Aluminum alloy for casting-forge, and aluminum casting forged product and manufacturing method therefor

Abstract

An aluminum casting forged product is provided by using an aluminum alloy for casting forge including a useless raw material for forging such as flash as a raw material and by controlling a weight percentage of an alloy element such as silicon, magnesium, copper, and manganese; the product having an enhanced fluidity, and an improved castability, with retaining a sufficient strength, preventing useless intermetallic compounds from forming, restraining deterioration due to oxidation and corrosion, and further improved strength by a forging effect: and there is also provided a simple manufacturing method, with a high yield and high productivity. An aluminum casting forged product of high tensile strength, high proof, and elongation, higher mechanical properties than those of the conventional casting forged product, high corrosion resistance, and high quality without defects, and being low in cost is also obtainable as a thick-wall aluminum product.

Description

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT[0001] The present invention relates to an aluminum alloy for casting forge and an aluminum casting forged product that is used for a vehicular part or the like and is less costly, and a manufacturing method for the aluminum casting forged product. More particularly, it relates to an aluminum alloy for casting forge that is used to manufacture vehicular suspension parts which are required to be light in weight to improve fuel economy of an automobile and can use useless forging materials such as flash produced in a forging process, an aluminum casting forged product that has high mechanical properties and contains particular amounts of silicon, magnesium, copper, and manganese, and a manufacturing method for the aluminum casting forged product.[0002] It is said that global warming, which is one of global environmental problems, is greatly affected by carbon dioxide produced by all human activities, and an decrease in carbon dioxid...

AI Technical Summary

Benefits of technology

[0012] However, for this aluminum alloy, although the strength is increased, there arises a new problem in that a low cost cannot be attained, and the corrosion resistance is low because a larger amount of copper is contained than the conventional raw material for forging (A6061 alloy), and also the fluidity decreases so that the castability is poor because much magnesium is contained.

Problems solved by technology

The reduction in weight of automobile is accompanied by a problem of increased cost that is to be solved.

However, such a material for reducing the weight is generally expensive.

However, castings having large thickness and high strength cannot be produced.

For the suspension parts required to reduce the weight as described above, a failure due to insufficient strength presents an important problem relating to safety, so that there has been a problem of difficulty in applying the casting.

However, these materials still have an unsolved problem of high cost, so that the application thereof is extremely limited at present.

The reasons why a so-called pure aluminum forging such as the conventional A6061 alloy forging is high in cost is that the number of manufacturing processes is large, that the raw material for forging itself is expensive, waste such as flash is caused during the manufacturing process, and that a useless material such as flash cannot be recycled as a raw material for forging.

Also, for a squeeze casting, because of a large number of processes and a low injection speed, the productivity is low and a low cost cannot be attained.

However, for this aluminum alloy, although the strength is increased, there arises a new problem in that a low cost cannot be attained, and the corrosion resistance is low because a larger amount of copper is contained than the conventional raw material for forging (A6061 alloy), and also the fluidity decreases so that the castability is poor because much magnesium is contained.

In this proposal, although the castability is improved, a low cost cannot be attained yet as compared with the conventional raw material for forging (A6061 alloy), and also the corrosion resistance is low because much copper is contained, so that there remains anxiety when this material is used for a suspension part.

Also, there arises a problem in that the fluidity decreases because much magnesium is contained, and the above-described rigorous control is needed in the casting process, so that the manufacturing cost rather increases.

In this proposal, although a shape close to the final product can be formed at the time of casting, and the manufacturing cost can be reduced because forging can be performed by omitting an extrusion process, there arises a problem in that the strength decreases because an excessive amount of manganese is contained.

If the content thereof is high, however, intermetallic compounds are liable to be yielded, so that the strength is rather decreased.

However, a suitable aluminum product has not been proposed.

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