JPS6244549A - Structural aluminum alloy having superior cold workability - Google Patents

Abstract

PURPOSE:To obtain a structural Al alloy having superior cold workability by adding a prescribed amount of a are earth element to an Al-Mg alloy contg. a relatively large amount of Mg. CONSTITUTION:The composition of this structural Al alloy is composed of 2-7wt% Mg, 0.005-2wt% one or more kinds of rare earth elements and the balance Al with inevitable impurities. the composition may further contain 0.05-2wt% Cu. The Al alloy has superior cold workability and enables the manufacture of a further complex product by cold forging.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is directed to the construction of high-strength aluminum alloys that are mainly constructed by cold rolling, processing, and cold working in a pickling tank. Especially M(A containing + to a moderate degree or more)
It relates to a ρ-Mg alloy with improved cold workability.

In this specification, all "%" are expressed on a 1,000 ton basis.

Conventional technology and problems AI2-M (A3056.508, which contains a relatively large amount of Mg as an l-based alloy) is used as a structural material.
Alloys such as No. 2 are commonly used because they have high strength and excellent corrosion resistance. These aluminum alloys containing M() at a medium or higher level have high deformation resistance and low deformability, so generally soft annealed materials are used. When subjected to cold working with a large hardness, cracks tend to occur due to large work hardening, resulting in poor cold workability.

The object of the present invention is to improve the cold workability of the above-mentioned ρ-M (1 series alloy) without degrading its own desirable inherent properties.

Means for Solving the Problems As a result of various experiments and studies for the above-mentioned purpose, the present invention has developed a Ω-Mq alloy containing a relatively large amount of Mq acid components, including Y, ta, and ce.

1) By adding rare earth elements such as R, Nd, 3M, etc. to a predetermined range, the work hardening rate of the alloy can be reduced and it has been completed by finding scales.

That is, this invention contains Mg: 2 to 7%, one or more rare earth elements in the range of 0.05 to 2.0%, and Cu: 0.05 to 2% as necessary. 0%, and the remainder is aluminum and unavoidable impurities, and has excellent cold workability.

The reasons for limiting each component of the alloy of this invention are as follows.

As is known, Mg has the effect of improving the strength of the alloy, and if the content is less than 2%, it cannot impart enough strength to be suitable for use as a structural material. However, if the content exceeds 7%, stress corrosion cracking resistance
Also, the workability becomes extremely poor and it cannot be used as a practical alloy.

The most suitable content is approximately 2.5 to 5.5%.

The type of rare earth element is not particularly limited. Specifically, for example, Y, La, Ce, pr, Nd
, 3m etc. are preferably used.

This rare earth element mainly contributes to reducing the work hardening rate of the alloy. In view of this effect, all of the rare earth elements can be evaluated as substantially equivalent to each other in the present invention. Therefore, one or more of them can be used in any combination, or if the total content of them in the alloy is less than 0.005%, the effect of reducing the work hardening rate is insufficient; If the content exceeds .0%, the above effects cannot be obtained. The most preferable content range for rare earth elements is approximately 0.05 to 0.5% when cost is also taken into consideration.

CI, which is an optionally included component, also has an odd slope in improving strength, and is ineffective if contained less than 0.05%.
If it exceeds 2%, the corrosion resistance and weldability of the alloy will deteriorate. The most suitable Cu-containing matrix is approximately 0.2 to 1.0%.

Unavoidable impurity components include Si, Fe, Mn, Cr,
These impurity components include Zr, Ti, etc., but the inclusion of these impurity components is permitted within a range that does not adversely affect the alloy of the present invention. Mn: 1.5%, especially useful for grain refinement
Hereinafter, the content of 0r = 0.3% or less and the content of Zr: 0.25% or less are treated as impurities in this invention.

Effects of the Invention As mentioned above, the present invention is based on a ρ-MQ alloy with high strength and excellent corrosion resistance, and a total of 0.0
By adding and containing rare earth elements in the range of 0.05 to 1.0, work hardening during cold working can be suppressed and cold workability can be improved. Therefore, the degree of cold work is reduced from the conventional structural A.
Not only can it be made much larger than the ρ-Mg alloy, but cold forging also makes it possible to process and manufacture products with even more compound conical shapes.

Examples Alloys having the various compositions shown in Table 1 were molded into a water-cooled mold with a diameter of 75 sides, and then homogenized at 500° C. for 8 hours. Then, the product was further extruded at 450'C into a rectangular rod shape with a thickness of 5 rrvn and a width of 30 m, which was used as a sample. Na a3
, the comparative example alloy is A50! :12 alloy (comparison N0.7>
and A3083 alloy (comparison No. 0.8) were used.

After annealing each of the above samples at 400'C, cold rolling was performed until cracks appeared in the sample, and the hardness and degree of cold working at that time were measured. The performance was evaluated. The results are shown in Table 2.

[Margin below U] Table 2 As shown in the results above, the alloy of the present invention exhibits a smaller increase in hardness due to cold working than the conventional typical Hemega-Mg alloy, and improves workability. We have confirmed that it is possible.

Amendment to the above procedure September 1, 1988 Commissioner of the Patent Office Black 1) Yu Akira 1, Indication of the case 1985 Patent Application No. 185474 26 Name of the invention Structural aluminum alloy with excellent workability 3, Amendment Relationship with the case involving the person who filed the patent application Address: 6-224 Kaizan-cho, Sakai City Name: Showa Aluminum Co., Ltd. Representative: Ishi
Chika I 4, agent address: 72-4 Unagidani Nakano-cho, Minami-ku, Osaka (08)
245-2718 '-""" 5. Date of amendment order (voluntary amendment) 6. Number of inventions increased by amendment 7. Target of amendment 8. Contents of amendment (1) Change the name of the invention in the application to "Processing". "A structural aluminum alloy with excellent properties."

(2) The entire text of the specification is amended as shown in the attached sheet.

Above description (amendment) 1. Name of the invention Structural aluminum alloy with excellent workability 2. Claims Mg: 2 to 7% One or more rare earth elements: 0.005 to 2.0 % and, if necessary, Cu: 0.05 to 2.0%, the balance being aluminum and unavoidable impurities, and having excellent workability.

3. Detailed Description of the Invention Industrial Field of Application This invention relates to an AQ-Mg-based aluminum alloy with improved workability, particularly Afl-Mg containing a medium or higher content of Mg.
The present invention relates to alloys having improved cold workability in cold rolling, drawing, forging, etc.

In this specification, all "%" are expressed on a weight basis.

Conventional technology and problems A3056.5082, which contains a relatively large amount of Mg, is an Afi-Mg alloy used as a structural material.
These alloys are commonly used because they have high strength and excellent corrosion resistance. Since these aluminum alloys containing Mg at a medium or higher level have high deformation resistance and low deformability, annealed soft materials are generally used. However, when cold working with a large degree of working is performed, there is a problem that cracks are likely to occur due to large work hardening and poor cold workability.

The object of the present invention is to improve the workability, particularly the cold workability, of the above-mentioned structural Aρ-Mg alloy without deteriorating its desirable inherent properties.

Means for Solving the Problems As a result of various experiments and studies for the above purpose, the present invention has developed an Afl-Mg alloy containing a relatively large amount of Mg.
To find scales that improve not only hot workability but also especially cold workability by reducing the work hardening rate of the alloy by adding rare earth elements such as S m in a predetermined amount range. It could be completed by.

That is, this invention contains Mg: 2 to 7%, one or more rare earth elements in the range of 0.05 to 2.0%, and Cu: 0.05 to 2.0% as necessary. 0%, and the remainder is aluminum and unavoidable impurities, and has excellent workability.

The reasons for limiting each component of the alloy of this invention are as follows.

As is known, Mg is effective in improving the strength of alloys, and if the content is less than 2%, it cannot impart enough strength to be suitable for use as a structural material. But 7
If the content exceeds %, the stress corrosion cracking resistance and workability will deteriorate significantly and it cannot be used as a practical alloy. The most suitable content is approximately 2.5 to 5.5%.

The type of rare earth element is not particularly limited. Specifically, for example, Y, La5CesP r s N
d SS m etc. are used as suitable materials.

Elements belonging to the rare earth group have the effect of contributing to improvement of cold workability by improving workability, particularly by reducing work hardening rate. In view of this effect, all of the rare earth elements can be evaluated as substantially equivalent to each other in the present invention. Therefore, one or more of them can be used in any combination, but if the total content of these in the alloy is less than 0.005%, the workability will be improved and the cold work hardening rate will be reduced. On the other hand, it is insufficient for 1.0
If the content exceeds %, the above effects cannot be obtained. The most suitable content range for rare earth elements is approximately 0.05 to 0.05 when considering cost. It is about 5%.

Cu, which is an optional component, also contributes to improving the strength, and if it is contained less than 0.05%, it has no effect.
If it exceeds 2%, the corrosion resistance and weldability of the alloy will deteriorate. The most suitable Cu content is approximately 0.2 to 1.0%.

Unavoidable impurity components include Sl, Fe, Mn, C'',
Zr5T1, etc. are included, but the inclusion of these impurity components is permitted within a range that does not adversely affect the alloy of the present invention. In particular, the contents of Mn: 1.5% or less, Cr: 0.3% or less, and Zr: 0.25% or less, which are useful for refining crystal grains, are treated as impurities in the present invention.

Effects of the Invention As mentioned above, the present invention is based on the AΩ-Mg alloy having high strength and excellent corrosion resistance.
By adding and containing rare earth elements in the range of os to 1.0, it is possible to improve workability, particularly by suppressing work hardening during cold working. Therefore, it is not only possible to increase the degree of cold working compared to conventional structural AQ-Mg alloys, but also to manufacture products with more complex shapes in cold forging.

EXAMPLES Alloys having various compositions shown in Table 1 were cast into water-cooled molds with a diameter of 75 ml, and then homogenized at 500'C for 8 hours. Then further heat at 450'C to a thickness of 5ml
The sample was extruded into a rectangular rod shape with a width of 30 mm.

The comparative example alloy is A3052 alloy (comparison No. 7)
and A3083 alloy (comparison No. 8) were used.

After annealing each of the above samples at 400'C, cold rolling was performed until cracks appeared in the samples.
By measuring the hardness and cold working degree at that time,
Cold workability was evaluated. The results are shown in Table 2.

[Hereinafter referred to as white thread] As shown in the above results in Table 2, the alloy of the present invention exhibits a smaller increase in hardness due to cold working than the typical conventional AΩ-Mg alloy, and improves workability. I was able to confirm that it was Shiuruchino.

that's all

Claims (1)

[Claims] Contains Mg: 2 to 7%, one or more rare earth elements: 0.005 to 2.0%, and if necessary, Cu: 0.05 to 2.0. %, a structural aluminum alloy with excellent cold workability, consisting of the balance aluminum and unavoidable impurities.