JPH02169694A - Oil for cold rolling of steel plate - Google Patents

Abstract

PURPOSE:To obtain the title oil excellent in seizure resistance and capable of both reducing the rolling load and improving the gloss by incorporating a specified amount of a polyalkyl methacrylate having a specified molecular weight into a base oil comprising a specified monoester. CONSTITUTION:0.3-5wt.% polyalkyl methacrylate having a molecular weight of 5,000 to 50,000 [e. g. a polylauryl methacrylate (of an average molecular weight of 20,000)] is incorporated into a base oil comprising a monoester of the formula R-COO-R' (R is an alkyl group of a fatty acid; P' is an alkyl group of an alcohol) wherein the total number of carbon atoms of P and R' is 23 or less and the difference in the number of carbon atoms between R and R' is at least 9 (e. g. methyl laurate), thus giving an oil for cold rolling of a steel plate. This rolling oil is excellent in heat scratch resistance in cold rolling of a stainless steel plate in particular, can reduce the rolling load, and can improve the gloss; therefore, it is effectively utilized for cold rolling of a stainless steel plate excellent in gloss.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a rolling oil used in the cold rolling of steel plates, particularly stainless steel plates, which has excellent seizure resistance and can reduce rolling load. This invention relates to a rolling oil that can improve gloss.

(Prior art) Cold rolling oil used when cold rolling steel sheets has the ability to reduce the number of friction between the work roll and the rolled material (hereinafter referred to as roll bite), reduce frictional heat generation, etc. Performance (hereinafter referred to as lubricity) is required to suppress the rolling load and to suppress the occurrence of seizure flaws (heat scratches).

The lubricity is determined by how much lubricating oil (rolling oil) is introduced into the roll-by 1- and the amount of lubricating oil 115! Strength is determined by how much it can withstand temperature increases due to processing heat and frictional heat.

In order to introduce a large amount of lubricating oil, it is effective to increase the viscosity of the lubricating oil.
The publication contains a high molecular compound (polymer) to increase viscosity.
A lubricant is shown using this as a base oil.

However, when lubricating oil is introduced into the rolled material, fine irregularities called oil pits (oil pools) are formed on the surface of the rolled material, reducing the surface gloss. Therefore, in the rolling of materials such as stainless steel sheets that require excellent surface gloss, it is inappropriate to increase the amount of lubricant introduced I to improve lubricity. Therefore, in order to obtain excellent gloss, it is necessary to reduce the amount of lubricant introduced, but if the amount introduced is too small, lubrication becomes insufficient and the work roll and the rolled material are likely to seize. When burn-in occurs, the surface texture deteriorates and the gloss decreases again.

Therefore, it is important to maintain lubricity with a small amount of lubricant introduced. In order to maintain lubricity even when the amount introduced is small, compounds that can be adsorbed or reacted with steel sheets and exhibit lubricity up to high temperatures are blended into rolling oil. 82
JP-201994 discloses a lubricating oil to which diester or monoester is added.

(Problems to be Solved by the Invention) These compounds exhibit lubrication performance by adsorption or chemical reaction on the surface of steel sheets, and they exhibit sufficient lubrication performance when they easily react, such as low carbon steel sheets. be able to.

However, in the case of a stainless steel plate whose surface is covered with a stable oxide film, adsorption and chemical reactions are difficult to occur, and the lubricating effect is not sufficiently exerted.

In addition, many compounds with excellent lubricity are polymeric,
Therefore, it has the disadvantage that it has a high viscosity and tends to form oil bits, and when blended as a rolling oil, it is necessary to make adjustments such as blending low-viscosity mineral oil or the like to lower the viscosity. However, since low viscosity mineral oil has extremely poor lubricity, rolling oils containing this have reduced lubricity and cannot achieve the purpose.

The present invention has been made in order to eliminate these drawbacks of the conventional technology, and provides a cap with excellent lubricity that can reduce the occurrence of heat scratches and reduce the rolling load, and has an excellent surface gloss after rolling. The object of the present invention is to provide a cold rolling oil for steel plates that can produce steel plates, particularly stainless steel plates.

(Means for solving the problem) It is not easy to find compounds that easily chemically react with stainless steel and exhibit lubricating properties, and even if it were possible to find them, they would be It corrodes the surface of the steel plate and causes rust, damaging its luster. Therefore, the inventor considered a mixed state (referred to as mixed lubrication) in which the lubrication state during cold rolling is a combination of boundary lubrication, which is controlled by the reaction and adsorption force of compounds, and fluid lubrication, which is controlled by the viscous resistance of the lubricant film. As a result, as mentioned above, it is difficult to expect boundary lubrication for stainless steel plates, so lubricants for driftwood lubrication (
The idea was to improve the performance of rolling oil (rolling oil).

In other words, it reduces the shear resistance (viscous resistance) of the lubricant introduced into the roll bite, lowers the coefficient of friction, and prevents compounds adsorbed on the rolls and steel plates from thermally deteriorating or desorbing due to heat generated by friction. The inventors of the present invention, who considered maintaining lubricity through the lubrication process, studied various compounds with low coefficients of friction in mixed lubrication to fluid lubrication conditions, and arrived at the present invention.

That is, the gist of the present invention is that in a monoester synthesized from a fatty acid and an alcohol, R and R' shown in the following formula
The base oil is a monoester in which the sum of carbon numbers is 23 or less and the difference in carbon numbers between R and R' is 9 or more, and 0.3 to 5 polyalkyl methacrylates having a molecular weight of 5,000 to 50,000 are added to this base oil. There is a cold rolling oil for steel sheets characterized in that only % of the above amount is added.

R-COO-R' R: alkyl group of fatty acid nl R': Alkyl group on alcohol side (for A1τ) The reasons for the limitations of the present invention will be explained in detail below.

It is generally known that under fluid lubrication conditions, compounds with low viscosity have a low coefficient of friction.

However, the inventor found that even if the viscosity is the same, rf1ty! ! It was found that the coefficients were different. That is, monoesters formed from fatty acids and alcohols have a lower If! friction coefficient than other monoesters containing arsenic, especially when the sum of the carbon numbers of R and R' is 23 in the case shown in the following equation. and R
If the carbon number difference between and R' is 9 or more, f' is low! ! Furthermore, when polyalkyl methacrylate having a molecular weight of 5,000 to 50,000 is added in an amount of 0.3 to 5 7% by weight, the friction coefficient decreases dramatically.

Therefore, the sum of the carbon numbers of R and Ro should be 23 or less, and R and R
The difference in carbon number of o was set to be t9 or more, the molecular weight of the polyalkyl methacrylate was set to 5000 to 5oooo, and the addition type thereof was set to 0.3 to 5% by weight.

R-COO-R' In the formula, R is fat Mffl! Indicates an alkyl group of I, R.

represents an alkyl group on the alcohol side.

Furthermore, the performance of the present invention does not change even if various conventionally used additives such as antioxidants and rust preventives are added to the cold rolling oil of the present invention. Even if such substances are added, the performance will not change in any way.

(Example) Hereinafter, the present invention will be explained to 3Y41fJ along with Examples.

No. in Table 1 for 1 kettle, No. in Table 2 for monoesters 1 to 7
, 1.4% by weight of polyalkyl methacrylate-I of 3 (
The rolling oils shown in Examples 1 to 7 in FIG. 1 were prepared by adding 1% double weight of Sanyo's "Hisei Niia Croup 727)".

In the same way, 2% by weight of the polyalkyl methacrylate was added to the monoester Nos. 8 to 15 in Table 1 and mineral oil to make the polyalkyl methacrylate 1.4% (Sanyo Kasei Near Group 727). Rolling oils of Comparative Examples 1 to 8 were created.

Products commercially available as polyalkyl methacrylates (for example, Acroup 727, etc.) are as shown in Table 2.
~50% by weight of diluent oil such as mineral oil and is not a pure substance.

Therefore, Examples 1 to 7 and Comparative Examples both contain a small amount of mineral oil. Hereinafter, unless otherwise specified, the amount of polyalkyl methacrylate will be expressed in net liters calculated based on the polymer purity (content 1) of the product.

Table 1 Table 2 X1! [mu]ji215 Using methyl palmitate as a base oil, various polyalkyl methacrylates 1 to 1 shown in Table 2 were added in the proportions shown in Fig. 2 to prepare the rolling oils of Examples 8 to 15 in Fig. 2.

Comparative Examples 9 to 2 were prepared by using methyl palmitate as a base oil and adding various polyalkyl methacrylates shown in Table 2 in the proportions shown in FIG. 12 was created.

The friction coefficients of these Examples and Comparative Examples were compared and measured, and the results are shown in FIGS. 1 and 2.

In addition, the test method for friction (JA'l&) was as follows.

(Test Conditions) Each Example and Comparative Example was tested under the conditions shown in Table 3 in the two-cylindrical rolling and sliding large friction tester shown in FIG. 3, the rotational torque was measured, and the friction coefficient was determined.

In addition, the coefficient of friction in the case where no polymer was added was also measured for the 9th time, and the results are shown in FIG.

(Test Results) (1) Test results for limiting the carbon number of monoesters Roll rotation speed 100 ram for various monoesters shown in Table 1, Examples 1 to 7, and Comparative Examples 1 to 8
, and the results of a friction test at 700 rpm are shown in FIG.

As is clear from the figure, the friction coefficient is lower at high speed of 70 Oram than at lateral speed of 100 rpm, indicating a lubrication state in which the amount introduced is large and the ratio of fluid lubrication is high.

Regarding monoesters alone, 70 of monoesters in which n + R' is 23 or less and IR-4'l is 9 or more.
The friction coefficient at 0 r9- is low, and the friction coefficients of monoesters and compounds outside this range are high, and these compounds are No. 2 in Table 2.

When polyalkyl methacrylate I shown in 4 is added, 1
00 rps + time r! The J friction coefficient decreases significantly, and the friction coefficient at 700 ram also decreases.

For monoesters in which fl+R' and l R-R' l are outside the above-mentioned ranges, the friction coefficient decreases little due to the addition of polyargyl methacrylate.

(2) Test results regarding the type of polymer and the limitations of Addition 1. In order to further investigate the phenomenon in which the r'J friction coefficient decreases significantly when a specific monoester polymer is added, methyl valmitate was used as a base oil. The friction coefficients were measured when the various polymers shown in No. 2 were added (Examples 8 to 15 and Comparative Examples 9 to 12), and the results are shown in FIG.

Polyalkyl methacrylate has a higher I than polybutene.
? Although the reduction in friction coefficient is remarkable, if the molecular weight is less than 5,000, the effect is small, and if it exceeds 50,000, the viscosity after addition becomes high and the friction coefficient at 700 rpm becomes high, which is not preferable.

In addition, the amount of polyalkyl methacrylate added is 0.2
! At In%, the effect is small, and when it exceeds 5%, the viscosity becomes high and the coefficient of friction at 700 ram becomes high.

From the test results shown above, the monoester (n-coo-rt') to be used in the rolling oil of the present invention is one in which the sum of the carbon numbers of R and R' is 23 or less, and the number of carbon atoms of R and n' is 23 or less. Furthermore, the polymer added thereto is limited to polyalkyl methacrylate with a molecular weight of 5,000 to 50,000, and the amount added is 0.3 to 5.
11J1%.

In addition to the compounds shown in Table 1, the monoesters of the present invention include ethyl laurate, methyl myristate, ethyl myristate, propyl myristate, butyl myristate, ethyl palmitate, propyl palmitate, butyl palmitate, and palmitic acid. Octyl, methyl stearate, propyl stearate, hexyl stearate,
Ethyl oleate, propyl oleate, butyl oleate, hexyl oleate, methyl arachiate, ethyl arachiate, isopropyl arachiate, isobutyl arachiate, aracyl propionate, stearyl propionate, oleyl propionate, cetyl propionate, propionic acid Myristyl, lauryl propionate, aracyl butyrate, stearyl butyrate, isostearyl butyrate, oleyl butyrate, cetyl butyrate, myristyl acetate, lauryl butyrate, stearyl caproate, instearyl caproate, oleyl caproate, cetyl caproate, myristyl caproate, capryl Examples include cetyl acid, aracyl methacrylate, isostearyl methacrylate, oleyl methacrylate, cedyl methacrylate, myristyl methacrylate, and lauryl methacrylate.

Further, in order to confirm the lubrication performance of the rolling oil according to the present invention based on the results of actually rolling a stainless steel plate, Examples 16 and 17 as shown in Person 4 were prepared.

L temporary craftsman 112li In addition, the same <'! as a comparative example in the above confirmation test.
Comparative Examples 13 to 15 were created using the compositions shown in <4.

Table 4 Table 6 (Rolling Test) The rolling test was carried out on stainless steel strips in the rolling mill shown in Table 5 at the rolling reduction ratio shown in Table 6.

Table 5 The rolling oil used in the test was Example 12゜16.1
7, Comparative Examples 13 to 15, and those using methyl palmitate without adding polymer (FIG. 1) were used. In addition, rolling was carried out at 0.0% as shown in Table 6 for each rolling oil. /1m
＋＊Thick 5U3430 stainless steel strip in the first path 2
It was rolled down to a thickness of 0°311Il at a rolling reduction rate of 5%, and the second pass was 30% and 35%.

, 10% and 45% rolling were performed.

The lubrication performance was evaluated using a method in which the rolling load of the second bath was expressed as an index when the second bath was rolled at 35%, with the case of Comparative Example 1 being 1OO, and a heat scratch on the surface of the steel plate in the second bath. While visually observing the presence or absence of
Two methods were used: the method indicated by the rolling reduction at which heat scratches began to occur. In addition, the surface gloss of the second pass rolling 1& was measured to evaluate the gloss of the product surface. The results are shown in Table 7.

Table 7 In Examples 16 and 17, the rolling Rffi was lower than that of the comparative example.
It has a low index of about 10% and can be rolled with a low load, and the critical reduction rate at which heat scratches occur is high.

Furthermore, the surface gloss after rolling is also high and excellent.

Comparative Example 1 uses the monoester of the present invention but does not add a polymer, and it has been shown that the addition of a polymer dramatically improves the lubricating performance.

Comparative Example 15 is an example of a rolling oil in which monoester is blended with conventional mineral oil, and if this is compared with the example of the present invention, the rolling load of the example of the present invention is about 20? ≦It can be seen that heat scratches are less likely to occur.

(Effects of the Invention) As described above, in the present invention, in the monoester (R-COO-4') synthesized from fatty acid and alcohol, the sum of the carbon numbers of R and R' is 23 or less, and R and R
A rolling oil is made by using a monoester with a difference in carbon number of 9 or more as a base oil and adding 0.3 to 5% by weight of polyalkyl methacrylate having a molecular star of 5,000 to 50,000. Therefore, it is particularly excellent in resistance to I-scratch during cold rolling of stainless steel sheets, can reduce rolling load, and can improve gloss. Therefore, it can be effectively used for rolling stainless steel sheets with a clear luster.

[Brief explanation of the drawing]

Figure 1 is a graph showing the friction coefficients of Examples and Comparative Examples of the present invention and various monoesters alone, and Figure 2 is a graph showing the friction coefficients of Examples and Comparative Examples prepared by adding various polymers to palmitate ester. This is a graph showing the coefficient of friction, and FIG. 3 is a diagram schematically showing the two-cylindrical rolling and sliding test machine used in the friction test. -v77 concave (tsul-'l η)

Claims (1)

[Scope of Claims] In a monoester synthesized from a fatty acid and an alcohol, the sum of the carbon numbers of R and R' shown in the following formula is 23 or less, and the difference in the number of carbon atoms between R and R' is 9 or more. R-COO-R' R: Cold rolling oil for steel sheets, characterized in that a certain monoester is used as a base oil and 0.3 to 5% by weight of polyalkyl methacrylate having a molecular weight of 5,000 to 50,000 is added thereto. Alkyl group R' on fatty acid side: alkyl group on alcohol side.