JP7358759B2 - Scroll member and scroll forging product manufacturing method - Google Patents

Description

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

In recent years, many scroll type compressors have been adopted in on-board electric compressors for automobiles such as electric cars and hybrid cars, and this scroll type is characterized by high efficiency and excellent quietness. As shown in FIG. 3, the scroll compressor includes a fixed scroll 50 having a spiral blade portion 51 on a bottom plate (flange) 52, and a scroll compressor that is substantially fitted facing the blade portion 51 of the fixed scroll. It consists of an oscillating scroll with a similarly shaped spiral blade and a bottom plate.

The oscillating scroll is made of aluminum alloy to reduce weight. The manufacturing method includes casting, die casting, forging, etc., but the manufacturing method by forging is advantageous from the viewpoints of strength and reliability as a part, molding into a complicated spiral shape, etc.

On the other hand, the oscillating scrolls used in automotive electric compressors are required to have excellent wear resistance. Ensures sex. In addition, in order to achieve thinner walls and lighter weight, it is also required that the root part of the blade, which bears the most load, has excellent mechanical strength (specifically, the tensile strength in the plane direction of the bottom plate of the scroll (required to be excellent at) That is, it is required to be excellent in both surface treatment properties and mechanical strength.

In Patent Document 1, as a high-strength wear-resistant aluminum alloy extruded material, Si: 6 to 12% (weight %, same 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%, and contains impurities. The average particle size of the eutectic Si particles dispersed in the matrix is 1.5 to 5.0 μm, and the balance is Al and impurities. A structure in which crystalline Si particles are present in a range of 5,000 to ^10,000 particles/mm ² is described.

Further, in Patent Document 2, it contains Si: 5 to 12% (mass%, the same hereinafter), Fe: 0.1 to 1%, Cu: less than 1%, Mg: 0.3 to 1.5%, The balance consists of Al and impurities, and the particle size of the eutectic Si particles dispersed in the matrix is 0.4 to 5.5 μm, and the particle size of the eutectic Si particles is 0.8 to 2.5 μm. A structure is described in which the size is 4 μm and occupies 60% or more, and the eutectic Si particles are present at 4000 pieces/mm ² or more and less than 40000 pieces/mm ² , and the film hardness Hv after alumite treatment is 400 or more. has been done.

Patent No. 3261056 Patent No. 4511156

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

In Patent Document 2, the film hardness after alumite treatment is Hv400 or more, but regarding mechanical strength, the extruded material described in the examples was subjected to a tensile test in the same direction as the extrusion direction, and the tensile test results It is evaluated only in a favorable direction. However, as mentioned above, in a scroll, the most important thing is the mechanical strength of the root part of the blade, which is subjected to the most load. Specifically, it is important that the bottom plate of the scroll has excellent tensile strength in the in-plane direction. be. In the case of an extruded material, the surface direction of the bottom plate of the scroll is perpendicular to the extrusion direction, so Patent Document 2 may not have sufficient mechanical properties.

The present invention was made in view of the above technical background, and the present invention provides a scroll member and a scroll forging that have excellent mechanical strength at the root portion of the blade, which is subjected to the greatest load, and in which an alumite film of sufficient hardness is formed. The purpose is to provide a method for manufacturing products.

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

[1] Si: 8.0 mass% to 12.0 mass%, Fe: 0.1 mass% to 0.5 mass%, Cu: 0.6 mass% to 1.1 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 0.8% by mass and the remainder consisting of Al and unavoidable impurities. ,
A scroll member characterized in that the bottom plate of the scroll forged product has a tensile strength in a plane direction of 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. %.

[3] The aluminum alloy further includes 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 at the above content rate. The scroll member according to item 1 or 2 above.

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

According to the invention [1], it is possible to provide a scroll member that has excellent mechanical strength at the root portion of the blade, which is subjected to the greatest load, and in which an alumite film of sufficient hardness is formed.

In the invention [2], the microstructure of the aluminum alloy can be made finer, and the mechanical strength can be further improved.

In the invention [3], by containing Mn, Cr or Zr, the microstructure of the aluminum alloy can be refined and the mechanical strength can be further improved, and by containing Mn, Cr or Zr, the mechanical strength can be further improved. In some cases, mechanical strength at high temperatures can be improved.

In the invention [4], by forging without extrusion, sufficient tensile strength in the plane direction of the bottom plate of the scroll forged product can be ensured, and the strength of the root portion of the blade, which is subjected to the most load, can be increased. We can secure enough.

FIG. 2 is a plan view showing an example of a scroll member according to the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 (the dotted line indicates the position where the tensile test piece is taken). It is a perspective view showing an example of a fixed scroll.

The scroll member 1 according to the present invention includes 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: 0.2% by mass to 0.8% by mass, and the remainder is Al and unavoidable impurities. (See FIG. 2), the scroll forged product 2 is characterized in that the bottom plate 21 has a tensile strength in the plane direction of 350 MPa or more and less than 400 MPa. With such a configuration, the scroll member 1 is provided which has excellent mechanical strength at the root portion of the blade portion 22, which is subjected to the greatest load, and in which the alumite film 3 of sufficient hardness is formed (Fig. 1, (see 2). Note that if the tensile strength in the plane direction exceeds 400 MPa, forging may become difficult.

An embodiment of a scroll member 1 according to the present invention is shown in FIGS. 1 and 2. The scroll member 1 includes a substantially disk-shaped bottom plate 21 and a spiral blade portion 22 protruding from the bottom plate 21 . This 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, and Sr: 0.001% by mass to 0.1% by mass. It is preferable to contain one or more metals selected from the group consisting of: at the above content rate. In this case, the microstructure of the aluminum alloy can be made finer, and the mechanical strength can be further improved.

Further, the aluminum alloy further includes 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, at the above content rate. is preferable. When Mn, Cr or Zr is contained, the microstructure of the aluminum alloy can be made finer and the mechanical strength can be further improved. Mechanical strength can be improved.

Next, a method for manufacturing a scroll forged product according to the present invention will be described. This production method includes 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, and Mg: 0% by mass. By forging an aluminum alloy continuous cast material containing .2% by mass to 0.8% by mass, with the remainder consisting of Al and unavoidable impurities, without extruding, the tensile strength in the plane direction of the bottom plate 21 is increased. The present invention is characterized by obtaining a scroll forged product having a pressure of 350 MPa or more and less than 400 MPa. According to this manufacturing method, sufficient tensile strength in the plane direction of the bottom plate 21 of the scroll forged product can be ensured, and sufficient strength can be ensured at the root portion of the blade, which is subjected to the greatest load.

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

The Si (component) can improve the strength of the aluminum alloy by precipitating Mg ₂ Si particles in coexistence with Mg, and also improves the strength and wear resistance due to the presence of eutectic Si. If the Si content is less than 8.0% by mass, the effect of increasing strength and wear resistance is poor. On the other hand, if the Si content exceeds 12.0% by mass, primary Si crystallizes and deteriorates surface treatment properties (alumite properties). Therefore, the Si content is in the range of 8.0% by mass to 12.0% by mass. Among these, 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 during heat treatment after forging, and improves the ductility and toughness of the scroll member. If the Fe content is less than 0.1% by mass, the effect of improving ductility and toughness is poor. On the other hand, if the Fe content exceeds 0.5% by mass, coarse Al-Fe-based or Al-Fe-Si-based crystallized substances increase, deteriorating surface treatment properties (alumite properties). Therefore, the Fe content is in the range of 0.1% by mass to 0.5% by mass. Among these, 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 effect of improving strength and hardness is 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. Among these, the Cu content is preferably in the range of 0.7% by mass to 1.0% by mass. Note that Cu is dissolved during alumite treatment, but since the dissolved Cu ions are noble metal ions, Cu precipitates again on the surface of the aluminum alloy base material, making it difficult to form an alumite film, and causing the film to deteriorate. However, by controlling the Cu content within the above range, the formability and density 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, thereby improving the strength of the aluminum alloy. If the Mg content is less than 0.2% by mass, the effect of improving strength is poor. On the other hand, when the Mg content exceeds 0.8% by mass, processability decreases. Therefore, the Mg content is in the range of 0.2% by mass to 0.8% by mass. Among these, the Mg content is preferably in the range of 0.3% by mass to 0.7% by mass.

Further, the aluminum alloy includes 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. It is preferable to contain one or more metals selected from the group consisting of the following at the above content rate. In other words, the inclusion of Ti and B both refine the structure of the ingot, prevent ingot cracking during casting, and further improve the workability of the ingot, making it easier to form complex shapes during forging. It is possible to mold it. If the Ti content is less than 0.01% by mass, the above effects will be poor. On the other hand, if the Ti content exceeds 0.3% by mass, huge intermetallic compounds will crystallize, which will have a negative effect on workability and alumite processability. Further, the inclusion of Sr makes the eutectic Si finer and improves workability and alumite property. If the Sr content is less than 0.001% by mass, the above effects will be poor. On the other hand, if the Sr content exceeds 0.1% by mass, the above effects will also be poor.

Further, the aluminum alloy further includes 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, at the above content rate. This is preferable for the following reasons. By containing these, Al-Mn particles, Al-Mn-Fe-Si particles, Al-Cr particles, Al-Cr-Fe-Si particles, Al-Ni particles, Al-Zr particles, By precipitating Al-V particles, recrystallization can be suppressed by heat treatment after forging, and ductility and toughness can be improved. When Mn is less than 0.01 mass%, Cr is less than 0.01 mass%, Ni is less than 0.01 mass%, Zr is less than 0.01 mass%, and V is less than 0.01 mass%, ductility is improved and toughness is improved. The improvement effect is small. When Mn exceeds 0.3 mass%, Cr exceeds 0.3 mass%, Ni exceeds 0.3 mass%, Zr exceeds 0.3 mass%, and V exceeds 0.1 mass%. , coarse crystallized substances increase, which adversely affects the alumite properties and reduces the ductility and toughness of the aluminum alloy.

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

<Example 1>
A molten aluminum alloy containing 8.0% by mass of Si, 0.25% by mass of Fe, 0.9% by mass of Cu, and 0.5% by mass of Mg, with the balance consisting of Al and unavoidable impurities is continuously heated on a hot top. 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 homogenization heat treatment by heating at 490° C. for 7 hours, and then surface milled to an outer diameter of 104 mm. Next, the cast material was cut to a thickness of 25 mm and heated to 200° C. in a heating furnace, immersed in graphite-based water-soluble lubricating oil for several seconds, and then taken out to form a lubricating film. Next, a scroll forged product shown in FIGS. 1 and 2 was obtained by forging a 25 mm thick cast material while heating it 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 subjected to alumite treatment. 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 with a thickness of about 40 μm on the surface of the scroll forged product 2. Thus, a scroll member 1 was obtained.

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

<Comparative example 14>
A cast material having an outer diameter of 203 mm and a length of 1000 mm was obtained by hot-top continuous casting of a molten aluminum alloy having the same composition as in Example 2. The obtained cast material was subjected to homogenization heat treatment by heating at 490° C. for 7 hours, and then extruded to an outer diameter of 104 mm. Next, the extruded material was cut to a thickness of 25 mm, heated to 200° C. in a heating furnace, immersed in 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 an extruded material having a thickness of 25 mm while heated to 400°C.

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

<Tensile strength test method>
To conduct a tensile test, an ASTM-R3 test piece was taken from the 10 mm thick bottom plate of the scroll member at the position shown by the dotted line in FIG. A tensile test was performed on the obtained test piece in the plane 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 number n was set to 3, and the average value of the three was taken as the tensile strength. In Table 2, those whose tensile strength was 350 MPa or more and less than 400 MPa were evaluated as "○", while those whose tensile strength was outside the above range were evaluated as "x".

<Yield strength measurement method>
The 0.2% proof stress at 25° C. was determined from the above tensile test results. The measurement results are shown in Tables 2 and 4. The number n was set to 3, and the average value of the three was set as 0.2% yield strength. In Tables 2 and 4, those with a 0.2% yield strength of 250 MPa or more and 300 MPa or less are marked with an evaluation of "○", while those whose 0.2% proof stress is outside the above range are marked with an evaluation of "×". did.

<Vickers hardness evaluation method of alumite film>
The scroll member on which the alumite film is formed is cut into a predetermined size, embedded in a resin frame, and the surface is micro-polished to the extent that the alumite film hardness can be measured.The Vickers hardness of the alumite film is then measured. was measured. The number n was set to 3, and the average value of the three was taken as the Vickers hardness. In Tables 2 and 4, those with a Vickers hardness (HV) of 400 or more are marked with an evaluation of "○", while those with a Vickers hardness (HV) of less than 400 are marked with an evaluation of "x".

As is clear from the table, the scroll members of Examples 1 to 16 have a tensile strength in the plane direction of the bottom plate of 350 MPa or more and less than 400 MPa, and have excellent mechanical strength at the root portion of the blade, which is subjected to the highest load. The Vickers hardness (HV) of the alumite film was 400 or more, and the hardness of the alumite film was high.

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

The scroll member according to the present invention is suitably used as an on-vehicle electric scroll for automobiles such as electric cars and hybrid cars.

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

Claims (4)

Si: 8.0 mass% to 12.0 mass%, Fe: 0.1 mass% to 0.5 mass%, Cu: 0.6 mass% to 1.1 mass%, Mg: 0.2 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 remainder consisting of Al and unavoidable impurities,
A scroll member characterized in that the bottom plate of the scroll forged product has a tensile strength in a plane direction of 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, and Sr: 0.001% by mass to 0.1% by mass. The scroll member according to claim 1 , containing one or more metals selected from the group consisting of: 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, and Zr. V : 0.01% by mass to 0.3% by mass, V: 0.01% by mass to 0.1% by mass. The scroll member described. Si: 8.0 mass% to 12.0 mass%, Fe: 0.1 mass% to 0.5 mass%, Cu: 0.6 mass% to 1.1 mass%, Mg: 0.2 mass% to By forging an aluminum alloy continuous cast material containing 0.8% by mass and the remainder consisting of Al and unavoidable impurities without extruding, the tensile strength in the plane direction of the bottom plate is 350 MPa or more and less than 400 MPa. A method for manufacturing a scroll forged product, the method comprising obtaining a scroll forged product.

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