JPH0543888A - Cold rolling oil - Google Patents

Abstract

PURPOSE:To provide a cold rolling oil which can facilitate the control of the thickness of a sheet irrespectively of the kind of the steel to be rolled and can provide a steel sheet free from surface defects even in high-speed drawing under high pressure. CONSTITUTION:The title oil comprises at least 60wt.% ester formed from a higher fatty acid component containing 5-60wt.% 12-22C saturated fatty acids and a polyalcohol component and having a viscosity of 150-350cSt at 40 deg.C and 1-20wt.% organosulfur compounds having a sulfur content of 5% or above and is capable of forming an emulsion of an average particle diameter (in terms of a volume fraction) of 4-15mum when diluted with water.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to cold rolling oils.

[0002]

2. Description of the Related Art Stainless steel and electromagnetic steel have greater deformation resistance than ordinary steel and require high pressure for rolling. Therefore, rolling at high pressure and high speed tends to cause seizure on the roll surface, and during acceleration / deceleration. The rolling load fluctuations of No. 1 also increase. As described in Plasticity and Processing '79 -April, pp. 323-330, the rolling oil base that is commonly used as a base oil having high lubricating properties is beef tallow, but stainless steel, It is impossible to prevent seizure in a high speed range in high speed rolling and high speed rolling of a material having a large deformation resistance such as electromagnetic steel. Further, since the friction coefficient in the low speed range is large as compared with the friction coefficient in the high speed range, a large load variation occurs during acceleration / deceleration, and it is difficult to control the plate thickness.

Japanese Unexamined Patent Publication Nos. 2-169110 and 2
JP-A-169111 discloses a cold steel for obtaining a stainless steel sheet having a good surface property by using a rolling oil satisfying one or both of a saponification value of 30 or more and a viscosity of 30 cSt (at 50 ° C.) or more. Although a hot rolling method is disclosed, the rolling reduction at which high speed rolling can be performed without causing seizure is limited to a relatively small rolling reduction.

On the other hand, in the case of a mineral oil base with low lubricity, the fluctuation of the friction coefficient between the low rotation speed and the high rotation speed in the roll wear tester is small, but the absolute value of the friction coefficient is large and the friction coefficient is high over the entire speed range. Because it is high, it is not suitable for high-pressure reduction rolling of stainless steel and electromagnetic steel.

[0005]

In cold rolling, in order to roll stainless steel, electromagnetic steel and ordinary steel having different required lubrication characteristics at a high speed and under a high pressure and without causing surface defects, and with high sheet thickness accuracy. Provide technology.

[0006]

[Means for Solving the Problems] Viscosity at 40 ° C. is 1
12 to 22 carbon atoms of 50 cSt or more and 350 cSt or less
Of 60% by weight or more of an ester of a higher fatty acid containing 5 to 60% of saturated fatty acid and a polyhydric alcohol, and 1 to 20% by weight of an organic sulfur compound having a sulfur content of 5% or more, and The present invention relates to a cold rolling oil capable of forming an emulsion having a volume fraction average particle size of 4 to 15 µm when diluted.

As the lubricating component used in the present invention, the proportion of saturated fatty acids having 12 to 22 carbon atoms is 5 to 60%,
More preferably, the viscosity of the higher fatty acid of 30 to 50% and the polyhydric alcohol at 40 ° C. is 150 cSt or more 35
Esters that are 0 cSt or less are used. The ester may be one kind or a mixture of two or more kinds, but the viscosity at 40 ° C must be 150 cSt or more and 350 cSt or less. If the viscosity is less than 150 cSt, or if the ratio of saturated fatty acids having 12 to 22 carbon atoms in the higher fatty acid that constitutes the ester is less than 5%, it is difficult to prevent seizure during high speed rolling of stainless steel, and In the roll abrasion tester, the coefficient of friction between the low rotation speed and the high rotation speed greatly varies, and even during actual rolling, the load variation during acceleration / deceleration increases, and the plate thickness accuracy decreases.

When the viscosity exceeds 350 cSt, it becomes difficult to make the amount of rolling oil uniform in the roll bite, which causes surface defects on the rolled steel sheet. In addition, the degreasing property of the rolled steel sheet in the cleaning line in the next step is significantly reduced.

When the ratio of the saturated fatty acid having 12 to 22 carbon atoms in the higher fatty acid constituting the ester exceeds 60%, the rolling point and the melting point of the rolling oil become high, so that the inside of the rolling mill becomes very dirty and the rolled steel sheet. Cause surface defects and poor cleaning.

As the ester used in the present invention, ethylene glycol, propylene glycol, glycerin,
Of polyglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, etc. and fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, erucic acid, ricinoleic acid, hydroxystearic acid etc. Examples of the ester include 12 to 2 carbon atoms in these fatty acids.
The proportion of saturated fatty acids of 2 should be between 5 and 60% by weight. Further, a dicarboxylic acid such as succinic acid, adipic acid, and sepacic acid or a dimer acid or trimer acid may be used as a part of the fatty acid to increase the molecular weight.

Examples of the sulfur compound having a sulfur content of 5% or more used in the present invention include sulfurized olefins, sulfurized perfume oils, sulfurized lard, sulfurized fats and oils such as sulfurized vegetable oils, and sulfurized fatty acids. The content of the organic sulfur compound is 1 to 2 of the total amount of rolling oil.
It is 0% by weight, more preferably 2 to 8% by weight. When the content of the organic sulfur compound is less than 1%, it is difficult to completely prevent high-pressure reduction of stainless steel and seizure during high-speed rolling. When the content exceeds 20%, ordinary steel, electromagnetic Oil stain is generated during rolling of steel depending on the rolling conditions.

The rolling oil in the present invention is used as an emulsion by diluting it into warm water. Water temperature is 30 ~ 75 ℃,
It is preferably 45 to 60 ° C. If the water temperature exceeds 75 ° C, the cooling capacity may be insufficient, and if it is less than 30 ° C, the emulsification may become unstable. The concentration of the rolling oil in the cold rolling oil emulsion is preferably 0.5 to 35% by weight, more preferably 1.0% by weight or more. If the rolling oil concentration exceeds 35% by weight, the economical efficiency becomes poor, and if it is 0.5% by weight or less, a sufficient plate-out amount cannot be secured, which is not preferable.

At this time, good results are obtained when the average particle size (volume fraction) of the emulsion is 4 to 15 μm. When the average grain size is 4 μm or less, when rolling materials with high deformation resistance (stainless steel, electromagnetic steel), even if a high-concentration emulsion is used, the amount of rolling oil supplied into the roll bite is not sufficient, and necessary lubrication is required. Property is not obtained, and the effect of the rolling oil of the present invention is not sufficiently exhibited. Also, the average particle size is 15 μm
As described above, in the rolling of ordinary steel, even if a low-concentration emulsion is used, the amount of rolling oil supplied into the roll bite becomes excessive, the advanced ratio becomes small, and the rolling becomes unstable.

The cold rolling oil of the present invention is another commonly used lubricating oil such as mineral oil, vegetable oil, animal oil and other synthetic oils; extreme pressure additives; emulsifiers such as ester type or ether type nonionic interfaces. An anionic surfactant such as an activator, a sulfonate or a sulfate, and an antioxidant may be added.

The present invention will be described below with reference to examples.

EXAMPLES Table 1 shows the rolling oil formulations of Examples and Comparative Examples and their viscosities. Fig. 1 shows the evaluation results of rolling characteristics at a low speed by a small rolling mill using these 5 wt% emulsions.
FIG. 2 shows the evaluation results of the frictional characteristics with respect to the number of roll rotations by the roll abrasion tester, and Table 3 shows the presence / absence of heat scratch during stainless rolling in the actual rolling mill.

[0016]

[Table 1]

The pentaerythritol mixed fatty acid ester, trimethylolpropane mixed fatty acid ester and sulfurized oil and fat used in the examples are shown below.

Pentaerythritol mixed fatty acid ester ¹ ) Pentaerythritol 25.0 parts by weight, oleic acid 37.
5 parts by weight, stearic acid 25.0 parts by weight, dimer acid 1
An ester having an acid value of 10 obtained by reacting 2.5 parts by weight under a nitrogen stream at 260 ° C. for 8 hours.

Trimethylolpropane mixed fatty acid ester ² ) 14.4 parts by weight of trimethylolpropane, 5 oleic acid
An ester having an acid value of 10 obtained by reacting 5.6 parts by weight and 30.0 parts by weight of stearic acid under a nitrogen stream at 260 ° C. for 8 hours.

Sulfurized fats and oils ³ ) Sulfurized lard having a sulfur content of 6% obtained by reacting lard with powdered sulfur at a reaction temperature of 174 to 177 ° C.

Evaluation Method Rolling Characteristic Evaluation at Low Speed by Small Rolling Mill A rolling test was conducted under the following conditions using a two-stage small rolling mill having a work roll size of 100φ × 130 L (mm). Roll peripheral speed: 12 m / min Roll roughness: Ra 0.2 μm Rolled steel plate: SPHC, 50 (W) × 2.3 (T) × 300 (L) Rolling oil concentration: 5% Rolling oil temperature: 50 ° C. The total strain (%) was calculated by the following formula. 1n (H ₀ / h) × 100 H ₀ : Original plate thickness, h: Delivery side plate thickness Evaluation is shown in FIG. 1.

The roll rotation speed measured by a roll wear tester
Evaluation of Friction Characteristics A friction test was performed under the following conditions using a two-stage roll abrasion tester having roll dimensions of 80φ × 50 L (mm). The evaluation of the frictional characteristics was carried out by measuring the difference (Δ in the coefficient of friction between 120 rpm and 1200 rpm).
μ) and the absolute value of the friction coefficient. Roll rotation speed: 120 to 1200 rpm Roll rotation gear ratio: 1 / 1.27 Roll material: SUJ-2, SUS-440 (pressurizing side) Load: 950 kg Rolling oil concentration: 5% Rolling oil temperature: 60 ° C Roll temperature: 60 ° C Friction coefficient was calculated from torque. Table 2 shows the emulsion average particle size at the time of the test. The average particle size of the emulsion was represented by the average particle size (volume fraction).

[0024]

[Table 2] The evaluation is shown in FIG.

Heat resistance during rolling of stainless steel in an actual rolling mill
Evaluation of Tooth Scratchability Rolling was performed under the following conditions using a 4-stand tandem mill with a large diameter work roll. Rolling speed: mpmMAX 910 Work roll diameter: 424 mm to 455 mm Work roll roughness: Ra 0.3 μm Rolled steel grade; SUS430 Total reduction: 77% (Inlet plate thickness 3 mm, Outlet plate thickness 0.7 mm) Rolling oil concentration: 5% Rolling Oil temperature: 50 ° C. Evaluation is shown in Table 3.

[0026]

[Table 3]

[0027]

EFFECTS OF THE INVENTION A cold rolling oil is provided which makes it easy to control the plate thickness regardless of the type of rolled steel and does not cause surface defects during high-speed rolling under high pressure.

[Brief description of drawings]

[Fig. 1] Evaluation of rolling characteristics during low speed rolling (latent axis: total strain rate; vertical axis: average rolling force)

[Fig. 2] Evaluation of frictional characteristics with respect to roll rotation speed (weft axis: rotation speed of roll wear tester; vertical axis: friction coefficient)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C10N 40:24 Z 8217-4H (72) Inventor Tetsuya Tsukamoto 2-chome, Shibukawa-cho, Yao-shi, Osaka No. 3 in Japan Quaker Chemical Co., Ltd. (72) Inventor Koichi Morikawa 2-3-1, Shibukawa-cho, Yao-shi, Osaka Prefecture Quaker Chemical Co., Ltd. Japan

Claims (1)

[Claims] 1. The viscosity at 40 ° C. is 150 cSt or more 3.
1 to 60 wt% or more of an ester of a higher fatty acid containing 5 to 60% of a saturated fatty acid having 12 to 22 carbon atoms and a polyhydric alcohol, which is 50 cSt or less, and an organic sulfur compound having a sulfur content of 5% or more. A cold rolling oil containing 20% by weight and capable of forming an emulsion having an average particle size of 4 to 15 μm when diluted with water.