CA2059901A1

CA2059901A1 - Powdery lubricant for aluminum alloy forging

Info

Publication number: CA2059901A1
Application number: CA002059901A
Authority: CA
Inventors: Takashi Hanano
Original assignee: Hanano Corp
Current assignee: Hanano Corp
Priority date: 1991-07-17
Filing date: 1992-01-23
Publication date: 1993-01-18
Also published as: JPH0517795A; KR930002489A; KR940010303B1; GB9202254D0; GB2257712A; DE4212667A1; TW198731B

Abstract

Abstract The present invention is directed to a powdery lubricant for aluminum alloy forging. A mixture of a lubricant base material composed of an inorganic compound and an organic compound is formed into the lubricant wherein at least the lubricant base material has a powdery or granulated form. The lubricant of the present invention allows for the production of high quality forging in a forging work, with good workability and without worsening environmental conditions.

Description

Powdery Lubricant for Aluminum Allov Forqinq This invention relates to a powdery lubricant for aluminum alloy forging for use in cold, warm or hot aluminum alloy forging work. The lubricant is sprayed onto metal molds or aluminum alloys by means of an ordinary spray method or an electro-static spray method.
Forged parts are frequently used for various parts in airplanes, automobiles, electric equipment, etc. Materials for these parts are now changing from iron to light alloys, for example aluminum alloys, in order to meet the demand for light weight materials. During the forging work, a lubricant or lubricating oil is disposed between the metal mold and the material so as to avoid deposition between both parts and to improve separation ability of the forged part from the metal mold.
Oil-soluble lubricants mixed with graphite and water-soluble lubricants consisting of synthetic esters, silicone oil, graphite, extreme-pressure additives and surface active agents are generally used for aluminum alloy forging lubricants.
In recent years, demands for lubricants that can be used to obtain products of high quality and with good workability have increased with the progress in the weight reduction of various parts and aluminum alloy forging technology. It has become impossible to satisfy such demands with conventional lubricants. Namely, the oil-soluble lubricants are associated with problems such as smoking, workshop contamination, flammability danger, etc. and the water-soluble lubriaants are associated with problems such as the necessity to conduct waste water treatment for water-pollution control after use and the resulting expenses for plant and equipment investment, etc. Accordingly, an aluminum alloy forging lubricant of a new type has been strongly requested.
This invention has been made on the basis of detailed studies and systematic experiments in due consideration of the foregoing situations. An object of this invention is to provide a powdery lubricant for aluminum alloy forging to obtain forging products of higher quality with better workability and without worsening environmental conditions in aluminum alloy forging work.
This invention is directed to a powdery lubricant for aluminum alloy forging comprising a mixture of a powdery or granulated lubricant base material composed of an inorganic compound as used for lubricant in a solid form and an organic compound giving adhesive property to the lubricant base material, wherein both have a powdery or granulated form, or the lubricant base material is coated with the organic compound.
The most outstanding feature of this invention is that the lubricant base material has the powdery or granulated form.
It is effective to select the content of the organic compound in relation to the inorganic compound to be in a range of 0.1 through 50 weight percent. The reason is that the adhesion effect of the inorganic compound to the inside of a metal mold is not enough when the content is smaller than 0.1 weight percent, and smoking or a build-up occurs to cause difficulties when removing the forging product from the metal mold, i.e. a decrease in lubricating efficiency or a worsening of dimensional accuracy of the product, when the content is larger than 50 weight percent.
There is no limitation as to the type of the lubricant base material for use in the present invention, provided that they are composed of solid inorganic compounds suitable for use as lubricants. Generally, boron nitride, fluoride, talc, mica, metal oxides, silicon nitride, boron compound, sulfur compound and phosphorus compound are preferably used therefor.
However, other well known solid lubricants may be used therefor. For example, those which have conventionally been used as the lubricants, e.g. graphite, molybdenum disulfide, etc. These inorganic compounds have a powdery or granulated form, they may be used alone or in combinations of two or more.

Further, there is no special limitation as to the type of organic compounds used for the present invention, provided that they have the characteristics of providing the adhesive and spreading properties to thè foregoing inorganic compounds.
Generally, metal soaps, high molecular weight compounds and liquid-form or paste-form compounds which are powdered or granulated by a cyclodextrin compound are preferably used.
Carboxylic acid construction annexed with sodium, calcium aluminium, barium, lithium, potassium, magnesium or zinc is preferably used for the metal soap; and polyethylene, polypropylene, epoxy resin, silicon resin, natural wax, phenol resin, acrylic resin, alkyd resin, urethane resin, styrene resin or fluoro resin are preferably used for the high molecular weight compounds. Synthetic esters, natural fats, mineral oils, silicon oil, polyphenyl ether, polyalkylene glycol or ethylene-propylene copolymers are preferably used for the liquid-form or paste-form compounds. These organic compounds are mixed with the lubricant base material in the powdery or granulated form or mixed with it in a heated molten state. Accordingly, in the lubricant according to the present invention, both the lubricant base material and the organic compound are formed into the powdery or granulate form, or the powdery or granulated lubricant base material is coated with the organic compound. Incidentally, one of the above-mentioned organic compounds can be used, or combinations oftwo or more can be used. The metal soaps, high molecular weight compounds, and powdered liquid-form or paste-form compounds may be combined and used.
In the powdery lubricant for aluminum alloy forging according to the present invention, its lubricant base material at least has a powdery form or a granulated form.
Therefore, the lubricant is hard to dissolve even when heat is applied to it during the forging work, the forged part can be easily removed from the metal mold, and gas can be prevented from being caught in the forged part so that the accuracy and quality of the products formed can be improved.
Further, since the lubricant of the present invention has a powdery or granulated form and includes no water, it does not pollute water after use as in the case of water-soluble lubricants, and in addition it does not contaminate the work environment as in the case of oil-soluble lubricants.
Accordingly, waste water treatment expenses and environmental contamination prevention expenses are unnecessary. Since the lubricant of this invention includes no oily material, it is not associated with such dangers as smoking and fire. The safety of the lubricant of the present invention can be secured.
Moreover, since at least the lubricant base material has a powdery or granulated form in the lubricant of this invention, the material (aluminum alloy) is securely separated from the metal mold inside by at least a clearance corresponding to the diameter of a grain of powder or a granule of the lubricant base material around a portion of the inside of the metal mold to which the lubricant adheres. The lubricant uniformly adheres to the inside of the metal mold, so that direct contact of the material with the inside of the metal mold can be avoided, deposition during plastic deformation can be prevented, wear of metal mold can be controlled, and the workability can be improved.
According to the present invention, the lubricant for aluminum alloy forging consisting of the mixture of an organic compound and the lubricant base material comprising an inorganic compound, is made into the lubricant wherein at least the lubricant base material has a powdery or granulated form. Therefore, the aluminum alloy deformation rate during the plastic deformation can be minimized, the deposition can be prevented, and high quality forged parts can be produced.
Further, environmental pollution before and after use can be fully controlled.
In particular, the quality of the forging products obtained can be improved by setting the content of the organic compound in relation to the inorganic compound to be in the range of 0.1 through 50 weight percent. The above-mentioned effect can be further enhanced when boron nitride, fluoride, talc, mica, metal oxides, silicon nitride, boron compounds, sulfur compounds and phosphorus compounds are used as the inorganic compound; and when the metal soap comprising the carboxylic acid construction annexed with sodium, calcium, aluminium, barium, lithium, potassium, magnesium or zinc, or the high molecular weight compound, e.g. polyethylene, polypropylene, epoxy resin, silicon resin, natural wax, phenol resin, acrylic resin, alkyd resin, urethane resin, styrene resin or fluoro resin is used as the organic compound; and when synthetic esters, natural fats, mineral oils, silicon oil, polyphenyl ether, polyalkylene glycol or ethylene-propylene copolymer is used as the liquid~form or paste-form compound powdered or granulated with a cyclodextrin compound.
And the lubricants which are suitable for use in respective forging works, can be obtained using two or more of the foregoing inorganic compounds and organic compounds respectively in a combined manner.
Specific embodiments of the present invention will be described below, but the invention is not limited to these embodiments.
The following lubricants (A) through (G) were obtained, aluminum alloy forging tests based on the forging method were carried out using these lubricants, and items listed in the TABLE were compared and examined. Incidentally, a JIS 2014 high tensile alloy was used, the forging temperature was 390C, and the lubricant was sprayed using an electro-static spray method.
Two types of mixtures; a mixture wherein an organic compound is mixed with an inorganic compound in a powdery or granulated form, and a mixture wherein an organic compound is mixed with an inorganic compound in a heated molten state;
were obtained for embodiments (A) through (D) of the present invention. The two types of mixtures were examined and the results obtained were the same for both mixtures. An organic compound, in which natural fat was powdered by an experimental method using a cyclodextrin compound, was used as the organic compound in lubricant (D) but other compounds were purchased ' .

from readily available sources.
(A) First embodiment of this invention composed of a mixture of 90 parts of mica (mean particle size; 6 microns) and 10 parts of polyethylene (B) Second embodiment of this invention composed of a mixture of 10 parts of boron nitride, 60 parts of mica and 30 parts of calcium stearate (C) Third embodiment of this invention composed of a mixture of 70 parts of talc, 10 parts of silicon nitride, 10 parts of natural wax and 10 parts of zinc stearate (D) Fourth embodiment of this invention composed of a mixture of 20 parts of boron nitride, 60 parts of talc, 5 parts of sodium borate and 15 parts of powdered natural fat (E) Boron nitride only (comparison embodiment 1) 5 (F) Commercial forging lubricant composed of mineral oil, natural fat and graphite (comparison embodiment 2) (G) Commercial forging lubricant composed of carboxylate, synthetic wax, extreme-pressure additive and surface active agent (comparison embodiment 3) X
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Claims

1. A powdery lubricant for aluminum alloy forging comprising a mixture of a powdery or granulated lubricant base material composed of an inorganic compound as used for lubricant in a solid form and an organic compound giving adhesive property to the lubricant base material, wherein both have a powdery or granulated form, or the lubricant base material is coated with the organic compound.

2. A powdery lubricant according to claim 1, which contains the organic compound at a content of 0.1 to 50 weight percent in relation to the inorganic compound.

3. A powdery lubricant according to claim 1, wherein the inorganic compound comprises one or more of boron nitride, fluoride, talc, mica, metal oxides, silicon nitride, a boron compound, a sulfur compound and a phosphorus compound.

4. A powdery lubricant according to claim 1, wherein the organic compound comprises one or more types of metal soaps, high molecular weight compounds, and liquid-form or paste-form compounds which are powdered or granulated with a cyclodextrin compound.

5. A powdery lubricant according to claim 4, wherein the metal soap comprises a carboxylic acid construction annexed with sodium, calcium, aluminium, barium, lithium, potassium, magnesium or zinc.

6. A powdery lubricant according to claim 4, wherein the high molecular weight compound comprises polyethylene, polypropylene, epoxy resin, silicon resin, natural wax, phenol resin, acrylic resin, alkyd resin, urethane resin, styrene resin or fluoro resin.

7. A powdery lubricant according to claim 4, wherein the liquid-form or paste-form compound comprises synthetic esters, natural fats, mineral oils, silicon oil, polyphenyl ether, polyalkylene glycol or ethylene-propylene copolymer.