JPH04272149A - Aluminum alloy for compressor parts - Google Patents

Abstract

PURPOSE:To obtain an aluminum allay having high strength and wear resistance as well as high cold workability and suitable for uses such as a piston and a plate used for a compressor of an air conditioner. CONSTITUTION:This is an aluminum allay for compressor parts contg., by weight, 6 to 13% Si, 0.15 to 0.5% Mg, 0.4 to 3.0% Cu, 0.05 to 0.5% Ni and 0.05 to 0.5% Mn, furthermore contg. one or >= two kinds among 0.05 to 0.5% Cr, 0.01 to 0.5% Ti and 0.05 to 0.25% Zr and the balance Al with impurities or is a one excellent in cold workability obtd. by subjecting the above allay to total >=20% working by forging or extruding to regulate the average grain size of Si to <=20mum and regulating its elongation after hardening and tempering treatment to >=5%.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an aluminum alloy suitable for parts such as pistons and plates used in air conditioner compressors that require high strength, wear resistance, and strong cold workability. .

0002

[Prior Art and its Problems] Conventionally, iron-based materials have been used for parts of compressors for room air conditioners and car air conditioners that are subject to strong friction. Recently, aluminum alloy parts have been increasingly used in car air conditioner compressors to reduce weight. For such parts, aluminum alloys are used, in which Al contains Si to improve wear resistance, and Cu and Mg are added to increase strength. In addition, in recent years, especially in car air conditioners, aluminum alloys with better wear resistance have been required due to regulations on fluorocarbon gas, making it necessary to change from conventional cast parts to forged parts with superior strength and wear resistance. It's coming. As mentioned above, conventional compressors also use Al-Si aluminum alloys,
These have been used in the form of a forged product finished by cutting. Recently, there has been a trend towards single-sided swash plate type compressors, and in this case the piston and rod plate are ultimately connected to the connecting rod by caulking. Conventionally used Al-Si alloys lack ductility when subjected to heat treatments such as quenching and tempering to increase strength, and cracks occur during caulking. Caulking is possible if it is softened by annealing, but
There were problems such as insufficient strength and abrasion resistance, and the caulked parts loosened during use.

0003

SUMMARY OF THE INVENTION The present invention has developed an aluminum alloy that has the strength and wear resistance required for compressor parts and is capable of cold working such as caulking.

0004

[Means for Solving the Problems] The present invention provides Si6-13
Weight %, Mg 0.15-0.5 weight %, Cu 0.4-3
．． 0% by weight, Ni0.05-0.5% by weight, Mn0.0
Contains 5-0.5% by weight, and Cr0.05-0.5
Weight%, Ti0.01~0.5wt%, Zr0.05~
It is an aluminum alloy for compressor parts containing 0.25% by weight of one or more kinds, and the remainder consists of impurities and Al, and also contains 6 to 13% by weight of Si, and 0.1% of Mg.
5-0.5% by weight, Cu0.4-3.0% by weight, Ni0
．． Contains 0.05 to 0.5% by weight, 0.05 to 0.5% by weight of Mn, and 0.05 to 0.5% by weight of Cr, and 0.0% of Ti.
1 to 0.5% by weight, Zr 0.05 to 0.25% by weight.
elongation after quenching and tempering an aluminum alloy containing one or more species and the remainder consisting of impurities and Al, processed by forging or extrusion to a total of 20% or more, with an average Si grain size of 20 μm or less This is an aluminum alloy for compressor parts that has excellent cold workability with a content of 5% or more.

[0005]

[Operation] The alloy composition of the alloy of the present invention will be explained below. Si is added for the purpose of improving wear resistance, but if it is less than 6% (hereinafter referred to as % by weight), the wear resistance is insufficient.
If it exceeds %, primary Si crystals will be generated coarsely and cold workability will deteriorate. Mg has the effect of improving strength, but 0.15%
If it is less than 0.5%, the effect is insufficient, and if it exceeds 0.5%, cold workability is reduced. Cu also improves strength and wear resistance, but if it is less than 0.4%, it has no effect, and if it exceeds 3.0%, it significantly reduces corrosion resistance. Ni has the effect of suppressing a decrease in strength in a heat-generating environment during use, but if it is less than 0.05%, this effect is not recognized, and if it exceeds 0.5%, it deteriorates corrosion resistance and cold workability. Mn improves stress corrosion cracking resistance and toughness, but 0
．． If it is less than 0.05%, the effect is insufficient, and if it exceeds 0.5%, cold workability will deteriorate. Like Mn, Cr has the effect of improving stress corrosion cracking resistance and toughness, but if it is less than 0.05%, no effect is produced, and if it exceeds 0.5%, cold workability is significantly reduced. Ti has the effect of refining crystal grains, but 0.0
If it is less than 1%, the effect is insufficient, and if it exceeds 0.5%, coarse crystallized substances are generated, which significantly reduces cold workability. Zr has the effect of improving stress corrosion cracking resistance, but 0.0
If it is less than 5%, the effect is insufficient, and if it exceeds 0.25%, coarse crystallized substances are produced, which significantly deteriorates cold workability. Next, the characteristics of this alloy will be explained. In conventional castings or parts with a working degree of less than 20%, the cast structure remains in the metallographic structure, the elongation of the material is small, and cold workability is poor. Therefore, it is essential to process the material by 20% or more by forging or extrusion to eliminate any cast structure and obtain a processed structure. Further, while Si particles have the effect of improving wear resistance, coarse particles deteriorate cold workability. When the average grain size exceeds 20 μm, cold workability deteriorates significantly. Further, in order to withstand strong caulking, elongation is required to be 5% or more, and the alloy needs to have a composition that provides elongation of 5% or more even after quenching and tempering.

[0006]

[Embodiment] An embodiment of the present invention will be described below. Example 1 An aluminum alloy having the chemical composition shown in Table 1 was cast into an ingot with an outer diameter of 140 mm by the DC method, homogenized at 470°C for 12 hours, then heated again to 450°C, and an ingot with an outer diameter of 9 mm was cast.
Hot extrusion was performed on a 0 mm round bar. Thereafter, samples were taken from the material which was cold-drawn to an outer diameter of 80 mm and the total degree of working was 67%, and the tensile strength, elongation, caulking property, and wear resistance were evaluated. That is, the tensile strength and elongation were determined by a tensile test of a cut sample, and caulking property was evaluated by caulking a sample processed into a pipe shape and determining the ease with which cracks occur. Wear resistance was compared by determining the specific wear amount using an Okoshi type abrasion tester.

[0007]

[Table 1]

The results are shown in Table 2. The alloy of the present invention has an elongation of 5% or more, and is excellent in both caulking property and wear resistance. Among the comparative alloys, mainly the JIS 4032 alloy of sample No. 4, high-strength alloys have low elongation and poor caulking properties, and low-strength alloys have poor wear resistance. In contrast, the alloy of the present invention is excellent in both properties.

[0009]

[Table 2]

Example 2 An alloy having the chemical composition of Invention Alloy 1 of Example 1 was prepared with an outer diameter of 60 m.
It was cast into continuous casting rods of m. Samples were cut out from this round bar, processed at different rates by upsetting using a cold forging machine, and the average Si grain size was determined using a metallurgical microscope. At the same time, Example 1
Elongation, caulking properties, and abrasion resistance were evaluated in the same manner as above.

[0011]

[Table 3]

The results are shown in Table 3. When the working degree is small, the average Si particle size is large, the elongation is low, and the caulking property is significantly deteriorated. In contrast, the material of the present invention has a small average Si particle size, high elongation, and excellent caulking properties and wear resistance.

[0013]

[Effects of the Invention] As explained above, the alloy of the present invention has excellent strength, wear resistance, and caulking properties, and is an optimal material for applications such as compressor pistons and plates.

Claims (2)

[Claims] [Claim 1] Si6 to 13% by weight, Mg0.15 to
0.5% by weight, Cu0.4-3.0% by weight, Ni0.0
5 to 0.5% by weight, Mn 0.05 to 0.5% by weight, and Cr 0.05 to 0.5% by weight, Ti 0.01 to
An aluminum alloy for compressor parts containing 0.5% by weight of Zr, one or more of 0.05 to 0.25% by weight of Zr, and the remainder consisting of impurities and Al. [Claim 2] Si6 to 13% by weight, Mg0.15 to
0.5% by weight, Cu0.4-3.0% by weight, Ni0.0
5 to 0.5% by weight, Mn 0.05 to 0.5% by weight, and Cr 0.05 to 0.5% by weight, Ti 0.01 to
An aluminum alloy containing one or more of 0.5% by weight, 0.05 to 0.25% by weight of Zr, and the balance consisting of impurities and Al is processed by forging or extrusion to a total of 20% or more, and the Si average An aluminum alloy for compressor parts that has a grain size of 20 μm or less and has an elongation of 5% or more after quenching and tempering, and has excellent cold workability.