and water turbines, material damage occurs due to mud erosion caused by sand and soil mixed into flowing water, and gas erosion caused by part-load operation. Especially in impellers, casings, etc., since mud erosion occurs repeatedly with gas erosion, high toughness is required, and excellent mud erosion resistance and gas erosion resistance are required. On impellers and sleeves, where damage is expected to occur, a wear-resistant spray coating can be applied in advance. After working for a certain period of time, the life of pumps, turbines and other equipment can be extended by repairing the damaged parts due to gas erosion and mud erosion by spraying.

The sputtering method has proposed various schemes, occupying an important position in the surface modification technology. Among them, the spraying and melting method heats the coating film sprayed with self-fluxing alloy powder by flame spraying method to a molten state, which reduces the pores in the coating, the combination between the sprayed particles and the tightness with the substrate. It is the most effective spraying method in terms of bonding strength, so it is widely used in parts requiring wear resistance. For mechanical parts used in environments where sand and soil wear are likely to occur, the thermal spray fusion method of mixing carbide powder such as tungsten and self-fluxing alloy powder with thermal spray powder is generally used. On machines that are prone to sand and soil abrasion, when the particle size of sand and soil is more than 0.1 mm, the intended purpose can be achieved by using tungsten carbide particles of about 0.1 mm to several mm.

Recently, nickel (Ni)-based alloy or cobalt (CO)-based alloy sprayed coatings dispersed into carbide particles of several microns are used on wear-resistant parts by high-velocity flame spraying (HVOF, HVF, etc.). High-speed flame-sprayed coatings are used on parts such as impellers and bushings for water turbines and pumps, and have been confirmed to exhibit excellent characteristics in terms of mud erosion resistance. However, high-velocity flame spraying is a method of forming a sprayed coating using a powder of several micrometers of carbide particles and a Ni-based or CO-based alloy powder, or a powder that is granulated, sintered, and pulverized. Since this method is partial melting, there are countless tiny voids in the sprayed layer, and the tight bonding force between particles is insufficient. For this reason, the gas erosion resistance of the high-speed flame sprayed coating is weak, and it is difficult to use it in a place where cavitation occurs.

Since water turbines and pumps overlap with gas erosion and cause mud erosion, it is imperative to develop sprayed coatings that are excellent in both mud erosion resistance and gas erosion resistance. Since the self-fluxing alloy sprayed film is melted by heating to a molten state, the pores in the protective film are reduced, and the bonding between the sprayed particles and the close bonding strength with the substrate are further improved, so the use of the self-fluxing alloy The sputtering fusion method is widely used for parts requiring mud erosion resistance and gas erosion resistance.

1 and 2 respectively show a conventional thermal spraying material powder and a conceptual diagram of thermal spraying by a flame spraying method. In machines that are prone to sand wear, since the average particle size of sand is 0.1 mm or more, tungsten carbide particles with a particle size of 0.1 mm to several mm are used as ceramic powder to achieve the specified purpose. Sputtered coating of tungsten carbide with an average particle size of 60 to 125 μm dispersed in river water mixed with relatively small sand with an average particle size of 0.1mm or less, suitable for impellers and casings. The thermal spraying material used for thermal spraying, as shown in Figure 1, uses a thermal spraying material powder that only mixes tungsten carbide powder 1 with a particle size from 45 μm to 125 μm and self-fluxing alloy powder 2 with a particle size from 15 μm to 125 μm 3. Moreover, in the flame spraying method, as shown in FIG. 2, the thermal spraying material powder 3 composed of tungsten carbide powder 1 and self-fluxing alloy powder 2 is supplied from the thermal spraying material supply nozzle 5, and the gas spraying out from the gas nozzle 6 simultaneously The high-temperature combustion gas 7 blows the spraying material powder from the supply nozzle 5 onto the surface of the base material B, melts the powder of the self-fluxing alloy and deposits it on the surface as the spraying layer 4, and simultaneously carbonizes the ceramics. The tungsten particles 1 enter into the sprayed layer 4 .

The inventors have observed that when flame spraying is performed using a spraying material powder mixed with tungsten carbide powder and self-fluxing alloy powder of various particle sizes, tungsten carbide particles scatter when the particle size is 100 μm or less. In particular, it is clear that when the particle diameter is 60 μm or less, the scattering of tungsten carbide particles becomes remarkable, and the thermal spraying efficiency is very low. In addition, in the experiments of the inventors, it was difficult to produce a thermally sprayed layer in which tungsten carbide was uniformly dispersed using a thermally sprayed material produced by a thermally sprayed fusion method using thermally sprayed powder mixed with tungsten carbide powder and a self-fluxing alloy. , and sufficient gas corrosion resistance characteristics cannot be obtained.

In order to solve the above-mentioned problems, the inventors of the present invention have found, as a result of intensive studies many times, that by granulating ceramic powder such as tungsten carbide and nickel-based self-fluxing alloy powder by means of a binder, due to the formation of agglomerated average secondary particles The granular body with a diameter of 15-125 μm prevents the scattering of tungsten carbide powder during flame spraying and improves the spraying efficiency. In addition, it was also found that by using powder composed of granular bodies, it was confirmed that a sprayed coating in which tungsten carbide was uniformly dispersed could be formed on the thermal sprayed layer, and a thermally sprayed layer excellent in mud erosion resistance and gas erosion resistance could be formed.

Contents of the invention

The object of the present invention is to provide a spray coating material that reduces scattering of hard ceramic powder during the spray coating process by mixing ceramic powder of various particle sizes and self-fluxing alloy powder to granulate or sinter and pulverize into granular bodies. .

Another object of the present invention is to provide a thermal spraying material that reduces scattering of hard ceramic powder during thermal spraying by making the size of the above-mentioned ceramic particles and the granular body of the self-fluxing alloy powder into an optimum size. .

Still another object of the present invention is to provide a rotary member that is thermally sprayed using the above-mentioned thermal spray material, and a fluid machine including the rotary member.

According to the present application, there is provided a ceramic particle-containing self-fluxing alloy spraying material, which is characterized in that at least one ceramic powder selected from the group consisting of carbides, oxides, nitrides or borides is mixed and agglomerated with At least one self-fluxing alloy powder selected from the group consisting of nickel-based self-fluxing alloy powder, cobalt-based self-fluxing alloy powder, or iron-based self-fluxing alloy powder, produced with an average particle size larger than the average primary particle size of the aforementioned powder As for the granular body with a secondary particle size, the average secondary particle size of the granular body is 15 to 250 μm.

In one embodiment of the above-mentioned self-fluxing alloy spraying material containing ceramic particles, when the average primary particle size of the aforementioned ceramic powder is R1, and the average primary particle size of the aforementioned self-fluxing alloy powder is R2, R2/R1 can be is under 20.

In addition, in another embodiment of the self-fluxing alloy spraying material containing ceramic particles, the average primary particle diameters of the ceramic powder and the self-fluxing alloy may be 1-60 μm and 1-60 μm, respectively.

Also, in another embodiment of the self-fluxing alloy spraying material containing ceramic particles, the aforementioned ceramic powder is at least one carbide powder selected from the group consisting of tungsten carbide, chromium carbide, and titanium carbide.

According to the present invention, there is provided an impeller comprising a hub and a plurality of wings spaced apart in a circumferential direction around the hub, at least a part of the surface of the impeller is sprayed with the self-fluxing alloy containing ceramic particles. Plating materials are sprayed.

According to the present invention, there is provided a fluid machine comprising: an impeller having a hub and a plurality of wings spaced apart in a circumferential direction around the hub; a housing defining a chamber for rotatably housing the impeller, the At least a part of the surface of the impeller and/or at least a part of the inner surface of the casing is sprayed with the above-mentioned ceramic particle-containing self-fluxing alloy spraying material.

Description of drawings

FIG. 1 is an enlarged explanatory view of a conventional thermal spraying material composed of a mixed powder of ceramic powder and self-fluxing alloy powder.

FIG. 2 is a conceptual diagram of a flame spraying method for explaining the principle of the flame spraying method.

Fig. 3 is an enlarged explanatory view of the thermal spraying material of the present invention obtained by forming ceramic powder and self-fluxing alloy powder into granular bodies.

Fig. 4 is a diagram showing a conventional hybrid spray powder, a spray powder according to Example 1 of the present invention, and a scanning electron microscope image of a spray cross section in parallel.

Fig. 5 is a diagram showing a conventional hybrid spray powder, a spray powder according to Example 2 of the present invention, and a scanning electron microscope image of a spray cross section in parallel.

Fig. 6 is a cross-sectional view showing an example of an impeller sprayed by high-velocity flame spraying with the ceramic particle-containing self-fluxing alloy spraying material of the present invention.

Fig. 7 is a sectional view of a pump equipped with the impeller of Fig. 6 .

Detailed ways

Embodiments of the present invention are described below

In this embodiment, first, ceramic powder 11 which is a carbide such as tungsten carbide (WC or W ₂ C), titanium carbide (TiC), chromium carbide (Cr ₂ C ₃ ) and a nickel-based self-fluxing alloy The powder 12 is granulated and aggregated by a known granulation method with a binder to form a granular body 10 as shown in FIG. The average primary particle size of ceramic powders such as WC and W ₂ C and nickel-based self-fluxing alloy powders is preferably in the range of 1 μm to 60 μm, more preferably in the range of 5 μm to 30 μm. The reason is that when the particle diameter is less than 1 μm, oxidation of the particles during thermal spraying becomes a problem. On the other hand, when the particle size exceeds 60 μm, it is because granulation becomes difficult. When the average primary particle size of the ceramic powder is R1 and the average primary particle size of the self-fluxing alloy powder is R2, R2/R1 is preferably 0.1 to 20, more preferably 0.1 to 10. The reason is that when R2/R1 exceeds 20, each self-fluxing alloy particle 12 is surrounded by fine ceramic particles 11 as shown in FIG. . The reason for making it 0.1 or more is that when ceramic particles are used in the range of 1 μm to 60 μm as described above, the practical particle size of the self-fluxing alloy is about 1/10 of the diameter of the ceramic particles.

The ceramics are not limited to the above-mentioned carbides, and may be oxides such as alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), titanium oxide (TiO ₂ ), nitrides such as boron nitride, or boron oxides such as Titanium (TiB) and other borides. The aforementioned carbides, oxides, nitrides, and borides may be used alone or in any combination of some of them. The average primary particle size of these oxides, nitrides or borides may be within the same range as described above. Taking nickel-based self-fluxing alloys as examples, there are, for example, Ni-B-Si, Ni-P, and the like. As the self-fluxing (low melting point self-fluxing) alloy, in addition to the above-mentioned nickel-based self-fluxing alloy powder, for example, cobalt-based self-fluxing alloys such as Co-B-Si, Co-P, or, For example, FeSi, Fe-B-Si, Fe-P and other iron-based self-fluxing alloys. These self-fluxing alloys may be used alone or in any combination thereof.

The method of making ceramic powder and self-fluxing alloy powder into granular bodies may be a method of solidifying their powders to a desired size, followed by sintering, and pulverization, in addition to the above-mentioned known granulation methods. The average particle diameter of the granules, that is, the average secondary particle diameter, is preferably in the range of 15 μm to 250 μm, more preferably in the range of 45 μm to 125 μm. The reason is that when the secondary particle size is less than 15 μm, the thermal spraying efficiency decreases, and when the secondary particle size exceeds 250 μm, thermal spraying using a normal flame spraying gas becomes difficult.

[Example 1]

As the ceramic powder, tungsten carbide (WC) powder with an average primary particle diameter of 5 μm was used, and as a powder of a nickel-based alloy which is a kind of self-fluxing alloy, a commercially available powder corresponding to Kolumonoi No. 4 was used. The average primary particle size of the powder is 20 μm or less. These powders were mixed, and a thermal spraying material composed of granular bodies with an average secondary particle diameter of 45 to 125 μm was prepared by a known granulation method.

When the thermal spraying material of this Example 1 and the mixed powder type thermal spraying material of the conventional example are observed with a scanning electron microscope, it becomes the microphotograph shown in the upper stage of FIG. When expressing the result of observing the thermal sprayed layer of the case where the thermal spraying material of Example 1 is used for thermal spraying treatment and the case of using the above-mentioned existing thermal spraying material for thermal spraying treatment with the above-mentioned microscope, it becomes the lower paragraph of Fig. 4 Photomicrograph. As shown in these photographs, the cross section of the thermal sprayed layer of the conventional example has a relatively large structure with many voids. On the other hand, the section of the sprayed coating of the present invention becomes a dense sprayed coating with few voids. The white part of the sprayed section is tungsten carbide, and its periphery is the parent phase of the self-fluxing alloy. In the case of the conventional example, it was observed that the size of the tungsten carbide particles ranged from several tens to 100 μm, and the tungsten carbide particles were unevenly dispersed. In the thermal spraying material of Example 1, a thermal spraying layer in which tungsten carbide with an average particle diameter of 5 μm was uniformly dispersed was obtained. The cavitation resistance of the thermal spraying material of Example 1 exhibited characteristics more than four times that of the base material CA6NM.

[Example 2]

As the ceramic powder, tungsten carbide (WC) particles with an average particle size of 5 μm were used, and as a cobalt-based alloy particle which is a kind of self-fluxing alloy, a commercially available powder corresponding to Columonoi No. 1 was used. The average primary particle size of the powder is 20 μm or less. These powders are mixed, and a thermal spraying material composed of a particle slurry having an average secondary particle diameter of 45 to 125 μm is produced by a known granulation method.

Showing the results of observing the sprayed material of Example 2 and the Co-based self-fluxing alloy powder type thermal sprayed material of the conventional example with a scanning electron microscope, it is a micrograph shown in the upper row of FIG. 5 . When showing the results of observing the thermal sprayed layer when using the thermal spraying material of Example 2 for thermal spraying treatment and using the above-mentioned conventional thermal spraying material for thermal spraying treatment with the above-mentioned microscope, it becomes the microscope photograph of the lower stage of Fig. 5 picture. As shown in this micrograph, the cross-section of the thermal sprayed layer in the conventional example has a relatively large structure with many voids. On the other hand, the cross-section of the thermal sprayed layer of Example 2 was a dense thermal sprayed layer with few voids. The white part of the sprayed section is tungsten carbide, and its periphery is the parent phase of the self-fluxing alloy. In the case of the conventional example, it was observed that the size of the tungsten carbide particles ranged from several tens to 100 μm, and the tungsten carbide particles were unevenly dispersed. In the present invention, a sprayed layer in which tungsten carbide having an average particle diameter of 5 μm is uniformly dispersed is obtained. The cavitation resistance of the thermal spraying material of this Example 2 exhibited characteristics more than 4 times that of the base material CA6NM.

The ceramic particle-containing self-fluxing alloy spraying material produced as described above is sprayed on the surface of the base material by flame spraying to form a wear-resistant protective film on the base material. Examples of substrates on which such a wear-resistant protective film is formed include parts of rotating machines such as pumps, water turbines, and compressors, and more specifically, materials requiring sand erosion resistance or mud erosion resistance. Such as impellers, casings, blades, bearings and seals, etc. By forming a wear-resistant protective film on such a base material, the wear resistance of such a base material can be improved, and the life of machines using such a base material, such as pumps, water turbines, compressors, etc., can be extended.

More specifically, as shown in FIG. 6, the impeller 30 consists of a hub 32 forming a shaft hole 31 for receiving a rotating shaft, a disc-shaped main plate 33 radially expanding from the hub 32 to the outside in the radial direction, and an axial direction (FIG. 6 The ring-shaped side plate 34 isolated from the main plate 33 in the upper and lower direction) is separated into an equidistant arrangement in the circumferential direction (circumferential direction around the axis 0-0 of the shaft hole) between the main plate 33 and the side plate 34 And it is composed of a plurality of wing plates 35 bent along a desired curved surface and formed integrally with the side plates and the main plate. The main plate 33 , the side plates 34 and the wing plates 35 define a fluid flow path 36 . A radially inner portion 37 of the flow path 36 serves as an inlet, and a radially outer portion 38 serves as an outlet. The annular side plate 34 has an axially extending portion 34 a inward in the circumferential direction and a portion 34 b extending radially outward, and the inlet 39 of the impeller 30 is defined by the axially extending portion 34 a. When such an impeller 30 is rotated to output a fluid, for example, when the impeller is rotated in water containing sand, the particles of the sand in the water and the surface of the impeller 30, in particular, define the flow path 36 in the impeller 30. The inner surface 41 of the main board 33, the inner surface 43 of the side plate 34 and the two sides of the wing plate 35, that is, the pressure surface 43, the negative pressure surface 44 collide and wear them, and their surfaces are worn very badly because of friction.

Therefore, among the inner surfaces 41 and 42, the pressure surface 43 and the negative pressure surface 44 of the above-mentioned flow path 36 forming the impeller 30, 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, desired On the surface, for example, it belongs to the predetermined range on the outer peripheral side of the impeller as the surface defining the flow path 36 defined by the outer peripheral surface 46 (region A1) of the side plate 34 and the main plate 33, side plate 34, and wing plate 35 ( In Fig. 6, on the surface of the area A2 of the circle enclosed by the circle of radius r ₁ and the circle of radius r), the self-fluxing alloy spraying material containing ceramic particles of the present invention is sprayed with high-velocity flame spraying mode .

The impeller 30 whose surface is treated with a self-fluxing alloy spraying material containing ceramic particles by the above-mentioned high-velocity flame spraying method can be used in a fluid machine such as a water turbine or a pump. In FIG. 7, as an example of such a fluid machine, a vertical pump 50 is shown in section. In the same figure, the pump 50 is equipped with a casing 51 forming a pump chamber 52 for accommodating the impeller 30 of the present invention. The main shaft 57 is supported by a main bearing 58 on the housing, and a sealing device 59 for preventing fluid from leaking between the housing 51 and the main shaft 57 . The housing 51 is fixed to a tubular support 60 by known methods. The housing 51 includes an upper disc-shaped end plate 53 , a housing body 54 forming 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-mentioned pump, when the impeller 30 fixed at the lower end is rotated by rotating the main shaft 37, the fluid is sucked into the inlet 39 of the impeller in the suction pipe 61 as indicated by the arrow X, and passes through the flow path of the impeller 30. 36 is pressed out radially from the side of the outlet 38 and flows into the outlet chamber 55 . Fluid in the outlet chamber exits from an outlet not shown. In addition, at least a part of the inner surface of the housing may be surface-treated with a self-fluxing alloy spraying material containing ceramic particles.

Industrial Utilization Possibility

According to the present invention, the following effects can be obtained.

(1) It can greatly suppress the scattering of ceramic particles during spraying construction, and can improve the spraying efficiency of ceramics.

(2) The ceramic particles can be efficiently dispersed and then entered into the welded film, which can improve gas erosion resistance and mud erosion resistance.

Claims (10)

1. contain ceramic particle self-melting alloy depositing materials, it is characterized in that, mix and at least a ceramic powder that cohesion is selected from the group of being made up of carbide, oxide compound, nitride or boride and at least a self-fluxing alloyed powder of from the group of forming by nickel base self-fluxing alloy powder, cobalt-based self-melting alloy or ferrio self melting-ability alloy powder, selecting, making has the granular solid of the average aggregate particle size bigger than the average primary particle diameter of described powder, and the described average aggregate particle size of described granular solid is 15～250 μ m.

2. the ceramic particle self-melting alloy depositing materials that contains as claimed in claim 1 is characterized in that, is R1 at the average primary particle diameter of described ceramic powder, and the average primary particle diameter of described self-fluxing alloyed powder is the situation of R2, and R2/R1 is below 20.

3. the ceramic particle self-melting alloy depositing materials that contains as claimed in claim 2 is characterized in that, described R2/R1 is more than 0.1 below 10.

4. as each described ceramic particle self-melting alloy depositing materials that contains of claim 1 to 3, it is characterized in that the average primary particle diameter of described ceramic powder and described self-melting alloy is respectively 1～60 μ m and 1～60 μ m.

5. the ceramic particle self-melting alloy depositing materials that contains as claimed in claim 4 is characterized in that, the average primary particle diameter of described ceramic powder and described self-melting alloy is respectively 5～30 μ m and 5～30 μ m.

6. as each described ceramic particle self-melting alloy depositing materials that contains of claim 1 to 5, it is characterized in that described ceramic powder is at least a carbide powder of selecting from the group of being made of wolfram varbide, chromium carbide, titanium carbide.

7. the ceramic particle self-melting alloy depositing materials that contains as claimed in claim 6 is characterized in that described ceramic powder is a tungsten-carbide powder, and described self-melting alloy is a nickel-base alloy.

8. the ceramic particle self-melting alloy depositing materials that contains as claimed in claim 6 is characterized in that described ceramic powder is a tungsten-carbide powder, and described self-melting alloy is a cobalt base alloy.

9. impeller, a plurality of wings that have wheel hub and install isolator in a circumferential direction around described wheel hub is characterized in that,

At least a portion on the surface of described impeller is carried out spraying plating and is handled with the described ceramic particle self-melting alloy depositing materials that contains of each of claim 1 to 8.

10. fluid machinery has:

Have wheel hub and the impeller of a plurality of wings is installed around described wheel hub in a circumferential direction isolator; And the housing of delimiting the chamber of accommodating described impeller revolvably, it is characterized in that,

At least a portion of at least a portion on the surface of described impeller and/or the inner face of described housing is carried out spraying plating and is handled with the described ceramic particle self-melting alloy depositing materials that contains of each of claim 1 to 8.

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