JP2951521B2 - Method of lubricating plunger tip in casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger in which a chill layer is not formed even when a water-soluble lubricant is used in casting of a non-ferrous metal such as aluminum and magnesium, and excellent lubricity is realized. The present invention relates to a method of lubricating a chip.

[0002]

2. Description of the Related Art Conventionally, as a method of lubricating a plunger tip in a casting apparatus, a lubricant has been supplied between an inner peripheral surface of an injection sleeve and the plunger tip to reduce friction between the plunger tip and the molten metal so that the molten metal is supplied to the cavity. The method of sending it in smoothly is adopted. As a plunger tip lubricant used for such a purpose, a water-insoluble lubricant and a water-soluble lubricant are conventionally known. As the water-insoluble lubricant, for example, a lubricant using a powder such as graphite (JP-A-1-144)
As examples of water-soluble lubricants, there are known lubricants composed of mineral oils, fats and oils, fatty acid esters, solid lubricants, and surfactants (JP-A-2-248497). ing.

However, the above-mentioned water-insoluble lubricants have a risk of fire since they contain oil as a main component, and also have a problem that they stain 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, while the latter has a problem that lubricity is poor. On the other hand, the above-mentioned water-soluble lubricant has a problem that lubricating properties are inferior to water-insoluble lubricants, and the plunger tip is seized.

Further, with the above-mentioned water-soluble lubricant, the inner peripheral surface of the injection sleeve is cooled by latent heat of evaporation of water in the lubricant,
If the heat insulation of the inner peripheral surface of the sleeve is low, the heat of the molten metal itself will be large, and the molten metal surface in contact with the cooled inner peripheral surface of the sleeve will solidify and a thin layer of metal (generally called a chill layer) will be formed. In some cases, the chill layer is peeled off by the plunger tip and is mixed into the cast product, which causes a problem of impairing the product quality after casting. As described above, in the casting of non-ferrous metals, no chill layer is formed even by the use of a water-soluble lubricant, and a lubrication method for a plunger tip having excellent lubrication has not been found. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the use of a water-soluble lubricant does not cause formation of a chill layer, maintains high lubricity, and causes a fire hazard. It is an object of the present invention to provide a method of lubricating a plunger tip having a good working environment without any problem.

[0006]

Means for Solving the Problems The present inventors have studied 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 of non-ferrous metals, and a water-soluble lubrication for a plunger tip. As a result of intensive studies on the relationship between the composition of the agent and the lubricity, and the method of lubricating the plunger tip using them, first, before supplying the lubricant, first, a coating of the heat insulating agent on the inner peripheral surface of the injection sleeve of the casting device. To form
Then, by the method of supplying a lubricant to the surface of the coating and / or the surface of the plunger tip, the conventional problems when a water-soluble lubricant is used, that is, generation of a chill layer, insufficient lubrication, etc. The inventors have found that the present invention can be solved, and have completed the present invention.

That is, in the method of lubricating a plunger tip according to the first invention, after forming a film of a heat insulating agent on the inner peripheral surface of an injection sleeve of a casting apparatus, a lubricant is supplied, and the heat insulating agent is (a).
Inorganic powder, (b) a dispersant, (c) a surfactant, and
(D) It contains water . The second invention is characterized in that the lubricant is supplied to the surface of the coating of the heat insulating agent and / or the surface of the plunger tip .
You. More specifically, the first and second aspects of the present invention will be described in detail. The above-mentioned "heat insulating agent" is previously spread on the inner peripheral surface of the injection sleeve by a method such as spraying to form a "film", and the "film" is formed on the film. After applying the `` lubricant '' by spraying, or spreading the heat insulating agent, the lubricant is dropped on the plunger tip surface, or sprayed at high pressure with air by an atomizer and supplied. And a method for improving the lubricity of the plunger tip.

As the "inorganic powder", for example, mica, talc, kaolin, sericite, zircon flour, zircon sand, quartz glass powder, boron nitride, graphite fluoride and the like can be used. In addition, as the “ dispersant ” , for example, one or more selected from the group consisting of cellulose ethers such as carboxymethylcellulose, methylcellulose, and hydroxycellulose, natural polysaccharides, and montmorolinite ores can be used. .

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

The water-soluble lubricant used in the method of lubricating a plunger tip according to the present invention includes (a) mineral oil, oil and fat,
1 selected from the group consisting of fatty acids and fatty acid esters
Seed or two or more kinds, (b) wax, (c) higher fatty acid metal salt, (d) surfactant, and (e) lubricant containing water and the like can be used. The lubricant does not necessarily need to contain all of the above components. 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 fixed to the inner peripheral surface of the injection sleeve and / or the surface of the plunger tip is removed by washing with water. As long as it does not prevent uniform mixing and dispersion of the whole, the same materials as in the case of the above-mentioned heat insulating agent can be used.

The above mineral oil, fat, fatty acid and fatty acid ester are used in a water-soluble lubricant for plunger chips.
In particular, it is a component for exhibiting lubricity in a low temperature range.
Examples of the oils and fats include animal and vegetable oils and fats such as rapeseed oil, soybean oil, coconut oil, palm oil, beef tallow, and lard. Examples of the above fatty acids include coconut oil fatty acids, oleic acid, stearic acid, lauric acid, palmitic acid, and tallow fatty acids. Further, examples of the fatty acid ester include a monohydric alcohol ester or a polyhydric alcohol ester of the above fatty acid.
Among these, from the viewpoint of heat resistance and solubility with other components,
Esters of coconut oil fatty acids, oleic acid, stearic acid and the like with trimethylolpropane and neopentyl alcohol are preferred.

Examples of the wax include natural or synthetic hydrocarbon waxes and waxes, and oxides and acid-modified products thereof. Here, examples of natural waxes include animal and plant waxes such as beeswax, spermaceti, hydrogenated spermaceti, carnauba wax, canderia wax, wood wax, bran wax, paraffin wax, microcrystalline wax, montan wax, sericin And mineral wax such as wax.

Further, the above-mentioned metal salt of higher fatty acid is a component of a water-soluble lubricant for plunger chips which prevents breakage of an oil film in a high-temperature region and exhibits lubricity at a high temperature. Salts of higher fatty acids such as acids, stearic acid, lauric acid, palmitic acid and tallow fatty acids with metals such as sodium, potassium, magnesium, lithium, calcium, aluminum and 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 the above components, such as an anticorrosive, a thickener, a wetting agent, an antiseptic / antifungal agent, an antifoaming agent and the like. Additives can be appropriately added and used.

[0014]

According to the present invention, the inner peripheral surface of the injection sleeve is formed in advance by forming a film of a heat insulating agent on the inner peripheral surface of the injection sleeve of the casting apparatus, and the inner peripheral surface of the injection sleeve is cooled by the latent heat of evaporation of water in the water-soluble lubricant supplied thereafter. Thus, even if the temperature of the molten metal partially decreases, the dissipation of the heat taken from the inner peripheral surface of the injection sleeve and the molten metal to the outside of the injection sleeve is suppressed. for that reason,
The temperature drop on the surface of the molten metal is small, no chill layer is formed, the performance of the supplied lubricant is sufficiently exhibited, and excellent lubricity is maintained.

[0015]

The present invention will be specifically described below with reference to examples and comparative examples. (1) Preparation and composition of heat insulator and lubricant The heat insulator and lubricant used in Examples and Comparative Examples are shown in Table 1.
Were prepared by mixing the following components. In addition, the numerical value regarding the composition in a table | surface shows that the total amount of a heat insulating agent or
Parts by weight when expressed as parts by weight. In Table 1, the following components were specifically used.

A) Talc: manufactured by Nippon Talc Co., Ltd., trade name “Micro Ace P4” (average particle size: 1.5 μm) b) Boron nitride: manufactured by Mitsui Toatsu Chemicals, trade name “M”
BN-050 "(average particle size: 0.1 to 0.2 [mu] m) c) Dispersant: carboxymethyl cellulose d) Surfactant A: trade name" Nonipol SN60 "manufactured by Sanyo Chemical Industries, Ltd. e) Surfactant B : Trade name "Nonipol SN85" manufactured by Sanyo Chemical Industries, Ltd. f) Surfactant C: sorbitan monooleate g) Mineral oil: trade name "SAE30" manufactured by Nippon Oil Co., Ltd.
(Kinematic viscosity at 40 ° C .; 100 mm ² / s) h) Wax: manufactured by Allied Chemical Company, trade name “AC polyethylene 629” (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.
After applying the heat insulating agent shown in Table 1 to the outer peripheral surface and the bottom surface by spraying in the molten aluminum 1 at 80 ° C. to form a film, the lubricant of Table 1 is similarly sprayed onto the formed heat insulating agent film. Jig 5 coated with a lubricant to form a lubricant film
Was immersed, and the time until the jig temperature reached 600 ° C. (insulation properties) 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 film and the jig wall. A thermocouple, 6 is a glass wool fitted in a donut shape on the upper part of the space in order to prevent heat in the space between the electric furnace and the melting crucible from escaping to the outside, and 7 is a temperature measured by the thermocouple. Is a recorder for recording a time sequence.

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

Heat insulation Melt temperature: 780 ° C. Melt material: ADC12 Jig material: SKD61 Jig dimensions: 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 shown in Table 2, it can be seen that in each example, the time required to reach 600 ° C. was long and the heat insulation was 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 in each of the examples, and the heat insulating property is also excellent.
Because no lubricant is used, it is burned. In Comparative Examples 2 to 5, the amount of the lubricant attached was larger than in each of the examples, and the values of the coefficient of friction were almost the same. However, since the heat insulating agent was not used, the time was slightly more than half that of each of the examples. At 6
The temperature reached up to 00 ° C., which indicates that the heat insulating property is poor.
It should be noted that the present invention is not limited to the specific embodiments described above, but can be variously modified within the scope of the present invention according to the purpose and application.

[0023]

When the non-ferrous metal is cast by the method of lubricating the plunger tip according to the present invention, the heat insulating property of the inner peripheral surface of the injection sleeve is excellent. Therefore, the performance of the supplied lubricant is sufficiently exhibited, lubricity equivalent to the case of using a water-insoluble lubricant is realized, and there is no occurrence of burning or the like. Further, in the present invention, since a water-soluble lubricant is used, there is no danger of fire, and there is no problem of contamination by oil around the device.

[Brief description of the 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 plunger tip lubrication method 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;

Continuing from the front page (72) Inventor Mitsuyoshi Yokoi 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan Inside Denso Corporation (72) Inventor Sumi Yoshikawa 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Corporation (56 References JP-A-1-144494 (JP, A) JP-A-4-89167 (JP, A) JP-A-3-5057 (JP, A) JP-A-4-198395 (JP, A) 60-137541 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B22D 17/20 C09K 5/00 C10M 173/00

Claims (2)

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