JPH108230A - High speed flame spraying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high speed flame spraying method capable of performing easily thermal-spraying coating having wear resistance and seizing resistance on the surface of the substrate to be thermal-sprayed at a high speed under the conditions of high speed rotation, high loads and nonlubrication. SOLUTION: This terminal spraying method is the one in which high speed flame is generated using a combustion gas, and terminal spraying raw material powder is thermal-sprayed on the surface of the material to be thermal-sprayed using the above high speed flame to form coating on the surface of the substrate to be thermal-sprayed. In this case, as the thermal spraying raw material powder, a powdery mixture contg. 90 to 75vol.% Cu base bronze alloy powder of 84 to 95wt.% Cu, 4 to 11wt.% Sn, 1 to 7wt.% Zn, and the balance impurities and 10 to 30vol.% Mo, MoO3 or polyester resin powder is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a method in which a high-speed flame (flame) is generated by using a combustion gas, and the material to be sprayed is sprayed on the surface of a substrate to be sprayed by using the high-speed flame. The present invention relates to a high-speed flame spraying method for forming a coating on the surface of a base material, and in particular, lubricating a part or all of the surface of a swash plate for an air compressor pump made of aluminum alloy, cast iron or a steel-based alloy, It is suitably used for forming a film having excellent wear resistance.

[0002]

2. Description of the Related Art Conventionally, for example, a swash plate of an air compressor pump is configured to reciprocate a piston through a shoe which is in contact with a circumference of both sides of the swash plate by rotating, and accordingly, the swash plate is Is configured such that the shoe slides on the circumferential surface.

[0003] Usually, the swash plate is made of aluminum alloy, cast iron or steel-based alloy, and the shoe of the mating part to be slid is made of SUJ2. Occurs. Therefore, conventionally, the surface of the swash plate has been subjected to a treatment such as Sn plating or Teflon coating, and further application of MoS ₂ (lubricant).

[0004]

However, under the operating conditions in which the Sn-plated swash plate is in a non-lubricated state and is subjected to high load at high speed rotation, the amount of wear on the surface of the swash plate increases, and finally, And the shoe will burn. or,
In the case of performing Sn plating, it takes about 30 minutes to form a 10 μm plating film, and at the time of plating, it is necessary to mask a portion of the swash plate that does not need to be plated, and a masking material is applied and peeled off. It takes a lot of time, and there is a problem in workability.

[0005] Similarly, under the operating conditions in which the swash plate coated with Teflon is in a non-lubricated state and a high load is applied at a high speed, the amount of wear on the surface of the swash plate increases. Also, at the time of Teflon coating, as in the case of Sn plating, it is necessary to mask a coating unnecessary portion on the surface of the swash plate. For this reason, much time is required as described above. There is a problem in terms of gender.

At present, as far as the present inventors know, a shoe made of material SUJ2 exhibits abrasion resistance, seizure resistance and pressure resistance under high-speed rotation, high load and no lubrication conditions. For example, there is no suitable coating material for a swash plate made of aluminum alloy, cast iron or steel-based alloy.

[0007] Further, there is no surface modification method that can easily mask portions that do not require film formation by a wet method, can be quickly peeled off after film formation, and have a high film formation (film formation) speed.

Accordingly, an object of the present invention is to easily and thermally spray a coating having wear resistance and seizure resistance on a surface of a substrate to be sprayed at a high speed, under a high load and without lubrication. To provide a high-speed flame spraying method that can be used.

Another object of the present invention is to provide lubricating properties on a part or the whole surface of a swash plate for an air compressor pump made of an aluminum alloy, cast iron or a steel-based alloy.
An object of the present invention is to provide a high-speed flame spraying method capable of forming a coating having excellent wear resistance.

[0010]

The above object is achieved by a high-speed flame spraying method according to the present invention. In summary, the present invention is a thermal spraying method in which a high-speed flame is generated by using a combustion gas, and a thermal spraying raw material powder is sprayed on the surface of the substrate to be sprayed using the high-speed flame to form a coating on the surface of the substrate to be sprayed. In the method, as the thermal spraying raw material powder, Cu = 84 to 95% by weight, Sn = 4 to 11% by weight, Zn = 1 to 7% by weight, and 90 to 70% by volume of a Cu-based bronze alloy powder composed of the balance impurities, , MoO ₃ or polyester resin powder 10
A high-speed flame spraying method using a mixed powder containing 30% by volume. Preferably, the C
The particle diameter of the u-based lead bronze alloy powder and the Mo, MoO ₃ or polyester resin powder is 10 to 60 μm.
According to a preferred embodiment of the present invention, the base material to be sprayed is subjected to grit blasting so that the surface has a roughness of μRz = 10 to 60, and then to 50 to 150
After being heated to ℃, thermal spraying is performed to form a coating having a thickness of 0.02 to 0.5 mm on the surface of the substrate to be sprayed. or,
As the combustion gas, a mixed gas of any one of oxygen / propane, oxygen / propylene, oxygen / natural gas, oxygen / ethylene, oxygen / kerosene or oxygen / hydrogen is used, the flame speed is 1000 to 2500 m / sec, and the flame temperature is 2200
A high-speed flame of ~ 3000 ° C is generated, and the spray distance is 1
Thermal spraying is performed while maintaining the thickness at 70 to 350 mm.

According to a preferred embodiment of the present invention,
The coating formed on the surface of the substrate to be sprayed has a surface roughness Ra
= 0.4-6.0S.

[0012] The thermal spraying method of the present invention comprises an aluminum alloy,
It is suitably used for thermal spraying on a swash plate for an air compressor pump made of cast iron or a steel alloy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The high-speed flame spraying method according to the present invention will be described below in more detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a thermal spraying apparatus (thermal spray gun) 1 for implementing the high-speed flame spraying method of the present invention. In brief, the spray gun 1 has a powder injection port 2 for introducing a spraying material powder at a central portion thereof, and a nozzle insert 3 and a shell around the same center from the inside to the outside. 4 and an air cap 5 are arranged to form a combustion gas passage 8 and compressed air passages 7 and 9.
Further, an air cap body 6 is provided outside the air cap 5.
Is arranged. Since the structure of such a spray gun 1 is well known to those skilled in the art, further detailed description will be omitted.

The thermal spraying raw material powder is conveyed by an inert gas such as nitrogen gas, supplied to the powder input port 2 and ejected from the tip of the port into a combustion flame. On the other hand, the high-pressure combustion gas supplied from the combustion gas passage 8 burns at the outer periphery of the tip of the nozzle insert 3 and the shell 4. This combustion flame is wrapped in compressed air and is jetted from the air cap 5 at high temperature and high pressure to form a cylindrical ultra-high-speed flame (frame). The thermal spray raw material powder ejected from the tip of the port 2 by the ultrahigh-speed frame is heated at the center of the frame, melted, accelerated, and ejected at a high speed from the thermal spray gun 1. The sprayed raw material droplets are separated by a predetermined distance, that is, 170 to 3
It collides with a desired base material 100 arranged at 50 m, and a thermal spray coating 102 is formed on the surface.

Next, the thermal spraying raw material powder used in the present invention will be described.

In the present invention, the thermal spraying raw material powder includes Cu-based bronze alloy powder having high hardness and tensile strength, and Mo, MoO ₃ or polyester resin powder having seizure resistance and self-lubricating property. A mixed powder containing is used.

More specifically, a Cu-based bronze alloy is made of Cu
= 84-95% by weight, Sn = 4-11% by weight, Zn = 1
~ 7% by weight and the balance of impurities. As impurities,
Usually, Fe, Pb, P, Si, etc. are mentioned.

In a Cu-based bronze alloy, if Cu is less than 84% by weight, brittleness will occur, while if it exceeds 95% by weight, the bond strength of the coating will decrease. Therefore, Sn and Zn are added to the Cu matrix. Therefore, the amount of Cu is 8
The content is 4 to 95% by weight, preferably 86 to 95% by weight. The added Sn dissolves in Cu to improve the hardness and the tensile strength. If Sn is less than 4% by weight, toughness is low,
On the other hand, if it exceeds 11% by weight, a brittle δ phase is likely to be formed.
Therefore, the amount of Sn is 4 to 11% by weight, preferably 5 to 11%.
Preferably it is 10% by weight. In addition, Zn has an effect of suppressing generation of Sn oxide when melted. If Zn is less than 1% by weight, the effect of suppressing the formation of Sn oxide is low,
On the other hand, if it exceeds 7% by weight, there arises a problem that melting and casting becomes difficult. Therefore, the amount of Zn is 1 to 7% by weight,
Preferably, the content is 1 to 5% by weight.

The above Mo, MoO ₃ or polyester resin is a self-lubricating material, and the seizure resistance increases as the amount added increases. However, if the added amount of these materials is too large, the bond strength of the coating is impaired. Therefore, under high load sliding conditions, the amount of Mo, MoO ₃ or polyester resin powder is contained in the mixed powder in a volume ratio of 10 to 30%, preferably 10 to 20%.

The above-mentioned C which is used as a powder in the present invention.
u based bronze alloy, and Mo, the particle size of MoO ₃ or polyester resin, it is desirable to 10 to 60 [mu] m. In other words, when the particle size exceeds 60 μm, the particle temperature during thermal spraying decreases, and unmelted particles increase, which makes it difficult to form a dense coating. On the other hand, if the particle size is less than 10 μm,
In this case, the supply of the thermal spraying raw material is reduced, and continuous thermal spraying becomes difficult. Therefore, as described above, the particle size is 10 to 60 μm.
m, and preferably 15 to 45 μm.

The combustion gas used in the thermal spraying method of the present invention is preferably a mixed gas of oxygen / propane, oxygen / propylene, oxygen / natural gas, oxygen / ethylene, oxygen / kerosene or oxygen / hydrogen. Used for 1000 to 25
A frame speed of 00 m / s is obtained. As the flame speed increases, the speed of the sprayed particles also increases, and the particles dig into the substrate when colliding with the substrate to be sprayed, in other words, the anchoring effect is increased, so that the adhesion is improved. Further, when the speed of the particles is high, the thermal energy converted from the kinetic energy at the time of collision increases, and the outermost surface of the substrate is melted, so that the adhesion is improved. The frame speed required to ensure this adhesion is 1000 m / sec or more. On the other hand, the maximum speed of the frame is limited to 2500 m / sec due to the structure of the current thermal spray gun 1 having the above configuration. Further, in the combustion of the mixed gas as described above, the flame temperature is 2200 to 30.
00 ° C.

For example, gas conditions during thermal spraying when a mixed gas of oxygen / propane is used as a combustion gas include:
Oxygen gas pressure 9-13Bar, flow rate 150-400L
Propane gas pressure 5-8B to PM (liter / min)
ar, flow rate of 50 to 120 LPM, compressed air of pressure 5 to
7 Bar, flow rate 250-700 LPM. Further, the flow ratio of propane gas to oxygen gas is set so that the combustion efficiency becomes optimal propane: oxygen = 1: 3.8 to 4.8 (when converted to a standard state). If the ratio of oxygen to propane is less than 3.8, the amount of unreacted propane increases and the cost increases. On the other hand, if the ratio of oxygen to propane exceeds 4.8, the amount of unreacted oxygen increases, and an oxide is formed on the sprayed coating, resulting in deterioration of the coating.

When using a mixed gas of oxygen / propylene as the combustion gas, the gas conditions during thermal spraying are as follows: oxygen gas at a pressure of 9 to 13 Bar and a flow rate of 150 to 400 LPM.
At a pressure of 5 to 8 Bar and a flow rate of 40 to 1
30 LPM, compressed air pressure 5-7 Bar, flow rate 25
0-700 LPM. The flow rate ratio of propylene gas to oxygen gas is determined by the optimum combustion efficiency of propylene: oxygen =
1: 3.5 to 4.5 (when converted to the standard state). The ratio of oxygen to propylene is 3.
If it is less than 5, the amount of unreacted propylene increases and the cost increases. On the other hand, if the ratio of oxygen to propylene exceeds 4.8, the amount of unreacted oxygen increases, and an oxide is formed on the sprayed coating, resulting in deterioration of the coating.

When using a mixed gas of oxygen / hydrogen as the combustion gas, the gas conditions during thermal spraying are as follows: oxygen gas at a pressure of 9 to 13 Bar, flow rate of 150 to 400 LPM, hydrogen gas at a pressure of 8 to 12 Bar, flow rate of 500 to 900 LPM.
And compressed air at a pressure of 5 to 7 Bar and a flow rate of 250 to 700.
Change to LPM. The flow rate ratio between oxygen gas and hydrogen gas is set so that the combustion efficiency is optimal: oxygen: hydrogen = 1: 2.0 to 2.6 (when converted to a standard state). If the ratio of hydrogen to oxygen is less than 2.0, the amount of unreacted oxygen increases, and oxides are generated in the thermal sprayed coating to cause deterioration of the coating,
If the ratio of hydrogen to oxygen exceeds 2.6, the amount of unreacted hydrogen increases and the cost increases.

In the present invention, the spraying distance during spraying (the distance between the spray gun 1 and the substrate to be sprayed 100) is 170 to 350 mm.
To The reason is that the powder accelerates below 170 mm,
If the powder is not heated and exceeds 350 mm, the temperature and speed of the powder once accelerated and heated are reduced, and the adhesion strength between the substrate and the powder particles and between the particles is decreased, which is not preferable.

The surface of the base material 100 to be sprayed must be part of the surface of the base material to be sprayed before forming the coating in order to enlarge the adhesion surface and maintain the adhesion strength with the spray coating 102 high. Alternatively, it is necessary to remove all scales, perform cleaning beforehand, and perform a roughening treatment. The surface roughening treatment is preferably performed by grit blasting, in which grit such as SiC or alumina is sprayed onto the surface of the substrate to be sprayed at a pressure of about 0.5 MPa. The surface of the substrate after the surface roughening treatment preferably has irregularities with a surface roughness μRz = 10 to 60. These irregularities increase the contact area between the thermal spray coating and the substrate, and enhance the anchoring effect, that is, the mechanical coupling. Here, when the surface roughness is less than 10 μRz, the anchoring effect is insufficient, so that the adhesion strength is reduced. On the other hand, when the surface roughness is more than 60 μRz, the surface roughness of the coating becomes rough, and the finishing man-hour after the coating is reduced. More and less effective.

After such a blast treatment, it is preferable that the substrate to be sprayed is heated to 50 to 150 ° C. and then sprayed. Raising the temperature to 50 ° C. or higher is necessary to suppress the occurrence of dew condensation and increase the adhesion. Also, if the base material is 1
The temperature of 50 ° C. or lower is necessary in order to prevent thermal deformation of the base material and deterioration of the strength of the base material. The thickness of the coating is preferably 0.02 mm or more in order to obtain a wear resistance effect, and 0.5 mm or less in order to prevent peeling during thermal spraying or thermal stress during sliding. The surface roughness of the coating after thermal spraying is R
It is preferable to finish-process to a = 0.4 to 6.0S.
If Ra exceeds 6.0 S, the seizure resistance is impaired, and 0.4 S
If it is less, the cost is high.

Next, the present invention will be described in more detail with reference to examples.

Example 1 As the thermal spraying raw material powder, C having the composition shown in Table 1 below was used.
70% by volume of u-based bronze alloy, Mo (purity: 99.7% (trace amounts of W and Cr as impurities), particle size: 10 to 60 μm)
A mixed powder containing 30% by volume of m) was prepared and used.

As a substrate to be sprayed, a swash plate for an air compressor pump having an outer diameter of 105 mm, an inner diameter of 60 mm and a thickness of 6.5 mm was used. The material of the swash plate was FCD440.

First, as a pretreatment, grit blasting was performed by spraying alumina grit (particle size # 30) on the surface of the swash plate at a pressure of 0.5 MPa. By this pretreatment, the surface roughness of the swash plate was μRz = 40 to 55.

Next, a pre-heat treatment was performed using the thermal spray gun 1 shown in FIG. At this time, the spraying gun 1 was operated under the following spraying conditions, but without supplying the spraying raw material powder, maintaining the spraying distance at 300 mm, injecting only the frame, and heating the swash plate to 150 ° C. Then, moisture, water and water vapor on the surface of the swash plate were removed.

Next, a coating was formed on the swash plate using the thermal spray gun 1 under the following thermal spraying conditions.

(Spraying conditions) Combustion gas Oxygen: pressure = 12 Bar, flow rate = 310 SLM Propylene gas: pressure = 7 Bar, flow rate = 75 SLM Air: pressure = 7 Bar, flow rate = 400 SLM Here, “SLM” is a standard state. It means the converted gas flow rate (liter / minute (LPM)). Flame temperature 2700 ° C Flame speed 1500 m / sec Spray distance 225 mm Spray material powder supply 70 g / min

[0036]

[Table 1]

The thickness of the sprayed coating on the surface of the swash plate obtained in this manner is 0.20 mm, and the coating surface is then subjected to buffing after cutting to form a coating having a thickness of 0.12 mm.
And finished to a surface roughness Ra of 0.8 to 1.0 S.

Using a swash plate having a sprayed coating produced as described above, a shoe made of SUJ2 was pressed against the surface of the swash plate at a surface pressure of 330 MPa, and the swash plate was rotated at a peripheral speed of 20 m / m.
An actual friction and wear test was carried out by rotating in seconds. Further, as a comparative example, a swash plate (plating thickness: 0.01 mm) in which Sn was plated on a conventional surface was used, and a friction wear test on an actual machine was performed under the same conditions. As a result, the maximum wear depth of the conventional Sn-plated product was increased to 0.05 mm or more, and the underlying FCD440 was exposed and seized, whereas the amount of wear on the surface of the swash plate manufactured by the present invention was increased. Is 3 μm,
It was found that they had excellent wear resistance and seizure resistance.

Examples 2 to 4 As thermal spraying raw material powders, C having the composition shown in Table 2 below was used.
u-based bronze alloy (A) and Mo, MoO ₃ shown in Table 2 below
Alternatively, a mixed powder containing the polyester resin (B) at a mixing ratio shown in the table was prepared and used.

The substrate to be sprayed has dimensions of 115 mm in outer diameter × 65 mm in inner diameter × 6.5 mm in thickness.
A ring-shaped test piece for friction and wear prepared in Step No. 0 was used.

First, as a pretreatment, alumina grit (particle size # 30) was applied to the surface of the test piece at a pressure of 0.5MPa.
a, and grit blasting was performed. By this pretreatment, the surface roughness of the test piece was μRz = 40 to 55.

Next, a pre-heat treatment was performed using the thermal spray gun 1 shown in FIG. At this time, the spraying gun 1 was operated under the following spraying conditions, but without supplying the spraying raw material powder, maintaining the spraying distance at 300 mm, injecting only the frame, and heating the test piece to 150 ° C. do it,
Moisture, water and water vapor on the surface of the test piece were removed.

Next, a coating was formed on the test piece using the thermal spray gun 1 under the following thermal spraying conditions.

(Spraying conditions) Combustion gas Oxygen: pressure = 12 Bar, flow rate = 200 SLM Hydrogen: pressure = 10 Bar, flow rate = 880 SLM Air: pressure = 7 Bar, flow rate = 420 SLM Here, “SLM” is converted to a standard state. Gas flow rate (liter / minute (LPM)). Flame temperature 2700 ° C Flame speed 2100 m / sec Spray distance 225 mm Spray material powder supply 80 g / min

[0045]

[Table 2]

The thickness of the thermal spray coating on the surface of each test piece thus obtained was 0.2 mm. The coating surface of each of these test pieces was then subjected to buffing after cutting to a coating thickness of 0.10 mm, and the surface roughness was Ra = 0.4 to
Finished to 0.8S.

Using a ring-shaped friction-wear test piece having a sprayed coating prepared as described above, a block made of SUJ2 was pressed against the surface of the test piece at a surface pressure of 10 MPa, and the test piece was rotated at a peripheral speed of 1 m / cm. By rotating in seconds,
The wear amount of the coating was measured. Also, as a comparative example (conventional product), a ring made of the same shape and dimensions (FCD440) with Sn plating (plating thickness 0.01 mm) or Teflon coating (coating thickness 0.3 mm) on the surface was used. . The result is shown in FIG. Further, the load applied to the block was gradually increased, and the seizure load was measured. The result is shown in FIG.

From the results shown in FIGS. 2 and 3, those having the sprayed coatings shown in Examples 2, 3 and 4 manufactured according to the present invention are superior in the abrasion resistance and seizure resistance to the conventional products. I knew it was.

[0049]

As described above, according to the high-speed flame spraying method of the present invention, Cu = 84-9
5% by weight, Sn = 4 to 11% by weight, Zn = 1 to 7% by weight
-Based bronze alloy powder 90-70 consisting of
Volume%, Mo, MoO ₃ or polyester resin powder 1
Since a mixed powder containing 0 to 30% by volume is used, (1) a coating film having wear resistance and seizure resistance under high-speed rotation, high load, and no lubrication conditions can be formed at a high speed and It can be easily sprayed on the surface of the substrate to be sprayed. (2) In particular, a coating excellent in lubricity and abrasion resistance can be formed on a part or the whole surface of a swash plate for an air compressor pump made of an aluminum alloy, cast iron or a steel alloy. Many effects can be achieved.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of a thermal spray gun for performing a high-speed flame spraying method of the present invention.

FIG. 2 is a view showing abrasion resistance of a thermal sprayed coating obtained by a high-speed flame spraying method of the present invention and a conventional product.

FIG. 3 is a view showing a seizure load between a sprayed coating obtained by the high-speed flame spraying method of the present invention and a conventional product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal spray gun 2 Powder input port 3 Nozzle insert 4 Shell 5 Air cap 6 Air cap body 7 Compressed air passage 8 Combustion gas passage 100 Substrate to be sprayed 102 Thermal spray coating

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Hashimoto 11-19 Nibancho, Chiyoda-ku, Tokyo Sulzer Inside Metco Japan Co., Ltd. (72) Inventor Toshio Hotta 11-19 Nibancho, Chiyoda-ku, Tokyo Sulzer Meteco Japan Co., Ltd.

Claims (6)

[Claims] 1. A thermal spraying method for generating a high-speed flame using a combustion gas, spraying a thermal spray raw material powder on the surface of the substrate to be sprayed using the high-speed flame, and forming a coating on the surface of the substrate to be sprayed, As the thermal spraying raw material powder, Cu = 84
Cu-based bronze alloy powder 90 to 95% by weight, Sn = 4 to 11% by weight, Zn = 1 to 7% by weight and the balance of impurities
70 and volume%, Mo, high-velocity flame spraying method characterized by using a mixed powder containing 10 to 30 vol% MoO _3, or polyester resin powder. 2. The Cu-based lead bronze alloy powder and the M
o, MoO ₃ or polyester resin powder has a particle size of 10
2. The high-speed flame spraying method according to claim 1, wherein the thickness is from 60 to 60 [mu] m. 3. The substrate to be sprayed has a surface having a roughness of μ.
Perform grit blasting so that Rz = 10 to 60, then heat to 50 to 150 ° C., perform thermal spraying, and apply a thickness of 0.02 to 0.5 m on the surface of the substrate to be sprayed.
The high-speed flame spraying method according to claim 1 or 2, wherein a coating of m is formed. 4. The combustion gas includes oxygen / propane,
Oxygen / propylene, oxygen / natural gas, oxygen / ethylene,
Using a mixed gas of either oxygen / kerosene or oxygen / hydrogen, a high-speed flame with a flame speed of 1000 to 2500 m / sec and a flame temperature of 2200 to 3000 ° C. is generated. 4. The high-speed flame spraying method according to claim 1, 2 or 3, wherein: 5. The high-speed flame spraying method according to claim 1, wherein the coating formed on the surface of the substrate to be sprayed is finished to have a surface roughness Ra = 0.4 to 6.0S. 6. The sprayed substrate is an aluminum alloy,
The high-speed flame spraying method according to any one of claims 1 to 5, which is a swash plate for an air compressor pump made of cast iron or a steel alloy.