JPH06220471A - Lubricant for low-temperature working of aluminum or its alloy and process for low-temperature working - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a lubricant having properties suitable for low temperature processing, and to provide a method for low temperature processing using such a lubricant. [Composition] This low temperature processing lubricant has a kinematic viscosity of 50 cSt.
It is a lubricating oil whose temperature is less than / 40 ° C and whose pour point is adjusted to -40 ° C or higher. After applying the lubricating oil to the surface of aluminum and aluminum alloy plates in advance, the plate is cooled to a temperature of less than −30 ° C. to form a lubricating film, and then pressed. It is effective for aluminum products having severe shapes such as automobile parts, electric equipment parts, aircraft parts, etc., which are severely processed and have complicated shapes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the processing of aluminum and aluminum alloy sheets, and more specifically, it has a complicated and complicated shape for aluminum parts, such as automobile parts, electric equipment parts, aircraft parts, etc. The present invention relates to molding technology effective for aluminum products.

[0002]

2. Description of the Related Art Aluminum and aluminum alloys are excellent in corrosion resistance and formability in addition to their light weight. Therefore, they are used as general-purpose metal materials next to steel materials in various fields including automobiles. It is widely used in the industrial field.

Recently, the use of aluminum and aluminum alloy sheets has been gradually increasing in order to reduce the weight of automobiles. However, since aluminum and aluminum alloy sheets are inferior in formability to steel sheets, cracking during forming occurs. In addition, the shape is limited at the time of designing, which is a serious problem. Therefore, from the viewpoint of formability, development of materials with excellent ductility (e.g.,
Japanese Unexamined Patent Publication (Kokai) No. 63-89649) is under way. However, it is still inferior to steel sheets, so that improvement in terms of working is required.

From this point of view, the inventors of the present invention have advanced a processing method suitable for aluminum and aluminum alloys, and as a result, previously developed and proposed a low temperature processing method (Japanese Patent Application No. Hei 2).
-416279). This is to improve the formability by utilizing the improvement of the elongation of aluminum and aluminum alloy in the low temperature region, and more specifically, it is a method of low temperature working the plate using a lubricant for low temperature. But,
Even with this method, the required properties of the lubricant are unclear,
The formability varies depending on the type of lubricant, and the formability may be inferior to that of the steel sheet.

The present invention solves the above-mentioned problems of the prior art, provides a lubricant having characteristics suitable for low temperature processing, and provides a method for low temperature processing using such a lubricant. It is intended.

[0006]

In order to solve the above-mentioned problems, the present inventor has found that the characteristics of a lubricant suitable for low temperature processing of aluminum and aluminum alloys are unclear. As a result of earnest research on measures that can solve the problems of molding defects such as cracking, limitation of product shape or increase in the number of processes, we found that it can be solved by adjusting the characteristics of the lubricant and molding conditions, The present invention has been made here.

That is, according to the present invention, a lubricant used for pressing aluminum and aluminum alloys at a low temperature of less than -30 ° C has a kinematic viscosity of 50 cSt /
The gist is a lubricant for low-temperature processing of aluminum and aluminum alloys, which is a lubricating oil having a pour point adjusted to -40 ° C or higher at a temperature lower than 40 ° C.

According to another aspect of the present invention, after the above-mentioned lubricating oil is applied to the surface of aluminum and aluminum alloy plates in advance, the plate is cooled to a temperature of less than -30 ° C to form a lubricating film, The gist is a low-temperature processing method for aluminum and aluminum alloys, which is characterized by press working.

The present invention will be described in more detail below.

[0010]

[Action]

The reasons for limiting the properties of the lubricant of the present invention are as follows.

Lubricant characteristics: kinematic viscosity

Generally, the higher the viscosity, the better the lubricity,
Although a large moldability can be obtained, it is not necessary to improve the viscosity at the time of low temperature processing, because the viscosity improving effect can be obtained by the temperature decrease. On the contrary, when the kinematic viscosity is 50 cSt / 40 ° C. or higher, degreasing failure is likely to occur in the degreasing step after molding,
It may also be a cause of defective painting in the later painting process. Further, in the oiling work on the plate before pressing, if the viscosity is too high, it is difficult to uniformly apply the oil, and if the oiled plates are overlapped with each other, it is difficult to peel them off. Therefore, the lubricating oil should have a kinematic viscosity of 50 cSt or less. The kinematic viscosity is measured according to JIS K2283.

Lubricant Properties: Pour Point

As described above, it is desirable that the viscosity of the lubricating oil is as low as possible at room temperature. However, at the pressing temperature (less than -30 ° C), the viscosity is increased and the flow disappears. It needs to be semi-solid or solid. For that purpose, if the lubricating oil has a pour point of -40 ° C or higher, it acts like a gel-like semi-solid or solid lubricant during low temperature processing (less than -30 ° C) to improve the formability. Is obtained. However, when a lubricating oil having fluidity even at a low temperature of less than -40 ° C is used, a sufficient lubricating effect cannot be obtained at a low processing temperature,
Moldability is poor. Therefore, the lubricating oil has a pour point of -40 ° C.
More than that. The pour point is JIS K2269.
Measured by

The composition of the lubricant is not particularly limited as long as it is a lubricating oil having the above-mentioned characteristics (kinematic viscosity and pour point). For example, using liquid paraffin, aroma mineral oil, α-olefin, polyether oil, silicone oil, or a mixed oil thereof, the above,
Can be adjusted to provide the characteristics of Based on these, additives generally added to lubricating oils, that is, oiliness improvers, extreme pressure agents, antioxidants, stain inhibitors, anticorrosives and the like may be added based on these.

Next, the processing conditions of the present invention will be described.

Before press working, a lubricant having the above characteristics is applied in advance to the surfaces of aluminum and aluminum alloy plates. In order to form a lubricating film on the plate surface, it is necessary to cool the plate surface to which the above lubricating oil has been applied in advance to less than -30 ° C.

Even if the lubricating oil is sprayed onto the surface of the cooling plate during processing, a uniform film cannot be formed, and depending on the location, poor lubricity or excessive lubricity occurs, so sufficient moldability is obtained. Absent. In this respect, when cooled to less than -30 ° C, a solid film-like lubricant is formed, which acts as a heat insulating film and prevents a temperature rise due to the time from cooling to processing, thus improving cooling efficiency. be able to.

The press working temperature is lower than -30 ° C. It is known that the lower the temperature of aluminum and the aluminum alloy, the higher the strength and elongation, and the better the formability. At -30 ° C or higher, the effect is small. At least less than -30 ° C, preferably -50 ° C or less is desirable.

Any cooling method may be used. For example, it can be easily cooled to the target temperature by immersing it in liquid nitrogen. When the temperature becomes −196 ° C. or lower, a refrigerant such as liquid helium is required, which is not desirable in consideration of cost.

There are no particular restrictions on the materials such as aluminum and aluminum alloys to which the present invention is applied, and an appropriate component system and composition may be selected depending on the required performance of the final product. For example, when high strength is required, the Al-high Mg (3-6% Mg) system is desirable.

Next, examples of the present invention will be described.

[0024]

【Example】

Various lubricants shown in Table 1 were prepared and applied to the surface of a test material (JIS5182-O material, plate thickness 1.0 mm) (about 1 g / m ² ) and then immersed in liquid nitrogen. ,take out,
After reaching various predetermined temperatures, they are subjected to a molding test for moldability,
The degreasing property was evaluated. The results are also shown in Table 1.

The moldability was evaluated by performing molding under the following conditions using an 80 ton crank test press, and the maximum molding height until cracking occurred.

Ball head protrusion: punch diameter 50 mmφ, blank diameter 120 mmφ, wrinkle holding force 6.5 tons. Cylindrical diaphragm: punch diameter 50mmφ, blank diameter 120mmφ, wrinkle holding force 0.65 tons.

The degreasing property was evaluated by using a water-lubricated area ratio (%) in a degreasing test under the following conditions using a plate surface coated with a lubricant. The test is conducted with n = 3,
The average value was used.

Oiling conditions: Immediately before, degreasing liquid: commercial alkaline degreasing liquid (PH11) Degreasing conditions: 40 ° C. still immersion in degreasing liquid for 2 minutes Washing: tap running water for 1 minute.

As is clear from Table 1, when a lubricating oil having predetermined characteristics is used for molding at a molding temperature of less than -30 ° C., excellent moldability without cracks is obtained, and degreasing property is also good. That is, from Test Nos. 1 to 4, it can be seen that even if a lubricating oil having a predetermined characteristic is used, moldability cannot be obtained unless the molding temperature is appropriate as in Comparative Example No.1. Test N
As shown in No. 5 and No. 6, even if an additive is added or a mixed oil is used, excellent moldability can be obtained if the lubricating oil has predetermined characteristics. As compared with Test No. 7, as shown in Test No. 1 and Nos. 8 to 9, the lubricating oil having the characteristics outside the range of the present invention is inferior in moldability or degreasing property.

[0031]

[Table 1]

[0032]

As described in detail above, according to the present invention,
Moldability is greatly improved, and it becomes possible to mold even shapes that could not be conventionally molded. Further, the improvement in moldability makes it possible to reduce the number of steps in the related art, and the productivity can be improved. Therefore, the range of application of aluminum and aluminum alloy materials is expanded, and effects such as energy saving accompanying the achievement of weight reduction of automobile parts and prevention of environmental deterioration due to waste gas can be obtained.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C22F 1/04 // (C10M 111/02 101: 02 105: 72 105: 04) C10N 20:00 A 8217- 4H 20:02 8217-4H 40:24 A 8217-4H

Claims (3)

[Claims] 1. Aluminum and aluminum alloys
A lubricant used for press working at a low temperature of less than 30 ° C., which is a lubricating oil having a kinematic viscosity of less than 50 cSt / 40 ° C. and a pour point adjusted to −40 ° C. or higher, and Lubricant for low temperature processing of aluminum alloy. 2. After applying the lubricating oil according to claim 1 to a plate surface of aluminum and an aluminum alloy,
A low-temperature processing method for aluminum and aluminum alloys, which comprises pressing a plate after cooling the plate to a temperature of less than 30 ° C. to form a lubricating film. 3. A press product having excellent degreasing properties, which is formed by the low temperature processing method according to claim 2 and is made of aluminum and an aluminum alloy.