JP2006131726A - Lubricant composition for warm and hot working of magnesium and/or magnesium alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant composition which is excellent in lubricity and scratch resistance, does not leave residues on the worked surfaces and enables rolling and press forming of magnesium and/or magnesium alloys in warm and hot regions at 180-350°C. <P>SOLUTION: The lubricant composition for warm and hot working of magnesium and/or magnesium alloys is obtained by including at least one kind selected from alkyl alcohols, esters and fatty acids as an oiliness agent in a base oil comprising at least one kind selected from polybutenes, polyisobutylenes, polyacrylates, alkyl benzenes and isoparaffins. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  Magnesium or magnesium alloy has a feature that the sliding surface in the crystal of magnesium or magnesium alloy varies depending on the molding temperature, and the workability is extremely poor in a temperature range where there are few sliding surfaces of 180 ° C. or less. Rolled or pressed in a warm or hot region of ° C. At that time, there is a strong demand for a lubricant that reduces the processing load and surface flaws during processing in that temperature region and that does not leave residue on the surface of the workpiece after processing.

  Conventionally, lubricants such as fats and oils and esters used for plastic processing such as rolling, pressing and drawing are effective in reducing processing and preventing seizure flaws, but they have poor heat transpiration and are warm and hot. Residues remain on the surface of the workpiece after processing, causing problems such as multi-pass rolling and shape defects in subsequent processes, and are not currently applied.

  On the other hand, there is an example in which a lubricant composition in which a solid lubricant such as molybdenum disulfide and polytetrafluoroethylene is dispersed in a base oil such as mineral oil is applied to warm deep drawing of a magnesium alloy plate. When put into practical use, due to the solid lubricant, there are problems such as deterioration in workability and difficulty in removing surface residues after processing, and it is almost never put into practical use.

  Therefore, a lubricant for magnesium or its alloy, which can solve the above problems, is now strongly desired.

  The problem of the present invention is that, in the rolling and press working in the warm and hot regions of magnesium and / or magnesium alloy, no residue remains, the thermal transpiration of the lubricant is excellent, and the processing load is reduced. To provide a lubricant composition for warm and hot working that can prevent wrinkles and has good lubricity, and to provide a supply method that enables rolling and press forming in the warm and hot regions. .

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that a base oil comprising at least one of a zipping polymer such as polybutene, polyisobutylene, and polyacrylate having excellent heat transpiration, alkylbenzene, isoparaffin, and the like. In addition, the present inventors completed the present invention by finding the fact that the lubricant composition to which an oily agent such as alkyl alcohol, ester and fatty acid is added reduces processing load, prevents wrinkles, has no surface residue after processing, and has excellent workability. It came to do.

  That is, the lubricant for warm and hot working of magnesium and / or magnesium alloy of the present invention comprises 50 to 98 parts by weight of at least one of polybutene, polyisobutylene, polyacrylate, alkylbenzene and isoparaffin as a base oil ( The total composition is used at a ratio of 100% by weight) and 2 to 50 parts by weight (based on the total composition of 100% by weight) of an oily agent comprising at least one of alkyl alcohol, ester and fatty acid is contained. It is characterized by.

  Conventionally, the processing load reduction, surface wrinkle prevention, and post-processing problems due to post-processing residues could not be solved. However, by supplying and applying the lubricant of the present invention, all of the above problems can be solved. Or) Warm or hot working of magnesium alloys is now possible.

  In the present invention, 50 to 98% by weight of at least one of polybutene, polyisobutylene, polyacrylate, alkylbenzene and isoparaffin is used as a base oil.

  Specifically, polybutene having an average molecular weight of 300 to 4,000, kinematic viscosity (100 ° C.) of 2.7 to 5,700 cst, an average molecular weight of 30,000 to 60,000, kinematic viscosity (160 ° C.) of 20,000 to 157 000 cst polyisobutylene, average molecular weight 50,000 to 300,000, kinematic viscosity (100 ° C.) polyacrylate and polymethacrylate 500 to 2,000 cst, kinematic viscosity (40 ° C.) alkylbenzene and isoparaffin having 20 cst or less The above is used as the base oil.

  Polybutene having a low average molecular weight and low kinematic viscosity, and alkylbenzene and isoparaffin having a low kinematic viscosity are effective when used in combination with polybutene, polyisobutylene, polyacrylate and polymethacrylate having a high average molecular weight and high kinematic viscosity. The kinematic viscosity (40 ° C.) of the mixed base oil is usually 20 to 400 cst, preferably 40 to 300 cst. That is, if the kinematic viscosity is lower than that, the adhesion to a heated tool or roll (50 to 150 ° C.) is poor and the lubricating oil film tends to be thin, which is not very effective. Further, if the kinematic viscosity is higher than that, the workability is poor, and when the temperature of the workpiece is relatively low, the residue remains and the stainability tends to deteriorate.

  In the present invention, 2 to 50% by weight of at least one of alkyl alcohol, ester and fatty acid is used as the oily agent.

  If the amount of the oily agent is less than 2% by weight, the lubricating effect of reducing the processing load and preventing wrinkles is insufficient, and if it exceeds 50% by weight, the good heat transpiration of the base oil is impaired and it is uneconomical. is there.

  These oil-based agents will be described in more detail.

  Examples of the alkyl alcohol include monovalent alkyl alcohols having 6 to 20 carbon atoms such as linear and branched hexyl alcohols, octanol, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol and the like.

  The ester is an ester synthesized from a fatty acid and an alcohol, the fatty acid is a monobasic acid having 12 to 18 carbon atoms, the alcohol is a monohydric or polyhydric alcohol, specifically butyl stearate, palmitic acid Examples include ethylhexyl, butyl oleate, butyl carbitol isostearate, neopentyl glycol oleate, trimethylol propane laurate, tromethylol propane oleate, pentaerythritol oleate, and the like.

  As the fatty acid, a linear or branched saturated or unsaturated fatty acid having 10 to 18 carbon atoms is preferably used, and specific representative examples include lauric acid, myristic acid, palmitic acid, oleic acid, and isostearic acid. Dibasic acids such as basic acid, sebacic acid and dimer acid are particularly preferable.

  Examples of the magnesium alloy used in the invention include Mg-Al-Zn-based AZ-31, AZ-61A, AZ-80A, AZ-91A, and the like, Mg-Al-Zr-based ZK-91A, ZK- Examples thereof include 60A and Mg-Al-Si-based AS-41A.

  As a supply method enabling the rolling and press forming of magnesium and / or magnesium alloy in the warm and hot regions, the stock solution of the lubricant composition is applied by spray coating, brush coating, roller coating, etc., 50-250 Feed directly to rolling rolls and tools heated to ℃. In the case of rolling, it is continuously supplied to the roll entry side. What is necessary is just to select a supply amount suitably as needed. In the case of press molding, the stock solution is sprayed on a tool or a mold in advance and applied by brushing. What is necessary is just to select the application quantity suitably.

  In order to facilitate understanding of the present invention, examples and comparative examples are shown below.

  Predetermined components shown in Table 1 below are blended in predetermined amounts, and the warm and hot working lubricant composition No. 1-No. 10 was produced.

Comparative Example 1

  A predetermined amount of the predetermined components shown in Table 2 below were blended to obtain a lubricant composition No. 1 as a comparative example. 1-No. 8 was produced. The physical properties of these were measured. The physical properties of these were measured. The results are shown in Table 2.

<Rolling test method>
1. Testing machine (two-stage small rolling mill)
Rolling speed 10m / min
Roll SUJ-2 (150φ × 200mm) # 600 Emery paper polishing
1. Roll temperature is heated to 70 ° C. Test material
AZ-31 (1.0 x 50 x 150 mm)
Material temperature 280 ℃
(310 ° C panel heater warming, 280 ° C confirmed with a contact-type thermometer immediately before rolling)
3. Test Method In the apparatus shown in FIG. 1, the lubricant of (1) was dropped in advance on the roller of (2), the roller with the lubricant attached was pressed against the roll of (3), and the lubricant was applied to the roll. Then, the heating test material of (4) is rolled.
1. 3 passes
2. Rolling N number 3 sheets 4. Evaluation 1. Lubricity: Unit rolling load (ton / mm ² ) = 1-3 load total / total rolling amount / sheet width measured in each example and comparative example, with Comparative Example 4 (Ester B simple substance) as a reference (Ester B simple substance is set to 1.00)
The smaller the relative load ratio, the better the lubricity.
2. Surface wrinkles after rolling: Visual evaluation of presence / absence and size of wrinkles.
No wrinkle is good with ◎, large size is bad with ×
3. Surface residue after rolling: Visual evaluation of residue and oil burn (stainability)
No stain is good for ◎, stain large is bad for ×

<Test results>

1. Polybutene A: average molecular weight 300 (LV-7 = Nippon Oil)
2. Polybutene B: Average molecular weight 430 (LV-50 = Nippon Oil)
3. Polybutene C: average molecular weight 1400 (HV-50 = Nippon Oil)
4). Polyisobutylene D: average molecular weight 60,000 (Tetrax 6T = Nippon Oil)
5. Polyacrylate E: Average molecular weight 230,000 (Kanerube 815 = Kanebo)
6). Alkylbenzene: (8.4 cst / 40 ° C)
7). Isoparaffin: (2.6 cst / 40 ° C)
8). Alkyl alcohol A: C13-15 alcohol (Dialen 135 = Mitsubishi Chemical)
9. Alkyl alcohol B: oleyl alcohol 10. Ester A: trimethylolpropane oleate ester Fatty acid: oleic acid

12 Mineral oil A: Spindle oil (10 cst / 40 ° C)
13. Mineral oil B: Machine oil (46cst / 40 ℃)
14 Ester B: Neopentyl glycol oleate 15. Oil and fat: Palm oil

From Tables 1 and 2, the following can be clearly seen.

  1. Comparative Example No. As in 1-4, polybuden, alkylbenzene, and isoparaffin alone have good stain properties, but poor lubricity and surface defects occur.

  2. Comparative Example No. The oily agent added to the mineral oil as in 5 to 6 is improved in lubricity, but has poor stainability and cannot be used.

  3. Esters and oils and fats have good lubricity and no surface flaws, but their stainability is very poor and cannot be used.

  4). Example No. 1, 2 and 5 have the same lubricity as that of the ester B, and the stain property is remarkably excellent.

  5. Example No. Nos. 6, 7 and 8 also have good stain properties, and the lubricity is equivalent to that of esters and fats and oils and is remarkably superior.

  6). Example No. 3, 4 and 9, 10 have remarkably good lubricity, surface flaws and stain properties.

  7. Example No. Nos. 1 to 10 have good lubricity, good surface resistance after rolling, little residue after rolling, good stainability, for warm and hot working of magnesium and magnesium alloys Judged to be applicable as a lubricant.

FIG. 1 is a schematic explanatory diagram of an example of a rolling tester used for measuring physical properties of the composition of the present invention and a test method thereof.

Explanation of symbols

1. 1. Lubricant stock solution 2. Rolling roll Roller (lubricant application)
4). Heat test material

Claims (2)

Base oil comprising at least one of polybutene, polyisobutylene, polyacrylate, alkylbenzene and isoparaffin is 50 to 98% by weight (based on the whole composition as 100% by weight), and one or more selected from alkyl alcohol, ester and fatty acid. A lubricant composition for warm and hot working of magnesium and / or magnesium alloy, comprising 2 to 50% by weight of an oily agent (100% by weight of the whole composition). A lubricant composition wherein the polybutene according to claim 1 has an average molecular weight of 300 to 4,000, polyisobutylene has an average molecular weight of 30,000 to 60,000, and polyacrylate has an average molecular weight of 50,000 to 300,000.

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