JPH05345896A - Lubricant for warm forming processing of aluminum material - Google Patents

Abstract

PURPOSE:To obtain a lubricant causing neither seizing nor dragging to aluminum materials especially in a high-temperature range, providing excellent lubrication by dispersing soap of a specific saturated fatty acid and CaCO3 powder into water. CONSTITUTION:(A) 2.5-20wt.% soap of a saturated fatty acid composed of 12-18C alkyl, having a temperature to reach 20% solubility in water of lower than 50 deg.C, (B) 2.5-20wt.% CaCO3 powder having 0.05-200mum particle size and extreme-pressure agent such as graphite, mica and sulfur are uniformly dispersed into water to give the objective lubricant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant used during warm forming of aluminum materials. In addition,
In this specification, the aluminum material includes not only industrial pure aluminum material but also various aluminum alloy materials. Further, in the present specification, the warm forming process is a process of forming into a predetermined shape while being in contact with a mold, a tool, or a roll, and is at least room temperature or higher and a recrystallization temperature or lower at least when the material is subjected to forming. Refers to processing. However, in order to remarkably obtain the effect of warm forming, 180 ° C to 300 ° C
Is preferred.

[0002]

2. Description of the Related Art If an aluminum material can be used in place of the mild steel conventionally used for various purposes, the weight can be greatly reduced. However, among various aluminum materials, those having strength equivalent to mild steel have poor ductility as compared with mild steel and are inferior in formability in ordinary forming at room temperature. Therefore, various forming methods for improving the formability of the aluminum material have been studied, and various methods have been studied as the warm forming method as one of them. The warm forming method is one in which the work is heated to room temperature or higher and the recrystallization temperature or lower to perform the forming process, and at that time, how to improve the formability and prevent seizure and galling is a problem. Is becoming Therefore, lubricants are used to improve moldability and prevent seizures. Conventionally known lubricants are vegetable oils such as soybean oil, sheets of tetrafluoroethylene (commonly called Teflon: trade name), and polymers. There is a mixture of graphite with, or a mixture of grease, mineral oil with graphite, molybdenum disulfide, or mica.

[0003]

However, in a warm forming process of an aluminum material, a lubricant which has sufficient formability and is satisfactory in terms of seizure and galling has not yet been obtained, so that it can be put to practical use. Is far from the situation. That is, in warm forming, the temperature range of forming is higher than that of cold forming, so if a conventional lubricant is used as it is, it decomposes and produces smoke, which worsens the working environment and further
There is a problem in work such as ignition. In addition, there is also a problem that lubricity is deteriorated due to the transformation of the lubricant, workability is deteriorated, material breakage and seizure, and galling are caused to deteriorate the quality of the molded product. The present invention has been made in view of the above circumstances, and an object thereof is to provide a lubricant having good lubricity without causing smoke / ignition, seizure, or galling when used for warm forming of an aluminum material. It is a thing.

[0004]

The inventors have reached the present invention as a result of various studies for solving the above problems. That is,
The present invention has a temperature of 50% at which the solubility in water reaches 20%.
1. 2.5% to 20% by weight of saturated fatty acid soap consisting of an alkyl group having a carbon number C of 12 to 18 and having a carbon number C of 12 to 18% by weight, and CaCO ₃ powder having a particle size of 0.05 to 200 μm.
It is a lubricant for warm forming of an aluminum material containing 5% to 20% dispersed in water.

[0005]

The function of the present invention will be described in detail below.
The lubricant of the present invention is one in which an appropriate amount of CaCO ₃ powder is dispersed in an aqueous solution of soap having specific characteristics. In use, it is applied to an aluminum material in advance, dried, and then subjected to warm forming processing. Is. If this lubricant is used while it is wet, the aluminum may be discolored during warm forming, resulting in poor appearance. Further, it is desirable that the coating is performed at a temperature of about room temperature. Applying at high temperature will cause discoloration and corrosion of aluminum. The base of the present invention is a saturated fatty acid soap having an alkyl group, mainly an aqueous solution of sodium salt or potassium salt. Some of the so-called soaps are unsaturated fatty acid soaps,
Although it has excellent solubility in water, it has the problem that seizure easily occurs during warm forming, which deteriorates the quality of the molded product, and it decomposes during warm forming to generate smoke and the odor of paraffin is strong. There is also a problem that the working environment becomes worse. In addition, lubricants based on mineral oils other than fatty acids or synthetic oils (polybutene) decompose at temperatures above 200 ° C to generate smoke, deteriorating the working environment, and reducing lubricity in this temperature range. Gnawing ability deteriorates, and further 2
May ignite above 50 ° C. Further, the grease reacts with the aluminum material at a temperature of 180 ° C. to 300 ° C., which makes it difficult to degrease after molding. Therefore, use saturated fatty acid soap.

If the carbon number C of the alkyl group is less than 12, lubricity is poor and galling is likely to occur. If the carbon number C exceeds 18, the adhesion to the aluminum material is poor and coating unevenness is likely to occur. It is not suitable for actual use because the scuffing property tends to vary and the seizure property deteriorates. Therefore, the carbon number C is an alkyl group having 12 to 18 carbon atoms. The soap used in the present invention is solid or semi-solid at room temperature and cannot be applied uniformly to an aluminum material as it is. Therefore, an aqueous solution is applied to an aluminum material and dried to form a uniform soap film on the surface of the aluminum material to form a lubricating film. Solubility in water is 2
Soap that requires a temperature of 50 ° C or higher to reach 0% requires heating to form an aqueous solution for uniform application, and aluminum material for maintaining a dissolved state during application. Alternatively, it is necessary to heat the lubricant. However, when an aluminum material is brought into contact with an aqueous solution containing soap at a high temperature, corrosive stains are generated, which lowers the commercial value of the surface of a molded product. Further, the addition of the extra heating step increases the processing cost. Therefore, the soap is one that is easily dissolved even at a low temperature of less than 50 ° C. at which the solubility reaches 20%.

If the aqueous solution concentration of soap is less than 2.5%, the lubricity is poor, and galling is likely to occur, and if it exceeds 20%, the seizure property is deteriorated and the commercial value of the product surface is reduced.
Therefore, the concentration of the soap is 2.5 to 20%.

As described above, the base material of the present invention is a soap of a fatty acid consisting of an alkyl group having a carbon number C = 12 to 18, and the temperature at which the solubility in water reaches 20% is 50 ° C.
An aqueous solution containing less than 2.5% to 20%.

The aqueous solution of soap, which is the base of the present invention described above, can be used as a lubricant for warm forming of aluminum materials as compared with conventional lubricants, and can be used at low temperatures in the warm forming temperature range. Shows good performance.
However, when the molding temperature is higher, that is, the aluminum material or the mold or tool, the roll temperature is 180 ° C to
In the processing at 300 ° C., galling is likely to occur and continuous processing is difficult. Therefore, as a result of further diligent research, the particle size of the above soap solution was 0.05.
It has been found that the continuous gallability on the high temperature side is significantly improved and continuous processing is possible by dispersing and containing 2.5% to 20% of CaCO ₃ powder having a particle size of up to 200 μm.

If the particle size of the CaCO ₃ powder is less than 0.05 μm, galling is likely to occur and there is no effect of addition, and if the particle size is small, the cost will be high. Further, even if it exceeds 200 μm, the effect on the galling due to its addition does not change, but it becomes easy to peel off after coating and drying, and the effect becomes unstable. Therefore, the particle size of CaCO ₃ powder is 0.05 μm to 200 μm.
And Further, if the content of CaCO ₃ powder is less than 2.5%, the galling resistance effect due to the addition is not exerted, and if it exceeds 20%, not only the economical efficiency deteriorates from the viewpoint of the cost of CaCO ₃ powder, but also after coating and drying. It has a drawback that it is easy to peel off and the effect becomes unstable. Therefore, the present invention has a particle size of 0.05 to 200 μm with respect to the base of the above-mentioned aqueous solution of soap.
2.5 to 20% of CaCO ₃ powder is dispersed and contained.

It should be noted that coexistence of powders of graphite, mica, ethylene tetrafluoride resin, boron nitride, talc, etc. together with CaCO ₃ powder does not reduce the above effect. further,
Extreme pressure additives such as sulfur type, phosphorus type, chlorine type, etc.
For example, diphenyl disulfide
l disulfide), trilauryl phosphate, monochlorobenzene (monochlorobenzene)
The load resistance is improved by adding.

When the lubricant according to the present invention is used, it is desirable to sufficiently stir it so that it can be applied in a uniformly dispersed state. Further, the warm forming process may be performed by heating the molding die, tool, or roll to indirectly heat the contacting aluminum material, or preheating the aluminum material itself, or both. In any case, the lubricant of the present invention is applied to an aluminum material in advance at room temperature.
After being dried, it shall be subjected to warm forming processing. When the lubricant of the present invention is applied at a high temperature, corrosive stains are generated on the surface of the aluminum plate. Further, since it is an aqueous solution, if it is left wet or is subjected to warm forming as it is, the aluminum plate is corroded by the water contained in the lubricant. Therefore, it should be applied and dried at room temperature in advance. If the lubricant according to the present invention is applied and dried not only on the aluminum plate but also on the surfaces of molding dies, tools, rolls, etc., the effect is further stabilized. This is because in warm forming, once galling occurs, galling tends to increase rapidly,
It is desirable to apply a lubricant to a molding die or the like in order to prevent galling at the initial stage of molding. Since the application to the molding die or the like has a great effect on the prevention of initial galling, it is sufficient to apply the composition to the molding die or the like only once before the start of processing.

[0013]

EXAMPLES The effects of the present invention will be described in detail based on the following examples. Using a JIS 5182-O aluminum plate having a thickness of 0.8 mm, warm forming was performed under the following conditions. Mold: Punch 60mm x 60mm x 2 double sinks: Distance between punches 60mm: Blank holder force 1000kgf Molding temperature: Molded after holding at 300 ° C for 1 minute Molding depth: Max 60mm Also, the results are based on the following criteria. evaluated. Working environment: The situation of odor and smoke during actual use. -: Strong odor, much smoke and poor visibility. ±: Smell odor, slightly smoked. +: The odor is weak, and the smoke is minimal. Galling property: The galliness limit number in the Bowden friction test (at 300 ° C). -: 5 times or less. ±: 6 times or more and 10 times or less. +: Over 10 times. Moldability: The height at which molding is possible without cracking. -: 20 mm or less. ±: 21 mm or more and 59 mm or less. +: 60 mm. (Maximum of 60 mm due to equipment limitation) Image sticking: Strength of stain generated on aluminum material (at 300 ° C) in the air. -: Strong. ±: Medium. +: Weak. Adhesion: Adhesion and detachment of lubricant before drying after pressing. -: Adhesion was poor and there was dropout. ±: Adhering state. +: Good adhesion and no falling off.

[Preliminary Experiment] Performance Comparison of Bases First, the above-mentioned working environment, galling property, moldability, and seizure property were investigated with various bases. The results are shown in Table 1. However, No. The "lubricant" column of 4 to 8 shows the C number of the alkyl group, the type of soap, and the concentration of the soap aqueous solution.

[0015]

[Table 1]

As can be seen from Table 1, No. 1 which is a comparative example. 1: Unsaturated fatty acid soap aqueous solution No. 3: Synthetic oil No. 2: An aqueous solution of a fatty acid soap having an alkyl group, which has a solubility in water lower than the claimed range, No. 2 4 to 7: A soap of a fatty acid having an alkyl group, which has a high C solubility and a high solubility in water, but whose C number and concentration are out of the scope of the claims of the present application, is evaluated as "-" by any of the evaluation items. On the other hand, a base material (N
o. In 8), all galleries are evaluated as “+” except that they are evaluated as “±”, indicating that they have excellent performance as a lubricant for warm forming of aluminum materials. ..

[Example] Performance comparison when CaCO ₃ was added as an inorganic component. It examined the CaCO ₃ Effect of particle size and content of the powder when present claims was added CaCO ₃ powder all satisfactory base the scope of the term used as 8. The results are shown in Table 2. Note that the work environment and lubricity are all “+” ratings and are not listed in the table.

[0018]

[Table 2]

When CaCO ₃ powder having a particle size and content satisfying the scope of the claims of the present application was added (Nos. 2 to ₃ ), in addition to the characteristics of the above-mentioned base material, further improvement in galling property was observed.
Therefore, galling is unlikely to occur during processing, and continuous processing becomes easy. On the other hand, CaCO ₃ powder with too small particle size (N
In the case of o1), the galling property is not good, and CaCO ₃ powder having a small particle size is expensive in manufacturing. On the contrary, if the CaCO ₃ powder has an excessively large particle size (No 4), the adhesion is poor. Further, if the content of the CaCO ₃ powder is too small (No 5), the galling property is not improved. Conversely, Ca
If the content of the CO ₃ powder is too large (No 6), the adhesion is poor.

[0020]

As described above in detail and as shown in the examples, the lubricant of the present invention (1) has good galling property in the warm forming temperature range of the aluminum material from room temperature to recrystallization temperature. (2) good lubricity, (3) good product surface quality, (4) good working environment,
(5) Good moldability is obtained. In particular, conventional lubricants show the above good characteristics on the high temperature side where smoke generation, modification, etc. occur, and are suitable for warm molding on the high temperature side,
It shows characteristics comparable to those on the low temperature side. Therefore, although the advantages in processing have been confirmed in the past, the lubricant has an insufficient performance, so that it has excellent performance as a lubricant for warm forming of aluminum materials, which has been difficult to industrialize.

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Claims (1)

[Claims] 1. A saturated fatty acid soap consisting of an alkyl group having a carbon number C = 12 to 18 and having a solubility in water of 20% below 50 ° C. is 2.5% to 2.5% by weight (hereinafter the same). 20% and particle size 0.05-200 μm
Lubricant for warm forming of aluminum material containing 2.5% to 20% of CaCO ₃ powder dispersed in water.