JPH108178A - Aluminum torque rod and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque rod made of aluminum, used, e.g. as a torque rod to be fitted to a suspension of a truck and having annular end members at both ends. SOLUTION: In this torque rod, a connecting rod 3 made of aluminum extruded pipe is welded or welded with pressure to ends 1, 2 prepared by cutting an aluminum extruded shape, having a cross-section where a connecting part 5 is integrated with an annular part 4, in round slices. At this time, the aluminum extruded shape and the aluminum extruded pipe are composed of an aluminum alloy having a composition containing, by weight, 4.0-6.5% Zn, 0.5-2.0% Mg, 0.01-0.2% Cu, 0.2-0.7% Mn, 0.05-0.3% Cr, 0.05-0.25% Zr, and 0.01-0.4% Fe. Further, after extrusion, heating is performed up to 430-480 deg.C, followed by air cooling or furnace cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum torque rod used as a torque rod or the like mounted on a truck suspension and provided with ring-shaped end members at both ends, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A torque rod, which is one of the components of a rear suspension such as a truck, has a structure in which rod-shaped or pipe-shaped ends are provided with ring-shaped ends. As the torque rod, an iron-based material integrally formed by forging has been conventionally used. However, due to the recent problem of overloading regulations, it is required to reduce the weight of trucks and truck parts, and torque rods are no exception. Therefore, as shown in FIGS. 1 and 2, a light weight structure in which the torque rod is divided into two ends 1 and 2 and a connecting rod 3 has been studied. In this structure, in order to reduce the weight, the connecting rod 3 is made of an iron thin pipe, and the forged irons 1 and 2 are welded or pressed to the connecting rod 3.

[0003]

The torque rod shown in FIGS. 1 and 2 uses a thin-walled iron pipe for the connecting rod 3, so that it can be compared with a conventional solid torque rod made by casting and forging. It is getting lighter. However, since iron is used as a material, there is a limit to weight reduction. In order to achieve further weight reduction, it is necessary to use a material having strength comparable to iron and lighter than iron. In addition, since the suspension is a part having a function of holding the axle with respect to the vehicle body, the required characteristics of the torque rod, which is one of the components thereof, cannot be satisfied only with a light material. That is, it is necessary for a product having a predetermined size and shape to satisfy required characteristics such as strength, elongation, and stress corrosion cracking resistance. Specifically, the iron torque rod currently used has a center-to-center distance between the ends 1 and 2 of 522 mm, and has a tensile strength and a compressive strength of 32,000 kgf or more, and a repetitive load of ± 6,000 kgf. Tensile and compressive fatigue strength to withstand 2 × 10 ⁶ times or more and 1
It is required to have an elongation of 0% or more. An object of the present invention is to reduce the weight of a torque rod by producing a torque rod using an Al material satisfying such required characteristics.

[0004]

In order to achieve the object, the torque rod of the present invention is manufactured by extruding an aluminum extruded member having a cross section in which a connecting portion is integrated with an annular portion, and the end is made of aluminum. It is welded or pressed against both ends of a connecting rod made from an extruded alloy pipe. As the aluminum extruded shape and the aluminum extruded pipe, Zn: 4.
0 to 6.5% by weight, Mg: 0.5 to 2.0% by weight, C
u: 0.01 to 0.2% by weight, Mn: 0.2 to 0.7% by weight, Cr: 0.05 to 0.3% by weight, Zr: 0.05
-0.25% by weight and Fe: 0.01-0.4% by weight.
What was heated to ° C and air-cooled or furnace-cooled is used. Alternatively, an aluminum alloy extruded at 430 to 480 ° C. and then air-cooled or furnace-cooled can be used. In the alloy composition, Ti: 0.005 to 0.2% by weight, B: 0.
One or more of 0001 to 0.05% by weight and V: 0.01 to 0.1% by weight can be contained. After air or furnace cooling, an aging treatment of keeping at 110 to 130 ° C for 23 to 25 hours, or an aging treatment of keeping at 115 to 125 ° C for 3 to 6 hours and then keeping at 170 to 180 ° C for 6 to 8 hours Is preferred. The round cutting of the extruded aluminum material may be performed at any stage before, during or after the heat treatment.

[0005]

In the present invention, an Al-Mg-Si-based aluminum alloy extruded profile is used as an end, and an Al-Mg-Si-based aluminum alloy extruded pipe is used as a material for a connecting rod.
As shown in FIG. 3, the end is formed by cutting an extruded aluminum section having a cross-sectional shape in which the connecting portion 5 is integrated with the annular portion 4. When these ends 1 and 2 are connected to the connecting rod 3 as shown in FIG. 4, the direction of extrusion of the extruded profile is in a direction perpendicular to the direction of the tensile force / compression force applied to the end portion of the torque rod. Become. Therefore, as for the mechanical properties of the extruded profile having a cross section in which the connecting portion 5 is integrated with the annular portion 4, the mechanical properties in the direction perpendicular to the extrusion direction are important. In this regard, it is preferable that an extruded profile having a cross section in which the connecting portion 5 is integrated with the annular portion 4 be produced by indirect extrusion. The indirectly extruded extruded profile consists only of a homogeneous fiber structure running in the direction of extrusion. The mechanical properties in the direction perpendicular to the extrusion direction are slightly inferior to the mechanical properties in the extrusion direction, and the other properties are almost the same. On the other hand, the hollow material as shown in FIG. 3 made by direct extrusion has inferior mechanical properties in the direction perpendicular to the extrusion direction as compared with the mechanical properties in the extrusion direction due to the fusion structure. However, even if it is a directly extruded material, it can be used as an end material if the design value is satisfied.

The required strength of the aluminum alloy used in the present invention is ensured by the precipitation of fine Mg ₂ Si. Further, when welded or pressed, the heat-affected zone recovers to a strength close to that of the base material due to natural aging, so that excellent joint strength can be obtained. Utilizing such Al-Zn-Mg-based features,
In order to obtain an aluminum alloy that is more suitable for a torque rod in this type of alloy, in other words, an aluminum alloy having higher strength, it is conceivable to increase the amount of Zn or Mg and increase the amount of Zn-Mg based precipitate. . However, the stress corrosion cracking resistance and weldability are degraded accordingly. The present inventors have found that Zn
-In order to achieve both the effect on the strength improvement of Mg-based precipitates and excellent weldability and stress corrosion cracking resistance, it is necessary to determine alloy components, their contents, heat treatment conditions, etc. in consideration of their mutual relations. I came to the conclusion. Hereinafter, the alloy components, contents, and the like of the extruded aluminum material and the extruded aluminum pipe material (hereinafter, collectively referred to as aluminum extruded materials) used in the present invention will be described.

Zn: 4.0-6.5% by weight Zn is an alloy element that forms a fine precipitate of Zn—Mg with Mg and improves the strength of the aluminum alloy. Such an effect of improving the strength becomes remarkable when the Zn content is 4.0% by weight or more. However, when a large amount of Zn exceeding 6.5% by weight is contained, the stress corrosion cracking resistance and the workability deteriorate. Mg: 0.5 to 2.0% by weight Like Zn, it is an alloy element indispensable for improving the strength.
Sufficient strength can be obtained with a content of 5% by weight or more. However, when a large amount of Mg exceeding 2.0% by weight is contained, stress corrosion cracking resistance and workability deteriorate. Cu: 0.01 to 0.2% by weight An alloying element for improving the stress corrosion cracking resistance.
The effect of adding Cu becomes remarkable when the content is not less than% by weight. But C
If the u content exceeds 0.2% by weight, the stress corrosion cracking resistance deteriorates and the weldability also deteriorates.

Mn: 0.2-0.7% by weight The effect of stabilizing the structure and improving the strength is exhibited.
The effect of adding Mn becomes remarkable at a content of 0.2% by weight or more. However, when a large amount of Mn exceeding 0.7% by weight is contained, a giant compound may be generated, and toughness and workability may be deteriorated. Cr: 0.05 to 0.3% by weight Similar to Mn, Cr is an effective alloying element for stabilizing the structure. At a content of 0.05% by weight or more, the effect of adding Cu becomes remarkable. However, the presence of a large amount of Cr exceeding 0.3% by weight not only saturates the structure stabilizing effect but also causes the formation of a giant compound harmful to toughness and workability. Zr: 0.05-0.25% by weight Like Mn, it is an alloy element effective for stabilizing the structure.
When the content is 0.05% by weight or more, the effect of adding Zr becomes remarkable. However, when a large amount of Zr exceeds 0.25% by weight, not only the tissue stabilizing effect is saturated, but also
It can cause the formation of giant compounds harmful to toughness and workability.

Fe: 0.01 to 0.4% by weight An alloy element that stabilizes the structure and improves stress corrosion cracking resistance. Such effects become remarkable at a content of 0.01% by weight or more. However, a large content of Fe exceeding 0.4% by weight deteriorates toughness and workability. Ti: 0.005 to 0.2% by weight An alloy element added as necessary, and has a function of stabilizing the structure and improving the mechanical properties of the welded portion or the press-welded portion. Such effects become remarkable at a content of 0.005% by weight or more. However, a large Ti content exceeding 0.2% by weight causes formation of a giant compound harmful to toughness and workability. B: 0.0001 to 0.05% by weight An alloy element added as necessary,
The effect of stabilizing the structure becomes remarkable when B is added in an amount of not less than% by weight.
However, even if it is added in excess of 0.05% by weight, B
Not only saturates the effect of addition, but also causes the formation of giant compounds harmful to toughness and workability. V: 0.01 to 0.1% by weight An alloy element added as needed, and has an effect of improving stress corrosion cracking resistance. Such an addition effect
It becomes remarkable at 0.01% by weight or more. However, excessive addition exceeding 0.1% by weight rather deteriorates workability and toughness.

The extruded aluminum alloy used in the present invention is:
In addition to the above alloying elements, it is permissible to contain less than 0.3% by weight of Si as an impurity and other elements of less than 0.05% by weight alone. When these impurity elements are restricted to an allowable range, required characteristics as a torque rod are satisfied. Conditions for heat treatment and extrusion: In order to improve the strength of the extruded aluminum alloy having the above-described composition, it is necessary to completely dissolve the strength improving element first. For this purpose, it is necessary to heat the extruded aluminum alloy to a temperature of at least 430 ° C. after extrusion. However, 480 ° C
At temperatures above, partial melting occurs and defects occur. Alternatively, it is necessary to extrude at a temperature of 430 ° C. or higher. However, at extrusion temperatures above 480 ° C., partial melting occurs and defects occur. The aluminum alloy extruded material after the solution treatment or the high-temperature extrusion is cooled by air cooling or furnace cooling since rapid cooling such as water cooling causes excessive internal strain and causes stress corrosion cracking.

[0011] The cooled aluminum alloy extruded material is in a state where the alloying elements are supersaturated and solid solution. This aluminum alloy
When kept at room temperature, Zn-Mg based fine precipitates are formed, and the quality is stabilized and the target strength is obtained. However, such natural aging requires a long period of one month or more. Therefore, in order to promote the generation of Zn-Mg based fine precipitates, artificial aging is performed at 110 to 130 ° C for 23 to 25 hours, or 170 to 180 ° C after maintaining at 115 to 125 ° C for 3 to 6 hours. It is preferred to stabilize the quality early by artificial aging for up to 8 hours. In addition, in the extruded material extruded at a high temperature and the solution treatment is omitted, the Zn-Mg based fine compound is uniformly precipitated, and the internal strain at the time of the extrusion process that may cause stress corrosion cracking is removed. But aging is effective. When the aging temperature and the holding time are out of the range described above,
The aging effect is not sufficient, or a problem due to overaging occurs. The aluminum alloy extruded material whose components and composition were adjusted in this way and heat-treated after extrusion was 32 kgf / m2.
It exhibits a tensile strength of not less than m ² and an elongation of not less than 11%, and sufficiently satisfies the required characteristics as an end of a torque rod and a connecting rod. As an end manufacturing method, an extruded material can be forged. However, the extruding method according to the present invention alone sufficiently satisfies the design conditions, so that a torque rod that is less expensive than a forged product can be obtained.

[0012]

EXAMPLE An aluminum alloy having the composition shown in Table 1 was extruded to produce an extruded profile (FIG. 3) having a cross section in which a connecting portion was integrated with an annular portion, and then heat-treated. As shown in (a) and (b), outer diameter φ ₁ = 130 mm,
End 1 with inner diameter φ ₂ = 105 mm and width W = 51 mm
2 was produced. A connecting portion 5 having a tip diameter of 60 mm and a rising radius of 50 mm on one side of the annular portion 4 of the ends 1 and 2.
Was formed. On the other hand, as the connecting rod 3, a pipe having an outer diameter of 60 mm and an inner diameter of 40 mm produced from a similar heat-treated extruded aluminum alloy was used. The connecting rod 3 was pressed against the end face of the connecting part 5 to form a joint 6 by MIG welding or friction welding, and the ends 1 and 2 were integrated with the connecting rod 3.
The MIG welding conditions were as follows.
8 V, current 280 A, welding speed 1 m / min. For the friction welding, a heating pressure of 550 kgf / cm ² , a heating time of 6 seconds, an upset pressure of 1000 kgf / cm ² and an upset amount of 10 mm were employed.

[0013]

Example 1 An aluminum alloy of alloy number 1 is indirectly extruded, heated to 450 ° C., air-cooled, and then cooled to 120 ° C.
An end was made of the material held for 24 hours. The connecting rod was manufactured by extruding an aluminum alloy of alloy number 1 to a predetermined size and performing the same heat treatment as the end. The torque rod obtained by MIG welding the end and the connecting rod has a tensile strength of 38,000 kgf and a compressive strength of 37.0 kg.
00 kgf, elongation at the end 11.0%, elongation at the connecting rod 14.1%, elongation at the joint 13.0%, ± 6,00
The repeated load of 0kgf even after giving 2 × 0 ⁶ times had never damaged by fatigue. Further, a test piece was cut out from the joined torque rod and subjected to a stress corrosion cracking test in accordance with JIS H8711. That is, 7
Dipping in 3.5% NaCl solution with 5% added, 1
Repeated immersion for 0 minutes → drying for 50 minutes was continued for 30 days.
When the torque rod after the test was observed, no stress corrosion cracking was detected in any of the end, the connecting rod, and the joint. On the other hand, the torque rod whose end is joined to the connecting rod by friction welding has a tensile strength of 38,500 kgf,
Compressive strength 37,000kgf, end extension 10.8
%, Elongation of connecting rod 14.0%, elongation of joint 12.5
Percent, had never damaged by fatigue even after giving 2 × 0 ⁶ times the repeated load of ± 6,000kgf. Also,
In the results of the similar stress corrosion cracking test, no stress corrosion cracking was detected in any of the end, the connecting rod, and the joint.

Example 2: An aluminum alloy having an alloy number 1 was replaced with 45
After extruding hot at 0 ° C., air-cooled, and kept at 120 ° C. for 4 hours, then an end was made of a material kept at 175 ° C. for 7 hours. The connecting rod was also manufactured from the aluminum alloy of alloy number 1 by a similar process. These ends and connecting rods are
The torque rod obtained by IG welding has a tensile strength of 3
7,000 kgf, compressive strength 37,000 kgf, end portion elongation 11.0%, connecting rod portion elongation 14.5%, joint portion elongation 13.0%, 2 × 0 cyclic load of ± 6,000 kgf. Even after being given ^six times, it did not break due to fatigue. When subjected to the same stress corrosion cracking test as in Example 1, no stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion. On the other hand, the torque rod whose end is joined to the connecting rod by friction welding has a tensile strength of 3
With 7,500 kgf, compressive strength of 37,000 kgf, elongation at the end part 10.7%, elongation at the connecting rod part 14.5%, and elongation at the joint part 12.5%, the repetitive load of ± 6,000 kgf is 2 × 0. Even after being given ^six times, it did not break due to fatigue. Further, in the results of the similar stress corrosion cracking test, no stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion.

Example 3 An aluminum alloy of alloy number 2 was extruded indirectly, heated to 450 ° C., and furnace-cooled to produce an end. The connecting rod was also manufactured from the aluminum alloy of alloy number 2 by the same process. These ends and connecting rods are
The torque rod obtained by IG welding has a tensile strength of 3
8,000 kgf, compressive strength 36,000 kgf, end portion elongation 11.1%, connecting rod portion elongation 13.5%, joint portion elongation 12.5%, and a repetitive load of ± 6,000 kgf of 2 × 0. Even after being given ^six times, it did not break due to fatigue. When subjected to the same stress corrosion cracking test as in Example 1, no stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion. On the other hand, the torque rod whose end is joined to the connecting rod by friction welding has a tensile strength of 3
8,000 kgf, compressive strength 36,000 kgf, end portion elongation 11.0%, connecting rod portion elongation 13.5%, joint portion elongation 12.0%, and a repetitive load of ± 6,000 kgf of 2 × 0. Even after being given ^six times, it did not break due to fatigue. Further, in the results of the similar stress corrosion cracking test, no stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion.

Example 4: An aluminum alloy of alloy No. 1 is hot-extruded, heated to 460 ° C., air-cooled, and then cooled to 120 ° C.
Ends were made of the material held for 4 hours. The connecting rod was manufactured from an aluminum alloy of alloy number 2 by a similar process. The torque rod obtained by MIG welding the end and the connecting rod has a tensile strength of 38,000 kgf, a compressive strength of 36,500 kgf, an elongation of the end portion of 11.1%,
Elongation of connecting rod 14.2%, elongation of joint 13.0%
In, it had never damaged by fatigue even after giving 2 × 0 ⁶ times the repeated load of ± 6,000kgf. When subjected to the same stress corrosion cracking test as in Example 1, no stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion. On the other hand, the torque rod whose end is joined to the connecting rod by friction welding has a tensile strength of 38,000 kgf, a compressive strength of 36,500 kgf, and an elongation of the end portion of 11.0 kgf.
%, Elongation of connecting rod 14.0%, elongation of joint 12.5
Percent, had never damaged by fatigue even after giving 2 × 0 ⁶ times the repeated load of ± 6,000kgf. Also,
In the results of the similar stress corrosion cracking test, no stress corrosion cracking was detected in any of the end, the connecting rod, and the joint.

Comparative Example 1: An aluminum alloy of alloy No. 3 was directly extruded, heated to 450 ° C., air-cooled, and then heated to 120 ° C.
An end was made of the material held for 24 hours. The connecting rod was manufactured from Alloy No. 3 by the same process. The torque rod obtained by MIG welding the end and the connecting rod has a tensile strength of 39,000 kgf, a compressive strength of 35,
Although it showed a value of 000 kgf, the elongation at the end portion was insufficient at 5.0%. In addition, it was given 2 × 0 ⁶ times the repeated load of ± 6,000kgf, was damaged by fatigue. Therefore, it was unsuitable as a torque rod.

Comparative Example 2: An aluminum alloy of alloy number 4 was extruded indirectly, heated to 450 ° C., and furnace-cooled to produce an end. The connecting rod was manufactured from Alloy No. 4 by the same process. The torque rod obtained by MIG welding the end and the connecting rod has an elongation of 13.5% at the end,
Although the connecting rod showed a value of 16.0% and the joint showed a value of 14.0%, the tensile strength was insufficient at 29,000 kgf and the compressive strength was at 28,000 kgf. Also, ± 6,0
In after giving repeated load of 00kgf 2 × 0 ⁶ times, damage due to fatigue occurs. Therefore, it was unsuitable as a torque rod. On the other hand, the torque rod whose end is joined to the connecting rod by friction welding has an extension of 1 at the end.
3.5%, 16.1% at connecting rod, 13.0% at joint
, But the tensile strength is 29,000kg
f, the compressive strength was 28,000 kgf, which was insufficient. Further, after giving 2 × 0 ⁶ times repeated load of ± 6,000Kgf it is damaged by fatigue occurs. Therefore, it was unsuitable as a torque rod.

Comparative Example 3: An aluminum alloy of alloy number 5 was replaced with 45
Ends were made of material extruded hot at 0 ° C., cooled, held at 120 ° C. for 4 hours, and then held at 170 ° C. for 7 hours. The connecting rod was also manufactured from the aluminum alloy of alloy number 5 by the same process. Connect these ends and connecting rods to MI
The torque rod obtained by G welding has a tensile strength of 4
At 000 kgf, compression load of 36,000 kgf, ±
Damage due to fatigue the repeated load of 6,000kgf even after giving 2 × 0 ⁶ times did not occur. However, the elongation was 10.1% at the end, 11.2% at the connecting rod, and 1% at the joint.
The value was as low as 3.0%, and the stress corrosion cracking test showed that the stress corrosion cracking was detected in any of the end portion, the connecting rod portion, and the joint portion. Therefore, it was unsuitable as a torque rod. The torque rod joined end to the connecting rod by friction welding, tensile strength 41,000Kgf, with compressive strength 37,000Kgf, damage due to fatigue even after giving 2 × 0 ⁶ times repeated load ± 6,000Kgf Did not occur. However, the elongation showed a low value of 10.2% at the end portion, 11.2% at the connecting rod portion, and 12.5% at the joint portion. According to the results of the stress corrosion cracking test, the end portion, the connecting rod portion and the joint portion showed low values. In any of the samples, stress corrosion cracking was detected. Therefore, it was unsuitable as a torque rod.

[0021]

As described above, in the present invention, an end member and a connecting rod member are manufactured from an extruded aluminum alloy material whose components are regulated and subjected to heat treatment under specific conditions. By welding or pressing the connecting rod members, a torque rod made of an extruded aluminum alloy material having substantially the same size and shape as a conventionally used iron torque rod and having properties comparable to iron is obtained. In particular, ends obtained from extruded aluminum alloy sections produced by indirect extrusion exhibit excellent properties. This extruded aluminum alloy torque rod is 55 to 55 mm
The weight is reduced by about 60%, and there is no need to change the design of the bush and the parts that fix the torque rod into the end part. It is used like a conventional iron torque rod and contributes to the weight reduction of the truck. I do.

[Brief description of the drawings]

FIG. 1 is a side view of a conventional iron torque rod divided into three parts, an end and a connecting rod.

FIG. 2 is a plan view of the iron torque rod.

Fig. 3 Ends made by cutting aluminum alloy extrusions

FIG. 4 shows a part (b) of a torque rod obtained by welding or pressing an end (a) made of an extruded aluminum alloy into a connecting rod made of an extruded aluminum alloy pipe in an embodiment of the present invention.

[Explanation of symbols]

1,2: end 3: connecting rod 4: annular part
5: Connection part 6: MIG welded or friction-welded joint

Continued on the front page (72) Inventor Tatsu Yamada 1-34-1 Kambara, Kambara-cho, Abara-gun, Shizuoka Prefecture Inside the Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Kenji Tsuchiya 1-34, Kambara-cho, Kambara-cho, Abara-gun, Shizuoka No. 1 Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Harumichi Hino 1-34-1 Kambara-cho, Kambara-cho, Abara-gun, Shizuoka Prefecture Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Genji Hotta, Kambara, Ahara-gun, Shizuoka Prefecture 1-334-1, Machibara, Nippon Light Metal Co., Ltd. Group Technology Center

Claims (5)

[Claims] 1. A torque rod in which a connecting rod made of an aluminum extruded pipe is welded or pressed against an end formed by cutting an aluminum extruded shape having a cross section in which a connecting portion is integrated with an annular portion, and the aluminum extruded shape is used. And aluminum extruded pipes have Zn: 4.0-6.5% by weight, Mg: 0.5-
2.0% by weight, Cu: 0.01 to 0.2% by weight, Mn:
0.2 to 0.7% by weight, Cr: 0.05 to 0.3% by weight, Zr: 0.05 to 0.25% by weight, Fe: 0.01
A torque rod made of an aluminum alloy having a composition containing about 0.4% by weight, extruded, heated to 430 to 480 ° C., and air-cooled or furnace-cooled. 2. A torque rod in which a connecting rod made of an aluminum extruded pipe is welded or pressed against an end formed by cutting an aluminum extruded shape having a cross section in which a connecting portion is integrated with an annular portion, and the aluminum extruded shape is used. And aluminum extruded pipes have Zn: 4.0-6.5% by weight, Mg: 0.5-
2.0% by weight, Cu: 0.01 to 0.2% by weight, Mn:
0.2 to 0.7% by weight, Cr: 0.05 to 0.3% by weight, Zr: 0.05 to 0.25% by weight, Fe: 0.01
430-0.4% by weight of aluminum alloy
A torque rod extruded at 480 ° C. and then air-cooled or furnace-cooled. 3. The alloy composition according to claim 1, further comprising: 0.005 to 0.2% by weight of Ti;
A torque rod containing one or more of 001 to 0.05% by weight and V: 0.01 to 0.1% by weight. 4. An aging treatment in which air or furnace cooling is maintained at 110 to 130 ° C. for 23 to 25 hours, or 115 to 125.
6 to 8 hours after holding at 3 to 6 hours at 170 to 180 ° C.
The torque rod according to any one of claims 1 to 3, wherein an end made of an extruded aluminum member subjected to an aging treatment for holding for a time is welded or pressed to a connecting rod made of an extruded aluminum pipe. 5. An end is produced by cutting the extruded aluminum material before, during or after the heat treatment to produce an end, and the end is welded or pressed to a connecting rod made of an extruded aluminum pipe. 5. The method for manufacturing a torque rod according to any one of claims 1 to 4.