JPH083701A - Production of wear resistant aluminum alloy extruded material excellent in strength and machinability - Google Patents

Abstract

PURPOSE:To produce an aluminum alloy material excellent in strength, wear resistance and chip treatability. CONSTITUTION:An aluminum alloy having a compsn. contg. 8 to 12% Si, 1.5 to 4% Cu, 0.2 to 1.0% Mg, 0.25 to 0.6% Mn and 0.01 to 0.1% Sr, furthermore contg. one or two kinds of 0.05 to 0.3% Cr and 0.05 to 0.25% Zr, and the balance Al with inevitable impurities is subjected to semicontinuous casting. This aluminum allay cast ingot is subjected to homogenizing treatment at 480 to 540 deg.C for <=1hr, thereafter subjected to extrusion at 400 to 500 deg.C, then subjected to solution treatment at 490 to 540 deg.C, thereafter subjected to cold drawing at 5 to 15% working ratio and subjected to artificial aging treatment at 160 to 200 deg.C for 2 to 16hr so as to regulate its elongation to <=10%. Thus, the aluminum alloy material having high strength and excellent wear resistance and furthermore excellent in chip treatability can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aluminum alloy extruded material which is excellent in strength, machinability and wear resistance and is therefore suitable as a material for air-conditioning equipment parts processed by cutting.

[0002]

2. Description of the Related Art In recent years, sliding parts such as cylinders and pistons in air conditioners and industrial equipment have wear resistance to reduce weight. Al-Si alloy: Si: 11 .About.13.5% by weight of Al-eutectic Si-based alloy JIS4032 has come to be used. However, recently, as the needs for size reduction, weight reduction and high performance have become more severe, it has been required to improve the properties of conventional Al alloy materials. For the above-mentioned parts obtained by cutting the product shape, wear resistance, Good machinability with strength,
For example, the chip disposability at the time of cutting is becoming more important.

[0003]

However, although the conventional Al-Si alloys are excellent in wear resistance, they are inferior in machinability, especially in chip disposability. Specifically, the cutting chips become ribbon-shaped or spiral-shaped during cutting, which not only winds around the cutting tool and makes continuous automatic cutting difficult, but also scratches the work material and deteriorates the surface quality of the finished surface. There is a problem. On the other hand, a method of improving the machinability by improving the alloy composition and the manufacturing process (for example, Japanese Patent Publication No. 64-10587) has been proposed, but the improvement of the chip disposability is not sufficient. I haven't arrived. In view of such circumstances, the present invention has been made for the purpose of improving the machinability (cutting property) while maintaining the wear resistance and the strength.

[0004]

That is, the method for producing the wear resistant aluminum alloy extruded material of the present invention is
Si: 8-12%, Cu: 1.5-4%, Mg: 0.2
~ 1.0%, Mn: 0.25-0.6%, Sr: 0.0
1 to 0.1%, and further Cr: 0.05 to 0.3
%, Zr: 0.05 to 0.25% of one or two of them, and the balance of Al and inevitable impurities is semi-interlockingly cast into an aluminum alloy.
After performing homogenization treatment at a temperature of 80 to 540 ° C. for 1 hour or more, extrusion processing is performed at a temperature of 400 to 500 ° C., and then 4
Solution treatment is performed at a temperature of 90 to 540 ° C., and then cold drawing is performed at a processing rate of 5 to 15%, and then 2 to 3 at a temperature of 160 to 200 ° C. so that the elongation is 10% or less.
It is characterized by being subjected to artificial aging treatment for 16 hours.

[0005]

The reason why the present invention is limited will be described below together with its function. (Aluminum alloy component) Si: 8 to 12% Si is added for the purpose of improving wear resistance. However,
If Si is less than 8 wt% (hereinafter wt% is simply referred to as%), wear resistance is insufficient, and if it exceeds 12%, a large amount of coarse primary crystal Si is generated, resulting in hot and cold (drawing) workability. Since it decreases, it is limited to the above range.

Cu: 1.5-4% Cu enhances strength and at the same time improves wear resistance,
If it is less than 1.5%, the effect is small. On the other hand, if it exceeds 4%, the eutectic Si is coarsened, the elongation is lowered, and further the corrosion resistance is lowered. Mg: 0.2-1.0% Mg is also included to improve the strength, but 0.2%
If it is less than 1.0%, the effect is small. On the other hand, if it exceeds 1.0%, not only the contribution to the strength is reduced but also the hot and cold workability is deteriorated.

Mn: 0.25 to 0.6% Mn enhances strength and wear resistance, reduces deterioration of elongation due to Fe impurities, and prevents expansion and connection of voids formed during cold drawing, Disperses fine voids to make fine chips during cutting. If Mn is less than 0.25%, the effect is small. On the other hand, if it exceeds 0.6%, a coarse intermetallic compound containing Mn is crystallized to deteriorate hot workability and cold workability. In order to obtain the above effect sufficiently, M
The lower limit of n is preferably 0.4% or more.

Cr: 0.05 to 0.3% Cr has the effect of improving the strength and wear resistance, but further has the effect of promoting the effect of Mn. However, 0.05
If it is less than 0.1%, the effect is insufficient, while if it exceeds 0.3%, coarse crystallized substances are generated, and hot and cold workability are deteriorated. Zr: 0.05 to 0.25% Zr has an effect of improving strength and wear resistance similarly to Cr, and further improves stress corrosion cracking resistance. However,
If it is less than 0.05%, its effect is insufficient, while
If it exceeds 0.25%, coarse crystallized substances are generated, and the hot and cold workability are significantly deteriorated, so the above range is made.

Sr: 0.01 to 0.1% Sr is added for the purpose of refining eutectic Si to improve mechanical properties such as strength and elongation. If the Sr content is less than 0.01%, the effect is insufficient. On the other hand, if the Sr content exceeds 0.1%, a coarse intermetallic compound containing Sr is crystallized and the hot and cold workability are deteriorated. And

(Conditions of the manufacturing process) Homogenization treatment: 480 to 540 ° C. for 1 hour or more Next, the aluminum alloy ingot is homogenized to homogenize microsegregation and improve mechanical properties and workability. This is for making the eutectic Si spherical and improving the machinability in addition to the usual purpose. If the homogenizing temperature is lower than 480 ° C, the effect is insufficient, while if it exceeds 540 ° C, eutectic melting may occur. Therefore, the homogenizing treatment is performed at a temperature within the above range for 1 hour or more. .

Extrusion processing: 400 to 500 ° C. The subsequent extrusion processing is to change the casting structure into a processed structure. However, if the extrusion temperature is less than 400 ° C., the deformation stress at the time of extrusion is large and extrusion is difficult. Meanwhile, 500 ° C
If the temperature exceeds this, processing heat is generated, and there is a risk of eutectic melting, so the extrusion temperature was limited to the above range. Solution treatment: 490 to 540 ° C. Next, solution treatment is performed, but if the treatment temperature is lower than 490 ° C., solution treatment is insufficient and desired high strength cannot be obtained.
If the temperature exceeds 540 ° C, eutectic melting may occur, so the processing temperature was limited to the above range.

Cold drawing: processing rate 5 to 15% The cold drawing after the solution treatment is to introduce a processing strain into the material to form minute voids around the eutectic Si particles. As a result, chips are decomposed by the voids during cutting and become finer, improving the chip disposability. If the working ratio of cold drawing is less than 5%, the formation of fine voids is insufficient and the chips are not fine, and if it exceeds 15%, the material breaks during cold drawing. Since the material has good elongation and workability during this cold working, a large number of minute voids are formed.

Artificial aging treatment: 160 to 200 ° C., 2-1
The artificial aging treatment after the cold drawing for 6 hours is performed to obtain a desired material strength. When the treatment temperature is lower than 160 ° C, the progress of age hardening is slow, and it takes a long time to obtain the desired strength, which is not economical. On the other hand, even if the aging is performed at a temperature higher than 200 ° C, the desired strength cannot be obtained. Within the above temperature range. The aging time is within a practical range of 2 to 16 hours. In this aging treatment, the aging temperature and the aging time are appropriately selected so that the elongation of the extruded material is 10% or less. Growth 1
The reason for limiting the content to 0% or less is that if the content exceeds 10%, the ductility of the material becomes high and the chips are difficult to be divided. In addition,
For the same reason, it is desirable to limit the elongation to 9% or less. That is, in the present invention, before the aging treatment, sufficient elongation is ensured by optimizing the components, expansion of voids during cold drawing, prevention of connection and improvement of chip disposability, and further aging treatment. Suppresses elongation and further improves chip disposability.

[0014]

EXAMPLES Examples of the present invention will be described below. 2.28 mm of Al alloy having the alloy composition shown in Table 1 by the semi-connecting casting method
After being cast into a billet having a diameter and subjected to the treatment shown in Table 2, this was used as a test material to evaluate strength, elongation, wear resistance and machinability, and the results in Table 3 were obtained. The machinability is 1600 rpm for spindle speed, depth of cut / mm, and feed rate of 0.117 mm / rev with a carbide tool.
Under the cutting conditions of No. 3, the length and state of the cutting chips when cut without using the cutting oil were visually evaluated, and ranked into three ranks. The wear resistance was evaluated by determining the specific wear amount with an Ogoshi-type wear tester. FC25 is used for the wearer and the load is 2.1 kg.
The friction speed was 2.0 m / s.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

As is clear from the above evaluation test results, the test material obtained by the method of the present invention is excellent in all of the strength, wear resistance and chip disposability, whereas the test material obtained by the comparison method is excellent. The test materials were inferior in some respects, particularly those having high strength were inferior in chip disposability, and those having good chip disposability were insufficient in strength.

[0019]

As described above, according to the method for producing the wear resistant aluminum alloy extruded material of the present invention, the weight% is
Then, Si: 8-12%, Cu: 1.5-4%, Mg:
0.2-1.0%, Mn: 0.25-0.6%, Sr:
0.01-0.1%, and Cr: 0.05-
Aluminum alloy containing 0.3% and Zr: 0.05 to 0.25%, one or two of which is Al and inevitable impurities, and the balance is semi-continuously cast, and the aluminum alloy ingot is 480 After subjecting to homogenizing treatment at a temperature of ˜540 ° C. for 1 hour or more, extrusion processing is performed at a temperature of 400 to 500 ° C., then solution treatment is performed at a temperature of 490 to 540 ° C., and then a processing rate of 5 to 15 % After cold drawing,
Since the artificial aging treatment was performed at a temperature of 160 to 200 ° C. for 2 to 16 hours so that the elongation was 10% or less, high strength and wear resistance were obtained, and a large number of fine chips were generated during cutting. It is divided by voids, and has the effect of providing excellent chip disposability.

Claims (1)

[Claims] 1. By weight%, Si: 8-12%, Cu:
1.5-4%, Mg: 0.2-1.0%, Mn: 0.2
5 to 0.6%, Sr: 0.01 to 0.1%, Cr: 0.05 to 0.3%, Zr: 0.05 to 0.
An aluminum alloy containing one or two of 25% and the balance consisting of Al and unavoidable impurities is semi-continuously cast,
The aluminum alloy ingot at a temperature of 480 to 540 ° C. for 1
After the homogenization treatment for more than an hour, extrusion processing is performed at a temperature of 400 to 500 ° C., then solution treatment is performed at a temperature of 490 to 540 ° C., and then cold drawing processing at a processing rate of 5 to 15% is performed. After applying, 1 so that the elongation is less than 10%
A method for producing an abrasion-resistant aluminum alloy extruded material having excellent strength and machinability, characterized by performing artificial aging treatment for 2 to 16 hours at a temperature of 60 to 200 ° C.