JP3561193B2 - Lubricant and lubrication method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a lubricant and a lubrication method, and in particular, a lubricant used for lubricating a portion exposed to a high temperature, such as a sliding portion of a sliding opening / closing device attached to a tap of a molten metal container such as a ladle, and the like. It relates to a lubrication method.
[0002]
[Prior art]
In general, a sliding opening / closing device attached to a hot metal outlet of a molten metal container such as a ladle is provided with a fixed nozzle 4 so that the through hole 3 matches the hot water outlet 2 of the molten metal container 1 as shown in FIG. Is fixed to the bottom surface of the container 1, and a sliding nozzle 5 having a through-hole 6 similarly formed below the fixed nozzle 4 is slidable on the upper surface 7 with the lower surface 8 of the fixed nozzle 4. It is arranged and formed. Both the fixed nozzle 4 and the sliding nozzle 5 are manufactured in a plate shape from refractory bricks.
[0003]
This sliding opening / closing device adjusts the opening degree of the hot water outlet 2 by adjusting the matching area of both through holes 3 and 6 by reciprocating or rotating the sliding nozzle 5.
[0004]
The fixed nozzle 4 and the sliding nozzle 5 are exposed to a high temperature of about 1600 ° C. when the molten metal is poured out, and receive a large thermal shock, and the molten metal is formed between both sliding surfaces. A “bullion bar” to invade will occur.
[0005]
In order to prevent such inconvenience, various lubricants that are used by being applied to the sliding surface have been proposed, and examples thereof include graphite powder, starch paste, and water as components.
[0006]
When the lubricant is actually used, tar is first applied to the sliding surfaces of the fixed nozzle 4 and the sliding nozzle 5, and the lubricant is applied on the tar. .
[0007]
[Problems to be solved by the invention]
However, the use of tar is prohibited after it has been found that it is a carcinogen. At present, the tar is not used, and the sliding of the fixed nozzle 4 and the sliding nozzle 5 is improved. There is a need for lubricants that can be performed.
[0008]
On the other hand, as the refractory brick forming the fixed nozzle 4 and the sliding nozzle 5, when tar is used, the main material is porous alumina ceramic. The main material is alumina ceramic.
[0009]
Therefore, nowadays, the appearance of a lubricant capable of maintaining sufficient lubricity even in a high temperature range is expected for the fixed nozzle 4 and the sliding nozzle 5 made of refractory brick made of carbon alumina ceramic. ing.
[0010]
Therefore, as shown in Japanese Patent Application Laid-Open No. 11-50082, the applicant of the present invention is not more than 50% by weight of graphite powder, and is not less than 12% by weight based on an organic and / or inorganic water-soluble binder and other lubricants. In addition to the porous alumina ceramic, the sliding part composed of the fixed nozzle and the sliding part between the sliding nozzles, which are mainly made of carbon alumina ceramic, can be used in a high temperature range. In addition, the present inventors have proposed a lubricant and a lubrication method that can stably maintain the lubrication characteristics of the respective components of the lubricant, maintain sufficient lubricity, and can withstand thermal alternating impact.
[0011]
The present invention exhibits performance equivalent to that using the boric acid powder described above, and further, a melt covering the graphite powder or the water-soluble binder in a high temperature range even with a small amount of use, compared to the one using boric acid powder. This makes it possible to protect graphite powder or water-soluble binder and maintain lubricity, sealing performance, and sliding surface protection over a long period of time. It is an object of the present invention to provide a lubricant and a lubrication method capable of achieving the above.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the lubricant according to the present invention is characterized in that the graphite powder is 50% by weight or less, the organic and / or inorganic water-soluble binder and the other lubricant A are water, and the lubricant A 20 wt% or less of boron carbide powder, and a dry film is formed after application to the sliding portion. And since it has boron carbide powder by employ | adopting such a structure, when it becomes high temperature, it fuse | melts and exhibits lubricity, and sufficient lubricity can be maintained in a high temperature range. Furthermore, compared with the one using the boric acid powder, in a high temperature range even in a small amount of use, more melt is formed covering the graphite powder or the water-soluble binder, thereby protecting the graphite powder or the water-soluble binder, Lubricity, sealing performance, and sliding surface protection can be maintained over a long period of time, and manufacturing costs can be reduced by reducing material costs. Due to such a synergistic effect, the lubricant of the present invention is applied not only to porous alumina ceramic but also to a sliding part composed of a sliding part between a fixed nozzle and a sliding nozzle mainly made of carbon alumina ceramic. After that, a dry film can be formed so that sufficient lubricity can be maintained even in a high temperature range, and it is resistant to thermal alternating impact.
[0013]
Further, the lubrication method according to claim 3 is characterized in that the graphite powder is 50% by weight or less, the organic and / or inorganic water-soluble binder and the other lubricant A is water, and the lubricant A is 20%. It is in that a lubricant having a weight percent of boron carbide powder and forming a dry film after application to the sliding portion is interposed in the high temperature sliding portion. By adopting such a method, the lubricity of the lubrication part can be maintained at a high temperature and sufficient lubricity, and a lubricant that is resistant to thermal alternating impact can be obtained.
[0014]
Further, as described in claims 2 and 4, when the content of boron carbide powder and 2-5 wt%, as compared with those using the boric acid powder, in a high temperature range even with a small amount of use , To form more melt covering the graphite powder or water-soluble binder, thereby protecting the graphite powder or water-soluble binder and maintaining the lubricity, sealability and sliding surface protection over a long period of time In addition, the manufacturing cost can be reduced by reducing the material cost.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
[0016]
The inventor is a lubricant capable of maintaining sufficient lubricity even in a high temperature range with respect to a sliding surface between a fixed nozzle and a sliding nozzle made of refractory brick made of the above-mentioned carbon alumina ceramic. As a result, it has been found that the use of boron carbide instead of boric acid is extremely effective as a lubricant for these materials.
[0017]
The present invention has been made based on these findings, and the lubricant of the present invention contains a predetermined amount of boron carbide powder as one main component. And, as other main components of the boron carbide powder, a predetermined amount of graphite powder 50 wt% or less, organic and / or inorganic water-soluble binder and other water-based lubricant (hereinafter referred to as “lubricant A”) It is characterized by having.
[0018]
In the present embodiment, the lubricant A is composed of a graphite powder of 50% by weight or less, a starchy paste that is a water-soluble binder, and a composition containing water as the other, and exhibiting a pasty shape.
[0019]
Further, B4C can be used as the boron carbide powder, and the particle size thereof is set to be easily mixed with the graphite (graphite) powder to be mixed. Specifically, it is equal to or smaller than the particle size of the graphite powder. The particle size is as follows.
[0020]
Further, the graphite powder of the lubricant A will be described. This graphite powder is a soft layered crystal structure itself, and has strong adhesion to metal, so that the end face of the crystal is buried in the lubrication surface. The film (thin film) is formed (the metal oxide on the lubricating surface works more effectively). The particle size of the graphite powder is strong and need not be limited, but is usually fine powder, and is desirably 1 to 3 μm, for example. In such a lubricant A, the graphite powder is 50% by weight or less (usually 5 to 50% by weight) because if the amount is too small, the slippery action of the graphite becomes insufficient, and if the amount exceeds the upper limit, it is pasty. It is because it stops exhibiting.
[0021]
In addition, the starchy paste mentioned as the water-soluble binder means a starch paste that dissolves in water, and includes not only ordinary starches but also CMC (carboxymethylcellulose), sodium alginate and the like. . This starchy paste is an organic water-soluble binder, but the water-soluble binder may be inorganic or a mixture of both organic and inorganic. The amount of starch paste may be arbitrarily determined according to the amount of graphite powder, but if it is too small, it will not exhibit a pasty shape. Since it may occur, it may be appropriately adjusted to such an extent that these problems do not occur. In order to impart spreadability and adhesion to the paste, aluminum silicate, ethylene glycol, or the like may be added.
[0022]
Furthermore, this starchy paste is supposed to have the following properties.
[0023]
1) A coating film having a substantially constant thickness can be formed during application and after drying.
[0024]
2) Thermal expansion occurs due to heat transfer from the molten metal, and no gaps are created.
[0025]
3) Carbonization is caused by heat transfer from the molten metal, and this carbon-based layer fills the unevenness of the lower surface 8 and the upper surface 7 of each nozzle 4, 5 made of heat-resistant brick.
[0026]
Moreover, the water in this embodiment includes the thing of a single-piece | unit water, and the thing which mixed water and water glass and gave adhesiveness.
[0027]
Moreover, it is desirable that the starchy paste and water are preliminarily prepared as a paste by the above blending, and graphite powder is added thereto, mixed and stirred.
[0028]
The component ratio of the lubricant A and the boron carbide powder is 20 wt% or less, preferably 2 to 5 wt% of the boron carbide powder with respect to the lubricant A. If the boron carbide powder content exceeds 20% by weight, heavy boron precipitates and the mixed state with the lubricant A cannot be maintained. When the boron carbide powder content is 2 to 5% by weight, a melt covering the graphite powder or the water-soluble binder is formed in a high temperature region even when a small amount of lubricant is used. The protective binder can be protected, and the lubricity, sealing property, and sliding surface protection can be maintained over a long period of time, and the manufacturing cost can be reduced by reducing the material cost. Further, it is recognized that about 3% by weight of boron carbide powder contained in the boron carbide powder contained at high temperature acts to exert the above function.
[0029]
Next, a method for using the lubricant of this embodiment will be described.
[0030]
Since the lubricant of the present embodiment is paste-like, it is used by being applied to the sliding surfaces of the fixed nozzle 4 and the sliding nozzle 5 facing each other.
[0031]
That is, the fixed nozzle 4 and the sliding nozzle 5 are applied to the lower surface 8 and / or the upper surface 7 serving as sliding surfaces facing each other with a predetermined thickness.
[0032]
In this way, when the lubrication test was performed by interposing the lubricant of the present embodiment on the sliding surfaces of the fixed nozzle 4 and the sliding nozzle 5 facing each other, graphite powder, water-soluble binder, and boron carbide were obtained. The function of maintaining lubricity with powder and the function of a water-soluble binder, that is, the function of firmly attaching to a sliding part such as a metal and maintaining an appropriate adhesion to graphite or boron carbide powder, synergistically. As a result, it was found that a good lubricating action was exerted, and it was strong against thermal alternating impact.
[0033]
Since the lubricant of this embodiment has boron carbide powder and graphite powder in a predetermined ratio, both actions function synergistically to exhibit excellent lubricity. That is, when the boron carbide powder is heated and heated in the sliding portion, each graphite powder is wrapped from about 100 ° C. and shielded from the air, thereby reliably preventing the graphite powder from being oxidized. One of the graphite powders repeatedly slips between the crystal layers while maintaining the state of being encased in the boron carbide powder in a state where oxidation is prevented. Thereby, the lubricating action of the boron carbide powder and the graphite powder functions synergistically, and extremely excellent lubricity is maintained in a high temperature range.
[0034]
In addition, the starchy paste contained therein receives a load as a cushioning material due to “uptake action” or the like, and reduces the load on the graphite. The starchy paste is also wrapped in boron carbide and shielded from the air to prevent deterioration, and the lubricating function can be maintained even in a high temperature range. On the other hand, even if the boron carbide coating is torn, the starchy paste is changed to carbon dioxide and water when the temperature rises, and the water and the like make sliding between the crystals of the graphite well and lubricity is improved. Be improved.
[0035]
Further, since boron carbide powder does not react with water and is compatible with a water-soluble binder, it can be stably stored for a long period of time.
[0036]
As described above, in the lubricant according to the present embodiment, the actions of the respective components are exhibited synergistically, an extremely good lubricating action is exhibited, and the lubricant is extremely strong against thermal alternating impact.
[0037]
The lubricant according to the present embodiment is sufficient even when the refractory brick, which is the material of the fixed nozzle 4 and the sliding nozzle 5, is mainly made of carbon alumina ceramic as well as porous alumina ceramic. The lubricity could be maintained.
[0038]
Therefore, by using the lubricant of the present embodiment in accordance with the lubrication method of the present invention, the lubricity of the lubrication part can be maintained in a sufficient state in a high temperature range.
[0039]
The lubricant A can be appropriately mixed with other additives as long as the effects of the present invention are not reduced. For example, an appropriate amount of a surfactant or preservative may be added in order to improve mixing properties and storage stability.
[0040]
Next, specific examples of the present invention will be further described.
[0041]
The following examples of the present invention, together with their comparative examples, are shown in FIG. 2 in order to determine the change in lubricity by measuring the friction coefficient according to the number of frictions while keeping the temperature constant (750 ° C.).
[0042]
Inventive Example Lubricant A + 12 wt% Boron Carbide Powder (B ₄ C)
Lubricant A + 3 wt% boron carbide powder (B ₄ C)
Comparative Lubricant A + 12 wt% boric acid powder (H ₃ BO ₃ )
The friction coefficient was measured using a reciprocating slider type frictional wear tester, with a maximum friction speed of 0.019 m / sec, a friction stroke reciprocation of 80 mm, and a vertical load of 21.2 kgf.
[0043]
As shown in FIG. 1, the two examples of the present invention have a friction coefficient equal to or less than that of the comparative example using boric acid powder, and are excellent in wear resistance. While the coefficient is kept almost constant, the comparative example using boric acid powder gradually increases when the number of frictions exceeds 1150. Therefore, the two examples of the present invention have higher performance and longer life than the comparative example using boric acid powder, and even in the high temperature range even when a small amount of lubricant is used, graphite powder or water-soluble binder. More molten material covering the surface, which protects graphite powder or water-soluble binder, and can maintain lubricity, sealability, and sliding surface protection over a long period of time, and manufacture by reducing material cost Cost can be reduced.
[0044]
In addition, this invention is not limited to the said embodiment, It can change as needed.
[0045]
【The invention's effect】
As described above, since the lubricant and the lubricating method of the present invention are constituted and act, the same performance as that using the boric acid powder is exhibited, and the amount of the lubricant and the lubricating method is smaller than that using the boric acid powder. Even in use, in the high temperature range, more melt is formed to cover the graphite powder or water-soluble binder, thereby protecting the graphite powder or water-soluble binder, and providing lubrication, sealing and sliding surface protection over a long period of time. It is possible to maintain such an effect that the manufacturing cost can be reduced by reducing the material cost.
[0046]
Specifically, in the lubricant and the lubricating method according to claims 1 and 3, since it has boron carbide powder, it melts at a high temperature to exhibit lubricity and is sufficient in a high temperature range. Lubricity can be maintained. Furthermore, compared to those using boric acid powder, even in a small amount of use, more melt is formed covering the graphite powder or water-soluble binder in the high temperature range, thereby protecting the graphite powder or water-soluble binder and lubricating it. , Sealing performance and sliding surface protection can be maintained over a long period of time, and the manufacturing cost can be reduced by reducing the material cost. Due to such a synergistic effect, the lubricant of the present invention is applied not only to porous alumina ceramic but also to a sliding part composed of a sliding part between a fixed nozzle and a sliding nozzle mainly made of carbon alumina ceramic. After that, a dry film can be formed so that sufficient lubricity can be maintained even in a high temperature range, and it is resistant to thermal alternating impact.
[0047]
In addition, as described in claims 2 and 4, by setting the content of boron carbide powder to 2 to 5% by weight, graphite can be used in a high temperature range even in a small amount of use as compared with the case using boric acid powder. More melt to cover the powder or water-soluble binder, which can protect the graphite powder or water-soluble binder and maintain the lubricity, sealability and sliding surface protection for a long time, Manufacturing costs can be reduced by reducing costs.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a sliding opening / closing device. FIG. 2 is a characteristic diagram showing the relationship between the number of frictions and the friction coefficient in an embodiment of the present invention.

Claims (4)

A graphite powder of 50% by weight or less, an organic and / or inorganic water-soluble binder and other lubricant A containing water, and a boron carbide powder of 20% by weight or less based on the lubricant A, and sliding A lubricant characterized by forming a dry film after application to the part. The lubricant of claim 1, wherein the content of the boron carbide is 2 to 5% by weight. A graphite powder of 50% by weight or less, an organic and / or inorganic water-soluble binder and other lubricant A containing water, and a boron carbide powder of 20% by weight or less based on the lubricant A, and sliding A lubrication method comprising maintaining a lubricity of a sliding portion by interposing a lubricant which forms a dry film after application to the portion in a high temperature sliding portion. Lubricating method according to claim 3, characterized in that the content of the boron carbide is 2 to 5% by weight.

Images