JP3135728B2 - Cold rolling method of aluminum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cold rolling aluminum (including an aluminum alloy), and more particularly to a method for rolling a sheet material which is excellent in lubricating properties and which does not generate oil stain when the rolled sheet is annealed. The present invention relates to a method for cold rolling aluminum using an aqueous emulsion lubricant which has good oil-water separation properties and can be used in a stable and circulating manner.

[0002]

2. Description of the Related Art Generally, in cold rolling of aluminum, a low-viscosity mineral oil is rolled in order to obtain good surface properties and to prevent the generation of annealing residues (oil stainless steel) in the annealing step after rolling. It is used as a lubricant. Mineral oil is excellent in that it can obtain an aluminum plate with good gloss, but the cooling capacity of the rolled plate and rolls is inferior, so in high-speed, high-pressure rolling, the temperature rise of the rolled plate and rolls is remarkable, There is a problem that it is difficult to control the shape of the plate material and there is a risk of fire.

In order to solve this problem, a water-soluble lubricant for cold rolling aluminum has been proposed. However, the conventional water-soluble lubricant is an emulsion formed by mixing rolling oil and water together with an emulsifier, and has a problem that the emulsifier may cause the oil stain. In order to solve this problem, the present inventors have previously proposed an aqueous emulsion formed from a mixture of a specific α-olefin, a specific alkoxyalkyl ester and a refined mineral oil as an emulsifier-free aluminum cold rolling lubricant. Suggested. (Japanese Patent Application No. 3-261997) This aqueous emulsion is formed by pumping a mixture of the specific α-olefin, the specific alkoxyalkyl ester and the refined mineral oil into high-pressure water using the mixer shown in FIG. Although it has excellent rolling lubrication properties, in the cold rolling of aluminum, there is a strong demand for high-speed rolling and high-pressure rolling from the viewpoint of thinning, quality improvement and productivity improvement of aluminum products. In view of environmental requirements for circulation, regeneration, and reuse of lubricants, development of lubricants that are more excellent in lubricity and that can be circulated and reused in a stable manner has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention relates to the formation of the above-mentioned aqueous emulsion, which was previously developed by the present inventors, when ordinary city water was used as the water to be mixed. It has been found that the lubricity and oil-water separation of the emulsion may not be sufficient, and that the lubrication and oil-water separation may be reduced even if the water after oil-water separation is reused. It was made as a result of intensive studies on the relationship between the properties of the formed emulsion and the lubricity and oil-water separation properties of the formed emulsion, the purpose of which was to improve the previously developed water-based emulsion to achieve even better rolling lubricity and It provides oil-water separation so that high-speed rolling and high-pressure rolling can be performed stably, and a lubricant with stable properties can be supplied even when circulated and reused. And to provide a cold rolling process of aluminum was so that.

[0005]

According to the present invention, there is provided a method for cold rolling aluminum according to the present invention, which comprises mixing a self-emulsifying rolling oil and water to form an emulsion containing no emulsifier. A cold rolling method of aluminum for supplying the emulsion as a lubricant, wherein the emulsion used as a lubricant has a basic basic feature that the average particle size of the emulsion is 20 to 50 μm; As water to mix, pH: 5.0-6.2, conductivity: 1
5 μs or less, temperature: 25 to 75 ° C, ion content
The second feature of the construction is that water having a property of 3 ppm or less is used, and ion-exchanged water is used as water to be mixed with a rolling oil having self-emulsifying properties. The water content in the separated oil was 1000 ppm or less, the oil content in the separated water was 1000 ppm or less, the separated oil and the separated water were used as rolling oil and water for forming an emulsion, and the oil-water separation was used. The ion exchange of the separated water is performed in the third, fourth, and fifth configurations, respectively.
The feature of.

FIG. 2 is an explanatory view of a method for cold rolling aluminum according to the present invention. An emulsion 4 formed by introducing high-pressure water from a water tank 2 into a mixer 1 shown in detail in FIG.
Of the rolling mill 6 and the rolled aluminum material M
To supply. The used lubricant is recovered and enters the oil / water separator 7 where it is separated into oil 8 and water 9, each of which has a filter 1.
It is filtered by 0 and 11 and circulated to the oil tank 3 and the water tank 2.

In the present invention, as a rolling oil having no self-emulsifying properties, for example, a rolling oil composed of 40 to 95% by weight of an α-olefin, 5 to 20% by weight of an alkoxyalkyl ester, and a balance of refined mineral oil, polypropylene, polyisobutylene and polybutene are used. 80-95wt of base oil consisting of at least one or more
5 to 90% by weight of α-olefin in 8 to 93% by weight of a base oil composed of at least one of polypropylene oil, polyisobutylene and polybutene in which 5 to 20% by weight of alkoxyalkyl ester is added. A rolling oil to which 2 to 20% by weight of at least one of ester and glycerin derivatives is added can be used.

[0008] The particle size of the formed emulsion greatly affects lubricity and oil-water separation. The more uniform and large the particle size of the emulsion, the better the rolling lubricity and the better the oil-water separation characteristics. In order to obtain good lubricity and oil-water separation in cold rolling of aluminum, the average particle size of the emulsion is preferably in the range of 20 to 50 μm. If the average particle size is less than 20 μm, oil-water separation is not sufficient, and if the average particle size exceeds 50 μm, the amount of the emulsion supplied to the interface between the rolling roll and the surface of the aluminum material to be rolled tends to be uneven, Oil pits and seizure failure may occur partially.

[0009] The particle size and stability of the emulsion are particularly affected by the nature of the water to be mixed. When the water to be mixed is tap water or industrial water, the average particle size of the formed emulsion is as small as 5 to 25 μm, which causes unstable lubricity and oil-water separation of the emulsion. Among the properties of water, factors that particularly affect the properties of the emulsion include pH, conductivity, temperature, and Na, Ca, Cl, S
It is the content of ions such as O ₄ , Fe, and CO ₃ .

The emulsion formed according to the present invention is charged. If the pH is high, the emulsion particles repel each other to make the particle size smaller and more stable. On the other hand, when the pH is low, the emulsion particles tend to coalesce and become coarse. To make the average particle size of the emulsion 20-50 μm, use water
It is necessary to limit the pH to the range of 5.0 to 6.2. When the conductivity of water increases, the electrolyte concentration in the water increases, and Na ions, Ca ions, etc. react with fatty acids in the rolling oil to form metal soap, and the particle size of the emulsion tends to be reduced. In addition, it deteriorates rolling lubricity and oil-water separation.
In order to prevent deterioration, it is preferable to adjust the conductivity of water to 15 μs or less.

If the temperature of the water mixed with the rolling oil to form an emulsion is too high, the viscosity of the base oil decreases and lubricity becomes insufficient. Further, the particle size of the emulsion tends to be coarse and non-uniform, and surface defects such as oil pits and abrasion due to non-lubrication tend to occur during rolling. The optimal water temperature is in the range of 25-75 ° C. Na ion, Ca ion, Cl ion, SO ₄ ion, Fe ion, CO contained in water
_Since various ions such as _three ions react with the base oil and impair the lubricating performance, it is preferable to limit each to 3 ppm or less. It is desirable that the water whose properties are adjusted in this way be subjected to ion exchange in order to further maintain the water quality.

The emulsion used for rolling is collected in the oil / water separator 7 as described above, and is separated into oil and water by means such as centrifugation or a fiber membrane separator. in this case,
If the water content in the separated oil is large, the filtration pressure in the subsequent filtration step is increased, so that the water content in the separated oil 8 is 10%.
It is preferable to reduce it to not more than 00 ppm. For the separated oil, microfiltration is performed using diatomaceous earth and terra alba as a filter aid,
Removes fine aluminum abrasion powder contained in the separated oil. The separated water 9 is subjected to diatomaceous earth filtration or filtration using a paper filter to remove relatively large aluminum powder contained in the separated water. In this case as well, it is preferable to limit the amount of oil in the separated water to 1000 ppm or less, and if it exceeds 1000 ppm, clogging of the paper filter is likely to occur, shortening the life of the paper filter, and reusing the separated water. In this case, the concentration of the emulsion formed tends to be uneven. The separated oil and the separated water are circulated to the oil tank 3 and the water tank 2 after being treated as described above, respectively, and are reused. Since there is a possibility that the water is generated, the water is treated with a cartridge filter, an ion exchange resin and an activated carbon filter immediately before returning to the water tank 2 in order to maintain the water quality. Known heaters and cooling devices are disposed in the water tank 2 to maintain the water temperature within a range of 25 to 75 ° C.

[0013]

According to the constitution of the present invention, a self-emulsifying rolling oil and water are mixed to form an emulsion containing no emulsifier, and the average particle size of the emulsion is limited to the range of 20 to 50 μm. Rolling lubrication characteristics and oil-water separation characteristics can be maximized, and this emulsion is supplied to a rolling roll and an aluminum material to be rolled as a lubricant. The used emulsion is recovered, separated into oil and water, and the separated oil and separated water can be stably reused as rolling oil and water in the same property range as before use.

[0014]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 Tap water was treated with an ion exchanger (pure water apparatus manufactured by Kurita Technical Service Co., Ltd.), and various ions were added to obtain water having different pH and conductivity. PH of each sample water, conductivity,
Table 1 shows the water temperature and the ion content. These sample waters were rolled with a rolling oil composed of 90 wt% of polypropylene and 10 wt% of butyl glycol stearate and a mixer shown in FIG. 1 to have a rolling oil pressure of 0.8 MPa, a water pressure of 0.3 MPa, and a total flow rate of 4 MPa.
An emulsion was formed by mixing under mixing conditions of 1 / min.
The average particle size of the emulsion formed with each sample water was measured using a laser diffraction / scattering particle size distribution analyzer (L
A700) and shown in Table 1.

Next, each emulsion shown in Table 1 was supplied as a lubricant for rolling an aluminum alloy, the rolling load was measured, and the presence or absence of oil pits in the rolled aluminum material was observed. Rolling is performed using a JIS 5052 alloy sheet containing 1.2 to 2.8 wt% of Mg with a thickness of 1.2 mm, a width of 70 mm and a length of 70 mm as a material to be rolled.
It was rolled under the condition of 35 m / min. Rolling load measurement is 60% reduction
And the observation of the oil pit was carried out with a microscope. Further, the emulsion after rolling was recovered, separated into oil and water by a centrifugal separator, and the water content and oil content of the separated oil and separated water were measured, respectively. Table 2 shows the measurement results.

[0016]

[Table 1] << Table Notes >> 1. The number of samples in the emulsion particle size measurement was 5. 2. Sample water No. 11 is the ion-exchanged water obtained by collecting after rolling and separating oil and water.

As shown in Table 1, in accordance with the present invention, various ions are ion-exchanged and are limited to 3 ppm or less, and the conductivity is 14.9 or less.
μs or less, the emulsion formed by mixing the sample water whose water temperature was adjusted to 25 to 75 ° C. was uniform with an average particle size of 20.1 to 45.9 μm, and these emulsions were supplied as a lubricant to perform cold rolling. When the test was performed, as shown in Table 2, the rolling load was small, and no generation of oil pits was observed on the surface of the rolled aluminum material. The amount of water in the separated oil and the amount of oil in the separated water were also small, indicating excellent oil-water separation characteristics.

[0018]

[Table 2]

Comparative Example 1 As in Example 1, using ion-exchanged tap water,
Sample water with different pH, conductivity and ion content was prepared, an emulsion was formed using the same rolling oil as in Example 1, and under the same mixing conditions as in Example 1, and the same rolling and oil-water separation as in Example 1 were performed. Then, the rolling load, the presence or absence of an oil pit, and oil-water separation characteristics were examined. The results are shown in Tables 3 and 4. Note that items outside the scope of the present invention are underlined.

[0020]

[Table 3] << Table Notes >> 1. The number of samples in the emulsion particle size measurement was 5. 2. Sample water No. 21 is separated water (without ion exchange) obtained by rolling and rolling for one week, separating oil and water.

As shown in Table 4, the sample water No. 12
Since it was as high as 6.5, the particle size of the formed emulsion was too small, and both the lubricity and the oil-water separation property were reduced. No.1
Since the pH of Sample No. 3 was too low at 4.8, the emulsion particle size was large and the fluctuation was large, and oil pits were generated. No.14
, No. 15 and No. 17 had high contents of Na, Ca, Cl and Fe ions, so that the oil-water separation property was deteriorated. In No. 16, the content of SO ₄ ions was large, the conductivity was high, and the average particle size of the emulsion was large, and generation of oil pits was recognized. No.18
Because of the high content of CO ₃ ions, the conductivity was high and the pH was high, so that the particle size of the formed emulsion was too small and both the lubricity and the oil-water separation property declined. No.19 is
Since the water temperature was as low as 20 ° C., the particle size of the emulsion was small, and the oil-water separation property was not good. In No. 20, since the water temperature was as high as 80 ° C., the particle size of the emulsion was large and the fluctuation was large, and oil pits were generated on the rolled material surface. No. 21 was circulated without filtration for one week, so the content of Ca, Cl, Fe ions increased, the conductivity increased, and the pH was high, so the particle size of the emulsion was fine, and the rolling property decreased. Deterioration of oil-water separation characteristics was observed.

[0022]

[Table 4]

[0023]

As described above, according to the method for cold rolling aluminum of the present invention, an emulsion having excellent lubricating properties can be supplied as a lubricant, so that the rolling load is reduced and high-speed, high-pressure rolling is possible. Further, since the emulsion of the present invention has good oil-water separation characteristics, it is possible to stably circulate and use the separated oil and the separated water after the oil-water separation.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a mixer for forming an emulsion used in the present invention.

FIG. 2 is an explanatory view of cold rolling of aluminum of the present invention.

[Description of Signs] 1 Mixer 2 Water tank 3 Oil tank 4 Emulsion 5 Nozzle 6 Rolling machine 7 Oil-water separator 8 Separated oil 9 Separated water 10 Filter 11 Filter M Rolled aluminum material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C10M 105: 38) C10N 20:00 20:06 30:00 40:24 (56) References JP-A-5-57314 (JP, A) JP-A-2-151309 (JP, A) JP-A-59-10412 (JP, A) JP-A-48-50167 (JP, A) JP-A-62-192496 (JP, A) JP-A-3 -268812 (JP, A) JP-A-62-288693 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1/00-11/00 B21B 45/02 C10M 173/00

Claims (5)

(57) [Claims] 1. An emulsion used as a lubricant in a cold rolling method of aluminum in which a self-emulsifying rolling oil and water are mixed to form an emulsion containing no emulsifier and the emulsion is supplied as a lubricant. A cold-rolling method for aluminum, characterized in that the average grain size of the aluminum is 20 to 50 μm. 2. The method according to claim 1, wherein ion-exchanged water is used as the water to be mixed with the self-emulsifying rolling oil. 3. Water to be mixed with a self-emulsifying rolling oil, pH: 5.0 to 6.2, conductivity: 15 μs or less, temperature: 2
2. The method according to claim 1, wherein water having properties of 5 to 75 [deg.] C. and an ion content of 3 ppm or less is used. 4. A rolling oil for separating the lubricating oil after rolling into oil and water so that the water content in the separated oil is 1000 ppm or less and the oil content in the separated water is 1000 ppm or less, and the separated oil and the separated water are formed into a rolling oil and an oil. The cold rolling method for aluminum according to claim 1, wherein the method is used as water. 5. The method for cold rolling aluminum according to claim 3, wherein the separated water obtained by oil-water separation is subjected to ion exchange.