JPS5928360B2 - Cold rolling method of steel plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to improve rolling lubricity by precoating a steel plate with a polar substance and increasing the amount of emulsion rolling oil that adheres to the steel plate during cold rolling.

In the cold rolling of steel plates, palm oil, beef tallow,
Oils and fats such as are often used.

How to use: Forcibly stir oil and fat with hot water for 10 minutes.
It is sprayed at a high concentration of ~20 parts.

In this case, the lubricity is excellent, but since it is a non-circulating type, it is unavoidable that the amount of rolling oil used is high.

On the other hand, when rolling relatively thick plates that do not require a very high level of lubricity, it is recommended to use mineral oil as the main component or a mixture of mineral oil and oil as the main component, add an emulsifier, and then apply hot water to the rolling process. Emulsion type rolling oil is used after being emulsified.

It is well known that the lubricity of emulsion type rolling oils is greatly affected by the quality of emulsification.

That is, if the emulsifying property is too good, the emulsion will be stable and will be difficult to break when it hits the surface of the steel plate by spraying, and the amount of rolling oil that will adhere to the steel plate will be small, resulting in poor lubricity.

If the emulsification is poor, the emulsion will be unstable and a large amount of rolling oil will adhere to the steel plate, but since the rolling oil tends to separate and float to the surface, it is difficult to control the concentration and stable rolling operations cannot be performed.

The present invention improves the conflicting properties between the emulsifying properties of rolling oil and the rolling lubrication performance, thereby achieving excellent emulsifying properties for cold rolling of ultra-thin plates that require a high level of lubricity. Oil-based emulsion rolling oil can be reused.

That is, in the present invention, a small amount of a water-insoluble polar substance that does not contain an emulsifier is prerecorded on the surface of a steel sheet during cold rolling, and the steel sheet is rolled with a commercially available mineral oil-based or oil-based emulsion rolling oil with excellent emulsifying properties. It has been found that rolling performance is greatly improved compared to using only emulsion rolling oil.

The reason why the rolling performance improves so much is that even a stable emulsion easily adsorbs the pre-coated polar substances, resulting in an increase in the amount of oil adhering to the steel plate.
Since the lubricity of the pre-coated polar substance itself is relatively hard, it is thought that this is due to the synergistic effect of the two.

Furthermore, when the polar substance used in the present invention was added as a component of the emulsion rolling oil, the lubricity was only slightly improved;
No significant performance improvement was observed as in the case of pre-coating.

For this reason, even if a polar substance is added as a rolling oil component, the adsorption force is limited by the emulsifying effect of the emulsifier, so it does not have much effect on increasing the amount of rolling oil deposited, and as a result, rolling performance is reduced. However, it is thought that the improvement will not be significant.

Conventionally, pre-coating oil has been applied when winding up a steel plate after pickling, but the purpose of this is to prevent rust on the pickled steel plate, and to prevent the steel plates from sticking together by tightening when winding up the steel plate. Used to prevent scratches.

In this case, the precoat oil has almost no purpose of significantly improving rolling performance using low-concentration emulsion oil in the subsequent process, and is therefore generally used in cold rolling to minimize the negative effect on the cold rolling in the subsequent process. An oil with the same composition as the emulsion-type rolling oil, or an oil with almost similar composition, is used.

In the present invention, we researched the use of a polar substance that exhibits properties completely different from emulsified rolling oil as a pre-coat material, and found that a water-insoluble polar substance that does not contain an emulsifier as described below is used as a simple or polar substance. It has been found that the rolling performance of a low concentration emulsion is significantly improved only when a composition containing 20% or more of the substance in mineral oil is precoated.

If the polar substance has a coefficient of less than 20, the characteristics will approximate those of a non-polar substance, and the effects of the polar substance will hardly be exhibited.

Therefore, in the present invention, the best performance is obtained when the polar substance is used alone, but mineral oil may be contained to the extent that the effect of the polar substance is not impaired.

Next, the polar substance used in the present invention will be specifically explained.

(1) Organic phosphorus compounds Phosphoric esters are most suitable as organic phosphorus compounds, and alkyl phosphoric esters, alkylaryl phosphoric esters, etc. are also suitable, as well as phosphoric esters of polyoxyethylene alkyl allyl ether with polyoxyethylene added, and polyoxyethylene alkyl phosphates. It is preferable to use phosphoric esters of ethers, phosphoric esters of polyoxyethylene fatty acids, and the like.

These phosphoric acid esters include partial esters, saturated esters,
Good results can be obtained with any of the above and a mixture of the two.

The number of carbon atoms in the alkyl group of these phosphoric esters is 10.
The above is preferable.

In view of the gist of the present invention, it is not preferable if the number of carbon atoms is small or if the polyoxyethylene phosphate ester has a large number of ethylene oxides and is hydrophilic.

(2) Suitable amines include saturated or unsaturated aliphatic amines such as laurylamine, stearylamine, and oleylamine, as well as secondary and tertiary amines, as well as benzylamine, dicyclohexylamine, etc. Aromatic amines and cyclic amines can also be used.

Among amines, water-soluble amines such as alkanolamines are unsuitable for the precoat of the present invention.

Furthermore, fatty acid salts of amines produced by the reaction of the above-mentioned amines and fatty acids can also be used.

(3+ Alcohol Suitable alcohols include saturated or unsaturated aliphatic alcohols such as lauryl alcohol, stearyl alcohol, and oleyl alcohol, and aromatic alcohols such as benzyl alcohol.

In addition, aliphatic and cyclic polyhydric alcohols can also be used, but hydrophilic ones are not suitable.

(4) Fatty acids include fatty acids from animal oils such as beef tallow, liver fat, and wool fat, fatty acids from vegetable oils such as rapeseed oil, castor oil, and palm oil, and hydrogenated fatty acids thereof, as well as lauric acid, myristic acid, stearic acid, Straight chain saturated fatty acids such as oleic acid, linoleic acid, unsaturated fatty acids such as oleic acid, linoleic acid, oxyfatty acids, amino fatty acids, isofatty acids, synthetic fatty acids, etc. are suitable.

(5) Examples of fatty acid esters of monools include cetacean cormorant,
Natural waxes such as beeswax and other high-grade waxes are suitable.
Waxes synthesized from alcohols and fatty acids can also be used.

(6) Regarding polyhydric alcohols, fatty acid esters of polyalkylene glycol can be used as one type of fatty acid ester, and polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, etc. are suitable.

Suitable fatty acids used for esterification are those explained in the section on fats and fats above.

In addition, as fatty acid esters of other polyhydric alcohols, fatty acid esters and saturated esters of polyhydric alcohols that do not have a neopentyl nucleus and have three or more OH groups can be used, such as glycerin, polyglycerin, hexitol, mannitol, Single fatty acid partial esters and saturated esters such as glycose, saccharose anhydrone rubitol, and mixtures of two or more are suitable.

Suitable fatty acids used for esterification are those explained in the section on fatty acids above.

Furthermore, fatty acid partial esters and saturated esters of polyhydric alcohols having a neopentyl nucleus can also be used as fatty acid esters of other polyhydric alcohols, such as pentaerythritol, dipentaerythritol, neopentyl glycol, trimethylolethane, trimethylolpropane, Single fatty acid partial esters and fatty acid saturated esters, as well as mixtures of two or more thereof, are suitable.

Suitable fatty acids to be used in the ester are those explained in the section on fatty acids above.

In order to improve lubricity by precoating a polar substance as described above, the precoat amount is 0.01El/
m: Excellent effects can be obtained above.

However, considering that the amount of rolling oil deposited after normal rolling without pre-coating is 0.3 g/m" to 0.5 g/m", economically the amount of pre-coating is 0.39.
/ m” or less is desirable.

Next, the method of applying the precoat material of the present invention is to use it as a pickling oil when pickling a steel plate and winding it up;
There are two methods: spraying a polar substance onto the steel plate between the stands of a rolling mill or applying it with a cotton roll, and applying it to a roll and transferring it to the steel plate during rolling to pre-coat it for subsequent rolling. be.

In addition, the rolling method according to the present invention requires the use of an extra pre-coating material in addition to the original rolling oil that is circulated in an emulsified form. It is much more economical than the method of spraying at 20%) and not recycling.

Next, embodiments of the present invention will be described.

Table 1 shows the results of testing the rolling performance of combinations of precoat materials and commercially available emulsion type rolling oil.

The rolling test was conducted in the following manner. [Steel plate]: 0.6 m/m (thickness) x 100 m/m (width) coil low carbon steel plate [Rolling mill]: Double rolling mill work roll 200 m/m x 250 m/mφ
[Rolling speed]: 200 m7 minutes [Rolling rate]: Approximately 30% [Application of precoat material]: Lauryl alcohol, lauryl amine, oleic acid, etc. shown in Table 1, which are liquid at room temperature (20 to 25°C) As is, semicircular ones such as organic phosphoric acid esters, stearic acid monoglyceride, pentaerythritol tallow diester, etc. are heated to 40℃, and solid ones such as stearic acid, beeswax, sorbitan monostearate, etc. was heated to 60° C. and applied to the surface of a steel sheet before rolling by electrostatic spraying.

The amount of pre-coat can be adjusted for each pre-coat; after getting stuck, we conducted a preliminary test, determined the spray pressure and threading speed conditions for the steel plate to achieve the target coating amount, and applied the coating to the steel plate before rolling under the same conditions.

[Emulsion rolling fluid]: Commercially available beef tallow-based emulsion rolling oil (55% beef tallow + 37% mineral oil, 5% lubricity-improving additive, 3% emulsifier, weight ratio) and mineral oil-based emulsion rolling oil (87% mineral oil, lubrication A property-enhancing additive (10% emulsifier, 3 parts weight ratio) was used at a concentration of 3% wt.

The method for producing emulsion oil is to add the above-mentioned emulsion type rolling oil heated to 50°C little by little to hot water preheated to around 40°C while vigorously stirring it with a stirrer so that the roughness is 3%. The temperature of the emulsion oil was finally adjusted to 40° C. while stirring was continued for an additional 30 minutes.

Regarding palm oil, 20% w of palm oil was heated to 90℃ while vigorously stirring hot water that had been preheated to 90℃.
The mixture was added little by little to achieve a concentration of t, and stirring was continued for an additional 30 minutes.

[Emulsion rolling liquid supply method] The emulsion was sprayed into the roll squeezing opening at a spray pressure of 1.5 to 2.0 kg/crit.

[Rolling index (RI)]: A steel plate is rolled through a predetermined roll gap, and it is determined by comparing the elongation rate of standard oil and the elongation rate of the rolling method according to the present invention.

Palm oil was used as the standard oil.

The rolling index (RI) is calculated using the following formula l: Gauge distance of the steel plate after rolling by the method according to the present invention (m/m) lo: Gauge distance of the steel plate after rolling with standard oil (m/m) However, before rolling The distance between steel plate gauges was 300 mm.

In addition, the amount of rolling oil deposited was measured on the total surface area of the steel plate after rolling.
A test piece of di was cut out and measured using an organic solvent extractor using a Soxhlet extractor.

Examples are shown in Table 1.

The above rolling index (RI) will be explained in more detail.

In the example, first rolling was performed using palm oil and the rolling reduction was 30.
% (i.e. gauge distance after rolling is 390u+
The roll gap was adjusted so that the roll gap was fixed, and rolling was performed according to the method of the present invention, and l in the formula for calculating the RI was calculated.

In this case, from the above formula, ■ It is stipulated that

Therefore, for example, in the case of RI-110, the distance between the gauges after rolling is l = 399 mm, so the length of the gauge distance when rolled with palm oil is 90 mm (390 mm - 3001 nT
In this case, the distance between the gauges is 99 m for L).
m (399-300 mm), which means that the elongation rate is 10% higher than the rolling length of palm oil.

From Table 1, it can be seen that rolling according to the present invention greatly improves rolling performance.

That is, when rolling is carried out using a recirculated low-concentration oil-based emulsion rolling oil without precoating (Comparative Example 1), the rolling performance is 10% inferior to rolling using palm oil (RI is 0.
9).

Also, when pre-coated with non-polar mineral oil (Comparative Example 2)
When a commercially available emulsion-type rolling oil containing an emulsifier in addition to a polar substance is precoated (Comparative Example 3), hardly any improvement in rolling performance can be expected.

On the other hand, when rolling with a low-concentration oil-based emulsion rolling oil by precoating the polar substance according to the present invention, there are cases where the rolling performance is improved by as much as 30% compared to high-concentration rolling with palm oil (in Example 7, the RI is 1.3)0 Furthermore, in the case of mineral oil-based emulsion rolling oil, Example 1
As shown in Example 1 and Example 12, although the oil-based emulsion rolling oil is not as good as the other, it is clearly observed that the rolling properties are sufficiently improved.

Claims (1)

[Scope of Claims] 1. During cold rolling of steel sheets, the following water-insoluble water-insoluble groups that do not contain emulsifiers a: Organophosphorus compounds b Amines or their salts C Alcohols d Fatty acids e Fatty acid esters of monools F Fatty acids of polyhydric alcohols Cold rolling of a steel sheet, characterized in that the surface of the steel sheet is pre-coated with one or more polar substances consisting of esters, and then rolled using mineral oil-based or fat-based emulsion rolling oil containing an emulsifier. Law.