JP2729705B2 - Press forming method of Al alloy sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automotive parts, electric parts,
A suitable for applications where excellent molding is required for complex shapes that are difficult to mold, such as aircraft parts and equipment.
The present invention relates to a method for forming an alloy plate.

[0002]

2. Description of the Related Art Conventionally, there has been a limit in the processing of Al and Al alloys for forming automobile parts, electric parts, aircraft parts, and articles made of Al and Al alloys by ordinary press forming. In the case of a severe product or a product having a complicated shape, the forming by pressing must be abandoned, or the pressing process is divided into a plurality of times to gradually form the desired shape.

[0003] In the latter case, the molding cost naturally rises. However, recently, there has been an increasing demand for molding a product having a severe degree of processing and a complicated shape. Is strongly desired.

On the other hand, in view of environmental problems such as global warming and destruction of the ozone layer, lightening of automobiles has been studied in earnest in order to suppress the increase of carbon dioxide gas in the atmosphere. As one of the measures, Al or Al alloy sheets are increasingly used instead of steel sheets which have been mainly used as a material for press forming. However, since the press formability of the Al or Al alloy plate is inferior to that of the steel plate, there is a strong need for improvement in terms of the press forming method.

[0005] In this regard, Hatsumei Kyokai published technical report 89-1562.
No. 3 proposes a new forming method at a cryogenic temperature as a new forming method, but this method simply makes Al and an Al alloy extremely cryogenic, and changes the mechanical temperature of the material and the forming temperature exerted by the Erichsen value. It merely discloses the effect and does not fit the actual situation in terms of improving the actual press formability.

SUMMARY OF THE INVENTION The present invention has been made to meet the above-mentioned demand, and has as its object to provide a method capable of practically forming an Al plate having a large degree of processing, a severe shape, and a complicated shape. Things.

[0007]

In order to achieve the above object, the present inventor has conducted intensive studies on measures that can be put to practical use in the above-mentioned method for press-forming Al and Al alloy sheets, and as a result, has found that press lubricating oil It has been found that the above-mentioned problems can be effectively solved by controlling the application and forming temperature of the material, and the present invention has been made here.

That is, the present invention provides a liquid lubricating oil which becomes waxy at an extremely low temperature of -40 ° C. or less,
Oil coating on an Al-Mg alloy plate containing t% or more, immersing in liquid nitrogen, taking out, and then performing press forming in an extremely low temperature region of -40 ° C or less . The gist is a press molding method. In the present invention,
Waxy means that liquid lubricating oil is solid at a certain temperature range
Or, it refers to a semi-solid state. Hereinafter, the present invention will be described in more detail.

[0009]

Normally, press lubricating oil is applied to a molding material or a mold at room temperature, and press molding is performed.
It has been considered that lubricating oil deteriorates when lubricating oil is cooled to the following extremely low temperatures, and lubricity is impaired. However, in the case of liquid lubricating oil, it has been found that the oil actually becomes waxy when cooled to an extremely low temperature, and the lubricity is improved.

That is, after the molding material to which the liquid lubricating oil has been applied is immersed in liquid nitrogen and taken out, the properties of the oil change in the order of non-wax, wax and liquid over time, It was found that the lubricating property was improved in the state of the shape. In addition, even if it is not in a wax state, press forming at cryogenic temperature is
Since the mechanical properties at cryogenic temperatures are both higher than the properties at room temperature in both strength and elongation, it has also been found that they are very effective from the viewpoint of press formability. Therefore, in the present invention, press molding is performed at an extremely low temperature, preferably in a state where the liquid lubricating oil is in a wax state.

The liquid lubricating oil is used before press molding, that is,
Prior to immersion in liquid nitrogen, it is pre-applied to the molding material.
The application method and the application amount may be in accordance with a conventional method. Liquid lubricating oils include mineral oils (paraffin, naphthene, etc.) and synthetic oils.
Although there is an (ester) type, a mineral oil type is preferable. The liquid lubricating oil is applied as it is.

The method of cooling the material to which the liquid lubricating oil has been applied to an extremely low temperature is immersed in liquid nitrogen in terms of versatility and cost. As a standard for taking out the liquid lubricating oil after immersion and making it into a waxy state, when liquid nitrogen is used as a cooling medium, it is within 15 to 45 seconds after taking out after immersion.
Since it is 15 seconds or more, the working time from removal to press molding can be tolerated, which is convenient for practical use.

The molding material is an Al-Mg alloy containing 2.5 wt% or more of Mg. The reason is that Mg is strength,
It is an element that imparts moldability and is optimal as a molding material having both properties, but has an Mg content of 2.5.
If the amount is less than wt%, the strength as a product after the forming process is insufficient. In addition, as long as Mg is contained in an amount of 2.5 wt. Or more, a component composition which can be used for this kind of use is possible, and accordingly, other alloy components can be appropriately contained as needed.

Next, an embodiment of the present invention will be described.

[0015]

Example 1 An O material of JIS5182 alloy having a thickness of 1 mm was used as a forming material, and press forming was performed using a mechanical press with a ball-overhanging die shown in FIG.
At that time, first add mineral oil as liquid lubricating oil to the material.
After applying (liquid paraffin), it was immersed in liquid nitrogen for 2 minutes, taken out, and immediately pressed. Formability was evaluated by changing the stroke length of the punch.

[Table 1] Shows the results of measuring the moldable height. From the same table, the present invention example immersed in liquid nitrogen, taken out after cooling to extremely low temperature, and press-molded, the moldable height is higher than that of normal press molding not immersed in liquid nitrogen (comparative example). It can be seen that it is rising.

[0016]

Embodiment 2

[Table 2] 1-mm thick Al-Mg based alloy having the chemical components
The same press forming test as in Example 1 was performed using the material as a forming material. Table 2 shows the results of measuring the moldability and the hardness of the molded product. It can be seen that the comparative example having a small Mg content has insufficient strength as a molded product.

[0017]

Embodiment 3 JIS having a thickness of 1 mm as a material for forming processing
Using a 5182 alloy O material, it was immersed in liquid nitrogen, and a processing test was performed by changing the time before processing. Other conditions were the same as in Example 1. The result

[Table 3] Shown in In Table 3, the moldability is observed to be improved when the work is performed after about 30 seconds from immediately after immersion. This corresponds well with the wax state. That is, it does not become waxy immediately after being taken out, and has already changed to a liquid state 60 seconds after being taken out, and the lubricity is reduced. In addition, each moldability immediately after taking out and 60 seconds after taking out is improved compared with the case where it is not immersed in liquid nitrogen (comparative example in Example 1).

[0018]

As described above, according to the present invention,
Since the press forming process is performed in a cryogenic temperature range, the formability can be improved, and furthermore, the process can be performed even in a preferable lubricating state. Therefore, the effect is particularly excellent in molding processing having a severe degree of processing and a complicated shape, and is economical because the number of molding steps is small, and the effect that has made practical use remarkable.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a ball head overhang mold.

[Explanation of symbols]

 1 upper mold 2 lower mold 3 punch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location // C10N 40:24 (72) Inventor Shojiro Oya 9-13-1, Kasugadai, Nishi-ku, Kobe-shi, Hyogo (72) Inventor Mitsuo Hino 15-21, 3621 Kumakura-cho, Moka-shi, Tochigi

Claims (2)

(57) [Claims] 1. A liquid lubricating oil which becomes waxy at an extremely low temperature of -40 ° C. or less, containing 2.5 wt% or more of Mg.
A method of press-forming an Al alloy sheet, comprising applying oil to an l-Mg-based alloy sheet, immersing it in liquid nitrogen, taking out, and then press-forming in an extremely low temperature range of −40 ° C. or lower . 2. After being immersed in liquid nitrogen and taken out,
Claims and performing press molding within 45 seconds
Item 1. A method for press-forming an Al alloy sheet according to Item 1 .