JPH03250098A - Lubricant composition for warm and hot forging - Google Patents

Abstract

PURPOSE:To obtain a lubricant composition which is excellent in the resistance to seizure to a metal die at high temperature and in mold release properties and does not worsen the working environment by dispersing an ultrahigh- molecular-weight polyethylene powder in water or oil. CONSTITUTION:A lubricant composition made by dispersing a powder of an ultrahigh-molecular-weight polyethylene having a molecular weight of 1,000,000 or higher in a medium comprising water or oil. If the polyethylene used has a molecular weight of below 1,000,000, it will completely vaporize in a warm or hot forging temperature region, so that lubricity cannot be obtained. The polyethylene having a molecular weight of 1,000,000 or higher will not completely vaporize even if carbonized up to about 400 deg.C. The carbonized material will retain lubricity and, whether it is melted or in a state of carbonized material on a high temperature surface being lubricated, it provides excellent lubricant supply, shows a low coefficient of friction, and serves to prevent a forged material from coming into direct contact with a metal die and from causing seizure thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a white or light-colored lubricant composition for warm and hot forging.

[Conventional technology]

In warm/hot forging in which metals and alloy materials are heated and forged, TFI forging is performed by heating a mold to 100 to 400°C.

This forging requires the use of a heat-resistant lubricant.

Conventionally, heat-resistant forging lubricants are mainly black-based lubricants in which an inorganic solid lubricant such as graphite or molybdenum disulfide is dispersed in water, mineral oil, synthetic oil, or the like. This is because these solid lubricants have excellent lubricity at high temperatures.

In recent years, there has been a demand for a harmless white lubricant due to problems in the work environment such as black lubricants staining the surrounding area or being conductive, but normal white lubricants for forging are Compared to lubricants such as graphite, there was a problem in that the coefficient of friction in the warm and hot forging temperature ranges was large.

On the other hand, even with conventional black-based lubricants, the coefficient of friction in the warm and hot forging temperature ranges is not sufficiently small, and they may stick to the mold, and the release properties of forged products are not always satisfactory. It wasn't worth it.

[Problem to be solved by the invention]

In view of the above circumstances, the present invention provides a white or light-colored warm/hot forging material which is harmless to humans, has a sufficiently small friction coefficient in the warm/hot forging temperature range, and has excellent mold releasability and seizure resistance from the mold. An object of the present invention is to provide a lubricant composition for forging.

[Means to solve the problem]

A first invention for solving the above problems consists in dispersing and containing ultra-high molecular weight polyethylene powder having a molecular weight of 1 million or more in a medium consisting of water or oil. In addition, the second invention is a medium containing water or oil with a molecular weight of lo
The reason for this is that ultra-high molecular weight polyethylene powder with a molecular weight of more than 1,000,000 yen and an inorganic solid lubricant powder having a white or light color are dispersed. Furthermore, the third invention resides in that an ultra-high molecular weight polyethylene powder having a molecular weight of 1 million or more and an oxidized polyethylene powder having a melting point of 80 to 120''C are dispersed in a medium consisting of water.

The present invention is characterized by using ultra-high molecular weight polyethylene powder as a lubricant as described above, and this substance is known to be white and harmless to humans, and to have excellent self-lubricating properties at around room temperature. ing.

The ultra-high molecular weight polyethylene powder used in the present invention preferably has a particle size of about 30 μm or less. If it is larger than this, it is best to crush it appropriately.

As the medium used in the present invention, water or oil is used.

The oil may be appropriately selected from mineral oil, animal oil, synthetic oil, etc. depending on the conditions of use. However, for the purpose of providing a white or light-colored lubricant of the present invention, it is preferable to use a transparent lubricant, or a white or light-colored lubricant.

A lubricant composition can be obtained by dispersing ultra-high molecular weight polyethylene powder with a molecular weight of 1 million or more in such a medium. or other inorganic solid lubricants.

These additives not only can synergistically increase the lubricating effect but also have the effect of increasing the stability of the composition and stabilizing the lubricating performance.

Any of anionic, nonionic and cationic surfactants can be used as long as they are suitable for the dispersion medium.

As the preservative and thickener, those commonly used in lubricant compositions can be used.

The surfactant, preservative, and thickener may be added in amounts of 0 and 1 to 10% by weight, which are usually added to this type of lubricant.

Examples of inorganic solid lubricant powders include boron nitride (BN), cerium fluoride (CeF), and white inorganic solid lubricant powders.
s), zinc sulfide (ZnS), antimony trioxide (Sb,
0. ), zinc oxide (ZnO), calcium fluoride (
Ca F y) % white mica is used, and light-colored inorganic solid lubricant powders include green mica and light brown mica, and bentonite, kaolin, and other white or light-colored clay minerals can also be used.

Furthermore, when water is used as a medium, oxidized polyethylene powder having a melting point of 80 to 120° C. can be used as the lubricant powder.

The composition of the present invention is easily obtained by mixing ultra-high molecular weight polyethylene powder, a medium, and the above-mentioned additives. This lubricant composition is used by applying it to a mold by spraying, brushing, or dipping.

[Effect]

In the present invention, ultra-high molecular weight polyethylene powder having a molecular weight of 1 million or more is used because if the molecular weight is less than 1 million, it will completely volatilize in the warm/hot forging temperature range and lubricity cannot be obtained. It is. Those with a molecular weight of 1 million or more do not completely volatilize even when carbonized up to about 400℃, and this carbide maintains its lubricity, and even if it melts on a high-temperature lubricated surface or becomes a carbide, it will not completely volatilize. It exhibits a low coefficient of friction and prevents direct contact between the die and the forging, preventing seizure. When the sample mold is cooled, a relatively hard film is formed on the surface of the mold, which provides good mold releasability.

The ultra-high molecular weight polyethylene powder can be used in a range of 0.1 to 40% by weight. If it is less than 0.1% by weight, the amount remaining when carbonized at high temperature is too small and there is a risk of seizure, and if it is more than 40% by weight, the lubrication performance will not be improved any further, and the mold This may cause the recess to become clogged. The preferred blending amount is 5 to 20 [1ff
i%.

Inorganic solid lubricant powder with white or light color is 0
．． It can be blended in a range of 1 to 40% by weight.

When used in combination with ultra-high molecular weight polyethylene powder, the effect is produced from about 0.1% by weight, and even if the amount exceeds 40% by weight, the lubrication performance will not be improved any further. The preferred amount is 5 to 5.
It is 20% by weight.

Due to the presence of the ultra-high molecular weight polyethylene powder, this inorganic solid lubricant powder exhibits a lubricating effect that cannot be obtained when only the inorganic solid lubricant powder is blended in the medium. The reason for this is not clear, but even when the forging temperature is high and the ultra-high molecular weight polyethylene evaporates, the liquid ultra-high molecular weight polyethylene or its carbide remains in the recesses on the surface of the inorganic solid lubricant powder. This is thought to be due to the fact that this decreases the coefficient of friction on the surface of the inorganic solid lubricant powder.

In a lubricant composition containing ultra-high molecular weight polyethylene powder, when the lubricant composition is supplied to a mold by spraying, if the medium is water, the adhesion of the ultra-high molecular weight polyethylene powder to the mold is poor. When the amount of adhesion is insufficient, the coefficient of friction decreases and sticking to the mold may occur.

To prevent this, it is recommended to add polyethylene oxide. Oxidized polyethylene softens and melts at low temperatures, making it easier for the ultra-high molecular weight polyethylene powder to adhere to the mold, and has the effect of improving the coefficient of friction.

If the melting point of the oxidized polyethylene powder is less than 80° C., decomposition occurs early, and the adhesion of the ultra-high molecular weight polyethylene powder to a high-temperature mold cannot be improved. Further, since an oxidized polyethylene powder having a melting point exceeding 120°C has poor dispersibility in water, the oxidized polyethylene powder should have a melting point of 80 to 120°C.

The blending amount of polyethylene oxide powder is 0.5 to 20% by weight.
Good. If it is less than 0.5% by weight, sufficient adhesion cannot be obtained;
This is because even if the amount exceeds 20% by weight, the adhesion will not be improved any further.

The preferred amount is 0.8 to 2% by weight.

[Examples] Example 1 A total of 23 types of lubricant compositions were prepared using various components shown in Table 1 and blended in the proportions shown in Table 2.

The test was conducted using the ring compression test method, which is widely used to estimate the coefficient of friction during deformation that involves an increase in area, such as in forging.

For forging test pieces, JIS H3250, C-3
771 Forging Brass (Experiment No. 1-15) Aluminum A-6061, (Experiment No. 16-19), Low Carbon Steel 5
WC810K (experiment No. 20-23), outer diameter 21
．． 0mm, inner diameter 10.5mm, thickness 7゜0mm.
The one finished to m was used.

The pressure tool used was an alloy tool 113KD61 whose parallel pressure surfaces were finished to a surface roughness of 0.02 μm.

A test piece was inserted into the parallel pressing surfaces of the pressing tool so that the two disc-shaped surfaces were in contact with each other, and compressed to a compression ratio of 50% at a rolling speed of 0.1 mm and 7 seconds.

In Experiment Nos. 1 to 10116 to 23, approximately 0.1 g of the lubricant composition was applied with a brush at room temperature to the pressing surface of the pressure tool, heated to 350°C, and then heated to 700°C with brass.
A test piece heated to 500°C with aluminum and 800°C with low carbon steel was rolled down when the pressing tool temperature reached 300°C.

In Nos. 11 to 15, a pressure tool heated to 350°C was used with a nozzle diameter of 0.8 mm and a spray pressure of 174 kpa (1.5 kg).
f/cm') spray gun, apply the lubricant composition at 1
After spraying for seconds, experiment no.

A ring compression test similar to that in Examples 1 to 10 and 16 to 23 was conducted. The results are shown in Table 2.

In Table 2, the evaluation of mold releasability is as follows. In other words, Good: The forged product has separated from the mold and no special operation was required to remove it. Acceptable: The forged product has not separated from the mold, but was removed from the mold through normal operations. Not possible: This is the case when the forged product is stuck to the mold and cannot be removed by normal operation.

Note to Table 1: M is a surfactant made of a water-soluble vegetable oil derivative, N is a preservative containing nitrogen and sulfur, and the thickener is a cellulose resin thickener. Experiment No. 4-10.18.
19.22.23, all of the media containing lubricant powders other than ultra-high molecular weight polyethylene with a grain size of 1 million or more had friction coefficients that were about an order of magnitude higher, Experiment No.] ~ 3.
16.17.20.21, it can be seen that lubricant compositions containing ultra-high molecular weight polyethylene powder with a molecular weight of 1 million or more have extremely excellent lubricating performance, regardless of whether the medium is water or oil.

Experiments Nos. 11 to 15 were spray applied, and as can be seen by comparing Experiments Nos. 2 and 13.6 and 15,
When applied by spray, the coefficient of friction is larger than when applied by brush. However, as can be seen by comparing Experiment Nos. 11 and 13, the addition of oxidized polyethylene can greatly reduce the coefficient of friction. From Experiment No. 4, ultra-high molecular weight polyethylene with a molecular weight of 1 million or more was
．． It turns out that 0.05% by weight is too small.

Example 2 JIS G4303.5US630 as test piece material
Stainless steel, pressure tool material is alloy tool steel 5KD61
was used. The rolling speed of the test piece was about 152 mm/sec, the compression ratio was about 55%, the temperature of the pressure tool during rolling was 200°C, and if the medium was water, the following lubricant composition was diluted 5 times with water and 20 cm After spraying on the mold for 2 seconds from a distance of 1
The test piece heated to 100°C was immediately compressed. Other test conditions are the same as in Example 1.

The table below shows the lubricant composition and friction coefficient used.

Lubricant composition experiment No. 24 (example of the present invention) Weight % ultra-high molecular weight polyethylene Average molecular weight 2 million Average particle size 20-30 μm lO nS Average particle size 0.1-5 μm 10 Surfactant 2 Preservative, thickener 8 Water 70 Friction coefficient 0.17 Experiment No. 25 (Example of the present invention) Ultra-high molecular weight polyethylene Average molecular weight 2 million Average particle size 20 to 30 μm Lipophilic treated betonite particle size 0.5 μm or less (Commercial product trade name Nisben) Liquid paraffin 40°C viscosity 16 c s t.

Friction coefficient 0.12 Experiment No. 26 (comparative example) Ultra-high molecular weight polyethylene average molecule f12 million average particle diameter 20-30 μm Surfactant Preservative, thickener Water weight % Weight % Friction coefficient 0.20 Experiment No. 27 (Comparative example) Lipophilic treated betonite weight % Commercial product trade name Nisben 20 Liquid paraffin 40°C viscosity 16 cst, 80 Friction coefficient 0.25 Experiment No. 28 (Comparative example) Commercial water-based lubricant containing 25% graphite Friction coefficient 0. 19 Experiment No. 29 (Comparative Example) Weight % nS Average particle size 0.1 to 5 μm 10 Surfactant 2 Preservative, thickener 8 Water 80 Coefficient of friction 0.23 As described above, polyester with a molecular weight of 1 million or more When a high molecular weight polyethylene powder and an inorganic solid lubricant powder are used in combination, the coefficient of friction at high temperatures can be made smaller than that of a conventional lubricant composition in which only an inorganic solid lubricant is dispersed in a medium.

〔Effect of the invention〕

According to the lubricant composition of the present invention, the lubricant composition has a white color that has excellent anti-seizure properties to molds and mold release properties at high temperatures, and does not adversely affect the working environment, unlike conventional black lubricant compositions. Alternatively, a light-colored lubricant composition can be provided.

Claims (3)

[Claims] (1) A lubricant composition for warm and hot forging, comprising ultra-high molecular weight polyethylene powder having a molecular weight of 1 million or more dispersed in a medium consisting of water or oil. (2) Warm/hot forging made by dispersing ultra-high molecular weight polyethylene powder with a molecular weight of 1 million or more and an inorganic solid lubricant having a white or light color in a medium consisting of water or oil. lubricant composition for use. (3) A lubricant composition for warm and hot forging, comprising ultra-high molecular weight polyethylene powder with a molecular weight of 1 million or more and oxidized polyethylene powder with a melting point of 80 to 120°C dispersed in a medium consisting of water.