Method for manufacturing scroll member

Abstract

To provide a method for manufacturing a scroll member that is able to reduce cost and shorten a manufacturing period.SOLUTION: The method for manufacturing a scroll member includes a forging step of forging a forging material made of an aluminum alloy, without upsetting the forging material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a scroll member. [Background technology]

[0002] Scroll compressors, which have few components and operate quietly, are known as air conditioner compressors. A scroll compressor is composed of, for example, a fixed scroll with a spiral-shaped wall blade on one side of a flat flange, and an oscillating scroll with a spiral-shaped blade of approximately the same shape that fits over the blade of the fixed scroll.

[0003] These fixed scrolls and orbiting scrolls (hereinafter simply referred to as scroll members) are generally manufactured from aluminum alloys to reduce weight. Examples of methods for manufacturing such scroll members include casting and forging. From the viewpoints of strength and reliability, forging is preferred, and hot forging is generally used due to the complexity of the shape (see, for example, Patent Document 1).

[0004] FIG. 7 is a diagram showing an example of a procedure for a conventional method for manufacturing a scroll member made of an aluminum alloy, and is a diagram showing the procedure for the method for manufacturing a scroll member disclosed in Patent Document 1. In the manufacturing method of a scroll member, the flow chart of which is shown in Figure 7, the alloy composition is first adjusted and then melted, and the molten aluminum alloy is cast by a continuous casting method into a billet (BL) for extrusion with a diameter of 200 mm or more. This BL is then heat-treated to homogenize the inside, and then cut to the desired length of the extrusion material. The cut billets are extruded into round bars (extruded round bars) of the desired diameter. This extruded round bar is then cut after being lubricated with cutting oil to become the material for forging.

[0005] The forging material is expanded in diameter to correspond to the outer diameter of the flange portion of the scroll member by hot upsetting at high temperatures. The hot-upset forging material is then forged after applying a lubricant to the forging material and die to prevent surface seizure. Specifically, after the cutting oil applied to the surface of the forging material has evaporated during hot upsetting, a liquid lubricant composed of graphite mixed with water or mineral oil is applied or sprayed onto the forging material. Furthermore, a liquid lubricant composed of graphite mixed with water or mineral oil is applied or sprayed onto the die. The graphite in the liquid lubricant plays an important role in preventing seizure in the scroll member being formed and is considered an essential component for preventing lubrication shortage. In this state, the forging material is placed in a die and processed into a desired shape by hot forging under pressure in a heated environment. After age hardening, the surface is machined to obtain the desired shape. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4744766 Summary of the Invention [Problem to be solved by the invention]

[0007] However, there is a demand for a method of manufacturing a scroll member that can reduce costs and shorten the manufacturing period.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a scroll member that can reduce costs and shorten the manufacturing period. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides the following means.

[0010] (1) A method for manufacturing a scroll member according to one aspect of the present invention includes a forging step in which a forging material made of an aluminum alloy is forged without upsetting.

[0011] (2) The method for manufacturing the scroll member of (1) above includes a casting step of casting a round bar made of an aluminum alloy containing 8.0 to 12.5 mass% Si, 1.0 to 5.0 mass% Cu, 0.2 to 1.3 mass% Mg, with the remainder being Al and unavoidable impurities; a cutting step of cutting the round bar to obtain a forging material; and a forging step of placing the forging material in a die and forging it, wherein in the cutting step, the round bar is lubricated with a carbon compound, and in the forging step, the forging material is lubricated with the carbon compound.

[0012] (3) The method for manufacturing the scroll member of (1) above includes a casting step of casting a round bar made of an aluminum alloy containing 8.0 to 12.5 mass% Si, 1.0 to 5.0 mass% Cu, 0.2 to 1.3 mass% Mg, 0.005 to 0.03 mass% Sr, with the remainder being Al and unavoidable impurities; a cutting step of cutting the round bar to obtain a forging blank; and a forging step of placing the forging blank in a die and forging the die; wherein in the cutting step, the round bar is lubricated with a carbon compound, and in the forging step, the forging blank may be lubricated with the carbon compound.

[0013] (4) In the method for manufacturing a scroll member according to (2) or (3) above, the carbon compound may be an oil-based cutting agent.

[0014] (5) In the method for manufacturing a scroll member according to any one of (2) to (4) above, the forging step may be carried out subsequent to the cutting step. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a method for manufacturing a scroll member that can reduce costs and shorten the manufacturing period. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a scroll member according to one aspect of the present invention. [Figure 2] 1 is a flowchart showing the steps of a method for manufacturing a scroll member according to one aspect of the present invention. [Figure 3] 3A to 3C are schematic views illustrating a forging step in a method for manufacturing a scroll member according to one embodiment of the present invention. [Figure 4] 4 is a schematic view illustrating a forging step in a method for manufacturing a scroll member according to one embodiment of the present invention, showing a state after FIG. 3. FIG. [Figure 5] 4 is a schematic view illustrating a forging step in a method for manufacturing a scroll member according to a modified example of FIG. 3. FIG. [Figure 6] 6 is a schematic view illustrating a forging step in a method for manufacturing a scroll member according to one embodiment of the present invention, showing a state after FIG. 5. FIG. [Figure 7] FIG. 1 is a flowchart showing an example of a conventional method for manufacturing a scroll member made of an aluminum alloy, and is a flowchart showing the procedure of the method for manufacturing a scroll member disclosed in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0017] A forging die for a scroll member according to one embodiment of the present invention and a method for manufacturing a scroll member using the die will be described below with reference to the drawings. The following embodiments are specifically described to provide a better understanding of the spirit of the invention, and unless otherwise specified, do not limit the present invention. Furthermore, the drawings used in the following description may show essential parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional proportions of the components may not necessarily be the same as those in reality.

[0018] [Scroll member] FIG. 1 is a perspective view of a scroll member according to one embodiment of the present invention. According to the method for manufacturing a scroll member of the present invention, a scroll member 1 as shown in FIG. 1 is manufactured. The scroll member 1 shown in FIG. 1 has, for example, a disk-shaped flange 2 and a vane portion 3 which is a spiral wall portion protruding in the height direction from one surface 2a of the flange 2. In such scroll member 1, the flange 2 and the vane portion 3 are integrally formed by plastically flowing a forging material using a forging die described below.

[0019] The height h1 of blade portion 3 from one surface 2a of flange 2 is, for example, 40 mm or less, preferably less than 30 mm, more preferably 25 mm or less, and even more preferably 20 mm or less. The height h1 of blade portion 3 from one surface 2a of flange 2 may be 10 mm or more.

[0020] The thickness of the blade portion 3 is, for example, 4.0 to 7.0 mm, and preferably 5.0 to 6.0 mm. The blade portion 3 is formed so that the ratio of the height h1 to the thickness is, for example, about 2 to 5 times.

[0021] The scroll member 1 is made of, for example, an aluminum alloy to reduce weight. The aluminum alloy scroll is typically made of an aluminum alloy containing Si to provide wear resistance. The added Si crystallizes as fine particles, which enhances wear resistance against the mating material. An example of the composition of the aluminum alloy used for the scroll member 1 is 8.0 to 12.5 mass% Si (silicon), 1.0 to 5.0 mass% Cu (copper), and 0.2 to 1.3 mass% Mg (magnesium), with the remainder being Al (aluminum) and unavoidable impurities.

[0022] Up to a Si content of approximately 11% by mass, fine eutectic Si particles of several micrometers in size are dispersed and crystallized in the Al matrix in proportion to the Si content, enhancing the wear resistance of this alloy. Therefore, a higher Si content is preferable; a Si content of 8.0% or more by mass provides high wear resistance for sliding parts such as scrolls. When the Si content exceeds 12.5% by mass, Si crystallizes as primary crystals, which tend to coarsen, reaching sizes of several tens of micrometers. This can lead to problems with the saw blade during cutting, or with the cutting edge of the tool chipping during post-processing. Furthermore, if the primary crystals are unevenly distributed in areas near the outer surface of the forged product where stress concentration is likely to occur, they can become fracture bases and reduce mechanical strength. Therefore, a Si content of 12.5% by mass or less is preferred.

[0023] Addition of Cu in an amount of a few percent by mass improves the strength of the Al matrix during subsequent heat treatment and also contributes to wear resistance. Cu content of 1.0 mass% or more contributes to improved strength, but even if it exceeds 5.0 mass%, the effect of improving strength saturates. Therefore, the Cu content is set to 1.0 to 5.0 mass%.

[0024] Mg combines with Si to form fine precipitates of Mg2Si after heat treatment, contributing to product hardening. It also forms precipitates as an MgSiCu compound after heat treatment, contributing to product hardening, both of which increase strength. This effect is easily achieved with a Mg content of 0.2% or more by mass, but the effect does not improve even if the content exceeds 1.3% by mass. Furthermore, oxides are generated and mixed in during casting, resulting in defects. Therefore, the Mg content is set at 0.2 to 1.3% by mass.

[0025] In the present invention, the aluminum alloy may contain 2.0 mass% or less of Ni to increase the heat resistance strength, if necessary. An amount exceeding 0.1 mass% is effective, and a content of 2.0 mass% or less makes it difficult for coarse crystals to form. Therefore, the amount of Ni added is preferably in the range of 0.1 to 2.0 mass%.

[0026] This aluminum alloy utilizes so-called eutectic Si as one factor for wear resistance, but in order to disperse this eutectic more uniformly and finely and to suppress the occurrence of coarse primary crystals, one or more elements selected from Sr, Ca, Na, Sb, etc. can be added in a total amount of up to 0.5 mass%. Preferably, Sb is 0.05 to 0.5 mass% and Sr is 0.005 to 0.05 mass%, and Sr in particular is desirable because even a small amount of addition is effective and Sr is less likely to lose weight due to oxidation during melting.

[0027] The scroll member 1 of the present invention is not limited to the above example. For example, the aluminum alloy used for the scroll member 1 may have a composition containing 8.0 to 12.5 mass% Si, 1.0 to 5.0 mass% Cu, 0.2 to 1.3 mass% Mg, and 0.005 to 0.03 mass% Sr, with the remainder being Al and unavoidable impurities.

[0028] [Method of manufacturing scroll member] 2 is a flow chart showing the steps of a method for manufacturing a scroll member according to one embodiment of the present invention. The method for manufacturing a scroll member according to the present invention includes a forging step in which a forging material made of an aluminum alloy is forged without upsetting. The method for manufacturing a scroll member according to one embodiment of the present invention includes, for example, a melting step, a casting step, a cutting step, a forging step, a solution treatment step, an aging treatment step, and a cutting step, in this order. In addition, a homogenization treatment step and a peeling step may be performed between the forging step and the cutting step.

[0029] (melting process) First, raw materials are melted to obtain an aluminum alloy having the above-mentioned composition. That is, in the melting step, raw materials adjusted to the above-mentioned composition ratio are melted to obtain an aluminum alloy having a composition containing, for example, 8.0 to 12.5 mass% Si, 1.0 to 5.0 mass% Cu, 0.2 to 1.3 mass% Mg, and the balance being Al and unavoidable impurities, or 8.0 to 12.5 mass% Si, 1.0 to 5.0 mass% Cu, 0.2 to 1.3 mass% Mg, and 0.005 to 0.03 mass% Sr, and the balance being Al and unavoidable impurities.

[0030] (Casting process) Next, the molten raw material is used to cast a round bar made of aluminum alloy. Casting is preferably performed by continuous casting in parallel with the melting step. The diameter of the aluminum alloy round bar is the diameter of the recess 21 of the die 20A used in the forging step described below, and is formed to be a size corresponding to the outer diameter of the flange 2 of the scroll member to be manufactured. For example, a round bar with a diameter of about 85 to 95 mm is formed.

[0031] (Homogenization heat treatment process) The round bar obtained by the casting process may be subjected to a homogenization heat treatment process. The homogenization heat treatment process eliminates segregation of the added elements that occurs during casting to homogenize the composition, precipitates the supersaturated solid solution that occurs during solidification during casting, and converts the metastable phase that formed during solidification during casting to an equilibrium phase. The heating temperature in the homogenization heat treatment is, for example, in the range of 420°C to 500°C.

[0032] (Peeling process) Before the cutting step, the surface of the aluminum alloy round bar formed by casting may be chamfered by peeling. Peeling improves the accuracy of the material diameter and the surface condition of the outer periphery.

[0033] (cutting process) Next, the round bar is cut into a forging blank. In the cutting process, the forging blank is lubricated with a carbon compound, and the forging blank with its surface lubricated is cut to a predetermined thickness. During the cutting process, the entire surface of the forging blank is lubricated with the carbon compound.

[0034] As the carbon compound, an oil-based cutting agent such as mineral oil or animal or vegetable oil can be used. As the carbon compound, both water-soluble and water-insoluble cutting oils can be used. As the carbon compound, for example, one that does not contain graphite can be used.

[0035] (Forging process) Next, the forging blank obtained by cutting in the cutting process is forged without upsetting. The forging process is, for example, a process in which the forging process is performed following the cutting process, and is performed with the carbon compound applied in the cutting process remaining on the surface of the forging blank. Therefore, in the forging process, the forging blank is lubricated by the carbon compound. The forging process is performed, for example, within a period in which the carbon compound applied to the entire surface of the forging blank, including the cut surface, used to lubricate the forging blank does not evaporate. The forging process is performed, for example, within one month after the cutting process.

[0036] The forging step can be performed using an apparatus such as that shown in Fig. 3. Fig. 3 is a schematic view illustrating the forging step in the method for manufacturing a scroll member according to one embodiment of the present invention. Fig. 4 is a schematic view illustrating the forging step in the method for manufacturing a scroll member according to one embodiment of the present invention, showing the state after the method shown in Fig. 3. Figs. 3 and 4 show cross sections of a forging material 10, a die 20A, a punch 15, etc.

[0037] As shown in Fig. 3, the forging process is performed by applying pressure to the forging material 10 using a die 20A and a punch 15. The die 20A is formed entirely from a forging die alloy such as chromium-molybdenum steel or chromium-molybdenum-vanadium steel. The die 20A is formed with a recess 21 recessed in a depth direction perpendicular to the top surface 20a, and a die space 22A extending in the depth direction from the bottom surface 21a of the recess 21. The die space 22A penetrates the die 20A in the depth direction of the recess 21.

[0038] During forging, for example, a disk-shaped forging material 10 is placed in recess 21. Recess 21 may be formed to match the shape of flange 2 (see FIG. 1) of scroll member 1 to be forged, and may have any inner shape other than the cylindrical shape of this embodiment, such as a square tube shape.

[0039] The die space 22A is formed in a spiral shape that resembles the shape of the blade portion 3 of the scroll member 1 to be forged.

[0040] For example, a knockout pin 30 is inserted into the die space 22A of the die 20A. The knockout pin 30 includes a back pressure plate 31, a knock pin 32 extending in a direction perpendicular to the back pressure plate 31, and a knockout 33 provided at the tip of the knock pin 32. The knockout pin 30 is connected to, for example, a back pressure device (not shown) so as to be able to apply back pressure. The knock pin 32 and the knockout 33 are formed in a spiral shape that resembles the shape of the vane portion 3 of the scroll member 1 to be forged. The knockout pin 30 is provided so as to be movable in the depth direction of the die space 22A of the die 20A during forging. The height h1 of the vane portion 3 of the scroll member 1 is determined depending on the position of the knockout pin 30 at the end of the forging process.

[0041] The die 20A and the knockout 33 are lubricated with a liquid lubricant made by mixing graphite with water or mineral oil. The surfaces of the die 20A and the knockout 33 are lubricated by, for example, directly spraying the lubricant onto them.

[0042] At the start of the forging process, the knockout pin is inserted into the die space 22A up to the vicinity of the upper end thereof (FIG. 3). The upper end of the die space 22A is flush with the bottom surface 21a of the recess 21.

[0043] As the punch 15 begins to push the forging material 10 into the die space 22A and the forging material 10 begins to grow into a wing, pressure from the back pressure device in the direction opposite to the direction in which the punch 15 presses the forging material 10 is applied to the tip of the wing through the back pressure plate 31, knock pin 32, and knockout 33, causing the wing to grow uniformly. In Figures 3 and 4, the direction in which the punch 15 presses the forging material 10 and the direction of the back pressure applied to the forging material 10 by the knockout pin 30 are indicated by arrows.

[0044] During forging, the amount of metal flowing into the die space 22A can be made more uniform by applying back pressure. If the amount of metal flowing into the die space 22A can be made uniform, the uniformity of the height of the vane portion 3 can be improved. The surface pressure on the tip of the vane portion 3 can be, for example, 40 to 120 N / mm at a constant back pressure. 2 and 60 to 100 N / mm 2 It is preferable that:

[0045] Furthermore, the back pressure applied to the tip of the blade portion by the knockout pin 30 may be constant or may vary over time from the initial back pressure. For example, the back pressure applied to the tip of the blade portion may be maintained at an initial back pressure (Pfull) until the blade portion reaches a predetermined length, and then gradually decreased after the blade portion reaches the predetermined length. The final back pressure at the end of the forging process may be less than half the initial back pressure (Pfull). By varying the back pressure so that it decreases over time as described above, it is possible to prevent the filling rate of the recess 21 from being reduced due to the pull of the metal flowing into the blade portion. In this case, the final pressure at the end of the forging process is set to be equal to or less than the deformation stress of the forging blank 10. The deformation stress is the stress in the die space 22A, i.e., the stress in the blade formation direction. If the back pressure is equal to or less than the deformation stress, the workpiece flowing into the blade-forming portion will not be deformed by the back pressure, resulting in improved molding accuracy of the blade portion. Specifically, 40 to 120 N / mm 2 is appropriate, and preferably 60 to 100N / mm 2 is.

[0046] The depth d of the surface of knockout 33 on the recess 21 side from bottom surface 21a of recess 21 at the end of the forging process corresponds to the height h1 of blade portion 3 of the formed scroll member 1. The depth d is, for example, 40 mm or less, preferably less than 30 mm, more preferably 25 mm or less, and even more preferably 20 mm or less.

[0047] The forging process may be performed by hot forging or cold forging, for example. The heating temperature of the forging material 10 in hot forging is, for example, in the range of 350°C or more and 450°C or less.

[0048] During forging, as the blade portion 3 is formed, there are cases where parts that are not lubricated with the carbon compound are partially exposed, but by setting the depth d within this range, it is possible to prevent the blade portion 3 from becoming excessively large and to prevent the unlubricated parts from being exposed. If the unlubricated parts are exposed, it is possible to prevent seizure from occurring due to contact between the molded blade portion 3 and the mold 20A.

[0049] (Solution treatment process), (Aging treatment process) As described above, the scroll member 1 having the blade portions 3 formed therein with a predetermined height is preferably subjected to solution treatment and aging treatment to enhance strength and wear resistance. The solution treatment and aging treatment are treatments in which the material is heated to a predetermined temperature, quenched, and then held at another predetermined temperature for a predetermined period of time. For example, the solution treatment temperature is preferably 490 to 500°C, and after water quenching, age hardening can be achieved by selecting appropriate conditions such as 160 to 210°C (preferably 170 to 190°C) for 1 to 8 hours (preferably 3 to 6 hours), resulting in a forged product with sufficient hardness of approximately HRB 70 to 85.

[0050] Furthermore, the forged product after the heat treatment can be assembled into a compressor or the like as a scroll member 1 by precision cutting, mainly to adjust the height h1, shape, etc. of the blade portion 3, as required.

[0051] The scroll member 1 shown in FIG. 2 can be manufactured by the above-described method for manufacturing the scroll member.

[0052] According to the scroll member manufacturing method of this embodiment, scroll member 1 can be manufactured without the hot upsetting step and forging material lubrication step that are required in the conventional method as shown in Fig. 7, and while suppressing the occurrence of seizure. Therefore, according to the scroll member manufacturing method of this embodiment, it is possible to provide a scroll member manufacturing method that can reduce costs and shorten manufacturing time.

[0053] In the method for manufacturing a scroll member according to this embodiment, the forging process is performed without performing the upsetting process after the cutting process. Therefore, the carbon compound used to lubricate the round bar in the cutting process does not volatilize before the forging process, and separate lubrication of the forging material is not required. Conventionally, it has been thought that different lubricants must be used for the forging material and the round bar. Specifically, because both the forging material and the die are made of metal in the forging process, it has been thought that a lubricant containing graphite (not contained in cutting oil) must be used to prevent seizure. However, by forming the blade portion 3 within the above-described range, it is possible to prevent lubrication shortage and seizure even when the forging material is not newly lubricated and the forging process is performed with the carbon compound used in the cutting process applied to the carbon compound.

[0054] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a forging process using a die as shown in Figures 5 and 6 may be performed.

[0055] Fig. 5 is a schematic diagram illustrating the forging step in the method for manufacturing a scroll member according to the modified example of Fig. 3. Fig. 6 is a schematic diagram illustrating the forging step in the method for manufacturing a scroll member according to one embodiment of the present invention, showing the state after Fig. 5. Figs. 5 and 6 show cross sections of the forging material 10, die 20B, punch 15, etc.

[0056] The die 20B shown in Fig. 5 differs from the die 20A shown in Fig. 3 and Fig. 4 in that it does not have a die space 22A but has a groove portion 22Ba. In Fig. 5 and Fig. 6, the same components as those in the die 20A are denoted by the same reference numerals and their explanations will be omitted.

[0057] Groove portion 22Ba is formed in a spiral groove shape that resembles the shape of the blade portion 3 of the scroll member 1 to be forged. In die 20B, unlike die space 22A, most of groove portion 22Ba does not penetrate in the depth direction of recess 21 and is closed at one end. That is, groove portion 22Ba of die 20B has bottom portion 22b in the depth direction of recess 21. Depth d from bottom surface 21a of recess 21 to the bottom of groove portion 22Ba is the height h1 of the blade portion 3 of the scroll member 1 to be molded. Depth d from bottom surface 21a of recess 21 to groove 22Ba is, for example, 40 mm or less, preferably less than 30 mm, more preferably 25 mm or less, and even more preferably 20 mm or less.

[0058] As described above, the groove 22Ba of the die 20B includes a closed bottom portion, and no back pressure is applied during the forging process.

[0059] On the other hand, the groove 22Ba is provided with a hole 22Bb into which a pin member (knock pin) 32 is inserted for pushing out and removing the molded scroll. The maximum diameter of the hole 22Bb is configured to be smaller than the diameter of the groove 22Ba. For convenience of explanation, in FIGS. 5 and 6, the diameter of the hole 22Bb is shown larger than the diameter of the pin member 32. However, it is preferable that the diameter of the hole 22Bb be narrowed to the extent that the pin member 32 can push out the forged product. In other words, it is preferable that the diameter of the pin member 32 is equal to the diameter of the hole 22Bb. During the forging process, the tip of the pin member 32 may be flush with the bottom surface of the groove 22Ba or may be located below the bottom surface of the groove 22Ba.

[0060] The forging process using the die 20B can be performed under conditions where the die 20B is lubricated. The lubricant used to lubricate the die 20B can be the same carbon compound as can be used to lubricate the die 20A.

[0061] Even when the forging process is performed using the die 20B, the forging material obtained by cutting in the cutting process is forged without being upset. The forging process is, for example, a process in which the forging process is performed following the cutting process, and is performed with the carbon compound applied in the cutting process remaining on the surface of the forging material.

[0062] 5 and 6, a scroll member can be manufactured by forging an aluminum alloy forging material without upsetting it using a die 20B having a groove 22Ba with one end closed, omitting the upsetting process and the forging material lubrication process, and suppressing the occurrence of seizure. Therefore, the present invention can provide a method for manufacturing a scroll member that can reduce costs and shorten the manufacturing period.

[0063] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0064] According to the scroll member manufacturing method of the above embodiment, the forging process can be performed under lubricated conditions with the carbon compound used to cut the forging blank, eliminating the need for the upsetting process and the lubrication process for the forging blank, which require treatment in a high-temperature environment. As a result, the number of steps required to manufacture the scroll member, as well as the manufacturing costs and time required for manufacturing can be significantly reduced. [Explanation of symbols]

[0065] 1 Scroll member 2 flanges 2a one side 3. Wing 10 Forging materials 15 punch 20a top surface 20A, 20B molds 21 Recess 21a Bottom 22A Dice Space 22Ba Groove 22Bb hole 30 knockout pin 31 Back pressure plate 32 Knock pin 33 Knockout

Claims

1. A method for manufacturing a scroll member, comprising a forging step in which a forging material made of an aluminum alloy is forged without upsetting.

2. a casting step of casting a round bar made of an aluminum alloy containing 8.0 to 12.5 mass% of Si, 1.0 to 5.0 mass% of Cu, 0.2 to 1.3 mass% of Mg, and the balance being Al and unavoidable impurities; a cutting step of cutting the round bar into a forging material; a forging step of placing the forging material in a die and forging it, In the cutting step, the round bar is lubricated with a carbon compound, 2. The method for manufacturing a scroll member according to claim 1, wherein the forging material is lubricated with the carbon compound during the forging process.

3. a casting step of casting a round bar made of an aluminum alloy containing 8.0 to 12.5 mass% of Si, 1.0 to 5.0 mass% of Cu, 0.2 to 1.3 mass% of Mg, 0.005 to 0.03 mass% of Sr, and the balance being Al and unavoidable impurities; a cutting step of cutting the round bar into a forging material; a forging step of placing the forging material in a die and forging it, In the cutting step, the round bar is lubricated with a carbon compound, 2. The method for manufacturing a scroll member according to claim 1, wherein the forging material is lubricated with the carbon compound during the forging process.

4. The method for manufacturing a scroll member according to claim 2 or 3, wherein the carbon compound is an oil-based cutting agent.

5. The method for manufacturing a scroll member according to claim 2 or 3, wherein the forging step is carried out subsequent to the cutting step.

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