JPS62149846A - Metal for compressor - Google Patents

Abstract

PURPOSE:To produce a blade material for a rotary compressor having excellent wear resistance by pressurizing and molding Cr, Mo, V or further hard carbide forming element such as W as well as Fe and C powders and subjecting the molding to diffusion of C, deaeration, sintering, cooling and tempering treatment. CONSTITUTION:The C powder is added at 2.0-6.0% to the powder raw material of the compsn. contg., by weight %, 0.5-15% C, 0.5-7.0% Mo, 1.0-3.0% V or further 1-5% W and consisting of the balance Fe and further about 1% lubricating agent is added to the material. The powders are thoroughly mixed and are molded under pressurization to a desired shape. The molding is heated and held for 1hr to and at 1,100 deg.C in a vacuum to diffuse the C into the metallic powder raw material. The molding is then subjected to a deaeration treatment for 150min at 1,130 deg.C and thereafter the molding is sintered at 1,160-1,180 deg.C and is cooled down to a room temp. at a cooling rate of 60 deg.C/min. The cooled molding is subjected to the tempering treatment for 2hr at 750 deg.C in succession thereof.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a metal for a compressor, and more particularly, when used as a blade material that is a part of a compression mechanism, wear of the blade and parts that slide with the blade is reduced. The present invention relates to a metal useful for use in rotary compressors that can reduce the amount of heat generated, particularly for plates in high-speed rotating inverter compressors.

[Technical background of the invention and its problems] A rotary compressor used in a room air conditioner, etc. generally has a cylinder having a cylinder hole in the center, a bearing and a bottom plate that close the top and bottom surfaces of the cylinder, and is supported by the bearing. A rotating shaft passing through the cylinder hole, an eccentric rotating part formed in the part of the rotating shaft inside the cylinder hole, and a roller fitted on the outer circumferential surface of the eccentric rotating part, and a rotating shaft that is in contact with the roller. The compressor mechanism includes a compression mechanism section composed of a blade, and the components of the compression mechanism section are usually mainly formed of a metal material *4 such as an iron-based material.

By the way, in the compression mechanism section described above, each component is sliding in phase W, but due to repeated compression cycles, the blade surface and the sliding surface of each component that slides on the blade, especially,
The inner wall surface of the cylinder hole, the surrounding wall surface of the blade groove, the inner circumferential surface of the bearing, the outer circumferential surface of the rotating shaft, the inner circumferential surface of the roller, and the outer circumferential surface of the roller gradually wear out, and if the wear is significant, the sliding between each part A problem arises in that gaps are generated in the parts, impairing airtightness and causing a reduction in compression efficiency.

In particular, in recent years, the number of rotations of rotary compressors has tended to further increase, so that blades for rotary compressors are required to have higher wear resistance.

In order to solve this problem, all the components of the compression mechanism, namely cylinders, bearings, rotating shafts, rollers, and blades, are made of ceramic materials with good wear resistance, instead of conventional iron-based metal materials. The machine is Japanese Patent Application Publication No. 58-183.
It is disclosed in Japanese Patent No. 881. However, if all the components of the compression mechanism are made of ceramic materials, the wear resistance of the sliding surfaces will improve, but the manufacturing cost will increase, and furthermore, it will be difficult to attach the ceramic cylinder to the metal compressor case. This may cause problems such as a complicated mounting structure.

Efforts are also being made to improve the abrasion resistance of various types of high-hardness special steels by subjecting them to nitriding and ceramic coating treatments. However, these treatments require heat treatment again after finishing and further post-processing, resulting in problems such as complicated manufacturing and poor mass productivity.

[Object of the Invention] The present invention solves the above-mentioned problems, and reduces wear on the blade surface and the sliding surfaces of parts that slide on the blade.
Moreover, the object of the present invention is to provide a metal for a compressor that is inexpensive to manufacture, and is particularly useful as a blade material for a rotary compressor for an inverter that rotates at a high speed of 150 Hz or more.

[Summary of the Invention] In order to achieve the above object, the present inventors conducted sharpening research and found that when the carbon content in the alloy of a specific composition constituting the blade is increased, the wear on the blade surface is reduced. They have discovered that it is possible not only to reduce the amount of wear, but also to reduce the wear on the surfaces of each component that slides on the blade, leading to the completion of the present invention.

That is, the present invention comprises a first invention relating to a compressor metal based on iron and consisting of chromium, molybdenum, /ζ-nadium, and carbon, and a second invention in which the metal of the first invention further contains tungsten. Ru.

Hereinafter, the first and second inventions will be explained in detail.

However, in the following, all "%" represents "% by weight".

The plate metal of the first invention has 0.5 to 15% chromium.
, preferably 10 to 15%, more preferably 1 to 1% by weight
3%, molybdenum 0.5-7.0%, preferably 0.8
~1.2%, vanadium 1.0-3.0%, preferably 1.8-2.2%, carbon 2.0-8.0%, preferably 2.7-4.4% and the balance Consisting essentially of iron.

Among the elements that make up the metal, chromium is an element that contributes to improving hardenability, and if too much is present, it tends to become brittle.
On the other hand, if it is too small, hardenability tends to deteriorate, so 0.5 to 15% is preferable.

Molybdenum partially combines with carbon to form double carbide,
It is an element that provides wear resistance, increases tempering resistance by solid solution in the matrix, and contributes to making crystal grains finer. Too much of it tends to deteriorate grindability, while too little of it tends to deteriorate grindability. ＃Hard to produce abrasive effects. Therefore, 0.
5 to 7.0% is preferred.

Vanadium is a concentrated element that combines with carbon and contributes to the formation of MC type carbide, and if it is too much, the grindability tends to deteriorate, while if it is too little, the weight of L'i + it + grains increases, Strength tends to decrease.

Therefore, 1.0 to 3.0% is preferable.

Carbon is a component that improves the wear resistance of the metal obtained by including it. If the carbon content in the metal is too low, wear resistance will decrease, which is not preferable. Furthermore, metals are required to have excellent wear resistance, but are not particularly required to have toughness. However, if the carbon content is too high, the toughness will be extremely reduced, making it unsuitable for practical use. Therefore, 2.0
~6.0% is preferred.

The metal of the second invention is 0.5 to 15% chromium, preferably 0.5 to 5%, more preferably 1.0 to 3.0%.
, molybdenum 065-7.0%, preferably 4.5-5
, 5%, vanadium 1.0-3.0%, preferably 1.
7-2.3%, 1-5% tungsten, preferably 2.
0-3.5%, carbon 2.0-6.0%, preferably 2,
0-3.5% and the balance essentially composed of iron.

Among the elements constituting the metal, tungsten is a primary element that partially combines with carbon to form double carbides, providing wear resistance, increasing tempering resistance, and contributing to finer grains. If the amount is too high, the grindability tends to deteriorate, while if the amount is too low, the wear resistance effect is difficult to be obtained. Therefore, 1 to 5% is preferable.

Regarding constituent elements other than tungsten, it is preferable to include a predetermined amount in the metal for the reasons described above.

Next, a method for manufacturing metal according to the present invention (including the first and second inventions; the same applies hereinafter) will be described.

The metal of the present invention may vary depending on the type of starting material used.
The manufacturing process and manufacturing conditions are different.

These manufacturing methods are listed below.

(+) Each process of pressure forming, carbon diffusion, degassing, sintering, cooling, and tempering is performed on a mixture consisting of a predetermined amount of powder of each element: (2) From a predetermined amount of each element. (3) A predetermined amount of each element (however, the carbon content is at the lower limit of the predetermined amount, i.e. A predetermined amount range (i.e. 2.0 to B, 0%) for the alloy powder consisting of
For a mixture to which carbon powder is added so that (
The same steps as in method 1) are applied; explaining these methods in order of steps, pressure molding is
After filling the raw material powder into the mold, 5 to 8 t/cm
Do this with about 3 degrees of pressure. In this case, the density of the molded body after molding is 6.0 to 8.8 g in order to perform post-processing.
It is preferable that it is about ram3.

Next, after taking out the obtained molded body from the mold, in methods (1) and (3), under reduced pressure,
By heating for a certain period of time, a diffusion treatment is performed to uniformly diffuse the contained carbon.

In this case, in method (1), the degree of vacuum is 1
The temperature is 1000°C to 00°C, and the processing time is 5 to 2 hours. In method (3),
Vacuum degree to -2 Torr or less, temperature 1000 - weight 00
℃, treatment time 0.5 to 2 hours.

Degassing is carried out at 1050 to 50° C. for about 60 to 120 minutes. This is a preliminary treatment to prevent pores from forming in the sintered body in the first sintering step.

Sintering is carried out at a temperature of 00 to 1200°C for 0.5 to 1 hour.
The atmosphere at this time was 10' Tarr or less, and the cooling was 1
Lower the temperature at a rate of about 60℃ per minute, and then
Tempering is performed at 0 to 600°C for about 60 to 180 minutes.

In order to put the metal thus obtained into practical use, it is necessary that the final vacuum density ratio be approximately 90% or more.

In addition, the alloy powder used in (3) with a carbon content less than the specified value is die steel (chromium 10-15%, molybdenum 0.8-142%, vanadium 1.8-2.2%).
%, carbon 1.8-2.0% and balance iron) or high-speed steel (chromium 3.8-4.5%, molybdenum 4.5-5%
, 5%, vanadium 1.7-2.3%, tungsten 5
5-6.7%, 1 father element 1.1% and balance iron)'V,
can be mentioned.

By processing the metal thus obtained into a predetermined plate size, for example, by ωF machining, a blade for a rotary compressor, particularly a rotary compressor for an inverter, can be obtained.

[Example code for issue 1-1] Hereinafter, the present invention will be described in further detail with reference to Examples.

Example 1 1% graphite was added to 89% die steel powder consisting of 12% chromium, 1% molybdenum, 2% hethidium, 1.9% carbon, and the balance was essentially iron, and the die steel powder and graphite were further mixed. A lubricant of 1.0% based on the total weight was added and mixed uniformly. This mixture is then divided into 24X 28X 4+
The mixture was filled into an am mold and molded at a molding pressure of 6 t/cI weight 2 to obtain a molded product having a density of 8.2 g/cm 2 .

Next, this molded body was held at a weight of 00° C. for 1 hour in a vacuum of 10”” Tart or less to diffuse graphite into the die steel powder. Thereafter, deaeration was performed at a weight of 30° C. for 150 minutes. After degassing, the molded body was sintered by holding at a temperature of 60 to 80° C. for 30 minutes. After sintering.

The temperature was lowered at a rate of 60°C/min and cooled to room temperature. Next, it was heated at 570°C for 2 hours to perform tempering. In this way, the metal of the present invention was obtained. The sintered density of this metal was 7.8 g/am3.

Example 2 1% graphite was added to 98% high speed steel powder consisting of 4% chromium, 5% molybdenum, 2% henadium, 6% tungsten, 1.1% carbon and the balance was essentially iron, and further high speed steel was added. 1.0% moisture based on the total weight of powder and graphite
A lubricant was added and mixed uniformly. Then this mixture was
Fill a mold of 24X 28X 4mm and set the molding pressure St.
/cm'' to obtain a molded product with a density of 8-28/cm3.

This molded body is then subjected to a reduced pressure of 10-2 Torr or less.

The temperature was maintained at 1050° C. for 1 hour to diffuse graphite into the high-speed steel powder. After that, it was heated to 1080℃ for 80 minutes. After degassing, a temperature of 00° C. to 30° C. was maintained for 30 minutes to sinter the molded body. After sintering, the temperature was lowered at a rate of 80'O/min and cooled to room temperature. Then, 57
Tempering was performed by heating at 0° C. for 2 hours. In this way, the metal of the present invention was obtained. The sintered density of this metal is 8.0
g/am3.

Test Examples The metals obtained in Examples 1 and 2 were processed into blades of 28X 22X 3 m+e by grinding. Using this blade, its wear resistance was evaluated through an actual machine test at 180 Hz. As a comparative example, iron-5% chromium-1,3 with the same dimensions as the blade
% carbon, the surface of which was subjected to nitriding treatment was used.

As a result, the degree of wear resistance of the blade of the comparative example was reduced to 100.
In this case, both Examples 1 and 2 were 300.

[Effects of the Invention] The metal of the present invention has excellent wear resistance, and therefore, plates manufactured from it can be used at higher rotational speeds and for longer periods of time. , Bree I
- Since no special processing steps are required during manufacturing, manufacturing costs are reduced and it is suitable for mass production.

In addition, when the blade is used in a rotary compressor, it not only causes less wear on the blade surface, but also
It is also possible to reduce wear on the surface of each part that slides on the blade, and in this case, the material of the parts that slide on the blade is not particularly limited, and conventionally known materials can be used. For example, the cylinder is made of iron-carbon material or iron-based sintered material with its sintered holes filled with iron oxide and chromium oxide, and the roller is made of a hardened molybdenum-chromium cast iron or iron-based sintered material. When a binder material whose sintering pores are filled with iron oxide and chromium oxide is used, its wear-resistant effect can be particularly exhibited.

Claims (4)

[Claims] (1) Chromium 0.5~15% by weight, molybdenum 0.5~
7.0% by weight of vanadium, 1.0-3.0% by weight of vanadium, 2.0-8.0% by weight of carbon, and the balance substantially iron. (2) The metals include 10 to 15% by weight of chromium, 0.8 to 1.2% by weight of molybdenum, 1.8 to 2.2% by weight of vanadium, 2.7 to 4.4% by weight of carbon, and the balance is substantially The metal according to claim 1, which is iron. (3) Chromium 0.5~15% by weight, molybdenum 0.5~
7.0% by weight, 1.0-3.0% by weight of vanadium, 1-5% by weight of tungsten, 2.0-6.0% by weight of carbon and the balance substantially iron. metal. (4) The metals include 0.5 to 5% by weight of chromium, 4.5 to 5.5% by weight of molybdenum, and 1.7 to 2.3% of vanadium.
wt%, carbon 2.0-3.5 wt%, tungsten 2-3
．． 4. A metal according to claim 3, wherein 5% by weight and the balance is substantially iron.