JP2020169376A - Aluminum alloy for compressor slide components and compressor slide component forging - Google Patents

Abstract

To provide an aluminum alloy for compressor slide components that has excellent chip cutting properties during cutting, can reduce an amount of wear of tools, and can ensure sufficient tensile strength.SOLUTION: An aluminum alloy contains Si: more than 4.0 mass% and 6.0 mass% or less, Cu: 1.5 mass%-3.5 mass%, and Mg: 0.1 mass%-0.8 mass% with the balance being Al and unavoidable impurities, the aluminum alloy material having a tensile strength of 360 MPa-450 MPa.SELECTED DRAWING: Figure 3

Description

The present invention relates to sliding parts typified by a compressor for an automobile air conditioner, particularly an aluminum alloy that can be suitably used for scrolls and electric scrolls.

Due to the demand for improving fuel efficiency in the automobile industry in recent years, there is an increasing demand for weight reduction and high functionality in various components used in automobiles, for example, compressors for car air conditioners. There are various types of compressors for car air conditioners, but the scroll type has become widespread as a small compressor due to the above background. For such members, aluminum alloys having a large specific strength, which is the ratio of strength to weight, have been used instead of steel materials and cast iron materials. In particular, Al—Si alloys that have high strength under high temperature and have excellent wear resistance during sliding, such as the compressor for car air conditioners, which can be used in harsh environments under high temperature atmosphere. Forged materials made of aluminum alloy are attracting attention.

When producing this kind of aluminum alloy forged material, for example, as described in Patent Document 1, a car air conditioner is formed by molding an aluminum alloy having a predetermined metal composition by die casting and performing a predetermined heat treatment. Forging scrolls are being manufactured.

Japanese Patent Application Laid-Open No. 10-12215

By the way, when manufacturing a scroll using an aluminum alloy as described above, machining is performed, but there is a problem in machinability at that time. That is, when forming the spiral groove of the scroll by cutting, if the chips are connected to one and are not divided into small pieces, the long chips are caught in the cutting tool and the product (scroll) is scratched. Occurs. In order to prevent such scratches from occurring, it is necessary to improve the chip fragmentability, that is, to make the chips finer. It is possible to improve the chip fragmentability by adding a large amount of Si, but on the other hand, there is a problem that the amount of wear of the cutting tool increases due to the addition of a large amount of Si and the life of the cutting tool is shortened. was there.

The present invention has been made in view of such a technical background, and is a compressor slide which is excellent in chip breaking property at the time of cutting, can reduce the amount of bite wear, and can secure sufficient tensile strength. It is an object of the present invention to provide aluminum alloys for moving parts and forged products of sliding parts of compressors.

In order to achieve the above object, as a result of diligent research, the present inventor has excellent chip breakability at the time of cutting and bite by controlling Si, Cu, and Mg in the aluminum alloy within specific content ratio ranges. The present invention has been completed by finding that the amount of wear can be reduced and sufficient tensile strength can be secured. That is, the present invention provides the following means.

[1] Si: contains more than 4.0% by mass and 6.0% by mass or less, Cu: 1.5% by mass to 3.5% by mass, Mg: 0.1% by mass to 0.8% by mass. , The balance is an aluminum alloy composed of Al and unavoidable impurities.
An aluminum alloy for compressor sliding parts, wherein the tensile strength of the aluminum alloy material is 360 MPa to 450 MPa.

[2] The aluminum alloy for compressor sliding parts according to item 1 above, wherein the aluminum alloy further contains Ti: 0.001% by mass to 0.1% by mass.

[3] A forged compressor sliding component made of the aluminum alloy for the compressor sliding component according to the above item 1 or 2.

[4] An electric compressor sliding component forged product made of the aluminum alloy for the compressor sliding component according to the above item 1 or 2.

According to the invention of [1], it is possible to provide an aluminum alloy for a compressor sliding component which is excellent in chip breaking property at the time of cutting, can reduce the amount of bite wear, and can secure sufficient tensile strength.

In the invention of [2], since Ti is contained at a specific content, it can contribute to the refinement of crystal grains in the cast product.

The invention of [3] provides a compressor sliding component which is excellent in chip breaking property at the time of cutting (the product is not scratched), can reduce the amount of bite wear, and can secure sufficient tensile strength. it can.

In the invention of [4], an electric compressor sliding component which is excellent in chip breaking property at the time of cutting (the product is not scratched), can reduce the amount of bite wear, and can secure sufficient tensile strength is provided. Can be provided.

It is a perspective view which shows the casting material before forging. It is a perspective view which shows an example of the forging material. It is a perspective view which shows an example of the forged compressor sliding parts which concerns on this invention.

The aluminum alloy for compressor sliding parts according to the present invention has Si: more than 4.0% by mass and 6.0% by mass or less, Cu: 1.5% by mass to 3.5% by mass, Mg: 0.1% by mass. It is an aluminum alloy containing% to 0.8% by mass and the balance being Al and unavoidable impurities, and the tensile strength of the aluminum alloy material is 360 MPa to 450 MPa. With such a configuration, it is possible to provide an aluminum alloy for compressor sliding parts, which is excellent in chip breaking property at the time of cutting, can reduce the amount of bite wear, and can secure sufficient tensile strength.

Next, the composition of the "aluminum alloy" in the above-mentioned aluminum alloy for compressor sliding parts according to the present invention will be described in detail below. The aluminum alloy contains Si: 4.0% by mass or more and 6.0% by mass or less, Cu: 1.5% by mass to 3.5% by mass, and Mg: 0.1% by mass to 0.8% by mass. It is an aluminum alloy contained and the balance is composed of Al and unavoidable impurities.

The Si (component) has an action of improving high-temperature strength and an action of improving chip fragmentation during cutting (an action of making chips finer during cutting). However, if it is added in an excessive amount, the amount of wear of the cutting tool increases and the tool life of the cutting tool is shortened. If Si is 4.0% by mass or less, the chip fragmentation property during cutting becomes insufficient (the average length of chips during cutting becomes long), and the product (scroll) is scratched. On the other hand, when Si exceeds 6.0% by mass, the amount of wear of the cutting tool increases and the tool life of the cutting tool is shortened. Therefore, the Si content is set to be more than 4.0% by mass and 6.0% by mass or less. Above all, the Si content is preferably set to 4.5% by mass to 5.5% by mass.

The Cu (component) has an action of improving high temperature strength. The action of improving the high temperature strength is due to the precipitation of Cu, and the above effect can be obtained by applying an artificial aging treatment. If Cu is less than 1.5% by mass, sufficient precipitation strengthening cannot be obtained and the strength cannot be improved. On the other hand, if Cu exceeds 3.5% by mass, sufficient strength cannot be obtained. Therefore, the Cu content is set to 1.5% by mass to 3.5% by mass. Above all, the Cu content is preferably set to 2.1% by mass to 2.9% by mass.

The Mg (component) has an action of improving high temperature strength. Mg dissolves solidly during casting and forms a compound with Si and Cu during artificial aging treatment to precipitate, which contributes to the improvement of strength at high temperatures. Such an effect remarkably appears when the Mg content is 0.1% by mass or more, and the above effect does not remarkably appear when the Mg content exceeds 0.8% by mass. Therefore, the Mg content is set to 0.1% by mass to 0.8% by mass. Above all, the Mg content is preferably set to 0.4% by mass to 0.7% by mass.

The aluminum alloy preferably further contains Ti: 0.001% by mass to 0.1% by mass. Ti contributes to the refinement of crystal grains in the cast product by adding it finely. This effect is remarkable when the Ti content is 0.001% by mass or more, but when it exceeds 0.1% by mass, the compound containing Ti is coarsely crystallized, resulting in a decrease in ductility. Therefore, Ti is preferably contained in an amount of 0.001% by mass to 0.1% by mass. Above all, Ti is more preferably contained in an amount of 0.01% by mass to 0.08% by mass. When Ti is contained, it may be added in the form of an Al—Ti mother alloy or TiB ₂ additive.

As other metal elements, Zn, Fe, Ni, Mn, Cr, Co, V, Mo, Zr, Sc, Hf, Ce, Nb, Er, and Yb are allowed up to 0.5% by mass in the total amount thereof. it can. If it exceeds 0.5% by mass, it is crystallized before the Al matrix to become coarse crystallized products, resulting in a decrease in ductility.

A continuous cast material (billet) having the above alloy composition was produced by, for example, melting an aluminum alloy having the above composition by a well-known method, and the continuous cast material was heat-treated and further subjected to plastic working such as forging. After that, a compressor sliding part can be obtained by performing cutting or the like (see FIG. 3). The one shown in FIG. 3 is a scroll for a car air conditioner, 52 is a bottom plate, and 51 is a spiral blade portion.

Next, an example of a method for manufacturing a sliding component for a car air conditioner, which is one aspect of the present invention, will be described.

First, the molten aluminum alloy whose composition has been adjusted as described above is continuously cast. Assuming the manufacture of an electric scroll, for example, casting is performed with a diameter of about 60 mm to 80 mm. Although it is possible to obtain a forging billet having the above diameter by extrusion, it is preferable to obtain a forging billet by casting because the manufacturing cost is high.

Since the obtained cast material undergoes homogenization heat treatment because segregation of crystallized material occurs during casting, the homogenization heat treatment sets the heating temperature to 460 ° C. to 510 ° C. and sets the treatment time to 0. It is preferably set to 5 to 6 hours.

Next, the cast material is cut to a predetermined length to obtain a forging billet. In the forging step, it is preferable to set the mold temperature to 100 ° C. to 300 ° C. and the material temperature to 370 ° C. to 510 ° C.

Next, the forging billet is subjected to a solution treatment. In this solution treatment, it is preferable to set the heating temperature to 450 ° C. to 510 ° C. and the treatment time to 0.5 hours to 8.0 hours.

Next, quenching is performed. This quenching treatment is preferably quenched with water at 10 ° C to 80 ° C.

Then, artificial aging treatment is performed. In this artificial aging treatment, it is preferable that the heat treatment temperature is set to 160 ° C. to 220 ° C. and the heat treatment time is set to 1 hour to 18 hours.

Next, after the forged product subjected to the artificial aging treatment is cut by machining, peening is performed and plastic working is applied in the vicinity of the surface to improve the fatigue strength. In this shot peening step, it is preferable that the abrasive grain size is 1 mm or less, the abrasive grain type is SUS304, alumina or the like, and the peening pressure is 1 MPa or less.

The forged compressor sliding component according to the present invention manufactured as described above is excellent in normal temperature strength and high temperature strength, is also excellent in chip breakability during cutting, and can reduce the amount of bite wear. Therefore, it is suitable for car air conditioners.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to those of these examples.

<Examples 1 to 6, Comparative Examples 1 to 8>
The molten aluminum alloy prepared to the alloy composition (including unavoidable impurities) shown in Table 1 was cast by continuous casting to obtain a cast material 10 having a diameter of 82 mm (see FIG. 1). The cooling rate during casting was 15 ° C./sec. The obtained cast material was subjected to a homogenization heat treatment at 470 ° C. for 7 hours and then air-cooled. The cast material was cut to a length of 30 mm and then forged at a material temperature of 420 ° C. and a mold temperature of 180 ° C. In the forging, assuming the bottom plate 52 of the scroll forged product, the forged material 20 was obtained by embedding 80% in the direction parallel to the axial direction of the cast material (see FIG. 2). Next, the forged material was heated at 495 ° C. for 3 hours for solution treatment, and then water-quenched with water at 25 ° C. Next, an artificial aging treatment was carried out by heating at a heat treatment temperature of 180 ° C. for 8 hours to obtain a T6 forged product.

The T6 forged product obtained as described above was evaluated based on the following evaluation method. The evaluation results are shown in Table 1.

<Tensile strength measurement method>
The forged product was cut out to obtain a No. 4 tensile test piece specified in JIS Z2241. A tensile test was carried out on the No. 4 tensile test piece in accordance with JIS Z2241 to measure the tensile strength. In the table, those having a tensile strength of 360 MPa or more are indicated by "◯" (pass), and those having a tensile strength of less than 360 MPa are indicated by "x" (fail).

<Evaluation method for chip fragmentation>
Chip fragmentability during cutting was carried out using a continuous casting material (casting rod). The end face of the continuously cast rod was cut with a diamond tool at a cutting amount of 1.0 mm and a feed rate of 3 mm / sec in a state where the continuously cast material was chucked on a lathe and rotated at a rotation speed of 1030 rpm. 100 mg of chips generated during cutting was collected, and the number of chips was examined. If the number of chips in 100 mg of chips is large, the chips are fine and the chips are excellent in fragmentation. On the other hand, if the number of chips in 100 mg of chips is small, the chips are large and the chips are large. It can be seen that the fragmentation is low. In the table, those with 50 or more chips in 100 mg of chips are marked with "○" (pass), and those with less than 50 chips in 100 mg of chips are marked with "x". It was written as (failed).

<Bite wear evaluation method>
After repeating the above-mentioned cutting (rotation speed 1030 rpm, cutting amount 1.0 mm, feeding speed 3 mm / sec) 50 times, the amount of wear at the tip of the diamond bite was measured. The distance in the longitudinal direction of the bite at the point where the tip of the diamond bite was worn was measured and used as the amount of wear (mm). In the table, those having a bite wear amount of less than 0.20 mm are indicated by "○" (pass), and those having a bite wear amount of 0.20 mm or more are indicated by "x" (failure).

As is clear from the table, the forged products using the aluminum alloys of Examples 1 to 6 according to the present invention have excellent tensile strength, excellent chip breakability during cutting, and a small amount of bite wear. You can see that.

On the other hand, in Comparative Examples 1, 4, 6 and 8 which deviate from the specified range of the present invention, the tensile strength is insufficient, and in Comparative Examples 1 and 2, the chip breaking property at the time of cutting is inferior. In Examples 3, 5, 7, and 8, there was a problem that the amount of bite wear was large.

The compressor sliding component made of the aluminum alloy for the compressor sliding component according to the present invention can be suitably used as a sliding component represented by a compressor (compressor) for an automobile air conditioner, particularly a scroll and an electric scroll.

10 ... Casting material 20 ... Forged material 50 ... Compressor sliding parts Forged product

Claims (4)

Si: more than 4.0% by mass and 6.0% by mass or less, Cu: 1.5% by mass to 3.5% by mass, Mg: 0.1% by mass to 0.8% by mass, and the balance is An aluminum alloy composed of Al and unavoidable impurities.
An aluminum alloy for compressor sliding parts, wherein the tensile strength of the aluminum alloy material is 360 MPa to 450 MPa. The aluminum alloy for a compressor sliding component according to claim 1, wherein the aluminum alloy further contains Ti: 0.001% by mass to 0.1% by mass. A forged compressor sliding component made of the aluminum alloy for the compressor sliding component according to claim 1 or 2. An electric compressor sliding component forged product made of the aluminum alloy for the compressor sliding component according to claim 1 or 2.

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