JP2011246684A - Aqueous lubricant for plastic working of metallic material, having hardly crystallizable property, and excellent in hygroscopic resistance, corrosion resistance and workability, and metallic material having lubricating film thereof formed thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous lubricant for plastic working of a metallic material, capable of forming a lubricating film having the hardly crystallizable property, and excellent in the hygroscopic resistance, the corrosion resistance and the plastic workability.SOLUTION: The aqueous lubricant for plastic working of a metallic material contains alkaline metal borate salts (A), wherein the alkaline metal borate salts (A) contain lithium borate; the molar ratio of lithium to all the alkaline metals in the alkaline metal borate salts (A) is 0.1 to 1.0; and the molar ratio (B/M) of boron (B) to alkaline metals M in the alkaline metal borate salts (A) is 1.5 to 4.0.

Description

  The present invention provides steel, stainless steel, aluminum and aluminum alloys, titanium and titanium alloys, copper and copper alloys, magnesium and magnesium alloys, etc. in plastic working in the cold region such as forging, wire drawing, pipe drawing, roll forming, and pressing. A water-based lubricant for plastic processing of metal materials that is difficult to crystallize (not crystallize or hardly crystallize) on the surface of various metal materials and has excellent moisture absorption, corrosion resistance, and workability (lubricity and seizure resistance) ( This may also be referred to as an aqueous composition for metal material plastic working, the same applies hereinafter) and a metal material in which a film is formed by applying the lubricant on the material surface and drying it.

  In plastic working represented by forging, wire drawing, drawing, roll forming, press, etc., friction generated when metal surfaces (especially dies and workpieces) rub against each other violently increases processing energy, heat generation, and seizure. Various lubricants aimed at reducing the frictional force have been used because they cause phenomena. As lubricants, oil and soap have been used for a long time, and the frictional force has been reduced as a fluid lubrication film by supplying it to the friction surface, but it slides under high surface pressure with large heat generation due to surface area expansion. Plastic processing tends to cause seizure phenomenon due to insufficient lubricity or a lubrication film breakage. Therefore, borate (borax, borax) film, phosphorus which has sufficient film strength and can prevent lubrication film breakage and avoid direct contact between metals by interposing at the interface between die and workpiece even under high surface pressure A technique of previously coating a metal material surface with a solid film such as an inorganic film such as an acid salt crystal film has been generalized and widely used.

  On the other hand, in recent years, the processing energy has been further reduced and the degree of processing has been increased. There is a problem in terms of maintenance), and demands for solid coatings are increasing rapidly, such as support for lubrication powder-less and oil-less processing. A solid film having properties is being developed. This technique is to form a film having high lubricity by a simple process of applying a water-based plastic processing lubricant to the surface of a workpiece and drying it.

As such a technique, Patent Document 1 (WO2002 / 012420) discloses (A) at least one water-soluble inorganic salt selected from the group consisting of sulfate, silicate, borate, molybdate and tungstate ( B) A composition in which a surfactant is added and dissolved or dispersed in water when necessary, and the solid content mass ratio (B) / (A) is in the range of 0.3 to 1.5. An aqueous lubricant for plastic working of metallic materials is disclosed. In this technology, a lubricating film is formed by binding a lubricating component such as wax (B) in a solid film made of the water-soluble inorganic salt (A), and when this is coated on the surface of a work material, it is highly sophisticated. This is an excellent technique for obtaining a lubricating film having processing performance in a simple and labor-saving manner. This technology is widely used mainly in the field of plastic working, and it is a promising technology that can be applied to strong processing applications with a large surface area compared to industrially proven combinations of phosphate coatings and soap. It is. In addition, sodium tetraborate is specifically used in the water-soluble inorganic salt of (A).

  As disclosed in Patent Document 1, a water-soluble inorganic salt is an essential component of a solid film of an aqueous lubricant for plastic working. The reason is that a lubricating film composed of a water-soluble inorganic salt has a sufficient film strength, and as described above, it is difficult to cause the lubricating film to break by intervening at the interface between the die and the workpiece even under high surface pressure. This is because direct contact can be avoided. Therefore, in an aqueous lubricant for plastic working, a good lubricating state can be maintained during plastic working by combining an appropriate lubricant with a water-soluble inorganic salt.

  Regarding the film formation mechanism of the water-based lubricant for plastic processing composed of this water-soluble inorganic salt, sodium tetraborate is dissolved in water in the lubricant treatment solution, and the lubricant is applied to the surface of the metal material. It is believed that when dried, the solvent water evaporates and a lubricating film composed of the borate is formed. At that time, the borate precipitates as a solid on the surface of the metal material to form an amorphous continuous film. The film formed in this way has a film strength that can withstand plastic processing and has excellent adhesion to the metal material surface, so it shows good lubricity during plastic processing by adding an appropriate lubricant that reduces the friction coefficient. It will be.

  On the other hand, Patent Document 2 (Japanese Patent Laid-Open No. 2000-345361) describes a technique relating to a lubricating film composed of a borate having excellent moisture absorption resistance and corrosion resistance. In Patent Document 2, a pretreatment agent for drawing metal material containing 100 parts by weight of borate, 0.1 to 10 parts by weight of phosphonate, and 0.4 to 4 parts by weight of organic acid salt. A method is disclosed in which a metal material is brought into contact with a treatment solution in which the pretreatment agent is dissolved and then dried. The borate used here is described as at least one selected from lithium pentaborate tetrahydrate, sodium pentaborate tetrahydrate, and potassium pentaborate tetrahydrate.

WO2002 / 012420 JP 2000-345361 A

  However, the water-soluble inorganic salt (sodium tetraborate) described in Patent Document 1 is not low in hygroscopicity, and the solid film formed on the surface of the metal material is exposed to high temperature and high humidity environments such as summer and rainy season. Then, it absorbs moisture in the atmosphere and absorbs moisture. When absorbed, the borate film swells or dissolves in water and gradually changes from a solid to a fluid. When the film is fluidized, the film strength is remarkably lowered, causing a lubricating film to break at the interface between the die and the workpiece under high surface pressure during plastic processing, and direct contact between metals occurs. Therefore, plastic processing lubricants composed of such borates have a problem that when they are exposed to a high temperature and high humidity environment for a long time, they absorb moisture and the workability such as lubricity and seizure resistance is greatly reduced. It was. Moreover, there also existed a problem that there exists a tendency for corrosion resistance to fall.

  Furthermore, it has been found that sodium borate forms an amorphous continuous film as described above, but tends to crystallize after moisture absorption. When the continuous film is crystallized, the adhesion to the material surface tends to be greatly reduced, so the film is dropped during press processing and direct metal-to-metal contact occurs. Tend to decrease. In addition, since the crystallized borate may disappear from the surface of the material, such as peeling or dropping, rust will occur at the part where it has been peeled off or dropped (the part that has disappeared) when used on the surface of a metal material such as iron. Corrosion resistance may be reduced. When this rust is generated, not only the appearance is deteriorated but also the dimensional accuracy on the processed surface during press working tends to be lowered. In the plastic working, it is an important requirement that the metal material is molded according to the shape of the mold when pressed, and the smoother the dimensional accuracy and the forged skin, the better the quality. The rust generated before the press working reduces the lubricity to increase the frictional force, leading to deterioration of dimensional accuracy and forging skin. Moreover, there is a concern that the rust generated after press working increases the surface roughness on the processed surface, leading to a decrease in dimensional accuracy and a deterioration of the forged skin.

  In general, it is known that for lubricating films composed of hygroscopic components, the lubricity may be restored to the state before moisture absorption if heated to about 100 ° C. with hot air or the like immediately before pressing. ing. This is thought to be due to the fact that moisture taken into the lubricating film by moisture absorption evaporates by heating before pressing, so that the film strength returns to the state before moisture absorption. And sometimes on the production line during the summer. However, it is considered that this work not only obtains a stable lubricating state by evaporating moisture taken in the lubricating film by moisture absorption but also aims to soften the metal material by heating. That is, it is considered that the lubrication film is dried by heating immediately before pressing, and at the same time, the metal material of the base material is heated, so that the metal material is softened by heat, so that the deformation resistance at the time of pressing decreases and the molding load decreases. ing. As a result, the load on the press machine and the mold is reduced, and the life of the press machine and the mold is extended. In addition to the tendency of the corrosion resistance to decrease if the hygroscopicity of the lubricating film is large, a long time is required for re-drying, so a film with as low a hygroscopic property as possible is required from the viewpoint of quality and productivity. It has been.

  However, the lubricating film composed of sodium tetraborate described in Patent Document 1 has the property of crystallizing after moisture absorption as described above, and the film once crystallized is amorphous before moisture absorption even if heated immediately before pressing. There was a problem that good corrosion resistance and workability could not be obtained because of the property of not returning to the quality state.

  In addition, the lubricating film described in Patent Document 2 does not mention the phenomenon that the borate crystallizes after moisture absorption, and there is a problem that sufficient corrosion resistance is not obtained.

  Here, as one of the measures to make it difficult to absorb moisture, an in-line system that consistently performs the processes from formation of a lubricating film to press working has been studied and partly put into practical use. If this method is used, it is possible to ignore the influence of moisture absorption of the lubricating film because it is pressed before the lubricating film absorbs moisture or in a slightly absorbed state, and the production efficiency can be improved. Will be good. However, even in such a system, when it is assumed that there is a production trouble, for example, when there is a long-time line stop accompanying production trouble or maintenance, the lubricating film cannot prevent moisture absorption. Still, if the lubricating film is preheated in the drying process and the film temperature is higher than the outside air temperature, the moisture in the film works in the direction of evaporation, so it does not absorb moisture immediately, but the metal material cools and falls to near the outside temperature. In this case, since moisture absorption generally starts, there is a demand for a lubricating film with low moisture absorption even in this method of use. In any case, when the film temperature falls to the temperature of the outside air, the moisture absorption of the lubricating film is inevitable, and water-soluble inorganic salts, particularly those composed of sodium tetraborate, have a strong tendency to crystallize and the hygroscopicity is too large. Without it, the corrosion resistance will be bad.

  In this way, in the water-based lubricant for plastic working, alkali metal borate (alkali metal salt of boric acid) listed in borax (sodium tetraborate) is used for the purpose of preventing seizure between the mold and the material during processing. In general, however, the lubricating film of alkali borate is not small in hygroscopicity, so it absorbs water vapor in the atmosphere and partially dissolves when exposed to high temperature and high humidity environment such as summer and rainy season. In some cases, the film strength is greatly reduced and seizure occurs during press working, resulting in poor workability. In addition, the amorphous continuous film before moisture absorption has the property of crystallizing after moisture absorption, and if crystallized, the adhesion with the material surface is greatly reduced, so that only seizure is likely to occur during press working. In addition, there is a problem such as corrosion resistance such as rust generated in a metal material such as iron by dropping from the material surface.

  Therefore, it is a water-based lubricant for plastic working composed of alkali metal borate, which is hard to absorb moisture compared to, and does not crystallize after moisture absorption, or hardly crystallizes even if it does not cause any problems in performance. A lubricating film is desired. The present invention is a metal material that is hard to absorb moisture even under high temperature and high humidity environment, has poor crystallinity, has excellent moisture absorption resistance, corrosion resistance, and plastic workability. Is intended to provide.

  In order to solve the above-mentioned problems, the present invention is configured as follows.

  The present invention (1) is an aqueous lubricant containing an alkali metal borate (A), wherein the alkali metal borate (A) contains lithium borate, and all alkali metals in the alkali metal borate (A) The molar ratio of lithium to Al is 0.1 to 1.0, and the molar ratio (B / M) of boron B and alkali metal M of the alkali metal borate (A) is 1.5 to 4. An aqueous lubricant for plastic working of a metal material, characterized in that it is zero.

  The present invention (2) is an aqueous lubricant for plastic working of a metal material according to the invention (1), comprising a lubricant (B), and a solid content of alkali metal borate (A) and lubricant (B). Mass ratio (A) / [(A) + (B)] is a water-based lubricant for plastic working of metal materials, characterized in that it is 0.10 to 0.97.

  In the present invention (3), the lubricant (B) is wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, tungsten disulfide, graphite, melamine cyanurate, organically treated synthetic mica, layered structure The water-based lubricant for plastic working of a metal material according to the invention (2), characterized in that it is at least one selected from the group consisting of amino acid compounds.

  The present invention (4) is characterized in that a film is formed on the surface of the metal material by applying and drying any one of the metal material plastic working water-based lubricants of the inventions (1) to (3). It is a metal material with excellent plastic workability.

  In the present invention (5), after forming a lubricating undercoat composed of an alkali metal borate (A) on the first layer using the metal-based plastic working water-based lubricant described in the invention (1), the second layer is then formed. A metal material excellent in plastic workability, characterized in that a lubricating layer containing a lubricant (B) is formed on the surface.

  An aqueous lubricant for plastic working of a metal material according to the present invention is an aqueous lubricant containing an alkali metal borate (A), wherein the alkali metal borate (A) contains lithium borate, and the alkali metal borate The metal-based plastic working water-based lubricant is characterized in that the molar ratio of lithium to the total alkali metal is 0.1 to 1.0. And the molar ratio (B / M) of boron B and alkali metal M of alkali metal borate (A) is 1.5 to 4.0, and the like. First, the components, compositions, etc. of the water-based lubricant for processing a metal material composition according to the present invention will be described in order.

  The alkali metal borate (A) used in the water-based lubricant for plastic processing of a metal material according to the present invention indicates an alkali metal salt of boric acid, and neutralization reaction between the alkali metal hydroxide and boric acid. Can be synthesized. The alkali metal borate includes a case where boric acid is relatively larger than the alkali metal. Specifically, an alkali metal hydroxide is added to heated water, and after dissolution, boric acid is added and completely dissolved. Here, the alkali metal indicates a metal specified in Group 1 of the periodic table. Examples of the alkali metal hydroxide that can be used here include lithium hydroxide, potassium hydroxide, sodium hydroxide, and rubidium hydroxide. These alkali metal hydroxides may be used alone or in combination of two or more. However, it is characterized by containing lithium as an alkali metal.

  In the alkali metal borate (A), the molar ratio of lithium to the total number of moles of alkali metal must be 0.1 to 1.0. Within this molar ratio range, it is possible to obtain suppression of crystallization due to moisture absorption of alkali metal borate (that is, development of difficult crystallinity) and reduction of moisture absorption (that is, good moisture absorption resistance). As a result, it is possible to obtain a good coating appearance with excellent corrosion resistance and no or almost no crystals. However, if the molar ratio is less than 0.1, the effect of the present invention that suppresses crystallization of alkali metal borate due to moisture absorption of the lubricating film cannot be sufficiently obtained, and the crystallization of the film is sufficiently suppressed. The corrosion resistance is poor and the workability as a lubricating film tends to be poor. On the contrary, it has been found that the higher the lithium content in the lubricating film (the higher the molar ratio of lithium), the more difficult the alkali metal borate film absorbs moisture. Therefore, in order to obtain difficult crystallinity for suppressing crystallization and good corrosion resistance and moisture absorption resistance, the molar ratio of lithium to the total number of moles of alkali metal is 0.2 to 1.0, 0.3 to 1. It becomes preferable in order of the range of 0, 0.4-1.0, 0.45-1.0, More preferably, it is 0.5-1.0.

  Furthermore, the molar ratio (B / M) of boron B and alkali metal M in the alkali metal borate (A) must be 1.5 to 4.0. When this B / M is in the range of 1.5 to 4.0, an amorphous film can be obtained, and good hygroscopic resistance and corrosion resistance can be obtained. However, if the B / M is less than 1.5, the alkali metal M in the film is excessive, and the hygroscopicity tends to become very large. Therefore, it takes a long time to dry immediately before pressing. In addition, there is a tendency to generate rust (decrease in corrosion resistance) when exposed to high temperature and high humidity environments during the summer and rainy season, and the workability of lubricity and seizure resistance also decreases. . In addition, when B / M exceeds 4.0, the boric acid component becomes excessive, and a crystalline film tends to be formed, resulting in poor adhesion to the substrate, resulting in lubricity and seizure resistance. Workability and corrosion resistance tend to be insufficient. Therefore, in order to obtain an amorphous film having poor crystallinity, good moisture absorption resistance, and corrosion resistance, B / M is in the order of 1.5 to 3.5 and 1.5 to 3.0. Preferably, it is 1.5 to 2.5. When B / M is in the range of 1.5 to 4.0, the film is difficult to absorb moisture, and as a result, the film is easily re-dried.

  Here, it is considered that the cause and mechanism of crystallization of the alkali metal borate (A) after moisture absorption is not sufficiently clear, but as a presumption, between the alkali metal and boric acid. It is considered that the ease of crystal formation is involved. That is, lithium tends to hardly form crystals with boric acid, but sodium and potassium are presumed to easily form crystals with boric acid. Here, it is considered that the alkali metal borate film absorbs moisture to form a salt saturated solution of alkali metal borate, but when the alkali metal is sodium or potassium, boric acid and crystals are formed. Since it is easy to form, crystals are formed in this salt saturated solution. As a result, not a few crystals are generated in the film. This alkali metal borate crystallized once has an irreversible property even if it is heated with hot air or the like to evaporate water just before pressing, so it is considered that it does not return to an amorphous state. On the other hand, when the alkali metal is lithium, it is considered that crystals do not form or tend to be difficult to form with boric acid. In this case, if it is heated immediately before pressing to evaporate the water, it can be expected to be restored to the same amorphous continuous film as before moisture absorption, and it is assumed that excellent workability is obtained. .

  Next, the lubricant (B) itself is soft and slippery, and has a function of reducing the frictional force between the die and the workpiece during plastic processing. In general, when the frictional force increases during plastic processing, processing energy increases, heat generation, seizure, etc. occur. However, when the lubricant (B) is included in the water-based lubricant for plastic processing of the present invention, it is in a solid form in the lubricating film. It exists and the increase in frictional force is suppressed. The lubricant (B) having such functions and properties is not particularly limited as long as it has an action, for example, wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, Examples include tungsten disulfide, graphite, melamine cyanurate, organically treated synthetic mica, and layered structure amino acid compounds. These may be used alone or in combination of two or more.

  Here, when the lubricant (B) is a wax, specific examples include polyethylene wax, paraffin wax, microcrystalline wax, polypropylene wax, and carnauba wax. In the case of fatty acid soap and fatty acid metal soap, specific examples include soaps composed of alkali metals such as sodium stearate, potassium stearate, lithium stearate, calcium stearate, zinc stearate, barium stearate, magnesium stearate, etc. Metal soap. Fatty acid amide is an amide compound having two fatty acids. Specific examples thereof include ethylene bislauric acid amide, ethylene bis stearic acid amide, ethylene bisbehenic acid amide, NN′-distearyl adipic acid amide, ethylene Bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, NN′-dioleyl adipic acid amide can be mentioned.

  In the case where the lubricant (B) is an organically treated synthetic mica, it corresponds to an organic modifier introduced between layers of the synthetic mica having a layered structure. Here, the synthetic mica is called the host, and the organic modifier introduced between the layers is called the guest, but the organic treatment is performed by introducing the guest in a state where the host is swollen with water and the interlayer distance is widened. Yes. Specific examples of synthetic mica having the property of swelling with water include sodium tetrasilicon mica. The guest is a primary to tertiary alkylamine or alkyl quaternary ammonium salt that adsorbs between the layers to form a strong bond. Specific examples include stearyldimethylamine, distearylamine, distearyldimethylamine, stearyltrimethylammonium chloride, dialkyl Stearyldimethylammonium chloride can be mentioned.

When the lubricant (B) is a layered structure amino acid compound, it is an amino acid having a hydrocarbon group having 11 or more carbon atoms in the molecular structure or a derivative thereof. Specific examples of N- lauroyl -L- lysine _{[C 11 H 23 CONH (CH} 2) 4 CH (NH 2) COOH] can be cited.

  The aqueous plastic lubricant for plastic working of the present invention can be blended with a viscosity modifier for the purpose of imparting leveling properties and thixotropy in order to ensure a uniform application state when a lubricant treatment liquid is applied to a substrate. . In addition, 0.1 to 30% of these compounding quantities are preferable with respect to the total solid content mass. Specific examples of such viscosity modifiers include smectite clay minerals such as montmorillonite, saconite, beidellite, hectorite, nontronite, saponite, iron saponite and stevensite, and inorganic thickening such as finely divided silica, bentonite and kaolin. Agents. Moreover, organic polymer type | system | group thickeners, such as a hydroxyethylcellulose, carboxymethylcellulose, polyacrylic acid amide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, polymaleic acid, a urethane association type, are mentioned.

The water-based lubricant for plastic working of the present invention prevents seizure between the mold and the workpiece during pressing by using the alkali metal borate (A) and the lubricant (B) in combination, before and after pressing. However, for the purpose of further improving the seizure resistance and corrosion resistance, other inorganic salts, inorganic solid particles, organic water-soluble rust preventives and the like may be blended. Specific examples of the phosphate include magnesium phosphate, ammonium phosphate, aluminum phosphate, zinc phosphate, lithium phosphate, sodium phosphate, potassium phosphate, and calcium phosphate. The phosphate includes salts of condensed phosphoric acid such as tripolyphosphoric acid, metaphosphoric acid, and pyrophosphoric acid. Examples of vanadium oxyacid salts include ammonium vanadate, lithium vanadate, sodium vanadate, potassium vanadate, strontium vanadate, bismuth orthovanadate, and sodium hydrogen vanadate. Examples of molybdenum oxyacid salts include ammonium molybdate, calcium molybdate, lithium molybdate, sodium molybdate, potassium molybdate, and barium molybdate. Examples of the tungstate include lithium tungstate, sodium tungstate, potassium tungstate, ammonium tungstate, calcium tungstate, and zirconium tungstate. Examples of the sulfate include sodium sulfate, potassium sulfate, lithium sulfate, ammonium sulfate, calcium sulfate, barium sulfate, and aluminum sulfate. Examples of the silicate include lithium silicate, sodium silicate, potassium silicate, ammonium silicate, calcium silicate, magnesium silicate, and aluminum silicate. As the form of silicic acid, orthosilicate (nSiO _2. (N + 1) H ₂ O), metasilicate ( nSiO ₂ .nH ₂ O), mesosilicate (nSiO _2. (n-1) H ₂ O) and parasilicate (nSiO _2. (n-2) H ₂ O) (each n = 1, 2, 3, 4 , ...). Nitrite includes sodium nitrite, potassium nitrite, lithium nitrite, calcium nitrite, magnesium nitrite, lithium nitrite, and phosphite includes lithium phosphite, sodium phosphite, potassium phosphite, Calcium phosphite, zinc phosphite, aluminum phosphite, magnesium phosphite, zirconium compounds include water-dispersible zirconium oxide colloid, zirconium hydroxide, zirconium oxycarbonate, basic zirconium carbonate, potassium zirconium carbonate, ammonium zirconium carbonate, Examples include zirconium silicate, zirconium phosphate, zirconium titanate, lithium zirconate, aluminum zirconate, and magnesium zirconate. Examples of the carbonate include sodium carbonate, potassium carbonate, lithium carbonate, ammonium carbonate, calcium carbonate, magnesium carbonate, and barium carbonate. Examples of the metal hydroxide include calcium hydroxide, magnesium hydroxide, zinc hydroxide, barium hydroxide, and aluminum hydroxide. Organic water-soluble rust preventives include mixed components of alkanolamines such as triethanolamine, amine salts of pt-butylbenzoic acid, carboxylic acid amine salts, dibasic amine bases, alkenyl succinic acids, and their water solubility Well-known things, such as combined use of a salt, aminotetrazole, and its water-soluble salt, can be used. These inorganic salts, inorganic solid particles, water-soluble rust preventives, etc. may be used alone or in combination of two or more. These blending amounts are preferably 0.1 to 30% with respect to the total solid mass.

  The liquid medium (solvent, dispersion medium) in the aqueous lubricant for plastic working of the present invention is water. In order to shorten the drying time of the lubricant in the drying process, an alcohol having a boiling point lower than that of water may be blended.

  Next, the ratio of the lubricant in the metal-based plastic working water-based lubricant according to the present invention will be described. In the water-based lubricant for metal material plastic working, the ratio of the solid mass of the alkali metal borate (A) and the lubricant (B) is within the following range: (A) / [(A) + (B)] = 0 10 to 0.97 is preferable. Furthermore, (A) / [(A) + (B)] = 0.20 to 0.95 and 0.30 to 0.90 are more preferable in this order. As described above, the alkali metal borate (A) is a film forming agent for a lubricating film, and a solid solid film is formed, so that better workability can be obtained. Here, when (A) / [(A) + (B)] is less than 0.10, the relative amount of a solid film such as an alkali metal borate is small, and seizure resistance due to film breakage occurs at high surface pressure during processing. The seizure resistance and lubricity workability tend to decrease, such as easier, and if it exceeds 0.97, the frictional force due to the lack of lubricant (B) increases, resulting in seizure resistance and lubricity processing. There may be a tendency for sex to decline.

  The aqueous plastic lubricant for plastic working according to the present invention is obtained by adding and mixing the alkali metal borate (A) alone or further with the lubricant (B) and / or the viscosity modifier, etc., in the liquid medium water. Manufactured. The alkali metal borate (A) used here is water-soluble, but the lubricant (B) and viscosity modifier are insoluble or sparingly soluble in water, and it is necessary to disperse them in the lubricant. . If necessary, the dispersing method is carried out by adding a surfactant that can be a dispersing agent to water and sufficiently blending in water, and then stirring is continued until the dispersed state becomes uniform. The stirring method is performed by a general method such as propeller stirring or stirring with a homogenizer. In addition, in order to obtain a stable dispersion state, a known surfactant can be used.

  The water-based lubricant for plastic working of the present invention is applied to metal materials such as iron or steel, stainless steel, copper or copper alloy, aluminum or aluminum alloy, titanium or titanium alloy. The shape of the metal material is not particularly limited, and is not limited to materials such as rods and block materials, but may be processed forged shapes (such as gears and shafts) after forging.

  Next, a method for applying the aqueous lubricant for plastic working of the present invention will be described. The application method includes a metal material cleaning step, a plastic working aqueous lubricant application step, and a drying step. Hereinafter, each step will be described.

・ Cleaning process (pretreatment process)
Before the metal material is brought into contact with the metal-based plastic working water-based lubricant, at least one cleaning treatment selected from the group consisting of shot blasting, sand blasting, wet blasting, peeling, alkali degreasing, and acid cleaning may be performed. preferable. The purpose of cleaning here is to remove oxide scales and various types of dirt (oil, etc.) grown by annealing or the like.

Application Step The step of applying the aqueous lubricant of the present invention to a metal material is not particularly limited, but an immersion method, a flow coating method, a spray method, or the like can be used. The coating is only required to be sufficiently covered with the aqueous lubricant of the present invention, and the coating time is not particularly limited. Here, in this case, in order to increase the drying property, the metal material may be heated to 60 to 80 ° C. and brought into contact with the water-based lubricant for metal material plastic working. Further, an aqueous lubricant for metal material plastic working heated to 40 to 70 ° C. may be contacted. By these, drying property improves significantly and drying may be attained at normal temperature, and the loss of heat energy can also be reduced.

-It is necessary to dry the water-based lubricant for plastic working after applying the drying process . Drying may be performed at room temperature, but may be performed at 60 to 150 ° C. for 1 to 30 minutes.

Here, the adhesion amount of the lubricating film formed on the metal surface is appropriately controlled depending on the degree of subsequent processing, but the adhesion weight is preferably in the range of 0.5 to 40 g / m ² , and more preferably. Is in the range of ^{2 to 20} g / m ² . When the adhesion amount is less than 0.5 g / m ² , the lubricity is insufficient. On the other hand, if the adhesion amount exceeds 40 g / m ² , there is no problem in lubricity, but clogging of the mold and the like are not preferable. The amount of adhesion can be calculated from the weight difference and surface area of the metal material before and after the treatment. In order to control to be within the above-mentioned adhesion amount range, the solid content weight (concentration) of the water-based lubricant is appropriately adjusted. In practice, a high-concentration lubricant is often diluted with water and used in the treatment liquid.

  The step of forming a lubricating film on the surface of the metal material using the aqueous lubricant of the present invention may be performed in a two-stage process. In the two-stage treatment, a lubricating coating is formed by forming a first lubricating undercoat made of alkali metal borate (A) and then forming a lubricating layer containing a lubricant (B) in the second layer. Specifically, after the cleaning step, an aqueous lubricant containing an alkali metal borate (A) as a main component is applied and dried to form a base film. Then, in the next step, an aqueous lubricant containing the lubricant (B) as a main component is applied and dried to form a second layer. In addition, the formation of the second lubricating layer does not need to be wet. For example, the powdered lubricant (B) in the drawing process such as drawing or drawing can be drawn in before the die as a dry lubricant. A lubricating layer can be formed. In this method, a two-layer lubricating film composed of alkali metal borate (A) and lubricant (B) is formed at the same time as the drawing process, and excellent lubricity can be obtained in subsequent drawing and forging processes. Convenient.

  As described above, the water-based lubricant for plastic working of a metal material according to the present invention is a plastic working that is difficult to absorb moisture even in a high-temperature / high-humidity environment, and that can provide a metal material that has excellent resistance to moisture absorption, corrosion resistance, and workability that has poor crystallinity. Lubricant. Moreover, the metal material which formed the film | membrane on the metal material surface can be obtained by apply | coating and drying the water-system lubricant for metal material plastic working of this invention.

Spectra obtained by measuring the film of (A) -1 after moisture absorption with an X-ray diffractometer The spectrum figure obtained by measuring the membrane | film | coat of (A) -15 after moisture absorption with an X-ray-diffraction apparatus.

  The examples of the present invention will be described more specifically together with the effects of the present invention by listing them together with comparative examples. In addition, this invention is not restrict | limited by these Examples.

(1) Preparation of alkali metal borate (A) As shown in Table 1, an aqueous solution of alkali metal borate (A) in which the type of alkali metal and the molar ratio of boron to alkali metal were changed was prepared. The sample used and the method for preparing the aqueous solution are shown below.
(1-1) Samples All using the reagent grade made by Pure Chemical Co., Ltd. ・ Lithium hydroxide, monohydrate, sodium hydroxide, potassium hydroxide, boric acid (1-2) Alkali metal borate aqueous solution Preparation method {circle around (1)}. Heat deionized water to 60 ° C.
(2). Each alkali metal hydroxide is added to deionized water and completely dissolved.
(3). Add boric acid to dissolve completely.
The aqueous solution of all these alkali metal borates (A) had a weight ratio of total solids to water of 30:70.

(2) Formation method of alkali metal borate (A) film An aqueous solution of alkali metal borate prepared in (1) is applied to a base material (SPCC-SD plate material), and the alkali metal borate is formed on the base material. The film (A) was formed.
Base material: Cold-rolled steel plate (SPCC-SD plate material) 150 mm x 35 mm x 0.8 mm ^t
<Processing process in film formation>
(A) Degreasing: Commercially available degreasing agent (Product name: Fine Cleaner 4360, manufactured by Nihon Parkerizing Co., Ltd.) concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 30 seconds ( c) Pure water washing: deionized water, room temperature, immersion 30 seconds (d) Film formation treatment: Alkali metal borate (A) aqueous solution prepared in (1) Temperature 60 ° C., immersion 30 seconds (e) Drying: 100 ° C. 10 minutes (f) Dry film amount: about 8 g / m ²

(3) Evaluation of crystallinity, moisture absorption rate, and corrosion resistance Using the alkali metal borate (A) film prepared in (2), the crystallinity before and after moisture absorption, the moisture absorption rate, and the corrosion resistance when exposed indoors were evaluated. Test conditions and test methods are shown below.
(3-1) Crystallinity About each alkali metal borate (A) film | membrane, the presence or absence of crystallinity before and behind moisture absorption was confirmed visually and using the X-ray-diffraction apparatus. In addition, the measurement sample after moisture absorption used the membrane | film | coat after 40-hour progress in the constant temperature and humidity chamber of 30 degreeC of air temperature, and 70% of relative humidity. In the X-ray diffraction measurement, when the alkali metal borate (A) film is measured, a peak showing crystallinity is not detected in the case of amorphous, but when crystallized by moisture absorption, the peak showing crystallinity shown in the figure below is obtained. Detected. The crystallinity of the film was evaluated by the degree of whitening of the film when visually observed.
Criteria for judging crystallinity by visual observation 4: Formation of crystalline material is not observed. (Visually no whitening of the film is observed.)
3: A very small amount of crystal material is generated. (It is slightly whitened visually.)
2: Some crystalline material is produced. (It has been spotted and whitened.)
1: Crystalline material is remarkably generated. (It is whitened almost entirely by visual inspection.)
Measurement conditions in X-ray diffraction measurement Measuring device: Xpert-MPD (Panalytical)
X-ray: Cu tube Tube voltage-current: 45 kV-40 mA
Step size: 0.0167 (°)
Scan speed: 0.0423 (° / sec)
Measurement range: 10-85 °
(3-2) Moisture Absorption Rate The test piece on which the film of each alkali metal borate (A) prepared in (2) was formed was put into a constant temperature and humidity chamber maintained at an air temperature of 30 ° C. and a relative humidity of 70%. Weight increase due to moisture absorption was continuously measured with an electronic balance. The moisture absorption rate was calculated from the following equation.
Moisture absorption rate (%) = (weight increase due to moisture absorption / film weight before moisture absorption) × 100
The measurement time was 5 hours from the start of moisture absorption, and the maximum value of moisture absorption during that time is shown in Table 1.
(3-3) Corrosion resistance evaluation The test piece on which the alkali metal borate film was formed in (2) was exposed indoors for three months indoors in summer, and the area where rust was generated was visually observed.
Criteria for determining corrosion resistance 4: No rust generation 3: Less than 5% rust generation area relative to specimen surface area 2: Less than 20% rust generation area relative to specimen surface area 1: Generation of rust relative to specimen surface area Area is 20% or more

Table 1 shows the evaluation results of the crystallinity before and after moisture absorption, the moisture absorption rate, and the corrosion resistance in indoor exposure of the alkali metal borate (A) film.

  All of (A) -13 to (A) -16 and (A) -19, which do not contain lithium as an alkali metal or have a lithium ratio of 5%, crystallized after moisture absorption and had poor corrosion resistance. In contrast, at least significant crystallization did not occur in (A) -1 to (A) -12 containing 10% or more of lithium. Note that the effect of suppressing crystallization was obtained when the lithium ratio was 10% or more, and the effect was more exhibited when the ratio was 25% or more. Moreover, when (A) -1 to (A) -5 are compared, it can be seen that the higher the molar ratio of lithium, the lower the moisture absorption rate, and the better the moisture absorption resistance. Further, the molar ratio (B / M) of boron to alkali metal is suitably 1.5 to 4.0, and in the case of (A) -17 below 1.5, the moisture absorption is very large and the moisture absorption resistance is high. It was very bad and the corrosion resistance was poor even though it was not crystallized. Further, in the case of (A) -18 where B / M exceeds 4.0, the crystallinity was already shown in the state before the moisture absorption test, and the corrosion resistance was also poor. That is, regarding the corrosion resistance when the base material is iron, (A) -1 to (A) -12 which does not crystallize after moisture absorption showed good corrosion resistance, but (A) -13 to (A)- No. 19, including those that did not crystallize after moisture absorption, had the coating peeled off and dropped off from the substrate, resulting in significant rusting and very poor corrosion resistance.

  FIGS. 1 and 2 show the spectra obtained by measuring (A) -1 and (A) -15 after moisture absorption with an X-ray diffractometer, for reference. In (A) -1, only the peak derived from the iron of the base material was detected, and the peak indicating the crystallinity of the film was hardly detected. On the other hand, in (A) -15, the formation of a crystal substance was remarkably confirmed visually, and in the spectrum obtained by X-ray diffraction, a number of peaks showing crystallinity were detected. Although some differences may occur due to the adjustment of the test material, the crystal state of the film can also be grasped by such a spectrum.

(4) Preparation of water-based lubricant for plastic working Examples 1 to 20 in the combinations and proportions shown in Table 2 including the alkali metal borate (A) and the lubricant (B) prepared in (1) and other components. Water-based lubricants for plastic working of Comparative Examples 1 to 7 were prepared. All these water-based lubricants had a weight ratio of total solids to water of 15:85. The water-based lubricant was used by adjusting the concentration by diluting with water so that the dried lubricant film had the target film amount. Comparative Example 8 is a typical phosphate / soap treatment.

(5) Film treatment for cold forging test The aqueous lubricant for plastic working of Examples 1 to 19 and Comparative Examples 1 to 7 was applied to a test piece for evaluation to form a lubricating film. The pretreatment and film treatment steps are shown below. In Example 20, a lubricating film is formed by two-stage treatment.
Test piece for evaluation: S45C spheroidized annealing material 25 mmΦ × 30 mm
<Pretreatment and Film Treatment of Examples 1-19 and Comparative Examples 1-7>
(A) Degreasing: Commercially available degreasing agent (Product name: Fine Cleaner 4360, manufactured by Nihon Parkerizing Co., Ltd.) concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 30 seconds ( c) Lubricant film treatment: Water-based lubricant prepared in (4) Temperature 60 ° C., immersion 1 minute (d) Drying: 100 ° C., 10 minutes (e) Dry film amount: about 8 g / m ²
<Pretreatment and film treatment of Example 20>
(A) Degreasing: Commercially available degreasing agent (Product name: Fine Cleaner 4360, manufactured by Nihon Parkerizing Co., Ltd.) concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 30 seconds ( c) Lubricant film treatment (first stage): Water-based lubricant mainly composed of alkali metal borate (A) (d) Temperature 60 ° C., immersion 1 minute Formation of lubricating base film (e) Drying: 100 ° C., 10 Minute (f) Lubricant film treatment (second stage): Water-based lubricant mainly composed of lubricant (B) (g) Temperature 60 ° C., immersion 10 seconds Formation of lubricating layer (h) Drying: 100 ° C., 10 minutes ( i) Dry film amount: about 8 g / m ^{2 in} total (lubricant base: about 6 g / m ² , lubricating layer: about 2 g / m ² )

The pretreatment and film treatment steps of (phosphate / soap treatment) in Comparative Example 8 are shown below.
<Pretreatment and film treatment of Comparative Example 8 (phosphate / soap treatment)>
(A) Degreasing: Commercially available degreasing agent (Product name: Fine Cleaner 4360, manufactured by Nihon Parkerizing Co., Ltd.) concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 30 seconds ( c) Pickling: Hydrochloric acid concentration 17.5%, normal temperature, immersion 10 minutes (d) Washing: tap water, normal temperature, immersion 30 seconds (e) Chemical conversion treatment: Commercial zinc phosphate chemical conversion treatment agent (Product name: Palbond 181X (Manufactured by Nihon Parkerizing Co., Ltd.) Concentration 90 g / L, temperature 80 ° C., immersion 10 minutes (f) Water washing: tap water, room temperature, immersion 30 seconds (g) Soap treatment: Commercially available reactive soap lubricant (Product name: Paloub 235, manufactured by Nippon Parkerizing Co., Ltd.) concentration 70 g / m ² , 85 ° C., immersion 3 minutes (h) drying: 100 ° C., 10 minutes (i) dry film amount: about 10 g / m ²

(6) Cold forging test The lubricity and seizure resistance of the lubricating film that was re-dried after absorbing moisture in a high humidity environment were evaluated by a cold forging test. The test piece coated with the method of (5) was put into a constant temperature and humidity chamber maintained at an air temperature of 30 ° C. and a relative humidity of 70%, and allowed to stand for 40 hours. Thereafter, the test piece was taken out from the constant temperature and humidity chamber, and the test piece was heated with hot air of 200 ° C. for 5 seconds using a jet heater to evaporate the moisture, and then a forging test was performed. In the cold forging test, a spike test process according to the invention of Japanese Patent No. 3227721 was performed, and the maximum load (kNf) and spike height (mm) during the process were measured to evaluate the lubricity. Further, the seizure resistance was evaluated by observing the degree of seizure on the processed surface of the test piece.
Criteria for Spike Test Lubricity Performance Value = Spike Height (mm) / Working Load (kNf) x 100
The greater the value, the better the lubricity. ○: 0.95 or more △: 0.93 or more 0: less than 95 ×: Less than 0.93 Anti-seizure property Burning condition of the processed surface ○: No seizure △: Small seizure ×: Severe seizure

  Table 2 shows the test results in cold forging of the water-based lubricant for plastic working. As is apparent from Table 2, Examples 1-20, which are water-based lubricants for plastic working of metal materials of the present invention, use a hardly crystalline alkali metal borate (A). When re-dried, the cold forging test showed excellent workability (lubricity and seizure resistance). Further, sufficient workability was obtained even when the lubricating film was formed by two-stage treatment as in Example 20. On the other hand, since Comparative Examples 1 to 5 and 7 are those in which the alkali metal borate (A) is easily crystallized after moisture absorption, the lubricity and seizure resistance, which are workability, are greatly inferior to those of the Examples. Moreover, although the comparative example 6 is not crystallized after moisture absorption, since the moisture absorption resistance is very poor, the lubricity and seizure resistance, which are workability, were very inferior. Moreover, the thing which performed the reaction soap process to the phosphate membrane | film | coat of the comparative example 8 shows the outstanding lubricity and anti-seizure property, However, Wastewater treatment and liquid management are required and cannot be used with a simple process process and apparatus. Because of the waste generated in the reaction, the environmental impact is large.

滑剤（Ｂ）について
（Ｂ）−１：ポリエチレンワックス 粒子径０．５μｍ
（Ｂ）−２：パラフィンワックス 粒子径２μｍ
（Ｂ）−３：ポリテトラフルオロエチレン 粒子径０．２μｍ
（Ｂ）−４：二硫化モリブデン 粒子径２μｍ
（Ｂ）−５：グラファイト 粒子径２μｍ
（Ｂ）−６：エチレンビスステアリン酸アマイド 粒子径５μｍ
（Ｂ）−７：メラミンシアヌレート 粒子径０．５μｍ
（Ｂ）−８：Ｎε−ラウロイル−Ｌ−リジン 粒子径１０μｍ
（Ｂ）−９：ステアリン酸カルシウム 粒子径１０μｍ
その他：粘度調整剤（合成ヘクトライト）９％＋界面活性剤１％

About lubricant (B) (B) -1: Polyethylene wax Particle size 0.5 μm
(B) -2: Paraffin wax particle diameter 2 μm
(B) -3: Polytetrafluoroethylene particle diameter 0.2 μm
(B) -4: Molybdenum disulfide particle diameter 2 μm
(B) -5: Graphite particle diameter 2 μm
(B) -6: Ethylene bis-stearic acid amide particle diameter 5 μm
(B) -7: Melamine cyanurate Particle size 0.5 μm
(B) -8: Nε-lauroyl-L-lysine particle size 10 μm
(B) -9: calcium stearate particle diameter 10 μm
Others: Viscosity modifier (synthetic hectorite) 9% + surfactant 1%

  As is apparent from the above description, crystallization of the alkali metal borate (A) due to moisture absorption is suppressed when the metal-based plastic working water-based lubricant of the present invention is used. Workability is obtained. Moreover, since crystallization of the alkali metal borate (A) is suppressed, the corrosion resistance is also good. Therefore, the industrial utility value is extremely large.

Claims (5)

In the aqueous lubricant containing the alkali metal borate (A), the alkali metal borate (A) contains lithium borate, and the molar ratio of lithium to the total alkali metal in the alkali metal borate (A) is 0. 0.1 to 1.0, and the molar ratio (B / M) of boric acid B to alkali metal M of the alkali metal borate (A) is 1.5 to 4.0. The water-based lubricant for metal material plastic working according to claim 1. The metal-based plastic working water-based lubricant according to claim 1, comprising a lubricant (B), and the ratio of the solid content mass of the alkali metal borate (A) to the lubricant (B) (A) / [( A) + (B)] is from 0.10 to 0.97, an aqueous lubricant for plastic working of metal materials. The lubricant (B) is selected from the group consisting of wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, tungsten disulfide, graphite, melamine cyanurate, organically treated synthetic mica, and layered structure amino acid compound. The water-based lubricant for metal material plastic working according to claim 2, wherein the lubricant is at least one kind. A metal material excellent in plastic workability, characterized in that a coating film is formed on the surface of the metal material by applying and drying the water-based lubricant for plastic working of a metal material according to any one of claims 1 to 3. . A lubricant layer containing a lubricant (B) in the second layer after forming a lubricant base film made of an alkali metal borate (A) in the first layer using the water-based lubricant for plastic working of a metal material according to claim 1 A metal material with excellent plastic workability, characterized by forming

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