JP6936702B2 - Method for manufacturing hot-rolled oil for aluminum, hot-rolled coolant for aluminum, and rolled aluminum plate - Google Patents

Description

The present invention relates to a method for producing a hot rolling oil for aluminum, a hot rolling coolant for aluminum, and a rolled aluminum plate.

In hot rolling of aluminum materials (including aluminum and aluminum alloys; the same shall apply hereinafter), hot aluminum for the purpose of ensuring lubricity between the rolling roll and the aluminum material, cooling the rolling roll and the aluminum material, etc. Rolled coolant is used. The coolant is usually an oil-in-water emulsion in which hot rolling oil for aluminum is dispersed in water. Further, the hot rolling oil contains an emulsifier for forming oil droplets of the hot rolling oil in water.

In hot rolling of an aluminum material, the temperature of the coolant rises in the tank of the hot rolling mill or before reaching the rolling roll after being discharged from the tank. When the temperature of the coolant rises, the oil droplets in the coolant coalesce, and the hot rolling oil and water are likely to be separated and the hot rolling oil is likely to float. As a result, the concentration of the hot rolling oil in the coolant is reduced, resulting in a reduction in the amount of plate-out, that is, the amount of hot rolling oil adhering to the surface of the rolling roll after the rolling roll comes into contact with the coolant. If the amount of hot rolling oil adhering to the surface of the rolling roll is insufficient, the lubricity between the rolling roll and the aluminum material may decrease.

In order to avoid such a problem, it is preferable to increase the emulsion stability of the coolant and suppress the coalescence of the oil droplets of the hot rolling oil. However, when the emulsion stability of the coolant is increased, it becomes difficult for the coolant to be emulsified during hot rolling. Therefore, even in this case, the plate-out amount is reduced, which may lead to a decrease in the lubricity between the rolling roll and the aluminum material. Therefore, the coolant is required to have moderately high emulsification stability so as to suppress coalescence of oil droplets of hot rolling oil and to easily emulsify during hot rolling.

In order to adjust the emulsion stability of the coolant to the above-mentioned range, Patent Document 1 contains an organic soap composed of triethanolamine and a fatty acid as an ionic emulsifier, and a polyoxyethylene glycol type as a nonionic emulsifier. Hot rolling oils containing nonionic surfactants are described.

Patent No. 2899224

However, when hot rolling is performed using the hot rolling oil of Patent Document 1, the thickness of the oil film formed between the rolling roll and the aluminum material tends to be uneven, and the thin portion of the oil film is locally formed. Is easy to form. As a result, the friction between the rolling roll and the aluminum material becomes large, which may lead to deterioration of the surface quality of the aluminum material after rolling.

Further, in the conventional hot rolling oil, it is difficult to reduce the unevenness of the thickness of the oil film while appropriately increasing the emulsion stability of the coolant as described above. Therefore, a hot rolling oil having these characteristics and capable of further reducing the friction between the rolling roll and the aluminum material has been desired.

The present invention has been made in view of this background, and is a hot rolling oil for aluminum capable of reducing friction between a rolling roll and an aluminum material, a hot rolling coolant for aluminum containing this hot rolling oil, and a hot rolling coolant for aluminum. An object of the present invention is to provide a method for manufacturing an aluminum rolled plate using this coolant.

One aspect of the present invention is to use 50 to 65% by mass of mineral oil.
Containing 0.70 to 5.0% by mass of a non-ionic emulsifier,
The balance consists of one or more oily agents selected from the group consisting of natural fats and oils, synthetic esters and fatty acids.
The nonionic emulsifier uses deionized water as a solvent and sets a cloud point of an aqueous solution containing 1.0% by mass of the nonionic emulsifier with respect to the total mass of the deionized water and the nonionic emulsifier. At 25 ° C. , an aqueous solution containing the nonionic emulsifier at 1000% by mass based on the total mass of the deionized water and the nonionic emulsifier , which can be heated to ~ 100 ° C. and using deionized water as a solvent. It has the property that the surface tension can be 27 to 32 mN / m.
It is in hot rolling oil for aluminum.

Another aspect of the present invention is the hot rolling coolant for aluminum in which the hot rolling oil for aluminum of the above aspect is dispersed in water.
The conductivity at 25 ° C. is 1000 μS / cm or less.
The content of the hot rolling oil for aluminum is 3 to 10% by volume.
The median diameter of the oil droplets of the hot rolling oil for aluminum based on the volume-based particle size distribution is 1 to 7 μm.
Located in hot rolled coolant for aluminum.

Yet another aspect of the present invention is a method for manufacturing an aluminum rolled plate, which hot-rolls an aluminum material using the hot-rolled coolant for aluminum of the above-described aspect.

The hot rolling oil for aluminum (hereinafter referred to as "hot rolling oil") contains the above-mentioned specific range of mineral oil, nonionic emulsifier and oily agent. Further, the nonionic emulsifier has a property that the cloud point and the surface tension of the aqueous solution using deionized water as a solvent can be set in the specific ranges. The hot rolling oil for aluminum can reduce the friction between the rolling roll and the aluminum material by using a nonionic emulsifier having such characteristics.

That is, since the non-ionic emulsifier has a property that the cloud point of the aqueous solution can be set to 65 to 100 ° C., the hot rolling coolant for aluminum (hereinafter, "coolant") is used in a tank of a hot rolling machine or the like. When the temperature of) rises, it is possible to suppress the coalescence of oil droplets in the coolant. As a result, it is possible to suppress a decrease in the concentration of hot rolling oil in the coolant before reaching the rolling roll, and thus it is possible to suppress a decrease in the plate-out amount. Further, the non-ionic emulsifier can easily emulsify the coolant by contact with the rolling roll. As described above, by using the non-ionic emulsifier, the emulsion stability of the coolant can be appropriately increased.

Further, since the nonionic emulsifier has a property that the surface tension of the aqueous solution can be adjusted to 27 to 32 mN / m, it is possible to suppress excessive miniaturization of oil droplets in the coolant. Thereby, the decrease in the plate-out amount can be suppressed. In addition, the non-ionic emulsifier can appropriately reduce the surface tension of the coolant, making it easier for the coolant to wet and spread on the surface of the rolling roll. As a result, it is possible to reduce the bias of the amount of coolant in contact with the surface of the rolling roll, and thus reduce the bias of the oil film formed on the surface of the rolling roll.

Further, since the coolant easily wets and spreads on the surface of the rolling roll, the moisture in the coolant evaporates rapidly upon contact with the rolling roll, and the hot rolling oil can be efficiently adhered to the surface of the rolling roll.

Therefore, by adding a nonionic emulsifier having the above-mentioned characteristics to the hot rolling oil, the emulsion stability of the coolant can be appropriately increased and the surface tension can be appropriately reduced. As a result, the amount of plate-out, that is, the amount of hot rolling oil adhering to the surface of the rolling roll can be sufficiently increased. Further, according to the hot rolling oil, the wettability of the coolant can be improved and the uneven thickness of the oil film formed on the surface of the rolling roll can be suppressed. Then, the friction between the rolling roll and the aluminum material can be reduced by the synergistic action of these effects.

The coolant is an emulsion in which the hot rolling oil is dispersed in water. The coolant has a conductivity in the specific range, and the content of the hot rolling oil in the coolant and the volume average particle diameter of the oil droplets of the hot rolling oil are each within the specific range. .. The coolant has such a structure and is suitable for hot rolling of aluminum.

It is a side view which shows the main part of the hot rolling carried out for the lubricity evaluation in an Example.

The reason for limiting each component in the hot rolling oil for aluminum will be described.

・ Mineral oil: 50-65% by mass
The hot rolling oil contains mineral oil as a base oil. As the mineral oil, one kind or two or more kinds of mineral oils selected from unrefined mineral oils and refined mineral oils can be used. By setting the content of the mineral oil within the above-mentioned specific range, the emulsion stability of the coolant can be set within an appropriate range while suppressing an increase in the material cost of the hot rolling oil.

When the content of the mineral oil is less than 50% by mass, the content of other components contained in the hot rolling oil increases, which may lead to an increase in material cost. Further, when an aluminum rolled plate is produced using such hot rolling oil, there is a possibility that the production cost of the aluminum rolled plate may increase.

When the content of mineral oil exceeds 65% by mass, the difference between the required HLB value of hot rolling oil, that is, the HLB value that is the optimum emulsified state when made into a coolant, and the HLB value of a nonionic emulsifier. May increase and reduce the emulsion stability. As a result, oil droplets are likely to coalesce in the coolant, which may lead to a decrease in the concentration of hot rolling oil.

As the mineral oil, it is preferable to use refined mineral oil. Refined mineral oil has a lower pour point than unrefined mineral oil and is less likely to solidify in a low temperature environment. Therefore, for example, when the hot rolling oil is stored in a low temperature environment such as an outdoor tank in winter, the freezing of the hot rolling oil in the tank can be suppressed and the handleability of the hot rolling oil can be further improved. ..

As the refined mineral oil, for example, naphthenic refined mineral oil, paraffin refined mineral oil, aromatic refined mineral oil and the like can be used. More specifically, the refined mineral oil includes, for example, SUN40N, SUN100N, SUN500N, SUN2400N, SUNPAR (registered trademark) 110, SUNPAR115, SUNPAR150 (above, Nippon Sun Oil Co., Ltd.); SNH-95, SNH-220 (above). , Sankyo Yuka Kogyo Co., Ltd.), NCL-100, NCL-210 (above, Taniguchi Petroleum Co., Ltd.); EPX-1 (Fuji Kosan Co., Ltd.) and the like can be used.

-Non-ionic emulsifier: 0.70 to 5.0% by mass
The hot rolling oil contains 0.70 to 5.0% by mass of a nonionic emulsifier. By setting the content of the nonionic emulsifier to 0.70% by mass or more, the emulsion stability of the coolant can be appropriately increased and the surface tension of the coolant can be appropriately reduced. From the viewpoint of setting the emulsion stability and surface tension of the coolant in a more preferable range, the content of the nonionic emulsifier is preferably 0.90% by mass or more.

If the content of the nonionic emulsifier is less than 0.70% by mass, the emulsifying ability becomes insufficient, which may lead to a decrease in the emulsion stability of the coolant. Further, in this case, the surface tension of the coolant becomes high, and the wettability to the rolling roll may decrease. As a result, the amount of plate-out is reduced, which may lead to an increase in friction between the rolling roll and the aluminum material.

Further, by setting the content of the nonionic emulsifier to 5.0% by mass or less, it is possible to avoid excessively high emulsion stability of the coolant and easily emulsify the coolant when it comes into contact with the rolling roll. be able to. From the viewpoint of making it easier to emulsify the coolant when it comes into contact with the rolling roll, the content of the nonionic emulsifier is preferably 4.0% by mass or less.

When the content of the nonionic emulsifier exceeds 5.0% by mass, the emulsifying ability becomes excessively high, so that the coolant is less likely to be emulsified when it comes into contact with the rolling roll. Further, in this case, the oil droplets in the coolant tend to become finer. As a result, the amount of plate-out is reduced, which may lead to an increase in friction between the rolling roll and the aluminum material.

Further, the nonionic emulsifier uses deionized water as a solvent and sets a cloud point of an aqueous solution containing 1.0% by mass of the nonionic emulsifier with respect to the total mass of the deionized water and the nonionic emulsifier. The surface tension of an aqueous solution containing the nonionic emulsifier at 25 ° C. at 65 to 100 ° C. and 1000 mass ppm with respect to the total mass of the deionized water and the nonionic emulsifier using deionized water as a solvent. It has a characteristic that can be 27 to 32 mN / m.

The nonionic emulsifier having a cloud point of 65 ° C. or higher in the aqueous solution can suppress the coalescence of oil droplets in the coolant when the temperature of the coolant rises in the tank of a hot rolling mill or the like. .. As a result, it is possible to suppress a decrease in the concentration of hot rolling oil in the coolant in the tank of the hot rolling mill or the like. From the viewpoint of further enhancing the effect of suppressing the coalescence of oil droplets, it is preferable to use a nonionic emulsifier having a cloud point of 75 ° C. or higher in the aqueous solution.

When a nonionic emulsifier having a cloud point of less than 65 ° C. in the aqueous solution is used, the effect of suppressing the coalescence of oil droplets in the coolant is reduced, and the concentration of hot rolling oil in the coolant is reduced. It will be easier. As a result, the amount of plate-out is reduced, which may lead to an increase in friction between the rolling roll and the aluminum material.

Further, the nonionic emulsifier having a cloud point of 100 ° C. or lower in the aqueous solution can easily emulsify the oil droplets in the coolant when the coolant and the rolling roll come into contact with each other. Thereby, the amount of plate-out, that is, the amount of hot rolling oil adhering to the surface of the rolling roll when the coolant and the rolling roll come into contact with each other can be increased.

When a nonionic emulsifier having a cloud point of more than 100 ° C. in the aqueous solution is used, the coolant may be less likely to be emulsified when it comes into contact with the rolling roll. As a result, the amount of plate-out is reduced, which may lead to an increase in friction between the rolling roll and the aluminum material.

The cloud point can be measured by the following method. First, an aqueous solution containing 1.0% by mass of the nonionic emulsifier with respect to the total mass of the deionized water and the nonionic emulsifier is prepared. After the temperature of the aqueous solution is set to 20 ° C., the appearance of the aqueous solution is visually observed while gradually increasing the temperature, and the temperature at the time when the aqueous solution begins to become cloudy can be set as the cloud point. The deionized water refers to water that has been deionized and has a conductivity of 10 μS / cm or less at 25 ° C. As the deionization treatment, for example, a filtration treatment using a reverse osmosis membrane or an ion exchange treatment using an ion exchange resin or an electroregenerative ion exchange device can be adopted.

The nonionic emulsifier having a surface tension of 32 mN / m or less in the specific aqueous solution can appropriately reduce the surface tension of the coolant and improve the wettability of the coolant with respect to the surface of the rolling roll. As a result, unevenness in the thickness of the oil film formed between the rolling roll and the aluminum material can be reduced, and hot rolling oil can be efficiently adhered to the surface of the rolling roll. From the viewpoint of further enhancing these effects, it is preferable that the surface tension of the specific aqueous solution is 31 mN / m or less.

When a nonionic emulsifier having a surface tension of more than 32 mN / m in the specific aqueous solution is used, the surface tension of the coolant becomes high and it becomes difficult for the coolant to wet and spread on the surface of the rolling roll. As a result, the unevenness of the thickness of the oil film formed on the surface of the rolling roll becomes large, which may lead to an increase in friction between the rolling roll and the aluminum material.

Further, the nonionic emulsifier having a surface tension of 27 mN / m or more in the specific aqueous solution can appropriately increase the surface tension of the coolant. As a result, when the coolant is subjected to shear stress due to stirring of the coolant in the tank of the hot rolling mill, discharge of the coolant to the outside of the tank, etc., it is possible to prevent the oil droplets in the coolant from becoming finer. Can be done. Thereby, the plate-out amount can be increased. From the viewpoint of further enhancing the effect of suppressing the miniaturization of oil droplets, it is preferable that the surface tension of the specific aqueous solution is 28.5 mN / m or more.

When a nonionic emulsifier having a surface tension of less than 27 mN / m in the specific aqueous solution is used, oil droplets in the coolant tend to be finely divided by shear stress. As a result, the amount of plate-out is reduced, which may lead to an increase in friction between the rolling roll and the aluminum material.

The surface tension can be measured by the following method. First, an aqueous solution containing 1000 mass ppm of non-ionic emulsifier with respect to the total mass of deionized water and non-ionic emulsifier is prepared. The temperature of this aqueous solution is kept at 25 ° C., and the value of the surface tension measured by the Wilhelmy method can be used as the surface tension. The deionized water used for measuring the surface tension is the same as the deionized water used for measuring the cloud point.

Examples of the nonionic emulsifier include polyoxyalkylene branched decyl ether, polyoxyethylene tridecyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene isodecyl ether, and polyoxyethylene lauryl ether. , Polyoxyalkylene lauryl ether, polyoxyethylene alkyl ether, polyalkylene alkyl ether, polyoxyalkylene oleyl cetyl ether, polyoxyethylene polyoxypropylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycol, Polyoxyethylene fatty acid ester and the like can be used. These compounds may be used alone or in combination of two or more.

Further, in the hot rolling oil, a non-ionic emulsifier having the above-mentioned characteristics, that is, a cloud point and a surface tension, as long as the action and effect of the non-ionic emulsifier having the above-mentioned characteristics are not impaired. A non-ionic emulsifier in which at least one of the above is outside the specific range may be further contained.

-Oil-based agent The hot-rolled oil contains an oil-based agent. The amount of the oily agent in the hot rolling oil can be, for example, 20% by mass or more. By setting the amount of the oil-based agent to 20% by mass or more, an oil film containing the oil-based agent can be adhered to the surface of the rolling roll. As a result, the friction between the rolling roll and the aluminum material can be reduced.

As the oily agent, for example, one or more compounds selected from the group consisting of natural fats and oils, synthetic esters and fatty acids can be used. As the natural fats and oils, vegetable oils and animal oils containing an ester of fatty acid and glycerin as a main component can be used. More specifically, for example, hylinol saflower oil, hyoleic saflower oil, soybean oil, hyel chic rapeseed oil, low elsic rapeseed oil, palm oil, palm kernel oil, cottonseed oil, palm oil, rice bran oil, sesame oil, sunflower. Natural fats and oils such as oil, flaxseed oil, olive oil, tung oil, camellia oil, peanut oil, capoc oil, cacao oil, wood wax, sunflower oil, corn oil, pork fat, and beef fat can be used.

As the natural fat and oil, it is preferable to use one or more of palm oil, palm kernel oil, palm oil, olive oil, high elsic rapeseed oil, high oleic safflower oil and beef tallow. Since these natural fats and oils contain a relatively large amount of esters of fatty acids having a large number of carbon atoms and glycerin, friction between the rolling roll and the aluminum material can be further reduced. From the viewpoint of further reducing the friction between the rolling roll and the aluminum material, it is preferable to use one or more of palm oil, palm kernel oil, coconut oil, and beef tallow as natural fats and oils.

As the synthetic ester, a carboxylic acid ester obtained by a condensation reaction of an alcohol and a carboxylic acid can be used. As the carboxylic acid to be subjected to the condensation reaction, one or more compounds selected from the group consisting of saturated fatty acids and unsaturated fatty acids can be adopted. The structure of the hydrocarbon chain in these compounds may be a linear structure, a branched chain structure or a cyclic structure. Further, the carboxylic acid may be a monobasic acid or a polybasic acid having a dibasic acid and a higher ionizable proton.

More specifically, examples of the carboxylic acid include capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, eicosenoic acid, behenic acid, erucic acid and the like. Can be used.

As the alcohol to be subjected to the condensation reaction, a monohydric alcohol may be used, or a polyhydric alcohol may be used. As the monohydric alcohol, for example, butyl alcohol or the like can be used. As the polyhydric alcohol, for example, ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol and the like can be adopted. From the viewpoint of further reducing the friction between the rolling roll and the aluminum material, it is preferable to use one or more of neopentyl glycol, trimethylolpropane, and pentaerythritol as the polyhydric alcohol.

When a polyhydric alcohol is used as the alcohol, the synthetic ester may be a full ester in which all the hydroxyl groups of the polyhydric alcohol are esterified, or a partial ester in which some hydroxyl groups of the polyhydric alcohol are esterified. You may. From the viewpoint of improving the lubricity during hot rolling, it is preferable to increase the ratio of the full ester in the synthetic ester.

In the synthetic ester, the carbon number of the constituent unit derived from the carboxylic acid is preferably 10 or more and 24 or less. By setting the number of carbon atoms of the constituent unit derived from the carboxylic acid to 10 or more, the friction between the rolling roll and the aluminum material can be further reduced. Further, by setting the number of carbon atoms of the constituent unit derived from the carboxylic acid to 24 or less, it is possible to suppress an increase in the viscosity of the hot rolling oil. Therefore, by setting the carbon number of the constituent unit derived from the carboxylic acid to the above-mentioned specific range, it is possible to avoid deterioration of handleability due to an increase in the viscosity of the hot rolling oil, and between the rolling roll and the aluminum material. Friction can be further reduced.

As the fatty acid, one or more fatty acids selected from the group consisting of fatty acids having 10 to 22 carbon atoms can be used. By setting the number of carbon atoms of the fatty acid to 10 or more, the friction between the rolling roll and the aluminum material can be further reduced. Further, by setting the number of carbon atoms of the fatty acid to 22 or less, the fatty acid can be easily dissolved in the hot rolling oil.

The fatty acid may be a saturated fatty acid or an unsaturated fatty acid. Further, the structure of the hydrocarbon chain in these fatty acids may be any of a linear structure, a branched chain structure and a cyclic structure. More specifically, as fatty acids, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, eicosenoic acid, behenic acid, erucic acid and the like are used. Can be used.

-Alkanolamine: 0.10 to 1.0% by mass
The hot rolling oil may further contain an alkanolamine as an anionic emulsifier. The content of alkanolamine can be, for example, 0.10 to 1.0% by mass. By adding the above-mentioned specific range of alkanolamines to the hot rolling oil, the emulsion stability of the coolant is adjusted, the amount of plate-out is increased, and the oil film formed between the rolling roll and the aluminum material is formed. The unevenness of the thickness of the roll can be further reduced. As a result, the friction between the rolling roll and the aluminum material can be further reduced.

As the alkanolamine, for example, triethanolamine, diethanolamine, methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine, ethanolamine, dimethylethanolamine, diethylethanolamine, dipropylethanolamine, dibutylethanolamine and the like can be used. can. These compounds may be used alone or in combination of two or more.

-Other additives In the hot rolling oil, further, an antioxidant for suppressing the oxidation of the hot rolling oil, an antiseptic for suppressing the spoilage of the hot rolling oil, and lubricity during rolling. It may contain an extreme pressure agent or the like for improving the above. As the antioxidant, for example, sulfur compounds such as alkylphenols, aromatic amines, sulfide oils and fats and sulfide olefins can be used. As the preservative, for example, a phenol-based compound, a formaldehyde donor compound, a sultylanilide-based compound, or the like can be used. As the extreme pressure agent, for example, phosphorus compounds such as tricresyl phosphate and dilauryl hydrogenated phosphite, sulfur compounds such as sulfide fats and oils and sulfide olefins can be used.

The viscosity characteristics of the hot rolling oil are not particularly limited, but for example, the kinematic viscosity at 40 ° C. can be appropriately set from the range of ^{20 to 80 mm 2 / sec.} By setting the kinematic viscosity at 40 ° C. to 20 mm ² / sec or more, the friction between the rolling roll and the aluminum material can be further reduced. From the viewpoint of further reducing the friction between the rolling roll and the aluminum material, it is more preferable that the ^{kinematic viscosity at 40 ° C. is 30 mm 2 / sec or more.}

Further, by setting the kinematic viscosity at 40 ° C. to 80 mm ² / sec or less, the hot rolling oil can be more easily fed. Further, in this case, the oil droplets of the hot rolling oil can be more easily dispersed in water. From the viewpoint of further improving the liquid transfer property and more easily dispersing the oil droplets, it is more preferable that the ^{kinematic viscosity at 40 ° C. is 60 mm 2 / sec or less.}

-Courante The coolant can be prepared by mixing the hot rolling oil and water and dispersing oil droplets of the hot rolling oil in water. The conductivity of the coolant at 25 ° C. shall be 1000 μS / cm or less. By setting the conductivity of the coolant within the above-mentioned specific range, it is possible to apply a repulsive force due to electrostatic repulsion to the oil droplets of the hot rolling oil and suppress the coalescence of the oil droplets. As a result, it is possible to avoid a decrease in the emulsion stability of the coolant. From the viewpoint of further enhancing the emulsion stability of the coolant, it is preferable that the conductivity of the coolant at 25 ° C. is 700 μS / cm or less.

When the conductivity of the coolant at 25 ° C. exceeds 1000 μS / cm, the repulsive force due to the electrostatic repulsion between the oil droplets of the hot rolling oil tends to be small. Therefore, in this case, oil droplets are likely to coalesce, which may lead to a decrease in emulsification stability.

The content of the hot rolling oil in the coolant is 3 to 10% by volume. As a result, the lubricity during hot rolling can be maintained in an appropriate range. When the content of the hot rolling oil is less than 3% by volume, the amount of the hot rolling oil adhering to the surface of the rolling roll is insufficient, which causes an increase in friction between the rolling roll and the aluminum material. There is a risk.

On the other hand, when the content of the hot rolling oil exceeds 10% by volume, the amount of water is relatively insufficient, so that the cooling efficiency of the rolling roll may decrease. From the viewpoint of further improving the cooling efficiency of the rolling roll, the content of the hot rolling oil is preferably 8% by volume or less.

The median diameter of the oil droplets of the hot rolling oil dispersed in the coolant is 1 to 7 μm. As a result, the lubricity during hot rolling can be appropriately improved and the emulsion can be stabilized. When the median diameter of the oil droplets is less than 1 μm, a boiling film is likely to be formed between the oil droplets in the coolant and the surface of the rolling roll during hot rolling. Therefore, the amount of hot rolling oil supplied to the rolling roll may be insufficient, resulting in a decrease in lubricity. On the other hand, when the median diameter of the oil droplets exceeds 7 μm, the oil droplets in the emulsion are likely to float due to buoyancy, and in some cases, the hot rolling oil and water may be separated.

The median diameter of the oil droplets described above is the cumulative median diameter in the volume-based particle size distribution obtained by the laser diffraction / scattering method. A laser diffraction / scattering type particle size distribution measuring device (for example, “LA-950” manufactured by HORIBA, Ltd.) can be used for measuring the median diameter of oil droplets.

Examples of the hot rolling oil and a coolant containing the hot rolling oil will be described. The method for producing the hot rolling oil, coolant and aluminum rolled plate according to the present invention is not limited to the following aspects, and the configuration can be appropriately changed as long as the gist thereof is not impaired.

In this example, first, each component was mixed at the ratio shown in Tables 1 to 4 to prepare hot rolling oil (testing agents 1-38). The specific contents of the components listed in Tables 1 to 4 are as follows.
-Mineral oil Mineral oil A1: Naphthenic acid refined mineral oil (manufactured by Nippon Sun Oil Co., Ltd., kinematic viscosity at 40 ° C 99.1 mm ² / sec)
Mineral oil A2: Naphthenic refined mineral oil (manufactured by Nippon Sun Oil Co., Ltd., kinematic viscosity at 40 ° C, 420.6 mm ² / sec)

・ Oil-based agent Natural fat: Refined palm oil (manufactured by Miyoshi Oil & Fat Co., Ltd., kinematic viscosity at 40 ° C, 39 mm ² / sec)
Synthetic ester: Trimethylolpropane trioleic acid ester (NOF CORPORATION "Unistar (registered trademark) H381R")
Fatty acid: Oleic acid (manufactured by Wako Pure Chemical Industries, Ltd., 18 carbon atoms)
Non-ionic emulsifier Non-ionic emulsifier B1: Neugen (registered trademark) NL-Dash410 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 66 ° C., surface tension 31.4 mN / m)
Non-ionic emulsifier B2: Neugen TDS-90 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 67 ° C., surface tension 28.3 mN / m)
Non-ionic emulsifier B3: Neugen SD-80 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 80 ° C., surface tension 27.3 mN / m)
Non-ionic emulsifier B4: Neugen XL-140 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 100 ° C., surface tension 27.7 mN / m)
Non-ionic emulsifier B5: Neugen NL-100 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 100 ° C., surface tension 31.0 mN / m)

Non-ionic emulsifier B6: Neugen LF-100X (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 73 ° C., surface tension 31.8 mN / m)
Non-ionic emulsifier B7: Neugen NL-80 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 76 ° C., surface tension 28.5 mN / m)
Non-ionic emulsifier B8: Neugen SD-70 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 64 ° C., surface tension 26.2 mN / m)
Non-ionic emulsifier B9: Neugen ET-160 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 100 ° C. or higher, surface tension 37.6 mN / m)
Non-ionic emulsifier B10: Neugen CL-230 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., cloud point 56 ° C., surface tension 33.7 mN / m)

・ Anionic emulsifier Triethanolamine (manufactured by Mitsui Chemicals, Inc.)
Diethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.)
Na sulfonate ("SUL465" manufactured by MORESCO Co., Ltd.)

The cloud point and surface tension of the nonionic emulsifier are values measured by the following methods.

Regarding the cloud point, first, tap water was deionized using an ion exchange resin to prepare deionized water having a conductivity of 10 μS / cm or less at 25 ° C. A nonionic emulsifier was dissolved in this deionized water to prepare an aqueous solution containing 1.0% by mass of the nonionic emulsifier with respect to the total mass of the deionized water and the nonionic emulsifier. After the temperature of the aqueous solution was adjusted to 20 ° C., the appearance of the aqueous solution was visually observed while gradually increasing the temperature, and the temperature at the time when the aqueous solution began to become cloudy was defined as the cloud point.

Regarding the surface tension, after preparing deionized water in the same manner as described above, the nonionic emulsifier is dissolved in the deionized water, and the non-ionic emulsifier is 1000 mass ppm with respect to the total mass of the deionized water and the nonionic emulsifier. An aqueous solution containing an ionic emulsifier was prepared. The temperature of this aqueous solution was kept at 25 ° C., and the value of the surface tension measured by the Wilhelmy method was taken as the above-mentioned surface tension.

<Evaluation of hot rolling oil>
The kinematic viscosities of the test agents 1 to 38 prepared as described above were measured at 40 ° C. using a Canon-Fenceke viscometer by a method based on JIS K2283. The kinematic viscosities of each test agent at 40 ° C. were as shown in Tables 1 to 4.

<Evaluation of coolant>
First, tap water was deionized using an ion exchange resin to prepare deionized water having a conductivity of 10 μS / cm at 25 ° C. Further, sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd., purity 99.5%) was dissolved in this deionized water to prepare water whose conductivity was adjusted to either 1000 μS / cm or 1800 μS / cm. The conductivity was measured by the AC bipolar method. As a measuring device, "Portable Electric Conductivity System ES-71" manufactured by HORIBA, Ltd. was used.

The deionized water thus obtained, water having a conductivity adjusted to 1000 μS / cm, or water having a conductivity adjusted to 1800 μS / cm was used as a dispersion medium, and the concentrations shown in Tables 1 to 4 were used. A coolant was prepared by dispersing the test agents 1-38 in the dispersion medium. The conductivity of each coolant at 25 ° C. was as shown in Tables 1 to 4.

Using this coolant, the emulsion stability, plate-out property and lubricity were evaluated by the following methods. The coolants obtained in this example were all oil-in-water emulsions. The volume average particle diameter of the oil droplets in the test agents 24, 28, 30 and 37 was 0.3 to 0.8 mm, and the volume average particle diameter of the oil droplets in the other test agents was 1 to 7 μm. ..

-Emulsification stability A separatory funnel filled with 400 mL of coolant was placed in a constant temperature bath at 65 ° C. and allowed to stand for 60 minutes with the cock facing downward. After 60 minutes, the cock of the separating funnel was opened, and 100 mL of the coolant discharged from the legs of the separating funnel was collected first and 100 mL was discharged last. _{Then, the concentration V i} [volume%] of the hot rolling oil in the first discharged 100 mL coolant _{and the concentration V f} [volume%] of the hot rolling oil in the last discharged 100 mL coolant were measured.

The emulsification stability index ESI, which indicates the stability of the emulsion in an emulsified state, can be expressed by the following formula (1) using _{the concentrations V i} and V _{f of these hot rolling oils.}
ESI = V _i / V _f ... (1)

The values of the emulsion stability index of the coolant containing each test agent were as shown in Tables 1 to 4. If the value of the emulsion stability index exceeds 0.8, the symbol "A +" is displayed in the "evaluation" column of Tables 1 to 4, and if it is 0.7 or more and 0.8 or less, the same column is used. The symbol "A" is entered in the column, and if it is less than 0.7, the symbol "B" is entered in the same column.

In the evaluation of emulsion stability, it is shown that the closer the value of the emulsion stability index is to 1.0, the less likely it is that oil droplets coalesce and the oil droplets are less likely to settle. Therefore, the cases of the symbols "A +" and "A" in which the value of the emulsion stability index is 0.7 or more are passed because they have excellent emulsion stability and can suppress the coalescence of oil droplets in the coolant. Was judged. Further, in the case of the symbol "B" in which the value of the emulsion stability index is less than 0.7, the emulsion stability is inferior and the coalescence of oil droplets in the coolant is likely to occur, so that the result is determined to be unacceptable.

-Plate-out property An aluminum block having a length of 80 mm, a width of 25 mm, and a thickness of 5 mm was prepared, and while the temperature of the aluminum block was maintained at 100 ° C., a coolant heated to 65 ° C. was sprayed onto the aluminum block. The conditions for spraying the coolant were a discharge pressure of 0.3 MPa and a discharge time of 0.1 ms.

After cooling the aluminum block, the coolant was dried in a desiccator for 24 hours to remove water in the coolant. The mass (unit: g) of the test agent attached to the dried aluminum block was measured. Then, the value obtained by converting the mass of this test agent into the mass per unit area (unit: g / m ² ) was defined as the plate-out amount.

The plate-out amount of each test agent was as shown in Tables 1 to 4. Further, when the plate out amount exceeds 1.1 g / m ^2, the symbol "A +" to "evaluation" column of Table 1 to Table 4, in the case of 0.7~1.1g / m ² is The symbol "A" is entered in the same column, and the symbol "B" is entered in the same column when ^{the weight is less than 0.7 g / m 2.}

In the evaluation of the plate-out property, it is shown that the larger the plate-out amount, the more easily deemulsification occurs when it comes into contact with the rolling roll, and a large amount of hot rolling oil can be attached to the surface of the rolling roll. Therefore, the cases of the symbols "A +" and "A" in which the plate-out amount is 0.7 g / m ² or more are judged to be acceptable because the amount of hot rolling oil adhering to the surface of the rolling roll can be increased. Further, in the case of the symbol "B" in which the plate-out amount is ^{less than 0.7 g / m 2} , it was judged to be unacceptable because the amount of hot rolling oil adhering to the surface of the rolling roll may be insufficient.

-Lubricity An aluminum material 1 having a width of 40 mm, a length of 500 mm, and a thickness of 5.0 mm made of a JIS A5182 alloy was prepared and pre-rolled at a rolling reduction of 20%. Next, a pair of rolling rolls 2 having an arithmetic mean roughness Ra of 0.3 to 0.4 μm and a maximum height Rz = 3.5 to 4.0 μm when measured in the plate width direction (FIG. 1) was prepared. The surface roughness of the rolled roll was adjusted by polishing the surface of the roll in the rolling direction using abrasive paper.

As shown in FIG. 1, the aluminum material 1 was hot-rolled with a plurality of punches 21 attached to the side surfaces of one of the rolling rolls 2 (2a, 2b). The rolling conditions for hot rolling were as follows.
Plate temperature at the start of rolling: 450 ° C
Rolling speed: 40m / min
Reduction rate: 60%

_{After the hot rolling is completed, the distance L 1} [mm] between the punches 21 in the circumferential direction of the rolling roll 2a _{and the distance L 2} between the punch marks 11 transferred to the aluminum material 1 are measured, and the following equation ( The advanced rate δ was calculated based on 2).
δ = (L ₁ −L ₂ ) / L ₁・ ・ ・ (2)

Apart from this, the roll diameter R [mm] of the rolling roll 2, the Poisson's ratio ν of the rolling roll 2, the young ratio E [kgf / mm ² ] of the rolling roll 2, the rolling load P [kgf], the aluminum material before rolling. Using the values of the plate thickness h ₁ [mm] of 1, the plate thickness h ₂ [mm] of the aluminum material 1 after rolling, and the plate width b [mm] of the aluminum material 1, rolling based on the following formula (3). The flat roll diameter R ₂ [mm] of the roll 2 was calculated.
R ₂ = R × {1 + 16 × (1-ν ² ) × P / [π × E × b × (h ₁ −h ₂ )]} ・ ・ ・ (3)

Then, using the results of the formulas (2) to (3) and the value of the rolling reduction ratio r, the coefficient of dynamic friction μ between the rolling roll 2 and the aluminum material 1 was calculated based on the following formula (4).
μ = 0.5 × [(h ₁ −h ₂ ) / R ₂ ] ^0.5 / {1-2 × [(1-r) × δ / r] ^0.5 } ・ ・ ・ (4)

In the above formulas (2) to (4), the plate thickness h ₁ of the aluminum material 1 before rolling is 5.0 [mm], the plate thickness h ₂ after rolling is 2.0 [mm], and the rolling reduction ratio r. Was 0.6, and the plate width b was 40 [mm]. The roll diameter R of the rolling roll 2 was 80 [mm], the Poisson's ratio ν was 0.33, and the Young's modulus E was 21000 [kgf / mm ² ]. The Poisson's ratio ν and Young's modulus E are typical values of steel for rolling rolls.

The values of the dynamic friction coefficient μ obtained as described above are shown in the “Dynamic friction coefficient” column of Tables 1 to 4. Further, in the "evaluation" column in Tables 1 to 4, the symbol "A +" is displayed when the dynamic friction coefficient is 0.30 or less, and the symbol "A" is displayed when the coefficient is more than 0.30 and 0.35 or less. When it exceeds .35, the symbol "B" is described.

In the evaluation of lubricity, it is shown that the smaller the value of the coefficient of dynamic friction, the higher the lubricity between the rolled roll and the aluminum material, and the smoother the surface of the rolled plate can be. Therefore, the cases of the symbols "A +" and "A" in which the coefficient of kinetic friction is 0.35 or less are judged to be acceptable because the increase in the surface roughness of the rolled plate can be sufficiently suppressed. Further, the case of the symbol "B" in which the coefficient of kinetic friction exceeds 0.35 was determined to be unacceptable because it may cause an increase in the surface roughness of the rolled plate.

As shown in Tables 1 to 3, the test agents 1 to 23 contain mineral oil, an oily agent, and a nonionic emulsifier. Moreover, these contents are within the said specific range. The non-ionic emulsifiers contained in the test agents 1 to 23 have a property that the cloud point and surface tension in the specific aqueous solution can be set within the specific range. Therefore, these test agents were excellent in emulsification stability and plate-out property, and could reduce the friction between the rolling roll and the aluminum material.

On the other hand, as shown in Tables 3 and 4, the non-ionic emulsifiers in the test agent 24 and the test agent 33 have a property that the surface tension in the specific aqueous solution is lower than the specific range. .. Therefore, the oil droplets in the coolant were made finer, and the amount of plate-out was smaller than that of the test agents 1 to 23. As a result, the friction between the rolling roll and the aluminum material increased for these test agents.

The nonionic emulsifier in the test agent 25 and the test agent 34 has a property that the surface tension in the specific aqueous solution becomes higher than the specific range. Therefore, the coolant is less likely to wet and spread on the surface of the rolling roll, and the amount of plate-out is smaller than that of the test agents 1 to 23. As a result, the friction between the rolling roll and the aluminum material increased for these test agents.

The non-ionic emulsifier in the test agent 26 and the test agent 35 has a property that the surface tension in the specific aqueous solution is higher than the specific range and the cloud point is higher than the specific range. .. Therefore, the coolant is less likely to wet and spread on the surface of the rolling roll, and the amount of plate-out is smaller than that of the test agents 1 to 23. As a result, the friction between the rolling roll and the aluminum material increased for these test agents. In addition, these test agents had lower emulsification stability than the test agents 1 to 23.

The test agent 27 and the test agent 36 contained less nonionic emulsifier than the above-mentioned specific range. Therefore, the coolant is less likely to wet and spread on the surface of the rolling roll, and the amount of plate-out is smaller than that of the test agents 1 to 23. As a result, the friction between the rolling roll and the aluminum material increased for these test agents.

The test agent 28 and the test agent 37 contained a nonionic emulsifier higher than the specific range. Therefore, the oil droplets in the coolant were made finer, and the amount of plate-out was smaller than that of the test agents 1 to 23. As a result, the friction between the rolling roll and the aluminum material increased for these test agents.

Since the content of the mineral oil in the test agent 29 was higher than the above-mentioned specific range, the concentration of the nonionic emulsifier was low. As a result, the emulsion stability was lower than that of the test agents 1 to 23. Further, in the test agent 29, the concentration of the oil-based agent became low, so that the friction between the rolling roll and the aluminum material increased.

Since the content of the nonionic emulsifier in the test agent 30 was higher than the above-mentioned specific range, the oil droplets in the coolant were made finer. Further, in the coolant containing the test agent 30, the concentration of the hot rolling oil in the coolant was lower than the above-mentioned specific range. As a result, the amount of plate-out of the test agent 30 was smaller than that of the test agents 1 to 23, and the friction between the rolling roll and the aluminum material was increased.

The test agent 31 contained a non-ionic emulsifier less than the above-mentioned specific range. Further, in the coolant containing the test agent 31, the concentration of the hot rolling oil in the coolant was higher than the above-mentioned specific range. As a result, the emulsion stability of the test agent 31 was lower than that of the test agents 1 to 23.

Since water having high conductivity was used as the dispersion medium for the coolant containing the test agent 32, the conductivity of the coolant became higher than the above-mentioned specific range. Therefore, in this coolant, the repulsive force due to the electrostatic repulsion between the oil droplets became small. As a result, the emulsification stability of the test agents 32 was lower than that of the test agents 1 to 23.

In the coolant containing the test agent 38, the concentration of the hot rolling oil in the coolant was lower than the above-mentioned specific range. Therefore, the emulsion stability of the test agent 38 was lower than that of the test agents 1 to 23.

Claims (4)

With 50-65% by mass of mineral oil,
Containing 0.70 to 5.0% by mass of a non-ionic emulsifier,
The balance consists of one or more oily agents selected from the group consisting of natural fats and oils, synthetic esters and fatty acids.
The nonionic emulsifier uses deionized water as a solvent and sets a cloud point of an aqueous solution containing 1.0% by mass of the nonionic emulsifier with respect to the total mass of the deionized water and the nonionic emulsifier. At 25 ° C. , an aqueous solution containing the nonionic emulsifier of 1000 mass ppm with respect to the total mass of the deionized water and the nonionic emulsifier , which can be set to ~ 100 ° C. and using deionized water as a solvent. It has the property that the surface tension can be 27 to 32 mN / m.
Hot rolling oil for aluminum. The hot rolling oil for aluminum according to claim 1, wherein the hot rolling oil for aluminum further contains 0.10 to 1.0% by mass of alkanolamine as an anionic emulsifier. The hot rolling coolant for aluminum according to claim 1 or 2, wherein the hot rolling oil for aluminum is dispersed in water.
The conductivity at 25 ° C. is 1000 μS / cm or less.
The content of the hot rolling oil for aluminum is 3 to 10% by volume.
The median diameter of the oil droplets of the hot rolling oil for aluminum based on the volume-based particle size distribution is 1 to 7 μm.
Hot rolled coolant for aluminum. A method for manufacturing an aluminum rolled plate, wherein hot rolling of an aluminum material is performed using the hot rolling coolant for aluminum according to claim 3.

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