JPH07292381A - Lubricant for casting and hot processing - Google Patents

Abstract

PURPOSE:To obtain the subject lubricant free from generation of a harmful and uncomfortable-smell gas in casting and processing and capable of producing a smooth cast material free from a surface defect such as a crack or a subcutaneous fault by using a polytetrafluoroethylene resin powder and a sintered resin powder prepared by grinding a sintered resin. CONSTITUTION:This composition is prepared by blending (B) 1 to 25 pts. wt. sintered resin powder of polytetrafluoroethylene resin obtained by grinding a sintered material of polytetrafluoroethylene resin, having 1 to 5mum, preferably 2 to 20mum average particle diameter and including particles having a particle diameter within the above-mentioned range in a ratio of >=95% with (A) 99 to 75 pts.wt. lubricant composed of a vegetable oil or a mineral oil respectively having <=0.020wt.% water content or their mixture. In addition, the component (A) is preferably a mixture oil composed of one or more kinds of oils selected from rapeseed oil, castor oil and soybean oil and >=95 pts.wt. of the component (B) is preferably particles having <=3 aspect ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a function of releasing, lubricating, and
The present invention relates to a lubricant for casting and hot working, which also has a function of modifying the surface of an ingot or a hot worked ingot.

As a mold release / lubricant for ingots, dies for producing castings, dies for continuous casting, dies for hot metal working, and the like, various vegetable oils, mineral oils, and other tetrafluoroethylene resins. A lubricant in which the above powder is dispersed is known (Japanese Patent Application Laid-Open No. HEI 3)
-121197). This lubricant is superior in lubrication and demolding effect to the lubricants used in the past, in which lubricating substances such as graphite and molybdenum disulfide are mixed and dispersed in various oil agents. Since the decomposition gas generated when the molten metal comes into contact has a strong reducing action, no oxide film is formed on the surface of the ingot or hot-worked ingot, the casting surface is smooth and rough, and defects such as avatars and wrinkles are generated. There is less, cracks in the mold or hot working mold are less likely to cause flaws such as cracks, so the life of the mold is longer, graphite or metal oxides are less likely to adhere to the mold or hot working mold, and cleaning It has excellent features such as saving time and effort.

However, its use has hitherto been limited to special cases only because of the following drawbacks.

The first problem is that during casting or hot working,
The generation of offensive, hygienically harmful gases required ventilation at the casting and hot working sites, which significantly impeded the spread of this lubricant.

The second problem is that the dispersibility of the tetrafluoroethylene powder in the oil agent is extremely poor, which necessitates vigorous stirring after each use, which makes this lubricant practical. Was significantly spoiled.

A third problem is that pinholes and blowholes are easily generated under the ingot, and as a result, there is no choice but to take a large amount of shavings on the ingot skin, resulting in a poor casting surface. Even if it was improved, the yield improvement effect was only slight.

The fourth problem is the high price, which is due to the high price of tetrafluoroethylene powder.

[0008]

DISCLOSURE OF THE INVENTION The present invention produces less harmful gas during casting or hot working, has good dispersibility in an oil agent, does not require stirring, and further has a pin under the ingot. It is an object of the present invention to provide an inexpensive lubricant for casting and hot working, which is free from the occurrence of holes and blow holes.

[0009]

[Means for Solving the Problems] Means for solving the above problems will be described below while following the course of the present invention.

First, the inventors examined a poisonous gas having a foul odor generated during casting or hot working, which was mainly generated when virgin powder of tetrafluoroethylene resin was thermally decomposed during casting or hot working. It was found that there was a problem with the use of virgin powder due to the butyl-based and butylene-based monomer gas. Then, instead of the virgin powder, a sintered resin powder obtained by pulverizing the cutting powder of the tetrafluoroethylene polymer resin obtained by sintering the virgin powder was used, and no harmful gas having the above-mentioned malodor was generated. It was confirmed.

Next, the inventors examined the dispersibility of the tetrafluoroethylene resin polymer sintered resin powder in the oil agent, and the dispersibility was closely related to the particle size, particle shape and particle size distribution of the sintered resin powder. I knew it was related. First, regarding the particle size, it was found that the particles were extremely likely to aggregate when the particle size was 1 μm or less. When the particles agglomerate into a large mass, the dispersibility deteriorates, and as a result, it becomes difficult to obtain a smooth and flat casting surface.

On the other hand, when the particle size is 1 μm or more, the cohesiveness disappears, but when the particle size exceeds 50 μm, the difference in the specific gravity between the oil agent and the particles comes into play, and the sedimentation speed of the particles increases rapidly.
Even if it is stirred, the particles will settle out immediately, making it difficult to use. Therefore, the powder particle size is preferably 1 to 50 μm, and more preferably 2 to 20 μm.

It has also been found that variations in particle size also affect the dispersibility of the particles, and it is desirable that the width of the particle size distribution be as narrow as possible. Even if the average particle size is in the range of 1 to 50 μm, if there are many particles with a particle size outside the range, the dispersibility of the powder will deteriorate and it will be difficult to maintain a uniform dispersion. Therefore, it is desirable that at least 95% of the total powder weight be in the range of 1-50 μm, most preferably in the range of 2-20 μm.

Regarding the particle shape, the closer the particle diameter is to the spherical shape,
It was found that the cohesiveness was weak and the dispersibility was good. Specifically, if the ratio of the longest diameter to the smallest diameter of particles (aspect ratio) is 5 or more, aggregation is likely to occur even if the particle size distribution is within 1 to 50 μm, and if it is 3 or less, aggregation may occur. It was confirmed that there was almost no.

The tetrafluoroethylene polymer resin sintered body is
Even if it is pulverized by the usual mechanical pulverization method, it is impossible to produce a powder having a particle size of 50 μm or less.

As a result of various investigations by the inventors on the method of pulverizing a tetrafluoroethylene polymer resin sintered body, it is easy to pulverize the same sintered body by irradiating it after cooling it to liquid nitrogen temperature. It was found that a powder having a shape close to a sphere having a particle size of 50 μm or less can be obtained, and the powder necessary for the present invention could be secured.

Next, in order to suppress pinholes and blowholes just below the casting surface of the ingot, the cause of the occurrence was examined, and as a result, it was found that the water contained in the oil agent is related to these occurrences.

The vegetable oils that are used daily for the production of food products usually contain about 0.4% by weight of water. If this oil is used as a lubricant as it is, a large number of pinholes and blowholes are generated near the surface of the ingot, and as a result, the machining allowance is extremely large, and no improvement in yield can be expected.
When this oil is distilled under reduced pressure, the water content can be reduced to 0.025% by weight, but even if an oil having this water content is used, the occurrence of pinholes and blowholes cannot be completely suppressed. However, it is impossible to reduce the water content to 0.025% by weight or less by the conventional vacuum distillation method.

As a result of repeated studies on the method for reducing the water content in the oil agent to 0.025% by weight or less, the inventors of the present invention have conducted a vacuum pump while blowing an inert gas such as nitrogen gas into the oil agent heated to about 250 ° C. The water content is 0.0
I learned that it can be reduced to 10% or less. As a result of casting experiments using a lubricant using an oil agent with a low water content obtained by this method, when the water content in the oil agent was 0.017 wt% or less, pinholes and blowholes were almost completely generated. It has been found that this can be suppressed, and as a result, the cutting allowance of the ingot can be significantly reduced.

When the amount of water in the oil agent is large, carbon fluoride gas generated by decomposition of the tetrafluoroethylene polymer resin at the time of casting and hot working reacts with the water in the oil agent and has an irritating odor. Toxic hydrogen fluoride (HF) gas is generated, which also contributes to the bad odor during casting and hot working of conventional lubricants using virgin tetrafluoroethylene polymer resin powder. It was also found that the water content was 0.020% by weight.
Below, the generation of hydrogen fluoride gas is negligible and there is no need for ventilation.

The greater the amount of the tetrafluoroethylene polymer sintered resin powder added to the oil agent, the stronger the lubricating mold releasing action and the reducing action, but the mixing of 25 wt% or more causes the powder to be bulky, so in practice It is impossible. If the ratio of the powder weight to the oil weight increases, the fluidity of the lubricant decreases, so for continuous casting of large ingots that require automatic lubricant continuous supply, a low content of several percent or less Is suitable. However, if the content is 1% by weight or less, the above-mentioned effects cannot be expected.

On the other hand, in hot working such as die casting, hot extrusion and hot die forging, the viscosity of the lubricant is high because the lubricant is applied to the mold or tool with a brush, roller or the like. May be desirable. Further, in order to improve the durability of the lubricant, a lubricant having high viscosity and low fluidity may be required. In such a case, a thickener such as fatty acid amide may be added to the lubricant of the present invention before use. The proper amount of thickener is usually 0.5 to 12 weight per 100 weight of lubricant.

Finally, the problem of high cost of the lubricant using the conventional tetrafluoroethylene polymer resin powder is due to the use of expensive virgin powder. In the present invention, since an inexpensive sintered resin regenerated powder obtained by crushing the shavings of the tetrafluoroethylene polymer resin sintered body can be used, it is possible to greatly reduce the cost.

As the oil agent, various vegetable oils such as rapeseed oil, castor oil, soybean oil and linseed oil, mineral oils such as liquid paraffin oil, mineral oil, light oil, kerosene and heavy oil can be used. Some oils contain impurities that are harmful to metals such as sulfur, and when used in casting or hot working of alloys that have a strong affinity for these harmful elements, the ingot and work material may be contaminated and deteriorated. . Therefore, it is generally desirable to use vegetable oils that do not contain these harmful impurities. Among them, rapeseed oil, castor oil, soybean oil are particularly desirable in terms of dryness, fluidity, cost, etc. is there.

[0025]

Although the means for solving the problems of the conventional casting lubricant of the present invention and the effect thereof have been described in detail above, the present inventors have found that the casting lubricant of the present invention was used in the course of research. It was discovered that it has a completely new function that conventional products do not have.

As described above, the casting lubricant in which the virgin powder of tetrafluoroethylene resin is dispersed in various oil agents is the conventionally used lubricating substances such as graphite and molybdenum disulfide. Excellent lubrication action compared to dispersed lubricants. However, the lubrication effect of the lubricant for casting using this tetrafluoroethylene virgin powder is solely due to the physical lubrication effect originally possessed by the substance called tetrafluoroethylene, and therefore the lubricant is in the mold. The lubricating function is lost at the moment when the molten metal flowing in and / or the solidified metal ingot immediately after solidification is touched and thermally decomposed.

As a result, although a lubricating effect can be expected in the casting of a metal having a relatively low melting point such as aluminum, a lubricating action is exhibited almost or not at all in the casting of a high melting point metal such as iron, nickel and copper. Therefore, in casting of these refractory metals, it was necessary to add powder of expensive heat-resistant lubricating substance such as boron nitride (BN) to the oil together with tetrafluoroethylene powder. Even though the cost was increased, a sufficient lubrication effect was not obtained, and therefore it was difficult to obtain an ingot having a sufficiently smooth surface and free from serious defects such as cracks, microcracks, and molten metal shortage. .

However, the present inventors have tried the casting lubricant of the present invention for casting various aluminum alloys, copper alloys, iron alloys, nickel alloys, cobalt alloys, etc. As a result of observing the surface in detail, a conventional casting lubricant using virgin tetrafluoroethylene powder,
Alternatively, in the case of the lubricant of the present invention, as compared with a lubricant for casting which uses powder of an inorganic lubricating substance such as graphite or molybdenum disulfide, a significantly superior lubricating action works, and as a result, a sufficiently smooth surface is obtained. In addition, it was confirmed that an ingot having an excellent surface with no defects was obtained. Such an excellent effect is remarkable in the case of a metal having a high melting point, and particularly in the case of water-cooled continuous casting.

Next, the inventors of the present invention analyzed the components of the substance adhered very thinly to the surface of the obtained ingot, and found that it was a metal fluoride or a metal acid / fluoride. ,
Then, it was found that the surface of the ingot which was in contact with the mold was uniformly and densely covered with an extremely thin transparent film of these fluorides and / or acid / fluorides.

From the above examination results, in the case of the lubricant of the present invention, it is injected between the lubricant applied to the mold, or in the case of water-cooled continuous casting, between the water-cooled mold and the molten metal which is solidifying. A strong reducing gas such as CF ₄ , C ₂ F ₆ or the like generated by the decomposition of the lubricant that is in contact with the molten metal or the metal during solidification or immediately after solidification, and the surface of the molten metal or the solidification process or immediately after solidification The generated oxide reacts to form a liquid metal fluoride and / or an acid / fluoride near the solidification temperature of the metal, which has a melting point far lower than that of the metal oxide. It is considered that the product of (1) causes an extremely excellent lubricating action between the solidified metal and the mold.

As is clear from the above consideration, the above-mentioned lubrication action peculiar to the casting lubricant of the present invention has all the lubricating effects of the conventional casting lubricant, and the physical properties of the lubricating substance itself added to the oil agent. The present invention is based on the lubrication action, whereas it is based on a chemical lubrication action based on a chemical reaction, which is completely different from the lubrication action. This point also strongly characterizes the present invention.

Incidentally, the reason why such a chemical lubricating action does not occur in the conventional casting lubricant which also uses the powder of ethylene tetrafluoride is that the ethylene tetrafluoride used in this conventional lubricant is used. This is because the polymer powder is a virgin powder. That is, the virgin powder is fine with a particle size of 0.2 to 0.3 μm, and the particle shape is flaky and flat. Therefore, the total surface area of the powder particles per unit weight of the powder is orders of magnitude larger than that of spherical or granular powder having the same particle size.

On the other hand, the powder obtained by crushing a sintered body of tetrafluoroethylene polymer resin used in the lubricant of the present invention has an average particle size of 1 to 50 μm, which is much larger than virgin powder, and The shape of the particles is spherical or granular with an aspect ratio of 3 or less, and therefore the total surface area of the powder particles per unit weight is several orders of magnitude smaller than that of virgin powder. Therefore, before contact with the molten metal injected into the mold, or the metal being solidified in the mold or immediately after solidification,
In a conventional casting lubricant that uses a virgin powder of tetrafluoroethylene that is fine and has a large surface area, powder particles are extremely susceptible to heat and begin to decompose and evaporate as the temperature inside the mold rises. It instantly decomposes and evaporates.

As a result, CF ₄ and C generated by decomposition are generated.
Gases that have a strong reducing action at high temperatures, such as ₂ F ₆ ,
Although it is somewhat involved in the reduction of the oxide film on the surface of the molten metal or on the surface of the solidified metal, it is not possible to form a metal fluoride or an acid / fluoride reaction enough to give a sufficient lubricating action between the ingot and the mold. Therefore, when casting refractory metals, especially iron-based or nickel-based alloys, conventional casting lubricants using virgin tetrafluoroethylene powder have the above chemical lubrication effect. There is no ability.

On the other hand, in the case of the lubricant for casting hot working of the present invention, the powder of the tetrafluoroethylene polymer sintered resin used has a large average particle size, and the particle shape is spherical or granular. Therefore, it is much less sensitive to temperature than virgin powder, and powder particles rarely decompose and evaporate before they come into contact with the molten metal or during solidification or immediately after solidification on the metal surface,
Decomposition and evaporation on contact are much slower and more persistent than virgin powder. As a result, the gas having a reducing action generated by the thermal decomposition of ethylene tetrafluoride not only participates in suppressing the oxidation of the metal surface, but also completely covers the surface of the solidifying metal in the mold. Of the metal and / or acid / fluoride layers sufficient to

However, the melting temperature of metal fluorides and acids / fluorides is much lower than that of oxides, and particularly in the case of refractory metals such as iron, nickel and copper, fluorides of these metals and The acid / fluoride is a liquid near the solidification temperature of the metal, and therefore has an excellent lubricating function between the solidified metal and the mold. Thus, the casting lubricant of the present invention is a chemical lubricant that cannot be obtained by the conventional casting lubricant using the virgin tetrafluoroethylene powder in the casting of refractory metals such as iron, nickel and copper. It is possible to exert the action,
The effect is particularly remarkable in the case of water-cooled continuous casting of these metals.

Further, the inventors of the present invention have found that the casting lubricant of the present invention can be used in the case of performing water-cooled continuous casting by coating the upper surface of molten metal poured into the mold with flux (so-called "powder casting"). , It has been found that it exhibits a unique chemical lubrication effect, that is, in the water-cooled continuous casting of alloys such as iron, nickel and copper, the surface of the molten metal in the mold is silica, borax, to prevent oxidation. Casting is performed by covering with powder such as fluorspar. In this case, the powder melts into a glass and covers the surface of the molten metal (the surface in contact with the atmosphere) accumulated in the mold, while the surface of the molten metal and the mold are covered. From the contact portion with the inner side surface, it flows into the gap between the inner side surface of the mold and the side surface of the ingot that slides down and contributes to lubrication between them.
In this case, the frictional force acting between the mold and the ingot that solidifies and descends depends on the fluidity of the molten flux, that is, the viscosity, and the higher the viscosity, the greater the frictional force. It is easy for defects such as cracks, cracks, and hot water to occur.

Therefore, it is desirable that the viscosity of the molten flux is not more than a certain level. Usually, in order to reduce the viscosity, a low melting point fluoride salt such as fluorite or cryolite or a compound is used for the flux. Or increase the addition amount thereof to lower the melting point of the flux. However, when the melting point of the flux decreases and the fluidity increases, the infiltration speed of the flux flowing into the gap between the mold and the ingot that is solidifying increases, and as a result, the consumption of the flux increases, while the casting after solidification The amount of flux adhering to the surface of the ingot increases, which may hinder various processes after casting.
Therefore, lowering the melting point of the flux is
It is desirable to reduce the frictional force between the ingots, but it is not preferable from the economical point of view.

However, when the lubricant of the present invention is applied to the portion of the inner surface of the water-cooled mold which is in contact with the solidifying ingot by brushing or the casting is performed while pumping and supplying to this portion, CF ₄ and C ₂ F The decomposition gas of tetrafluoroethylene polymer such as ₆ reacts with the flux that has flowed into the gap between the mold and the ingot that is solidifying, and the fluoride and / or acid / fluoride having a lower melting point and lower viscosity than the flux is generated. To generate. As a result, even if the molten flux itself covering the upper surface of the molten metal has a high melting point, high viscosity, and poor lubricity, the lubricity of the flux at the contact portion between the mold and the ingot becomes extremely good, and the ingots such as cracks and cracks are While the occurrence of surface scratches is suppressed, the amount of flux flowing out through the gap between the mold and the ingot is small,
Therefore, the consumption of flux is also small.

In recent years, a flux having a high basicity tends to be used in order to reduce the consumption of casting equipment such as a pouring nozzle, but generally, when the basicity of the flux increases, the fluidity decreases, so that the mold-ingot There is a problem that the lubrication between the two becomes poor and casting defects such as cracks and cracks are likely to occur, but the use of the lubricant of the present invention is extremely effective in solving this problem. The above effects cannot be expected in the case of the conventional casting lubricant using the virgin tetrafluoroethylene polymer powder, which is fine and flake-like and easily affected by heat.

[0041]

EXAMPLES The effects of the present invention will be described below with reference to examples. In the following examples, the tetrafluoroethylene polymer sintered resin powder used in the products of the present invention was irradiated with an electron beam after cutting debris of the tetrafluoroethylene polymer sintered resin was degreased and washed. It was obtained by immersing it in liquid nitrogen, cooling it, and immediately pulverizing it with a high-speed ball mill at -30 ° C or lower.

Example (1) In semi-continuous water cooling casting of an aluminum alloy (JIS 5056), the effect of the lubricant of the present invention was compared with that of a conventional product. The composition of the lubricant and the experimental conditions are as follows.・ Ingot size: 330 × 500 × 1800 (mm) ・ Casting speed: 60 mm / min ・ Casting temperature: 700 ° C ・ Lubricant supply method Invention product (1): Water-cooled mold The inner side surface is smeared. The product of the present invention (2): Pumping supply (supply speed: 0.6cc / cm
/ Min) Comparative product (1): Same as above Comparative product (2): Same as above

Lubricant composition and experimental results

From the above results, when the product of the present invention is used, the depth of cracks generated on the surface of the ingot is comparable to that of the conventional product.
In the case of the product of the present invention, the number of pinholes under the surface of the ingot, which is much shallower than in the case of, and is large in the case of the comparative product, hardly occurs, and the surface smoothness is good. .
As a result, it was found that when the product of the present invention was used, the surface cutting margin was small and a remarkable improvement in yield could be expected.
In the present embodiment, no flux is used in any case.

Example (2) In semi-continuous water cooling casting of a stainless steel alloy (SUS 304), the effect of the lubricant of the present invention was compared with that of a conventional product. The composition of the lubricant and the experimental conditions are as follows.・ Ingot size: 350 × 550 × 2000 (mm) ・ Casting temperature: 1480 ℃ ・ Casting speed: 65mm / min ・ Method of supplying lubricant ・ Molding powder used: 40 parts by weight of SiO ₂ + CaO 40
Parts by weight + ₂₀ parts by weight of Na ₂ O ・ Lubricant supply method: Pumping supply (supply speed: 0.
65cc / cm / min)

Lubricant composition and experimental results

From the above results, when the lubricant of the present invention is used, the depth of cracks on the surface is much shallower than when the comparative product (conventional product) is used, and there are less binholes below the surface, and The smoothness is much better, and
Such an effect is obtained by using tetrafluoroethylene (PTFE)
It can be seen that the larger the average particle size of the regenerated powder, the more remarkable it is. From this result, even in the case of a high melting point iron-based alloy, the surface cutting allowance can be greatly reduced by using the product of the present invention,
It was found that a significant improvement in yield can be expected.

Example (3) In hot extrusion of brass (35 parts by weight of zinc + 65 parts by weight of copper), the effect of the lubricant of the present invention was compared with that of the conventional product.
The composition of the lubricant and the experimental conditions are as follows.・ Brass billet size: φ 250 × 750 L (mm) ・ Extruded material size: 50 φ × L (mm) ・ Extrusion temperature: 830 ° C ・ Extrusion speed: 1000 mm / min ・ Lubricant usage: lubricant 100 before use Parts by weight,
Add 5 parts by weight of fatty acid amide to increase the viscosity and apply by brush to the inside of the extrusion die and the inner surface of the sleeve.

-Lubricant composition and experimental results

From the above results, when the product of the present invention is used, the pushing force is remarkably smaller than that when the comparative product (conventional product) is used, and the surface of the extruded material is much better, which causes a crack. It can be seen that there are no cracks, scratches, and other scratches, and the life of the extrusion die is significantly longer.

Example (4) The effect of the lubricant of the present invention was compared with that of the conventional product in the die casting of a nickel alloy (20% by weight of chromium-1% by weight of silicon-the balance of nickel). The composition of the lubricant and the experimental conditions are as follows.・ Ingot size: 150 × 250 × 1500 ・ Mold material: Cast steel ・ Casting temperature: 1465 ℃ ・ Lubricant usage: Before use, add 4 parts by weight of fatty acid amide to 100 parts by weight of lubricant to increase viscosity. Apply on the inner surface of the mold with a brush.

-Lubricant composition and experimental results

From the above results, when the lubricant of the present invention was used, the occurrence of pinholes under the surface of the ingot was completely suppressed, and the surface of the ingot was wrinkled, as compared with the case of the comparative product.
Since there are no creases or dents, and there is no contamination due to oxidation, etc., it is remarkably smooth and beautiful, and the occurrence of cracks on the inner surface of the mold is suppressed, so the life of the mold is greatly extended. You can see that it is done.

[0054]

As described above, the present invention provides a lubricant for casting and hot working in which a tetrafluoroethylene polymer resin powder is mixed and dispersed in various oil materials, and the oil material contains water. Use a low-moisture oil agent with a rate of 0.020% by weight or less, and use a sintered resin powder with a predetermined particle size, grain shape, and particle size distribution obtained by crushing a sintered resin into a tetrafluoroethylene polymer resin powder. As a result, no harmful foul-smelling gas is generated during casting and processing, a physical lubrication action of the tetrafluoroethylene polymer resin, and an oxidation inhibiting action of a reducing gas generated by thermal decomposition of the resin, and An ingot which is smooth and free from surface defects such as cracks and cracks and has no subdermal defects such as pinholes and blowholes due to a chemical lubrication action based on a low melting point and low viscosity fluoride formed by the reaction with the gas. It is also possible to manufacture hot-worked materials In addition, it is possible to provide an inexpensive and highly practical lubricant for casting and hot working, which has good powder dispersibility and does not require stirring. This is an epoch-making effect in improving manufacturing cost and reducing manufacturing cost.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C10M 101: 04 147: 02) C10N 20:06 Z 30:10 40:24 Z 40:36 70: 00 (72) Inventor Kozo Komatsu 171-1-18 Nase-cho, Totsuka-ku, Yokohama

Claims (4)

[Claims] 1. A vegetable oil having a water content of 0.020% by weight or less,
Alternatively, 99 to 75 parts by weight of an oil agent comprising a mineral oil or a mixed oil of a vegetable oil and a mineral oil, and an average particle size of 1 to 50 μm, and at least 95% of the total powder weight belong to the particle size range, A lubricant for casting and hot working, comprising 1 to 25 parts by weight of a pulverized powder of a sintered tetrafluoroethylene polymer resin, which is obtained by pulverizing a coalesced resin sintered body. 2. A tetrafluoroethylene polymer sintered resin powder having an average particle diameter of 2 to 20 μm and at least 95% of the total powder weight.
The lubricant for casting and hot working according to claim 1, wherein is within the particle size range. 3. The oil agent is any one kind of rapeseed oil, castor oil and soybean oil, or a mixed oil of two or more kinds.
Lubricant for casting and hot working described. 4. The particles of which the aspect ratio (the ratio of the longest axial length to the shortest axial length of the powder particles) is 3 or less in at least 95 parts by weight of the pulverized powdered tetrafluoroethylene polymer sintered resin. Lubricant for casting and hot working according to any one of 3 to 3.