JPH07132357A - Lubricating method for plunger tip of casting device - Google Patents

Abstract

PURPOSE:To provide the lubricating method for a plunger tip which does not form a chill layer by the partial temp. fall of a molten metal surface in spite of using a watersoluble lubricant in casting of a nonferrous metal, maintains high lubricity, eliminates the danger of fire and is good in working environment. CONSTITUTION:The film of a heat insulating material consisting of 10 to 20 pts.wt. inorg. powder, 1 to 2 pts.wt. dispersant, 0.5 pt.wt. surfactant and the balance water is formed on the inner peripheral surface of the injection sleeve of a casting device. The water-soluble lubricant consisting of 5 to 35 pts.wt. mineral oil, etc., 5 to 15 pts.wt. wax, 15 pts.wt. higher fatty acid metal salt, 0.5 to 5 pts.wt. surfactant and the balance water is then supplied, by which the lubrication of the plunger tip is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger which does not form a chill layer even when a water-soluble lubricant is used in casting of non-ferrous metals such as aluminum and magnesium, and has excellent lubricity. A method for lubricating chips.

[0002]

2. Description of the Related Art As a method of lubricating a plunger tip in a casting apparatus, conventionally, a lubricant is supplied between the inner peripheral surface of the injection sleeve and the plunger tip to reduce the friction between them and to melt the molten metal into a cavity. The method of sending it inside smoothly is adopted. As the plunger tip lubricant used for such a purpose, a water-insoluble lubricant and a water-soluble lubricant have been conventionally known. As the water-insoluble lubricant, for example, a lubricant using powder such as graphite (Japanese Patent Laid-Open No. 1-144)
As the water-soluble lubricant, for example, mineral oil, oil and fat, fatty acid ester, solid lubricant, lubricant composed of a surfactant (JP-A-2-248497), and the like are known. ing.

However, since the water-insoluble lubricant contains oil as a main component, it has a risk of fire and also has a problem of contaminating the periphery of the machine. On the other hand, a water-insoluble lubricant containing no graphite and using a white solid lubricant (JP-A-2-215894), or a water-insoluble lubricant containing no powder (JP-A-2-22839).
No. 3) has been proposed, but the former still has a risk of fire and the latter has a problem that lubricity is inferior. On the other hand, the above water-soluble lubricant has a problem that the lubricity is inferior to that of the water-insoluble lubricant, and galling of the plunger tip occurs.

Further, in the above water-soluble lubricant, the inner peripheral surface of the injection sleeve is cooled by latent heat of vaporization of water in the lubricant,
When the inner peripheral surface of the sleeve has low heat insulation, the heat of the molten metal itself dissipates greatly, and the molten metal surface in contact with the cooled inner peripheral surface of the sleeve solidifies to form a thin metal layer (usually called a chill layer). There is a problem in that the chill layer may be formed, and the chill layer is peeled off by the plunger tip and mixed in the cast product, thereby impairing the product quality after casting. As described above, in the non-ferrous metal casting process, the chill layer is not formed even by the use of the water-soluble lubricant, and the method of lubricating the plunger tip having excellent lubricity has not been found. .

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems. Even when a water-soluble lubricant is used, a chill layer is not formed, high lubricity is maintained, and there is a risk of fire. It is an object of the present invention to provide a method for lubricating a plunger tip which has no working property and has a good working environment.

[0006]

The inventors of the present invention have found the composition and effect of a heat insulating agent for the inner peripheral surface of an injection sleeve for preventing the formation of a chill layer in the casting process of non-ferrous metal, and a water-soluble lubricant for a plunger tip. As a result of diligent studies on the relationship between the composition of the lubricant and the lubricity and the lubrication method of the plunger tip using them, first, before supplying the lubricant, first, a film of a heat insulating agent was formed on the inner peripheral surface of the injection sleeve of the casting machine. To form
Then, by the method of supplying the lubricant to the surface of the film and / or the surface of the plunger tip, the conventional problems when the water-soluble lubricant is used, that is, formation of a chill layer, insufficient lubricity, etc. The inventors have found that they can be solved and have completed the present invention.

That is, the plunger tip lubricating method according to the first aspect of the present invention is characterized in that the lubricant is supplied after forming a heat insulating agent film on the inner peripheral surface of the injection sleeve of the casting apparatus. A second invention is characterized in that the lubricant is supplied to the surface of the film of the heat insulating agent and / or the surface of the plunger tip, and the third invention is that the heat insulating agent is
It is characterized by containing (a) inorganic powder, (b) dispersant, (c) surfactant, and (d) water. The first and second inventions will be described in more detail. The "heat insulating agent" is spread on the inner peripheral surface of the injection sleeve in advance by a method such as spraying to form a "film".
Is formed, and the above "lubricant" is applied to the film by spraying or the like, or after spreading the heat insulating agent, the lubricant is dropped on the surface of the plunger tip, or is sprayed at a high pressure with air by an atomizer and supplied. Further, a method of improving the lubricity of the plunger tip by using them in combination is included.

As the above-mentioned "inorganic powder", for example, mica, talc, kaolin, sericite, zircon flour, zircon sand, quartz glass powder, boron nitride, fluorinated graphite and the like can be used. Further, as the dispersant,
For example, carboxymethyl cellulose, methyl cellulose, cellulose ether such as hydroxy cellulose,
One or more selected from the group consisting of natural polysaccharides and montmorillonite ore group can be used.

Further, the above-mentioned "surfactant" is a component used for dispersing and wetting the inorganic powder in the heat insulating agent used in the lubricating method of the present invention, and specifically, the whole heat insulating agent. If it does not hinder the uniform dispersion and mixing of cations, cationic surfactants such as aliphatic amine salts, pyridinium salts, imidazolinium salts, anions such as fatty acid soaps, alkylbenzene sulfonates, alkylnaphthalene sulfonates, etc. -Based surfactants, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters,
A nonionic surfactant such as polyethylene glycol fatty acid ester can be used.

Examples of the water-soluble lubricant used in the method of lubricating the plunger tip of the present invention include (a) mineral oil, fats and oils,
1 selected from the group consisting of fatty acids and fatty acid esters
It is possible to use a lubricant containing one kind or two or more kinds, (b) wax, (c) higher fatty acid metal salt, (d) surfactant, and (e) water. The lubricant does not necessarily need to contain all of the above components, and for example, a lubricant lacking the component (c) or a lubricant lacking the components (a) and (b) can be used. The surfactant in the lubricant is a component having a function of solubilizing the lubricant when the lubricant adhered to the inner peripheral surface of the injection sleeve and / or the plunger tip surface is removed by washing with water. As long as it does not hinder the uniform mixing and dispersion of the whole, the same materials as those for the heat insulating agent can be used.

The above-mentioned mineral oil, fats and oils, fatty acids and fatty acid esters are used in a water-soluble lubricant for plunger tips.
Especially, it is a component for exerting lubricity in a low temperature range.
Examples of the fats and oils include animal and vegetable fats and oils such as rapeseed oil, soybean oil, coconut oil, palm oil, beef tallow and lard. Examples of the fatty acid include coconut oil fatty acid, oleic acid, stearic acid, lauric acid, palmitic acid, beef tallow fatty acid and the like. Furthermore, examples of the fatty acid ester include monohydric alcohol esters and polyhydric alcohol esters of the fatty acids.
Of these, from the viewpoint of heat resistance and solubility with other components,
Esters of coconut oil fatty acid, oleic acid, stearic acid and the like with trimethylolpropane and neopentyl alcohol are preferable.

Examples of the above waxes include natural and synthetic hydrocarbon waxes and waxes, and oxides and acid modified products thereof. Examples of the natural wax include animal waxes such as beeswax, spermaceti wax, hydrogenated spermaceti wax, carnauba wax, candelia wax, wood wax, bran wax, paraffin wax, microcrystalline wax, montan wax, sericin. Mineral wax such as wax can be used.

Further, the above-mentioned higher fatty acid metal salt is a component which prevents oil film breakage in a high temperature region and exhibits lubricity at a high temperature in a water-soluble lubricant for a plunger tip, such as coconut oil fatty acid and olein. A salt of a higher fatty acid such as an acid, stearic acid, lauric acid, palmitic acid, or beef tallow fatty acid with a metal such as sodium, potassium, magnesium, lithium, calcium, aluminum or zinc can be used. The water-soluble lubricant used in the method for lubricating the plunger tip of the present invention may be any of anticorrosion agents, thickeners, wetting agents, antiseptic / antifungal agents, defoaming agents, etc., in addition to the above components. Additives can be appropriately added and used.

[0014]

According to the present invention, by forming a film of a heat insulating agent on the inner peripheral surface of the injection sleeve of the casting apparatus in advance, the inner peripheral surface of the injection sleeve is cooled by latent heat of vaporization of water in the water-soluble lubricant supplied thereafter. Even if the temperature of the molten metal is partially lowered, the heat taken away from the inner peripheral surface of the injection sleeve and the molten metal is prevented from escaping to the outside of the injection sleeve. for that reason,
The temperature drop on the surface of the molten metal is small, a chill layer is not formed, the performance of the supplied lubricant is fully exhibited, and excellent lubricity is maintained.

[0015]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. (1) Preparation and composition of heat insulating agent and lubricant The heat insulating agent and lubricant used in Examples and Comparative Examples are shown in Table 1.
It was prepared by mixing the composition components shown in. In addition, the numerical values relating to the composition in the table are 100% of the total amount of the heat insulating agent or the lubricant.
The parts by weight are shown when the parts are parts by weight. Further, in Table 1, each component specifically used the following.

A) Talc: Nippon Talc Co., Ltd., trade name "Microace P4" (average particle size: 1.5 μm) b) Boron nitride: Mitsui Toatsu Chemical Co., Ltd., trade name "M
BN-050 "(average particle size; 0.1 to 0.2 μm) c) Dispersant: carboxymethyl cellulose d) Surfactant A: Sanyo Chemical Industries, Ltd., trade name" Nonipol SN60 "e) Surfactant B : Sanyo Chemical Industry Co., Ltd., trade name "Nonipol SN85" f) Surfactant C: sorbitan monooleate g) Mineral oil: Nippon Oil Co., Ltd., trade name "SAE30"
(Kinematic viscosity at 40 ° C .; 100 mm ² / s) h) Wax: Allied Chemical Co., trade name “AC polyethylene 629” (oxidized polyethylene wax, acid value; 16) i) Higher fatty acid metal salt: calcium stearate

[0017]

[Table 1]

(2) Performance test Using the test apparatus shown in FIG. 1, the temperature in the melting crucible 3 was reduced to 7
The heat insulating agent shown in Table 1 was applied by spraying on the outer peripheral surface and the bottom surface of the molten aluminum 1 at 80 ° C. to form a film, and then the lubricant of Table 1 was also sprayed on the formed heat insulating agent film. 5 with a lubricant applied to form a lubricant film
Was immersed, and the time until the jig temperature reached 600 ° C. (heat insulating property) was examined. In the figure, 2 is an electric furnace for keeping the molten metal in a molten state, 4 is a sheath type for measuring the temperature rise due to the heat transmitted to the inside of the jig through the lubricant and heat insulating agent coating, and the jig wall. A thermocouple, 6 is a glass wool that is fitted in a donut shape at the upper part of the space to prevent the heat in the space between the electric furnace and the melting crucible from escaping to the outside, and 7 is the temperature measured by the thermocouple. It is a recorder for recording the time.

Further, after forming a heat insulating agent film on the test piece (material: SPCC-SB, size: 20 × 160 × 1 mm) in the same manner as described above, the lubricant of Table 1 is applied to the surface of the film, Lubricity (friction coefficient) was examined using a Bowden friction tester. In Comparative Example 1, only the heat insulating agent film was formed on the jig surface, and in Comparative Examples 2 to 5, the heat insulating agent film was not formed, and the lubricant film was directly formed on the jig surface for the test. The heat insulation test conditions and lubricity test conditions are shown below,
The results are shown in Table 2.

Adiabatic property Molten metal temperature: 780 ° C. Molten metal material: ADC12 Jig material: SKD61 Jig size: φ13.8 × 95 Lubricity Steel ball: SUJ-2 Test temperature: 200 ° C. Load: 0.5 Kgf Sliding speed: 4 0.0mm / s Sliding distance: 30mm

[0021]

[Table 2]

From the results of Table 2, it can be seen that in each Example, the time required to reach 600 ° C. is long and the heat insulating property is high.
Further, it can be seen that the coefficient of friction is small and the lubricity is excellent. On the other hand, in Comparative Example 1, the amount of the heat insulating agent attached is the same as that in each Example, and the heat insulating property is also excellent to the same degree.
Since no lubricant is used, it has burned in. Further, in Comparative Examples 2 to 5, the amount of lubricant adhered is larger than that in each example and the friction coefficient values are almost the same, but since a heat insulating agent is not used, the time is a little over half of each example. In 6
It can be seen that the temperature reaches up to 00 ° C and the heat insulating property is poor.
The present invention is not limited to the specific examples described above, and various modifications may be made within the scope of the present invention depending on the purpose and application.

[0023]

EFFECTS OF THE INVENTION When a non-ferrous metal is cast by the plunger tip lubrication method of the present invention, the inner peripheral surface of the injection sleeve is excellent in heat insulation. Therefore, even if a water-soluble lubricant is used, a chill layer is not formed. Therefore, the performance of the supplied lubricant is sufficiently exerted, the lubricity equivalent to the case of using the water-insoluble lubricant is realized, and the occurrence of burning etc. does not occur. Further, in the present invention, since the water-soluble lubricant is used, there is no risk of fire and there is no problem of contamination by oil around the device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a test device for evaluating the heat insulating property of an inner peripheral surface of an injection sleeve in a method of lubricating a plunger tip of the present invention.

[Explanation of symbols]

1; molten metal, 2; electric furnace, 3; melting crucible, 4; sheath type thermocouple, 5; jig, 6; glass wool, 7; recorder

Front page continued (72) Inventor Mitsuyoshi Yokoi, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nihon Denso Co., Ltd. (72) Inventor, Sumi Yoshikawa, 1-1, Showa-machi, Kariya city, Aichi prefecture, Nihondenso Co., Ltd.

Claims (3)

[Claims] 1. A method for lubricating a plunger tip, which comprises supplying a water-soluble lubricant after forming a film of a heat insulating agent on the inner peripheral surface of an injection sleeve of a casting apparatus. 2. The method for lubricating a plunger tip according to claim 1, wherein the water-soluble lubricant is supplied to the surface of the film of the heat insulating agent and / or the surface of the plunger tip. 3. The heat insulating agent is (a) inorganic powder, (b)
The method for lubricating a plunger tip according to claim 1 or 2, further comprising a dispersant, (c) a surfactant, and (d) water.