JPH059661A - Material for vane and vane - Google Patents

Abstract

PURPOSE:To provide a material for a vane improving the wear and corrosion resistances of the vane used in a compressor using a substitute for chlorofluorocarbon as a refrigerant. CONSTITUTION:A vane 1 is made of a material obtd. by dispersing nitride particles and/or carbonitride particles in a matrix consisting of 1.0-3.5% C, <=1.5% Si, <=1.0% Mn, 3-6% Cr, <=20% W and/or <=10% Mo (W+2Mo<=23%), <=12% V and/or Nb, <=20% Co and the balance Fe with inevitable impurities by 2-20%, in total. The nitride particles and carbonitride particles have lower affinity for iron than the matrix.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane used in a compressor such as a rotary compressor and a vane pump.

[0002]

2. Description of the Related Art As shown in FIG. 1, an example of a compressor using a vane, a vane 1 is always provided with a rotor 2 by means of a spring 4.
Is pressed against the eccentric rotation of the rotor 2,
The gas is compressed by the volume change of the space formed by the rotor 2 and the cylinder 3. Conventionally, Freon gas has been used as the refrigerant gas. Since the tip of the vane always slides in contact with the rotor and the side surface of the vane slides in contact with the cylinder, the characteristic required for the vane is that the vane itself does not wear, and at the same time the mating rotor and cylinder do not wear. is there. Conventionally, molten high speed steel corresponding to SKH51 type has been generally used for this vane, and a part of this has been subjected to surface treatment such as oxynitriding. Further, for the purpose of improving the material and composition of the vane, improving wear resistance and improving self-lubricating property, JP-A-56-47550.
JP-A-59-20446, JP-A-61-4855
6, JP-A 64-35091, JP-A-2-1023.
The one described in No. 92 has been proposed.

[0003]

The refrigerant used in the above compressor is a chlorofluorocarbon (hereinafter referred to as CFC).
The CFC diffuses into the stratosphere, then decomposes by being exposed to ultraviolet rays and releases chlorine, thereby destroying the ozone layer. For this reason, CFC is planned to be completely abolished by the year 2000, and development of a refrigerant agent to replace it is in progress. As an alternative refrigerant, hydrofluorocarbon (hereinafter referred to as HFC) -based CFC containing no chlorine is the most promising, and this type of CFC has little environmental damage. However, vane pumps and rotary compressors that use HFC-based CFCs are
There are the following problems as compared with those using the Freon of the system. The lubricity of the refrigerant is poor. It is necessary to increase the compression ratio, which increases the load on the vane. The hygroscopicity of the refrigerant is high. The lubricity of lubricating oil is inferior. The hygroscopicity of the lubricating oil increases.

Due to the above-mentioned causes, sliding wear with the rotor is extremely accelerated in the conventional vane, and in the worst case, it may cause galling with the rotor, so that the practical life of the compressor cannot be obtained. It became clear. An object of the present invention is to provide a novel vane material and a vane used mainly in a compressor using HFC-based CFC as a refrigerant.

[0005]

The present invention provides a new HFC
In the case of using the Freon of the system, it was made paying attention to reducing the sliding wear with the rotor in view of the above-mentioned problems, and the characteristic of the material is that the fine carbide is evenly distributed. Two or more kinds of nitride particles and carbonitride particles are further added to the dispersed base having a specific composition.
~ 20% dispersion. That is, the first invention of the present invention is that C 1.0 to 3.5% by weight, Si 1.5% or less, Mn
1.0% or less, Cr 3 to 6%, W 20% or less, Mo 10% or less 1 type or 2 types, W + 2Mo, 23% or less, V or Nb 1 type or 2 types, 12% or less, Co 20% One or two or more kinds of nitride particles and carbonitride particles are dispersed in a base composed of the balance Fe and unavoidable impurities in a total amount of 2 to 20% with respect to the vane weight. The second invention is a material for vanes, wherein the nitride and carbonitride are Ti, Zr, V, Nb, Hf.
The vane material according to the first invention, which is a compound particle of Further, the third invention is that one or more kinds of nitride particles and carbonitride particles are dispersed in the base material having the composition described in the first invention in a total amount of 2 to 20% with respect to the vane weight. It is a characteristic vane. The base in the present invention refers to all of the particles other than the nitride particles and carbonitride particles added separately,
This matrix is achieved by producing a powder of the steel composition that constitutes the matrix. The vane of the present invention is formed by dispersing 1 to 2 or more of 2 to 20% of nitride particles and carbonitride particles in the powder having this matrix composition in a proportion of the total weight of the vane, and sintering. It is manufactured by carrying out. Further, the vane material and the vane of the above-mentioned invention relate to the base material of the vane and can be used as they are. In addition to processing, Ti by CVD or PVD
It can also be used after being subjected to a surface treatment such as a hard film treatment of C, TiN or the like. Such surface treatment lowers the friction coefficient between the vane and the rotor, reduces the galling with the mating material, and protects the base material from the corrosive environment.

[0006]

The function of each element and the reason for limiting the numerical values in the present invention will be described below. C is added at the same time W, M
Combined with o, V, etc., it forms a hard carbide, which has the effect of increasing wear resistance and reducing galling with the mating material. Also,
Some of them also form a solid solution in the matrix to increase the hardness of the matrix and also have the effect of improving wear resistance. Therefore, there is an optimum C content in consideration of the addition amounts of carbide forming elements such as W, Mo, and V. In the range of the present invention, if C is less than 1.0%, the hardness of the matrix cannot be sufficiently obtained and the amount of carbide formed is small. vice versa
If it exceeds 3.5%, the toughness deteriorates, so C was made 1.0 to 3.5%.

Si has the effect of improving the steel quality as a deoxidizing element. It also has the effect of increasing the hardness of the base by forming a solid solution in the base. However, if it exceeds 1.5%, the toughness decreases, so S
i was set to 1.5% or less. Since Mn also has an effect of improving hardness as a deoxidizing element, Mn is set to 1.0% or less.

Cr has the effect of forming carbides and enhancing wear resistance. Furthermore, it is solid-dissolved in the substrate to give hardenability,
It also improves the corrosion resistance of the base. Particularly in the present invention, the vane operates in a light corrosive environment because the alternative CFC HFC has a high hygroscopic property and the lubricating oil decomposes to form a carboxylic acid such as formic acid and acetic acid. Therefore, it is estimated that the abnormal wear on the vanes is caused not only by simple abrasive wear but also by a mechanism involving corrosion. in this case,
In addition to Cr, Mo and Co, which will be described later, are dissolved in the matrix to enhance the corrosion resistance of the vane and reduce wear. Cr is 3%
If less than 6%, the above effect is small, and if it exceeds 6%, hardness is hardly obtained by heat treatment.
It was set to ~ 6%.

W and Mo combine with C to form an M ₆ C type carbide, which enhances wear resistance and galling resistance. Further, some of W and Mo are solid-solved in the matrix and then tempered to precipitate and harden, which also has the effect of increasing the hardness of the matrix. Further Mo
Also has the effect of suppressing corrosion due to carboxylic acid. But,
Since the toughness decreases with an increase in W and Mo, one or two kinds of W 20% or less and Mo 10% or less were set to 23% or less in the amount of W + 2Mo.

V and Nb combine with C to form MC type carbides. When this carbide is finely and uniformly dispersed on the surface of the vane, the wear resistance and the galling resistance can be significantly improved. However, if it exceeds 12%, it is difficult to dissolve and the toughness decreases, so V and Nb
1 type or 2 types was set to 12% or less.

Co has the effect of forming a solid solution in the matrix to increase the hardness of the matrix, and also has a high effect of suppressing the corrosion due to the carboxylic acid, which is important in the present invention. That is, as described above, when the CFC substitute is used as the refrigerant, a corrosive wear action is also caused to cause abnormal wear of the vane, but the wear can be reduced by making Co a solid solution in the base. However, if Co exceeds 20%, the toughness decreases, so the Co was made 20% or less.

Dispersion of nitride and carbonitride particles is one of the most important constituents in the present invention. The vane functions as a compressor by sliding on the rotor and the cylinder. Therefore, even if the wear resistance of only the vane is strong, if the other cylinder or rotor wears abnormally,
The confidentiality cannot be maintained, and the performance as a compressor deteriorates. Since the rotor and the cylinder are generally made of cast iron, when the nitride particles or carbonitride particles having a small affinity for iron are dispersed in the matrix of the steel composition, the friction coefficient becomes extremely small, and Scoring with the mating material will not occur. Due to this action, the vanes themselves are less likely to wear, and at the same time, the wear of the mating rotor and cylinder is extremely reduced. If the amount is less than 2% of the vane weight, this effect is not sufficient. On the contrary, if it exceeds 20%, stable quality vanes cannot be mass-produced, so one or more of nitrides and carbonitrides must be added together. 2 to 20%.

As the nitride and carbonitride, Ti, Z
Compounds of r, V, Nb, and Hf are suitable because they are easily available and inexpensive, but other compounds are effective as long as they have a low affinity with iron. Further, the vane material of the present invention is produced by powder metallurgy because the nitride and carbonitride particles can be uniformly dispersed, and because the carbide grains dispersed in the base steel are also finely and uniformly dispersed. Is desirable.

[0014]

EXAMPLES Examples will be shown below. (Example 1) Water atomized powder composed of three kinds of steel compositions shown in Table 1 was prepared, and various kinds of nitrides, carbonitrides, or two kinds thereof were prepared.
After mixing at least the seeds in the proportions shown in Table 2, press molding and sintering were performed to prepare a vane material. It should be noted that for the purpose of comparison, a conventional molten high-speed steel SKH that has been used conventionally
51 was also produced. Table 3 shows the quenching-tempering hardness (HRC) of the vane material shown in Table 2, the wear loss and friction coefficient by the wear test, and the corrosion loss by the corrosion test.
The abrasion test was carried out as follows. The vane material was used as a plate, FC25 corresponding to the rotor material was processed into a ring, and HFC134a, which is a representative of HFC Freon, was dropped and slid on each other to determine the wear reduction. In Table 2, the conventional materials SKH51 and FC25 were used as plates, and the wear amount of each plate and ring when tested as a ring was set to 1.0, and the wear amounts of various vane materials and rings were obtained as relative comparison values and evaluated. Furthermore, the measured value of the friction coefficient at that time is also shown.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

The corrosion test is conducted in a 5% formic acid-5% acetic acid aqueous solution which is said to be produced by the decomposition of a lubricating oil for HFC type CFCs.
It was immersed at 60 ° C for 30 hours, and the corrosion weight loss was calculated. According to Table 2, the vane material of the present invention has less wear of the vane itself as compared with the conventional SKH51, and at the same time, the wear of the mating material is reduced and the friction coefficient is also reduced. At this time, the relative amount of wear decreases to less than 1/10. Further, since the corrosion resistance is also improved, this effect synergizes and appears as a great effect in practical use.

Example 2 A vane was actually produced by using the symbols B and C shown in Table 2 and the material of SKH51 which is a conventional molten high speed steel, and was used as an actual rotary compressor using HFC134a as a refrigerant. A built-in life evaluation test was performed. In the evaluation during the actual machine test, the wear or damage of the vane was estimated by the pressure change of the pressure gauge installed in the rotary compressor. As a result of the actual machine test, the pressure of the test machine using the conventional material SKH51 as the vane changed abruptly 131 hours after the start of operation, so the operation was stopped and the condition of the vane was observed. As a result, the SKH51 vanes were partially scratched on the surface sliding with the rotor, while scratches were also observed on the opposing rotor circumferential surface. On the other hand, in the rotary compressor using the vanes made of the symbols B and C of the present invention, the pressure change was not observed even after 720 hours of operation, and the test was stopped.

Example 3 Powders consisting of four kinds of steel compositions shown in Table 4 were prepared, and TiN dispersed particles were mixed in the vane weight ratio shown in Table 4 together, followed by press molding and firing. The material for vanes was produced by binding. Quenching the above four types of vane materials-
After the tempering treatment, the hardness is the same as in Example 1.
(HRC) measurement, wear loss and wear coefficient by wear test, and corrosion weight loss by corrosion test were obtained, and the results are shown in Table 5. The amount of wear reduction is obtained by setting the amount of wear of SKH51, which is the conventional material with the symbol E in Example 1, to 1.0, and the amounts of wear of various vane materials and rings as relative comparison values.

[0021]

[Table 4]

[0022]

[Table 5]

According to Table 5, the symbols 1 to 4 as the vane material of the present invention show less wear of the vane itself as compared with the conventional SKH51, and at the same time, the wear of the mating material due to the low friction coefficient. It can be seen that it also reduces Further, it is considered that the effect of improving the corrosion resistance also contributes to the improvement of the wear amount of both.

[0024]

EFFECTS OF THE INVENTION According to the present invention, in a compressor using an alternative CFC represented by HFC type CFC as a refrigerant, the wear resistance of the vane, which has been insufficient in the conventional SKH51 class of vane material, is significantly improved. improves. Further, the vane of the present invention has a high corrosion resistance against carboxylic acids such as formic acid and acetic acid formed by the decomposition of the lubricating oil of the HFC-based CFC compressor. Therefore, the vane of the present invention can be applied to a new refrigerant due to its large wear resistance and corrosion resistance, so that a compressor that meets environmental regulations can be put to practical use.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a rotary compressor.

[Explanation of symbols]

1 vane 2 rotor 3 cylinders 4 spring

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 28, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

EXAMPLES Examples will be shown below. (Example 1) Water atomized powder composed of three kinds of steel compositions shown in Table 1 was prepared, and various kinds of nitrides, carbonitrides, or two kinds thereof were prepared.
After mixing at least the seeds in the proportions shown in Table 2, press molding and sintering were performed to prepare a vane material. It should be noted that for the purpose of comparison, a conventional molten high-speed steel SKH that has been used conventionally
51 was also produced. Table 3 shows the quenching-tempering hardness (HRC) of the vane material shown in Table 2, the wear loss and friction coefficient by the wear test, and the corrosion loss by the corrosion test.
The abrasion test was carried out as follows. The vane material was used as a plate, FC25 corresponding to the rotor material was processed into a ring, and ester lubricant oil compatible with HFC134a, which is a representative of HFC flon, was dropped and slid on each other to determine the wear reduction amount. In Table 2, the conventional material SKH51 is a plate,
When the wear amount of each of the plate and the ring when FC25 was tested as a ring was set to 1.0, the wear amount of each vane material and the ring was obtained as a relative comparison value and evaluated. Furthermore, the measured value of the friction coefficient at that time is also shown.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

In the corrosion test, the weight loss of corrosion was determined by immersing the product in a 5% formic acid-5% acetic acid aqueous solution, which is said to be produced by decomposition of an ester type lubricating oil for HFC type CFCs, at 60 ° C. for 30 hours. According to Table 2, the vane material of the present invention has the conventional SKH
Compared with 51, the wear of the vane itself is less, the wear of the mating material is reduced at the same time, and the friction coefficient is also smaller. Therefore, when installed in an actual compressor, the relative wear amount is 1 /
Reduced to 10 or less. Further, since the corrosion resistance is also improved, this effect synergizes and appears as a great effect in practical use.

Claims (3)

[Claims] 1. C 1.0 to 3.5% by weight, Si 1.5% or less,
Mn 1.0% or less, Cr 3 to 6%, W 20% or less, Mo 10% or less 1 or 2 are W + 2Mo, 23% or less, V, Nb 1 or 2 12% or less, Co 20 % Or less, and one or two or more kinds of nitride particles and carbonitride particles are dispersed in a base consisting of the balance Fe and unavoidable impurities in a total amount of 2 to 20% with respect to the vane weight. Material for vane. 2. The nitride and carbonitride are Ti, Zr, V, Nb and Hf.
The vane material according to claim 1, wherein the vane material is the compound particles. 3. A base comprising the composition of claim 1,
A vane comprising one or more of nitride particles and carbonitride particles dispersed in a total amount of 2 to 20% based on the weight of the vane.