KR100319946B1 - Aluminium alloy for bracket of suspending insulator and fabricating method thereof - Google Patents

Abstract

The present invention relates to an aluminum alloy for a bracket of a suspension insulator and a method for manufacturing the same, comprising: melting a aluminum-silicon-copper-magnesium-titanium-based alloy and casting at 720 to 780 ° C to make a casting; Solution casting the casting at 510-515 ° C. for 8 hours; Quenching the solution which has been solution treated; And sintering the quenched casting at 160 to 170 ° C. for 6 hours in sequence, so that the tensile strength is 30 kgf / mm ² or more, 4.0-5.0 wt% copper, 0.3 wt% or less silicon. , Aluminum for brackets of suspension insulators, comprising 0.3-0.4% magnesium, 0.3-0.45% titanium, 0.2% iron or less, 0.1% zinc or less, 0.05% nickel or less, and the balance aluminum The alloy is prepared to provide an aluminum alloy for the suspension insulator bracket, which is lighter in weight than the conventional bracket and has improved mechanical properties.

Description

Aluminum alloy for bracket of suspension insulator and manufacturing method {ALUMINIUM ALLOY FOR BRACKET OF SUSPENDING INSULATOR AND FABRICATING METHOD THEREOF}

The present invention relates to an aluminum alloy, and more particularly to an aluminum alloy used in the bracket of the suspension insulator and a manufacturing method thereof.

In general, in order to attach the suspension insulator to the telephone pole, brackets made of metal are installed at both ends of the suspension insulator, and the suspension insulator is connected to the telephone pole and the wire by the respective brackets.

At this time, the important mechanical properties required as the material of the bracket is that the tensile strength must be high. The products mainly used as materials of conventional brackets are spherical castings or forgings, and their KS standards are KS GCD40 and KS SM20C, respectively. As a result of measuring the mechanical properties of these spherical castings and forgings, the tensile strength of both products was 40 kgf / mm ² or more, the yield strength was 26 kgf / mm ² or more, and the elongation was 18% or more in the spherical castings. And more than 28% in forgings.

Chemical compositions of the spherical cast articles and forged articles, which are the materials of the conventional bracket having the above mechanical properties, are shown in Table 1 below.

Chemical Composition of Spherical Castings and Forgings Kinds KS standard Chemical composition (% by weight) C Si Mn P S Balance Thought casting article GCD40 3.3-3.8 2.0-3.0 0.2-0.6 0.1 or less 0.05 or less Fe Forging SM20C 0.18-0.23 0.15-0.35 0.3-0.6 0.03 or less Less than 0.035 Fe

However, in order to improve processability and to prevent corrosion, the spherical castings and forged products as described above must be subjected to zinc hot dip plating. Therefore, there was a troublesome manufacturing process.

In addition, the above-described spherical castings and forgings are sand-cast castings manufactured using casting sands, so that the surfaces thereof are made rough. When the brackets are pressed against the insulating rods inside the suspension insulator due to the surface roughness, There was a problem that the crack is caused to the insulation rod under the stress of 50-100 kg applied to eventually break the insulation rod.

The present invention has been made to solve the problems as described above, an object of the present invention is to provide an aluminum alloy for a suspension insulator bracket and a method of manufacturing the light weight and improved mechanical properties than conventional brackets.

1 is a cross-sectional view of the suspension insulator bracket.

Figure 2 is a graph showing the tensile test results of the aluminum alloy containing 0.3 wt% titanium prepared according to the present invention.

3 is a graph showing the tensile test results of the aluminum alloy containing 0.45% by weight of titanium prepared according to the present invention.

In order to achieve the object as described above, the aluminum alloy for the bracket of the suspension insulator according to the present invention is cast at 720 ~ 780 ° C and then subjected to solution treatment and age hardening treatment has a tensile strength of 30 kgf / mm ² or more .

At this time, the aluminum alloy for the bracket of the suspension insulator according to the present invention is 4.0-5.0% by weight of copper, 0.3% by weight or less of silicon, 0.3-0.4% by weight of magnesium, 0.3-0.45% by weight of titanium, 0.1% by weight or less Iron, 0.05 wt% or less nickel, 0.1 wt% or less zinc, balance aluminum and other unavoidable impurities.

In addition, the manufacturing method of the aluminum alloy for the bracket of the suspension insulator according to the present invention comprises the steps of making a casting by melting the aluminum-silicon-copper-magnesium-titanium-based alloy and casting at 720 ~ 780 ℃; Solution casting the casting at 510-515 ° C. for 8 hours; Quenching the solution which has been solution treated; And age hardening the quenched casting at 160 to 170 ° C. for 6 hours.

At this time, it is preferable to melt the aluminum-silicon-copper-magnesium-titanium alloy by adding a flux, a degassing agent, and an improved treatment agent.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a cross-sectional view of the suspension insulator bracket. As shown in FIG. 1, the suspension insulator 1 surrounds the insulating rod 2, and brackets 3 are installed at both ends of the suspension insulator 1, and the suspension insulator 1 is connected to the suspension insulator 1. The bracket 3 of the part has a hollow rod shape, and an insulating rod 2 is inserted into the rod. The bracket 3 (located on the left side in FIG. 1) installed at one end of the suspension insulator 1 is connected to a wire (not shown) as the cap P, and the bracket 3 installed at the other end of the suspension insulator 1. (Located on the right side in FIG. 1) is connected to the telephone pole (not shown) as the clamp (L).

In order to be used as a material of such a bracket, high tensile strength of 30 kgf / mm ² or more is required, and the tensile strength of aluminum alloy is usually about 18 to 27 kgf / mm ² . However, the aluminum alloy casting for the suspension insulator according to the present invention is a spherical casting (KS GCD40) or forged product (KS SM20C), which has been used as a material for the conventional suspension insulator while satisfying the high tensile strength requirement of 30 kgf / mm ² or more. Much lighter than)

Among the aluminum alloys, aluminum-copper alloys have been used for the longest time, and various specifications have been developed to improve the initial poor castability, and are currently using high strength and toughness obtained by heat treatment, particularly for parts requiring strength. It is used. Aluminum alloys contain approximately 4.0-5.0% by weight of copper, adding silicon improves castability, and adding titanium or magnesium improves strength.

The aluminum alloy for the bracket of the suspension insulator according to the present invention is an aluminum-silicon-copper-magnesium-titanium-based alloy containing silicon, titanium, magnesium, and the like, the chemical composition of which is shown in Table 2 below.

Chemical Composition of Aluminum Alloy for Bracket of Suspension Insulator According to the Present Invention Kinds Chemical composition (% by weight) Cu Si Mg Ti Fe Ni Zn Balance The present invention 4.0-5.0 0.3 or less 0.3-0.4 0.3-0.45 0.10 or less 0.05 or less 0.1 or less Al

The weight of the aluminum alloy according to the present invention having the chemical composition as shown in Table 2 is about 1/3 of the weight of the conventional spherical cast article (KS GCD40) or forged article (KS SM20C). As such, the weight of the aluminum alloy according to the invention is much lighter than before, and at the same time, the tensile strength is improved than before.

Suspension insulator aluminum alloy according to an embodiment of the present invention, the molten aluminum-silicon-copper-magnesium-titanium-based alloy is cast at 720 ~ 780 ℃ to form a casting, and the casting 510 ~ 515 It is prepared by sequentially performing a solution treatment for 8 hours at ℃, quenching the solvated casting, and age hardening the quenched casting for 6 hours at 160 ~ 170 ℃. Such a manufacturing method is referred to as Example 1) and described in detail as follows.

Example 1) A method for producing an aluminum alloy for the bracket of a suspension insulator.

In order to manufacture the aluminum alloy for the bracket of the suspension insulator according to an embodiment of the present invention, first, 4.0-5.0% by weight of copper, 0.3% by weight or less of silicon, 0.3-0.4% by weight of magnesium, 0.3-0.45 Charge a charge of chemical composition consisting of up to 0.1% by weight of titanium, up to 0.1% by weight of iron, up to 0.05% by weight of nickel, up to 0.1% by weight of zinc and the balance of aluminum, and as a flux to promote dissolution. Coveral No. 11 product was added 0.1% of the total weight of the charge, and then heated to melt at 720 to 780 ° C. At this time, in order to remove the hydrogen gas generated in the molten metal during heating, the degaser No. A degassing agent of 190 products was added at 750 ° C. near 0.1% of the total weight of the charge. Also, in order to refine the structure after casting, nucleant No. An improved treatment agent for the 186 product was added at 750 ° C. near 0.1% of the total weight of the charge.

Then, the molten metal is stabilized, and the molten metal at 720 to 780 ° C is injected into the mold to make bracket castings of 3 (P) and 3 (L) shapes shown in FIG. 1, wherein the structure of the casting is austenite It is important to be in the austenite state. If the casting temperature is 780 ° C or higher, the solidification structure becomes ferrite after casting, and thus the tensile strength is lowered. As a result, it cannot be used for the bracket of the suspension insulator. And if casting temperature becomes 720 degrees C or less, casting will become difficult. Therefore, as for casting temperature, 720-780 degreeC as mentioned above is preferable. In particular, the optimum casting temperature of the aluminum alloy according to the present invention is more preferably 720 ~ 750 ℃.

Next, after the above-mentioned bracket casting was charged in a furnace, it heated to 510-515 degreeC, and maintained the temperature for 8 hours, and performed solution treatment.

Next, the cast solution bracket solution was quenched in water to maintain the austenitic structure at room temperature.

Next, the quenched bracket casting was heated to 160-170 ° C. and maintained at that temperature for 6 hours, followed by air cooling to age hardening.

Finally, the part of the aging-cured bracket casting connected to the suspension insulator is processed by an end mill machine to produce a hollow rod shape, for example, a rod inner diameter of 17.40 mm, according to the present invention. The manufacture of the aluminum alloy for the suspension insulator bracket was completed.

Tensile tests were performed to determine whether the aluminum alloys produced by the method described above had the tensile strength required for the suspension insulator brackets. This is referred to as Example 2), and the detailed description of Example 2) is as follows.

Example 2) Tensile test of the aluminum alloy prepared by Example 1).

First, a tensile test was performed on an aluminum alloy containing 0.3 wt% titanium. Tensile test was measured for 3 (P) (cap) of the two forms of 3 (P) (cap) and 3 (L) (clamp) shown in Figure 1, but the tensile strength of the two forms is the same For the sake of simplicity, either form may be used. Referring to the size of the specimen used in the tensile test using the 3 (P) (cap) of Figure 1, the inner diameter of the bar connecting the suspension insulator is 17.4 mm, the outer diameter is 27.75 ± 0.25 mm, The width of the portion connected to the opposite wire was 37.5 mm, the thickness was 15 mm, and the diameter of the hole formed in the portion was 17.25 ± 0.25 mm. Tensile strength of the 3 (P) type aluminum alloy specimens was measured using a 20 ton universal tensile tester manufactured by Sampung Works. The measured temperature was 18 ° C, humidity was 50%, and the test speed was 0.73 mm. It was / min. A graph showing the measurement result is shown in FIG. 2, and the results of the tensile test of FIG. 2 are summarized in Table 3 below.

Tensile test results of aluminum alloy containing 0.3 wt% titanium Load (kgf) Displacement (mm) Strength (kgf / mm ² ) Elongation (%) Max 7075.20 10.53 56.7195 21.06 Breaking point 6646.73 10.78 53.2847 21.55 yield point 4396.97 8.15 35.2491 16.30

Obtained from Figure 2 and Table 3, the mechanical properties of the aluminum alloy according to the invention containing 0.3 wt% titanium is as follows. In other words, the tensile strength at the maximum point is 56.7195 kgf / mm ² , the yield strength is 35.2491 kgf / mm ² , and the elongation at break is 21.55%.

On the other hand, Figure 3 is a graph showing the tensile test results performed in the same manner as in Example 2) for the aluminum alloy containing 0.45% by weight of titanium, summarized in the tensile test results of Figure 3 Table 4 Same as

Tensile test results of aluminum alloy containing 0.45% by weight of titanium Load (kgf) Displacement (mm) Strength (kgf / mm ² ) Elongation (%) Max 7177.73 12.26 57.5416 24.52 Breaking point 6734.62 12.53 53.9893 25.07 yield point 5361.33 9.70 42.9800 19.41

3 and Table 4, mechanical properties of the aluminum alloy according to the present invention containing 0.45% by weight of titanium are as follows. That is, the tensile strength, which is the strength at the maximum point, is 57.5416 kgf / mm ² , the yield strength is 42.9800 kgf / mm ² , and the elongation at break is 25.07%.

In fact, as a result of performing an experiment applying a load to the aluminum alloy according to the present invention, it was possible to maintain a load of 7 to 10 tons.

As mentioned above, the aluminum alloy for the bracket of the suspension insulator according to the present invention is much lighter than 1/3 of the weight of the conventional spherical casting (KS GCD40) or forging (KS SM20C), but the mechanical properties are improved. It has the effect of indicating.

In addition, since the aluminum alloy according to the present invention does not need to be subjected to hot-dip plating after fabrication, the manufacturing process is simpler than in the related art.

In addition, the aluminum alloy according to the present invention has an effect that solves the problem of breaking the insulating rod due to the surface roughness in the prior art because the surface is not smooth because it is easy to manufacture a mold.

Claims (5)

In the (crystal) aluminum-silicon-copper-magnesium-titanium-based alloy, 4.0-5.0 wt% copper, 0.3 wt% or less silicon, 0.3-0.4 wt% magnesium, 0.3-0.45 wt% titanium, 0.1 wt% or less iron, 0.05 wt% or less nickel, 0.1 wt% or less Made of zinc and the balance of aluminum, Aluminum alloy for suspension insulator brackets with a tensile strength of 30 kgf / mm ² or more. (delete) (Correction) 4.0-5.0 wt% copper, 0.3 wt% or less silicon, 0.3-0.4 wt% magnesium, 0.3-0.45 wt% titanium, 0.1 wt% or less iron, 0.05 wt% or less nickel, 0.1 wt% In the manufacturing method of the aluminum alloy which consists of% or less of zinc and remainder aluminum, Melting the aluminum-silicon-copper-magnesium-titanium based alloy and casting at 720˜780 ° C. to form a casting; Solution casting the casting at 510-515 ° C. for 8 hours; Quenching the solution which has been solution treated; And Age hardening the quenched casting at 160-170 ° C. for 6 hours Method for producing an aluminum alloy for the bracket of the suspension insulator comprising a. (delete) (delete)