JP2009144184A - Aluminum alloy for continuous casting, and forged article composed of the alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy for continuous casting which has high specific gravity and high rigidity, and also is excellent in wear-resistance. <P>SOLUTION: The aluminum alloy for continuous casting is characteristically composed of 13 to 16 mass% Si, 10 to 18 mass% Cu, 0.2 to 1 mass% Fe, and the balance Al with inevitable impurities. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aluminum alloy for continuous casting having high specific gravity and high rigidity and excellent wear resistance, and a forged product of the aluminum alloy.

As a compressor for an air conditioning system for a vehicle such as an automobile, a one-side swash plate type variable displacement compressor capable of accurately performing capacity control is often used. When the swash plate is rotated by this one-side swash plate type variable displacement compressor, centrifugal force due to its own weight and reciprocating inertia force due to piston weight act on the swash plate. In one-side swash plate type variable displacement compressors, the discharge flow rate increases at high speed rotation, so it is desirable to reduce the swash plate tilt angle so as to reduce the capacity. As a result, the compressor may be operated at a larger capacity than necessary. In order to solve the above problems and to increase the centrifugal force acting on the swash plate in order to accurately control the capacity, a material (iron-based, copper-based material, etc.) having a higher specific gravity than the piston is selected for the swash plate material. (See Patent Document 1). Further, it is considered that the swash plate material needs to have high rigidity due to the reciprocating inertia force of the piston.
JP 2002-81372 A

  However, in the case of the swash plate made of iron or copper, there is a problem that the former has a high material cost and the latter has a high processing cost such as cutting.

  The present inventor has conceived that an A390-based aluminum alloy having excellent wear resistance used in a double-headed piston type fixed displacement compressor is used as the material of the swash plate. Or there was a problem that specific gravity was too small compared with copper. In other words, the known aluminum alloys are excellent in wear resistance, high specific gravity and high rigidity.

  The present invention has been made in view of such a technical background, and provides an aluminum alloy for continuous casting and a forged product of an aluminum alloy having high specific gravity, high rigidity, and excellent wear resistance. Objective.

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

  [1] Aluminum alloy for continuous casting, comprising Si: 13-16% by mass, Cu: 10-18% by mass, Fe: 0.2-1% by mass, the balance comprising Al and inevitable impurities .

  [2] The aluminum alloy for continuous casting as described in 1 above, further containing 1-3% by mass of Zn.

  [3] The aluminum alloy for continuous casting as described in 1 or 2 above, further containing 0.4% by mass or less of Mg.

  [4] The aluminum alloy for continuous casting according to any one of items 1 to 3, further containing 0.003 to 0.015% by mass of P.

  [5] A forged molded product obtained by further forging a casting obtained by continuously casting the aluminum alloy according to any one of items 1 to 4.

  [6] The forged molded product according to item 5 above, wherein the forged molded product is used as a member for an air conditioner.

  [7] The forged molded product according to item 5 above, wherein the forged molded product is used as a swash plate of a one-side swash plate type variable capacity compressor.

  The aluminum alloy for continuous casting according to the invention of [1] contains 13 to 16% by mass of Si, so that sufficient wear resistance is obtained, and since it contains 10 to 18% by mass of Cu, it has high specific gravity and high rigidity ( High strength). Further, since Fe is contained in an amount of 0.2% by mass or more, the effect of increasing the specific gravity can be obtained, and since the upper limit of the Fe content is 1% by mass or less, the occurrence of ingot cracking during continuous casting is sufficiently reduced. it can.

  The aluminum alloy for continuous casting according to the invention of [2] further has a composition containing 1 to 3% by mass of Zn. By containing 1% by mass or more of Zn, the specific gravity and rigidity can be further improved, and when the Zn content is 3% by mass or less, the occurrence of ingot cracking can be sufficiently suppressed.

  Since the aluminum alloy for continuous casting according to the invention of [3] has a composition containing 0.4% by mass or less of Mg, the hardness can be improved.

  Since the aluminum alloy for continuous casting according to the invention of [4] has a composition containing 0.003 to 0.015% by mass of P, the primary Si is refined without deteriorating the melt fluidity ( For example, the average particle size can be reduced to 20 μm or less.

  The forged molded product according to the invention of [5] has high specific gravity, high rigidity and excellent wear resistance, and is therefore suitable as a member for air conditioning equipment, particularly as a swash plate for a one-side swash plate type variable capacity compressor. Used.

  The member for air-conditioning equipment (forged product) according to the invention of [6] has high specific gravity and high rigidity, and is excellent in wear resistance.

  The swash plate (forged product) of the one-side swash plate type variable capacity compressor according to the invention of [7] has high specific gravity and high rigidity and is excellent in wear resistance.

  The aluminum alloy for continuous casting according to the present invention contains Si: 13 to 16% by mass, Cu: 10 to 18% by mass, Fe: 0.2 to 1% by mass, and the balance is made of Al and inevitable impurities. Features. An aluminum alloy having such a composition has high specific gravity and high rigidity, and is excellent in wear resistance. Moreover, the occurrence of ingot cracking can be sufficiently reduced during continuous casting.

  In the casting aluminum alloy of the present invention, the Si content is set in the range of 13 to 16% by mass. If it is less than 13% by mass, it is difficult to obtain sufficient wear resistance, and if it exceeds 16% by mass, it is difficult to suppress the generation of coarse crystals. Especially, it is preferable that the content rate of Si is set to the range of 13-15 mass%.

  Further, the Cu content is set in a range of 10 to 18% by mass. If it is less than 10% by mass, sufficiently high strength and high specific gravity cannot be obtained, and if it exceeds 18% by mass, ingot cracking tends to occur. Especially, it is preferable that the content rate of Cu is set to the range of 10-14 mass%.

  Moreover, the content rate of Fe is set to the range of 0.2-1 mass%. The specific gravity and rigidity can be further improved by containing Fe by 0.2% by mass or more, and the occurrence of ingot cracking can be sufficiently prevented by making the Fe content 1% by mass or less. The generation of Al-Cu-Fe-based crystallized substances that can exert a sufficient resistance can be sufficiently prevented. Especially, it is preferable to contain 0.5-1 mass% of Fe.

  The aluminum alloy for casting according to the present invention preferably further contains 1 to 3% by mass of Zn. Inclusion of 1% by mass or more of Zn can further improve the specific gravity and rigidity, and the occurrence of ingot cracking can be sufficiently prevented by setting the Zn content to 3% by mass or less. Especially, it is especially preferable to contain 2-3 mass% of Zn.

  Moreover, it is preferable that the aluminum alloy for casting of this invention contains 0.4 mass% or less of Mg further. Hardness can be improved by containing Mg exceeding 0 mass%. In addition, even if the Mg content exceeds 0.4% by mass, there is only a slight improvement in strength. Especially, it is especially preferable to contain 0.3-0.4 mass% of Mg.

  Moreover, it is preferable that the aluminum alloy for casting of this invention contains 0.003-0.015 mass% of P further. By adding P in an amount of 0.003 mass% or more, primary crystal Si can be sufficiently refined. Even if the P content exceeds 0.015% by mass, no further refinement effect can be expected. Since coarse primary crystal Si may be the starting point of cracking or breaking during forging or when used as a product, forging can be improved forgeability and the durability of the product can be improved. It is preferable.

The aluminum alloy for continuous casting according to the present invention has a high specific gravity and high rigidity by having the above specific composition, and the high specific gravity is preferably 2.85 g / cm ³ or more. The high rigidity is preferably 85 kN / mm ² or more.

  When casting using the above aluminum alloy for casting, a known casting method such as a horizontal continuous casting method, a DC casting method, a hot top continuous casting method, a vertical continuous casting method, or the like can be used. Since the continuous casting method employs a method of drawing the ingot while casting, the freezing point moves at high speed, that is, the casting speed is fast (for example, 50 to 1500 mm / min), and ingot cracking occurs. In the alloy composition design, it is important to suppress the occurrence of ingot cracking in order to obtain stable operation and stable quality. Therefore, the effect of the alloy of the present invention is remarkable when casting by the continuous casting method.

  An example of casting by the horizontal continuous casting method will be described. FIG. 1 is a diagram illustrating an example of a continuous casting apparatus (3) that performs horizontal continuous casting. In this continuous casting apparatus (3), (31) is a tundish for storing the molten aluminum alloy (M) for continuous casting, and an opening (32) is provided on the side wall of the tundish (31). Yes. (33) is a refractory plate, and the refractory plate (33) is attached to the outside of the tundish (31) so as to surround the opening (32), and the opening (32). A pouring hole (34) communicating with is formed. (35) is a cylindrical mold, and the mold (35) is attached to the refractory plate (33) so that the central axis is substantially horizontal, and the mold (35) and the molten metal (M) Between the refractory plate (33) and the mold (35), a gas supply path (36) for supplying a gas, and a lubricant between the mold (35) and the continuous casting rod (41). A lubricating oil supply path (37) for supplying and a cooling water supply path (38) for supplying cooling water (39) to the periphery of the continuous casting rod (41) at the outlet are provided.

  The discharge port (38a) of the cooling water supply passage (38) is formed in an annular shape surrounding the continuous casting rod (41) and is provided in the casting direction of the continuous casting rod (41). Thus, the cooling water (39) ejected from the discharge port (38a) of the cooling water supply passage (38) is supplied to the entire circumferential direction of the continuous casting rod (41) and continuously cast. The continuous casting rod (41) is cooled by flowing in the casting direction on the surface of 41). The continuous casting rod (41) is cast through such cooling.

  Next, an example in which casting is performed by the DC casting method will be described. FIG. 2 is a diagram illustrating an example of a continuous casting apparatus (1) that performs DC casting. In this continuous casting apparatus (1), the molten aluminum alloy for continuous casting (M) stored in the gutter (17) is introduced into the water-cooled mold (13) through the float (16). The water cooling mold (13) is cooled by the cooling water (14). The molten aluminum alloy (M) introduced into the water-cooled mold (13) forms a solidified shell (solidified shell) at the portion in contact with the water-cooled mold (13), shrinks, and solidifies the aluminum alloy ingot (11). Is drawn downward from the water-cooled mold (13) by the lower mold (bottom block) (12). At this time, the aluminum alloy ingot (11) is further cooled by the spray cooling water (15) sprayed from the water-cooled mold (13) to be completely solidified. When the lower die (12) reaches the lowermost lower end, the aluminum alloy ingot (continuous casting rod) (11) is cut into a predetermined length at a predetermined position.

  Next, an example of casting by the hot top continuous casting method will be described. FIG. 3 is a diagram illustrating an example of a continuous casting apparatus (2) that performs continuous hot top casting. In the continuous casting apparatus (2), the molten aluminum alloy for continuous casting (M) stored above is introduced into the water-cooled mold (23). The water cooling mold (23) is cooled by cooling water (24). The molten aluminum alloy (M) introduced into the water-cooled mold (23) shrinks by forming a solidified shell (solidified shell) at a portion in contact with the water-cooled mold (23), and solidifies the aluminum alloy ingot (21). Is drawn downward from the water-cooled mold (23). At this time, the aluminum alloy ingot (21) is further cooled by the spray cooling water (25) sprayed from the water-cooled mold (23) to be completely solidified. The aluminum alloy ingot (continuous casting rod) (21) drawn downward is cut into a predetermined length at a predetermined position. In FIG. 3, (26) is a gas supply path, and (27) is a lubricating oil supply path.

  Thus, the continuous casting rods (41), (11), and (21) cast using the continuous casting apparatuses (1), (2), and (3) are preheated after being cut to a predetermined length as described above. Then, after passing through a step of setting up, a step of applying a lubricant, a step of forging and placing in a mold, the product is formed into a forged product. The forged molded product thus obtained uses an aluminum alloy having the above specific composition as an aluminum alloy for continuous casting as a starting material. It is suitably used as an apparatus member, particularly a swash plate (see FIG. 4) of a one-side swash plate type variable displacement compressor.

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

<Example 1>
Si: 14.5% by mass, Cu: 11.8% by mass, Fe: 1.00% by mass, Zn: 2.84% by mass, Mg: 0.01% by mass, Mn: 0.009% by mass, Ti: By continuously casting a molten aluminum alloy (M) of 0.013 mass%, the balance being Al and inevitable impurities, using a continuous casting apparatus (3) shown in FIG. 41) was obtained. Note that an aluminum alloy having an average molten metal temperature of 80 to 200 ° C. was continuously cast at a casting speed of 80 to 250 mm / min. When the same continuous casting was further performed twice using an aluminum alloy having this composition, a continuous cast bar could be obtained without any ingot cracking.

<Example 2>
As an aluminum alloy (molten metal), Si: 13.6 mass%, Cu: 12.1 mass%, Fe: 0.94 mass%, Zn: 2.80 mass%, Mg: 0.38 mass%, P: 0 .007 mass%, Mn: 0.014 mass%, Ti: 0.013 mass%, except that an aluminum alloy consisting of Al and inevitable impurities is used, by performing casting in the same manner as in Example 1, A continuous cast bar without ingot cracking was obtained. In addition, when the same continuous casting was further performed twice using an aluminum alloy having this composition, a continuous cast bar could be obtained without any ingot cracking.

<Comparative Example 1>
As an aluminum alloy (molten metal), Si: 13.9% by mass, Cu: 4.29% by mass, Fe: 0.10% by mass, Zn: 0.01% by mass, Mg: 0.49% by mass, P: 0 0.005% by mass, Mn: 0.014% by mass, Ti: 0.010% by mass, except that an aluminum alloy consisting of Al and inevitable impurities is used, by performing casting in the same manner as in Example 1, A continuous cast bar without ingot cracking was obtained.

<Comparative example 2>
As an aluminum alloy (molten metal), Si: 14.0 mass%, Cu: 12.3 mass%, Fe: 2.05 mass%, Zn: 2.80 mass%, Mg: 0.40 mass%, Mn: 0 Casting was performed in the same manner as in Example 1 except that an aluminum alloy composed of 0.010% by mass, Ti: 0.010% by mass, and the balance being Al and inevitable impurities was used.

<Example 3>
The continuous cast bar obtained in Example 2 is chamfered on its outer peripheral surface, cut to a predetermined length, and then forged to form a swash plate (forged) of the one-side swash plate type variable capacity compressor shown in FIG. Molded product) (50) was obtained.

  Various characteristics of each continuous cast bar (Example 1, Example 2, Comparative Example 1) obtained as described above were evaluated based on the following measurement methods. These evaluation results are shown in Table 2.

<Specific gravity measurement method>
Specific gravity (g / cm < ³ >) was measured based on JISZ8807-1976.

<Young's modulus measurement method>
The Young's modulus (kN / mm ² ) was measured according to JIS Z2241-1998.

<Method of measuring linear expansion coefficient>
The linear expansion coefficient (1 / K) was measured according to JIS Z2285-2003.

<Hardness measurement method>
Hardness (HRB) was measured according to JIS Z2245-2005.

  As is apparent from the table, the forging material obtained by casting the continuous casting aluminum alloy of Examples 1 and 2 of the present invention has higher specific gravity and higher rigidity than the conventional aluminum alloy, The linear expansion coefficient was also low. Moreover, both Examples 1 and 2 had good wear resistance.

  Moreover, the forging material obtained by casting the aluminum alloy for continuous casting of Example 2 containing 0.3 to 0.4% by mass of Mg obtained high hardness exceeding HRB90. Further, the forging material obtained by casting the aluminum alloy for continuous casting of Example 2 containing 0.003 to 0.015% by mass of P is less than that of Example 1 that does not contain P. The average particle size of can be made smaller.

  On the other hand, in Comparative Example 1 that deviates from the scope of the present invention, a sufficiently high specific gravity cannot be obtained, and a sufficiently high rigidity cannot be obtained. In Comparative Example 2 in which the Fe content exceeds the upper limit of the specified range of the present invention, ingot cracking occurred.

  Since the aluminum alloy for continuous casting of the present invention has high specific gravity and high rigidity and is excellent in wear resistance, the forged molded product cast and forged using this aluminum alloy is a member for air conditioning equipment, Among them, it is preferably used as a swash plate of a one-side swash plate type variable displacement compressor.

It is a figure which shows an example of the continuous casting apparatus used in casting the aluminum alloy for continuous casting of this invention. It is a figure which shows the other example of the continuous casting apparatus used in casting the aluminum alloy for continuous casting of this invention. It is a figure which shows the further another example of the continuous casting apparatus used in casting the aluminum alloy for continuous casting of this invention. It is a figure which shows the forge molded product (swash plate of a one-side swash plate type variable capacity compressor) obtained by further forging the continuous casting rod obtained by continuously casting the aluminum alloy for continuous casting of this invention, (a) is a perspective view, (b) is a side view.

Explanation of symbols

M ... Molten aluminum alloy 11, 21, 41 ... Continuous casting rod (cast)
50 ... Forged molded product (swash plate)

Claims (7)

  An aluminum alloy for continuous casting, comprising Si: 13 to 16% by mass, Cu: 10 to 18% by mass, Fe: 0.2 to 1% by mass, and the balance consisting of Al and inevitable impurities.   Furthermore, the aluminum alloy for continuous casting of Claim 1 which contains 1-3 mass% of Zn.   Furthermore, the aluminum alloy for continuous casting of Claim 1 or 2 containing 0.4 mass% or less of Mg.   The aluminum alloy for continuous casting according to any one of claims 1 to 3, further comprising 0.003 to 0.015 mass% of P.   A forged product obtained by further forging a casting obtained by continuously casting the aluminum alloy according to any one of claims 1 to 4.   The forged molded product according to claim 5, wherein the forged molded product is used as a member for an air conditioner.   The forged molded product according to claim 5, wherein the forged molded product is used as a swash plate of a one-side swash plate type variable capacity compressor.

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