JPH06228719A - Formation of bent part in aluminum alloy casting, and high rigidity aluminum alloy casting and its production - Google Patents

Abstract

PURPOSE:To obtain a high rigidity aluminum alloy material by subjecting an aluminum alloy casting, where a part to be bent is formed, to solution heat treatment and to rapid cooling and then applying bending at a specific angle to the above bent part. CONSTITUTION:A molten aluminum alloy is cast in a mold, and an aluminum casting 1, where a part 2 to be bent is formed, is prepared. This casting 1 is subjected to solution heat treatment and to rapid cooling, and bending 2a at an angle of >=45 deg. is applied to the part 2, to be bent, of the casting 1. Then, a jointed part 3 is formed in the parts, which are oppositely jointed by means of bending 2a, by means of welding, etc., to increase rigidity. By this method, the high rigidity aluminum alloy material where lightening in weight and reduction in costs are attained can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a bent portion in an aluminum alloy cast body, a high-rigidity aluminum alloy cast body, and a manufacturing method thereof, and a high-rigidity aluminum alloy cast suitable for vehicles and various operating mechanisms. It concerns the body and its proper manufacturing techniques.

[0002]

2. Description of the Related Art A member having a high load such as an automobile cross member or a side rail has a closed cross section to provide rigidity. Such a member has been conventionally manufactured by welding an iron plate, etc., but with the recent demand for weight reduction, an aluminum alloy is cast to manufacture such a member.

In addition, since it is difficult to directly manufacture a member having a closed cross-section structure with such an aluminum alloy casting technique, a rib having a large number of ribs is formed on a member having an open cross-section to form a high-rigidity member. ing.

[0004]

Since a member obtained by casting an aluminum alloy as described above generally has an open cross section, a member having a high rigidity can be obtained even if the weight can be considerably reduced. There is a disadvantage that cannot be done.

In order to avoid such disadvantages, in the case where the ribs or the like are provided on the open cross-section shaped member to have high rigidity as described above, the weight of the product is considerably heavy due to the many ribs provided. Inevitably, it becomes expensive, and in any case, the weight reduction as the original purpose of adopting the aluminum alloy is largely hindered, which is also disadvantageous in terms of cost.

[0006]

SUMMARY OF THE INVENTION The present invention was devised after repeated studies to solve the above-mentioned problems in the prior art, in which an aluminum alloy cast body is subjected to a specific treatment or working. It has succeeded in obtaining a high-rigidity aluminum alloy material that achieves appropriate high rigidity, secures weight reduction and low cost, without taking special rib arrangement, etc., and is as follows. .

An aluminum alloy cast body having a bent portion formed by subjecting the aluminum alloy cast body to a solution heat treatment and then quenching, and then subjecting the bent portion of the cast body to a bending process of 45 ° or more. A method of forming a bent portion.

Bending containing, in wt%, Si: 6 to 12%, and further containing any one or both of Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%. The high rigidity described above, characterized in that the aluminum alloy cast body in which the worked portion is formed is solution-cooled, then the bent portion is bent to 60 ° or more, and the bent end portions are joined. Aluminum alloy casting manufacturing method.

A method for producing a high-rigidity aluminum alloy cast body, which comprises subjecting the cast body obtained by the method described above or above to an aging treatment.

45 wt% contains Si: 6 to 12%, and further contains any one or both of Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%. An aluminum alloy cast body having a bent portion of not less than ° and having a tensile strength of 250
More than MPa, 0.2% yield strength 170-250MPa and elongation 1
A high-rigidity aluminum alloy cast body characterized by being set to 0 to 15%.

[0011]

Since the aluminum alloy cast body having the bent portion is simply formed with the bent portion, it can be easily and efficiently cast-molded with an open cross section by a generally simple mold member and molding method. .

The aluminum alloy cast body obtained in a simple and efficient manner as described above is melted and then rapidly cooled to be softened, and then the bent portion of the cast body is bent at 45 ° or more. As a result, it is possible to properly form a work having a relatively large bending angle in the cast body, and to obtain an aluminum alloy cast body whose strength is increased by heat treatment and whose rigidity is increased by bending work.

% By weight, Si: 6-12%, and
By including any one or both of Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%, it is possible to effectively increase the strength by the age hardening element in a predetermined heat treatment.

Tensile strength is 250 MPa or more, 0.2% proof stress is 1
By increasing the elongation at 70 to 250 MPa to 10 to 15%, the strength of such an aluminum alloy cast body is increased, and at 10 to 15%, the appropriate toughness can be obtained for vehicles and devices. As a member, it is possible to achieve favorable durability while ensuring lightness.

An aluminum alloy cast body having the above-described component composition and having a bent portion formed therein is subjected to solution heat treatment and then rapidly cooled, and in the cast body, the bent portion is 60 °.
By bending the above, further increase its rigidity,
However, by joining the bent end portions, the rigidity thereof can be improved more accurately and accurately. By subjecting the cast body thus obtained to an aging treatment, mechanical properties such as strength and yield strength are improved.

[0016]

EXAMPLE FIG. 1 schematically shows the production according to the present invention as described above, in which a prepared aluminum alloy melt is cast by a mold, and then this cast body is solution heat treated. Quench quickly.

A bending portion is formed in the cast body, and the bending portion is subjected to bending work in the solution-quenched and cast body as described above. Is made highly rigid by joining by welding or the like.

As the die casting mentioned above, for example, a low pressure casting method, a die casting method, a squeeze die casting method or a non-porous die casting method is adopted. Among them, those cast by the non-porous die casting method are solutionized. At this time, a preferable semi-finished product is obtained without causing swelling due to expansion of air bubbles.

The semi-finished product thus formed is subjected to solution treatment and then rapidly cooled. This solution heat treatment and quenching are performed to facilitate the subsequent bending work and to increase the effect of the aging treatment. That is, it has been found that a preferable temperature for solution heat treatment is 500 to 560 ° C., and that water cooling after solution heat treatment is preferable as the subsequent rapid cooling.

The bending process performed after the above treatment is applied to a necessary portion by a bending process method such as butt bending, press winding, and feed bending. By this bending process, the cross-sectional shape of the cast body can be made more rigid.

After bending, a product with higher rigidity can be obtained by joining the ends to form a closed cross section. FIG. 2 and FIG. 3 show an example of a cross-section structural material having high rigidity. Casting is performed by forming a bending portion 2 on a part of a cast body 1 having an U-shaped cross section and having an open cross section. Then, the bending portion 2 is bent 2a along the bending line 4 to form a closed section as shown by the imaginary line in FIG. To make a highly rigid product.

The product obtained as described above can obtain further improved preferable mechanical properties by adding an aging treatment of heating at 140 to 210 ° C. for 1 to 16 hours which is well known.

The composition will be described below.

Si: 6 to 12%: Si is for imparting fluidity to the molten aluminum, and is less effective below the lower limit value, and toughness due to crystallization of primary crystal Si above the upper limit value. Since it lowers, it is limited as described above.

Any one or both of Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%: Addition of Mg or Cu is for imparting strength to the aluminum alloy by aging treatment and has a lower limit value. Below, the effect is small, and when it is above the upper limit, the plastic working uniformity decreases in the case of Mg and the corrosion resistance decreases in the case of Cu.

Other elements such as Mn: up to 0.6%, Ni: up to 0.5%, and Zn: up to 0.3% are allowed to be added.

In the case of die casting, 0.5 to 1.% of the above additive is added in order to prevent the molten metal from being seized on the die.
Addition of about 1% is rather preferable.

A concrete example of manufacturing the product according to the present invention will be described. As an aluminum alloy material, Si: 8.3 is used.
wt%, Fe: 0.5 wt%, Mg: 0.27 wt%, the balance is
Prepare a molten metal having a composition of Al and unavoidable impurities,
Two aluminum alloy bodies each having the structure shown in FIG. 3 were prepared by casting by oxygen substitution die casting method, and one of them was subjected to solution treatment at 510 ° C. for 1 hour and then quenched with water. The other material was an as-quenched material and the other material was an as-cast material.

In order to compare the bending workability of the as-cast material with the solution-quenched material of the automobile cross member obtained as described above, the bending workability at various bending angles was compared. The results obtained are as shown in Table 1 below.

[0030]

[Table 1]

That is, it is understood that the quenched material after solution heat treatment according to the present invention can be easily processed with a large bending angle, and as shown in FIG. 2, the bent portions 2a are abutted against each other and the end portions are welded to each other. A high-rigidity member can be obtained by calculating the torsional rigidity of the present invention material and the comparative material as described above, while the result of the present invention material was 1.0.
It was 7.

The product thus obtained was subjected to an aging treatment at 160 ° C. × 2 Hr and the strength was measured. The results are shown in Table 2 below.

[0033]

[Table 2]

[0034]

As described above, according to the present invention, an aluminum alloy body having a relatively simple cross-sectional structure without further ribs is provided under the condition that the lightweight property is secured and the aluminum alloy body is simple. This is an invention having a great effect industrially because it is possible to provide an energy-saving and high-rigidity material suitable for vehicles and the like, by increasing the preferable rigidity under molding conditions, and at low cost and with high productivity.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process according to the present invention.

FIG. 2 is a cross-sectional view showing a bending process relationship of a specific example according to the present invention.

FIG. 3 is a perspective view showing an example of a general configuration of the cast body shown in FIG.

[Explanation of symbols]

 1 Cast body 2 Bending part 2a Bending 3 Joining part by welding 4 Bending line

Front page continued (72) Inventor Toshiya Anami 1-34-1 Kambara, Kambara-cho, Anbara-gun, Shizuoka

Claims (4)

[Claims] 1. An aluminum alloy casting characterized in that an aluminum alloy cast body having a bent portion formed therein is solution-cooled, and then the bent portion of the cast body is bent at 45 ° or more. A method of forming bends in the body. 2. The composition contains 6 to 12% by weight of Si and further contains Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%.
The aluminum alloy cast body having a bent portion containing seeds or both is solution-cooled, then the bent portion is bent to 60 ° or more, and the bent end portions are joined. The method for producing a high-rigidity aluminum alloy cast body according to claim 1. 3. A method for producing a high-rigidity aluminum alloy cast body, which comprises subjecting the cast body obtained by the method according to claim 1 or 2 to an aging treatment. 4. The composition contains 6 to 12% by weight of Si, and further contains Mg: 0.1 to 0.5% and Cu: 0.1 to 3.5%.
An aluminum alloy casting having a bent portion of 45 ° or more containing seeds or both, and having a tensile strength of 250M.
Pa or more, 0.2% proof stress 170-250MPa and elongation 10
A high-rigidity aluminum alloy cast body characterized by having been set to -15%.