JP2020158844A - Scroll member and method for manufacturing scroll forging - Google Patents

Abstract

To provide a scroll member having excellent mechanical strength of a root portion of a blade receiving the largest load and including an alumite coating having sufficient hardness.SOLUTION: An alumite coating 3 having a Vickers hardness of 400 or more is formed on the surface of an aluminium alloy scroll forging 2 including Si:8.0-12.0 mass%, Fe:0.1-0.5 mass%, Cu:0.6-1.1 mass%, Mg:0.2-0.8 mass% and the remainder consisting of Al and inevitable impurities, and the tensile strength of the scroll forging in the surface direction of the base plate 21 is 350 MPa or more and less than 400 MPa.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a scroll member and a scroll forged product used in a compressor for an air conditioner of an automobile such as an electric vehicle or a hybrid vehicle.

In recent years, many compressors used in in-vehicle electric compressors of automobiles such as electric vehicles and hybrid vehicles are scroll type, and this scroll type is characterized by high efficiency and excellent quietness. As shown in FIG. 3, the scroll type compressor is substantially fitted to a fixed scroll 50 having a spiral blade portion 51 provided on a bottom plate (flange) 52 facing the blade portion 51 of the fixed scroll. It consists of a swirling blade with a similar shape that swings and a swing scroll with a bottom plate.

The swing scroll is made of aluminum alloy for weight reduction. As the manufacturing method, there are manufacturing methods such as casting, die casting, and forging, but the manufacturing method by forging is advantageous from the viewpoints of strength and reliability as a part, molding into a spiral complex shape, and the like.

On the other hand, the swing scroll used in in-vehicle electric compressors is required to have excellent wear resistance, but the surface is alumite-treated or plated to impart film hardness and wear resistance. The sex is secured. In addition, in order to reduce the wall thickness and weight, it is also required to have excellent mechanical strength at the base of the blade, which is the most loaded (specifically, the tensile strength in the surface direction of the bottom plate of the scroll). Is required to be excellent). That is, it is required to be excellent in both surface treatment property and mechanical strength.

In Patent Document 1, as a high-strength abrasion-resistant aluminum alloy extruded material, Si: 6 to 12% (weight%, the same applies hereinafter), Fe: 0.1 to 1.0%, Cu: 1.0 to 5.0. %, Mn: 0.1-1.0%, Mg: 0.4-2.0%, Ti: 0.01-0.3%, Sr: 0.005-0.2%, impurities The average particle size of the eutectic Si particles dispersed in the matrix, which is composed of the balance Al and impurities, is 1.5 to 5.0 μm, and the average particle size of the eutectic Si particles is 1.5 to 5.0 μm. The structure in which eutectic Si particles are present in an amount of 5,000 / mm ² or more and less than 10,000 / mm ² is described.

Further, in Patent Document 2, Si: 5 to 12% (mass%, the same applies hereinafter), Fe: 0.1 to 1%, Cu: less than 1%, Mg: 0.3 to 1.5% is contained. The particle size of the eutectic Si particles dispersed in the matrix, which consists of the balance Al and impurities, exists in a width of 0.4 to 5.5 μm, and the particle size of the eutectic Si particles is 0.8 to 2. A configuration in which the size of 4 μm occupies 60% or more, the number of eutectic Si particles is 4000 / mm ² or more and less than 40,000 / mm ^{2 is} present, and the film hardness Hv after alumite treatment is 400 or more is described. Has been done.

Japanese Patent No. 3261056 Japanese Patent No. 4511156

In Patent Document 1, the content of Cu and Mg is adjusted in order to improve the wear resistance and strength of the aluminum alloy, but the film hardness Hv after the alumite treatment is about 310 to 370, which is a sufficient film hardness. There was a problem that it could not be obtained.

In Patent Document 2, the film hardness after alumite treatment is Hv400 or more, but with respect to the mechanical strength, the extruded material described in the examples is subjected to a tensile test in the same direction as the extrusion direction, and the tensile test result is obtained. It is evaluated only in the direction that is advantageous to. However, as described above, in scrolling, the mechanical strength of the base of the blade, which is the most loaded, is the most important, and specifically, it is important that the scroll bottom plate has excellent tensile strength in the surface direction. is there. In the case of the extruded material, the surface direction of the bottom plate of the scroll is the direction perpendicular to the extrusion processing direction, so that Patent Document 2 may not be sufficient in terms of such mechanical properties.

The present invention has been made in view of such a technical background, and is a scroll member and scroll forging in which an alumite film having sufficient hardness is formed while having excellent mechanical strength at the base portion of the blade to which the load is most applied. The purpose is to provide a method of manufacturing an article.

In order to achieve the above object, the present invention provides the following means.

[1] Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, Cu: 0.6% by mass to 1.1% by mass, Mg: 0.2 A scroll member in which an alumite film having a Vickers hardness of 400 or more is formed on the surface of a scroll forged product made of an aluminum alloy containing mass% to 0.8% by mass and the balance being Al and unavoidable impurities. ,
A scroll member characterized in that the tensile strength of the bottom plate of the scroll forged product in the surface direction is 350 MPa or more and less than 400 MPa.

[2] The aluminum alloy further contains Ti: 0.01% by mass to 0.3% by mass, B: 0.0001% by mass to 0.05% by mass, and Sr: 0.001% by mass to 0.1% by mass. The scroll member according to item 1 above, which contains one or more metals selected from the group consisting of%, in the above-mentioned content rate.

[3] The aluminum alloy further contains Mn: 0.01% by mass to 0.3% by mass, Cr: 0.01% by mass to 0.3% by mass, and Ni: 0.01% by mass to 0.3% by mass. %, Zr: 0.01% by mass to 0.3% by mass, V: 0.01% by mass to 0.1% by mass, containing one or more metals selected from the group at the above content. The scroll member according to item 1 or 2 above.

[4] Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, Cu: 0.6% by mass to 1.1% by mass, Mg: 0.2 By forging an aluminum alloy continuous cast material containing mass% to 0.8% by mass and the balance of which is Al and unavoidable impurities without extrusion processing, the tensile strength of the bottom plate in the surface direction is 350 MPa or more and 400 MPa. A method for manufacturing a scroll forged product, which comprises obtaining a scroll forged product that is less than or equal to.

According to the invention of [1], it is possible to provide a scroll member which is excellent in mechanical strength of a base portion of a blade to which a load is most applied and also has a sufficiently hard alumite film formed.

In the invention of [2], the structure of the aluminum alloy can be miniaturized, and the mechanical strength can be further improved.

In the invention of [3], by containing Mn, Cr or Zr, the structural structure of the aluminum alloy can be made finer and the mechanical strength can be further improved, and Ni or V is contained. In some cases, the mechanical strength in the high temperature range can be improved.

In the invention of [4], the tensile strength of the bottom plate of the scroll forged product in the surface direction can be sufficiently secured by forging without extrusion processing, and the strength of the base portion of the blade to which the load is most applied can be increased. It can be secured sufficiently.

It is a top view which shows an example of the scroll member which concerns on this invention. It is a cross-sectional view taken along the line AA in FIG. 1 (note that the dotted line portion indicates the position where the tensile test piece is collected). It is a perspective view which shows an example of a fixed scroll.

The scroll member 1 according to the present invention has Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, and Cu: 0.6% by mass to 1.1% by mass. , Mg: A scroll member in which an alumite film 3 is formed on the surface of a scroll forged product 2 made of an aluminum alloy containing 0.2% by mass to 0.8% by mass and the balance being Al and unavoidable impurities. (See FIG. 2), the bottom plate 21 of the scroll forged product 2 is characterized in that the tensile strength in the surface direction is 350 MPa or more and less than 400 MPa. With such a configuration, there is provided a scroll member 1 in which the base portion of the blade portion 22 to which the load is most applied is excellent in mechanical strength and an alumite film 3 having sufficient hardness is formed (FIG. 1, FIG. 1). 2). If the tensile strength in the plane direction is 400 MPa or more, forging may become difficult.

An embodiment of the scroll member 1 according to the present invention is shown in FIGS. 1 and 2. The scroll member 1 has a spiral-shaped blade portion 22 projectingly formed on a substantially disk-shaped bottom plate 21. The scroll member 1 is formed by forging.

The aluminum alloy further comprises Ti: 0.01% by mass to 0.3% by mass, B: 0.0001% by mass to 0.05% by mass, Sr: 0.001% by mass to 0.1% by mass. It is preferable to contain one kind or two or more kinds of metals selected from the above group at the above-mentioned content rate. In this case, the structure of the aluminum alloy can be miniaturized, and the mechanical strength can be further improved.

Further, the aluminum alloy further contains Mn: 0.01% by mass to 0.3% by mass, Cr: 0.01% by mass to 0.3% by mass, and Ni: 0.01% by mass to 0.3% by mass. , Zr: 0.01% by mass to 0.3% by mass, V: 0.01% by mass to 0.1% by mass, containing one or more metals selected from the group at the above content. Is preferable. When Mn, Cr or Zr is contained, the structure of the aluminum alloy can be refined to further improve the mechanical strength, and when Ni or V is contained, it is in a high temperature range. The mechanical strength can be improved.

Next, a method for manufacturing the scroll forged product according to the present invention will be described. In this production method, Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, Cu: 0.6% by mass to 1.1% by mass, Mg: 0 . By forging an aluminum alloy continuous casting material containing 2% by mass to 0.8% by mass and the balance of which is Al and unavoidable impurities without extrusion processing, the tensile strength of the bottom plate 21 in the surface direction can be increased. It is characterized in that a scroll forged product having a mass of 350 MPa or more and less than 400 MPa is obtained. According to this manufacturing method, the tensile strength of the bottom plate 21 of the scroll forged product in the surface direction can be sufficiently secured, and the strength of the base portion of the blade to which the load is most applied can be sufficiently secured.

Next, the composition of the "aluminum alloy" in the above-mentioned method for manufacturing the scroll member according to the present invention and the scroll forged product according to the present invention will be described in detail below.

The Si (component) can coexist with Mg to precipitate Mg ₂ Si particles to improve the strength of the aluminum alloy, and the presence of eutectic Si improves the strength and abrasion resistance. If the Si content is less than 8.0% by mass, the effect of increasing the strength and abrasion resistance is poor. On the other hand, when the Si content exceeds 12.0% by mass, primary crystal Si crystallizes and the surface treatability (anodizing property) is deteriorated. Therefore, the Si content is in the range of 8.0% by mass to 12.0% by mass. Above all, the Si content is preferably in the range of 9.0% by mass to 11.0% by mass.

The Fe (component) precipitates Al-Fe-based particles and Al-Fe-Si-based particles, suppresses recrystallization in heat treatment after forging, and improves ductility and toughness of the scroll member. If the Fe content is less than 0.1% by mass, the effects of improving ductility and toughness are poor. On the other hand, when the Fe content exceeds 0.5% by mass, coarse crystals of Al-Fe-based or Al-Fe-Si-based are increased and the surface treatability (anodizing property) is deteriorated. Therefore, the Fe content is in the range of 0.1% by mass to 0.5% by mass. Above all, the Fe content is preferably in the range of 0.15% by mass to 0.30% by mass.

The Cu (component) precipitates CuAl ₂ particles and contributes to improving the strength and hardness of the aluminum alloy. If the Cu content is less than 0.6% by mass, the effects of improving strength and hardness are poor. On the other hand, when the Cu content exceeds 1.1% by mass, the hardness of the alumite film decreases. Therefore, the Cu content is in the range of 0.6% by mass to 1.1% by mass. Above all, the Cu content is preferably in the range of 0.7% by mass to 1.0% by mass. Note that Cu dissolves during the alumite treatment, but since the dissolved Cu ions are precious metal ions, Cu precipitates again on the surface of the aluminum alloy base material, making it difficult to form an alumite film, which makes it difficult to form a film. However, by controlling the Cu content within the above range, the moldability and denseness of the alumite film can be improved, and the hardness of the alumite film can be improved.

The Mg (component) can coexist with Si and precipitate Mg ₂ Si particles to improve the strength of the aluminum alloy. If the Mg content is less than 0.2% by mass, the effect of improving the strength is poor. On the other hand, if the Mg content exceeds 0.8% by mass, the workability is lowered. Therefore, the Mg content is in the range of 0.2% by mass to 0.8% by mass. Above all, the Mg content is preferably in the range of 0.3% by mass to 0.7% by mass.

Further, the aluminum alloy has Ti: 0.01% by mass to 0.3% by mass, B: 0.0001% by mass to 0.05% by mass, Sr: 0.001% by mass to 0.1% by mass. It is preferable to contain one kind or two or more kinds of metals selected from the above group at the above-mentioned content rate for the following reasons. That is, both Ti and B contain micronizing the structure of the ingot to prevent ingot cracking during casting and further improving the workability of the ingot, resulting in a complicated shape during forging. It can be molded. If the Ti content is less than 0.01% by mass, the above effect is poor. On the other hand, when the Ti content exceeds 0.3% by mass, huge intermetallic compounds crystallize, which adversely affects workability and alumite treatment. Further, the content of Sr makes eutectic Si finer and improves processability and alumite property. If the Sr content is less than 0.001% by mass, the above effect is poor. On the other hand, when the Sr content exceeds 0.1% by mass, the above effect is poor.

Further, the aluminum alloy further contains Mn: 0.01% by mass to 0.3% by mass, Cr: 0.01% by mass to 0.3% by mass, and Ni: 0.01% by mass to 0.3% by mass. , Zr: 0.01% by mass to 0.3% by mass, V: 0.01% by mass to 0.1% by mass, containing one or more metals selected from the group at the above content. This is preferable for the following reasons. By containing these, Al-Mn-based particles, Al-Mn-Fe-Si-based particles, Al-Cr-based particles, Al-Cr-Fe-Si-based particles, Al-Ni particles, Al-Zr-based particles, Al—V particles can be precipitated and recrystallization can be suppressed by heat treatment after forging, and ductility and toughness can be improved. When Mn is less than 0.01% by mass, Cr is less than 0.01% by mass, Ni is less than 0.01% by mass, Zr is less than 0.01% by mass, and V is less than 0.01% by mass, ductility is improved and toughness is improved. The effect of improvement is small. When Mn exceeds 0.3% by mass, Cr exceeds 0.3% by mass, Ni exceeds 0.3% by mass, Zr exceeds 0.3% by mass, and V exceeds 0.1% by mass. , Coarse crystals increase and adversely affect alumite properties, and reduce the ductility and toughness of aluminum alloys.

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

<Example 1>
Hot-top continuous hot-top molten aluminum alloy containing Si: 8.0% by mass, Fe: 0.25% by mass, Cu: 0.9% by mass, Mg: 0.5% by mass, and the balance is Al and unavoidable impurities. By casting, a cast material having an outer diameter of 117 mm and a length of 1000 mm was obtained. The obtained cast material was subjected to a symptotic heat treatment by heating at 490 ° C. for 7 hours, and then surface-cut to an outer diameter of 104 mm. Next, the cast material cut to a thickness of 25 mm was heated to 200 ° C. in a heating furnace, immersed in a graphite-based water-soluble lubricating oil for several seconds, and then taken out to form a lubricating film. Next, the scroll forged products shown in FIGS. 1 and 2 were obtained by forging the cast material having a thickness of 25 mm in a state of being heated to 400 ° C. The height (H) of the blade portion 22 of the scroll forged product was 40 mm, the thickness (W) of the blade portion 22 was 5 mm, and the thickness (T) of the bottom plate 21 was 10 mm.

Next, the obtained scroll forged product was anodized. This alumite treatment was carried out using 15% by mass sulfuric acid as an electrolytic bath at a current density of 3 A / dm ² and a bath temperature of 5 ° C. to form an alumite film 3 having a thickness of about 40 μm on the surface of the scroll forged product 2. The scroll member 1 was obtained.

<Examples 2 to 16>
A scroll member 1 was obtained in the same manner as in Example 1 except that a molten aluminum alloy having an alloy composition (containing unavoidable impurities) shown in Table 1 was used.

<Comparative Examples 1 to 13>
A scroll member was obtained in the same manner as in Example 1 except that a molten aluminum alloy having an alloy composition (containing unavoidable impurities) shown in Table 1 was used.

<Comparative Example 14>
A molten aluminum alloy having the same composition as that of Example 2 was continuously cast by hot top to obtain a cast material having an outer diameter of 203 mm and a length of 1000 mm. The obtained cast material was subjected to a symptotic heat treatment by heating at 490 ° C. for 7 hours, and then extruded with an outer diameter of 104 mm. Next, the extruded material cut to a thickness of 25 mm was heated to 200 ° C. in a heating furnace, immersed in a graphite-based water-soluble lubricating oil for several seconds, and then taken out to form a lubricating film. Next, a scroll member was obtained in the same manner as in Example 1 except that a scroll forged product was obtained by forging a 25 mm thick extruded material in a state of being heated to 400 ° C.

Each scroll member obtained as described above was evaluated based on the following evaluation method.

<Tensile strength test method>
In order to carry out the tensile test, an ASTM-R3 test piece was taken from the bottom plate having a thickness of 10 mm of the scroll member from the position shown by the dotted line in FIG. A tensile test was performed on the obtained test piece in the surface direction of the bottom plate using AG100kNXplus manufactured by Shimadzu Corporation, and the tensile strength (MPa) at 25 ° C. was measured. The measurement results are shown in Tables 2 and 4. The n number was set to 3, and the average value of the 3 was taken as the tensile strength. In Table 2, those having a tensile strength of 350 MPa or more and less than 400 MPa are indicated by an evaluation "◯", while those having a tensile strength outside the above range are indicated by an evaluation "x".

<Proof stress measurement method>
From the above tensile test results, 0.2% proof stress at 25 ° C. was determined. The measurement results are shown in Tables 2 and 4. The number of n was set to 3, and the average value of the 3 was set to 0.2% proof stress. In Tables 2 and 4, those having a 0.2% proof stress of 250 MPa or more and 300 MPa or less are indicated by an evaluation "○", while those having a 0.2% proof stress outside the above range are indicated by an evaluation "x". did.

<Vickers hardness evaluation method for alumite film>
The scroll member on which the alumite film is formed is cut to a predetermined size, embedded in a resin frame, and the surface is micropolished to a measurable range of the alumite film hardness, and then the Vickers hardness of the alumite film is measured. Was measured. The n number was set to 3, and the average value of the 3 was defined as the Vickers hardness. In Tables 2 and 4, those having a Vickers hardness (HV) of 400 or more are indicated by an evaluation "○", while those having a Vickers hardness (HV) of less than 400 are indicated by an evaluation "x".

As is clear from the table, the scroll members of Examples 1 to 16 have a tensile strength of the bottom plate in the surface direction of 350 MPa or more and less than 400 MPa, and are excellent in mechanical strength of the base portion of the blade to which the load is most applied. The Vickers hardness (HV) of the alumite film was 400 or more, and the hardness of the alumite film was large.

On the other hand, in Comparative Examples 1 to 14 deviating from the specified range of the present invention, at least one of the tensile strength in the surface direction of the bottom plate and the alumite film hardness (anodizing property) was inferior.

The scroll member according to the present invention is suitably used as an in-vehicle electric scroll of an automobile such as an electric vehicle or a hybrid vehicle.

1 ... Scroll member 2 ... Scroll forged product 3 ... Alumite film 21 ... Bottom plate 22 ... Blade

Claims (4)

Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, Cu: 0.6% by mass to 1.1% by mass, Mg: 0.2% by mass to A scroll member in which an alumite film having a Vickers hardness of 400 or more is formed on the surface of a scroll forged product made of an aluminum alloy containing 0.8% by mass and the balance being Al and unavoidable impurities.
A scroll member characterized in that the tensile strength of the bottom plate of the scroll forged product in the surface direction is 350 MPa or more and less than 400 MPa. The aluminum alloy further comprises Ti: 0.01% by mass to 0.3% by mass, B: 0.0001% by mass to 0.05% by mass, Sr: 0.001% by mass to 0.1% by mass. The scroll member according to claim 1, which contains one or more metals selected from the above group at the above-mentioned content rate. The aluminum alloy further contains Mn: 0.01% by mass to 0.3% by mass, Cr: 0.01% by mass to 0.3% by mass, Ni: 0.01% by mass to 0.3% by mass, Zr. : 0.01% by mass to 0.3% by mass, V: 0.01% by mass to 0.1% by mass, according to the above claim, containing one or more metals selected from the group consisting of the above content. The scroll member according to 1 or 2. Si: 8.0% by mass to 12.0% by mass, Fe: 0.1% by mass to 0.5% by mass, Cu: 0.6% by mass to 1.1% by mass, Mg: 0.2% by mass to By forging an aluminum alloy continuous cast material containing 0.8% by mass and the balance being Al and unavoidable impurities without extrusion processing, the tensile strength of the bottom plate in the surface direction is 350 MPa or more and less than 400 MPa. A method for manufacturing a scroll forged product, which comprises obtaining a scroll forged product.

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