JP3027246B2 - Cold rolling for stainless steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold rolling method.

[0002]

2. Description of the Related Art The neat oil conventionally used for stainless steel rolling has a low cooling effect because it has a low viscosity mineral oil as a main component, and the rolling speed can be increased due to a high risk of fire. I could not do it. On the other hand, the emulsion average particle size of the circulating cold rolling oil generally used is 5 to 10 μm, and in the use of stainless steel rolling, even if the work roll roughness is small, the oil pit is large, The roughness is also large. That is, the gloss required for the stainless steel plate is impaired. When low-viscosity rolling oil is used as an emulsion, heat scratch becomes a problem in high-speed, high-pressure rolling, and in high-speed, low-pressure rolling, the target surface roughness on the outgoing side depends on the degree of roughness on the incoming side. I can't get it. Further, there is a problem that productivity cannot be obtained at low speed and high pressure.

[0003]

SUMMARY OF THE INVENTION The present invention provides a technique for rolling a stainless steel at a high speed and with a good yield in a stainless steel roll.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an ester of a polyhydric alcohol and a higher fatty acid having a viscosity at 40 ° C. of 80 cSt to 400 cSt.
A rolling oil containing ９９99.5% by weight has an average particle size of 3 μm or less in volume distribution, a standard deviation of 1 μm or less, and a volume fraction of particles not exceeding 3 times the standard deviation from the average particle size is 90%.
% Of the emulsion as a coolant.

[0005] The rolling oil used in the present invention uses, as a lubricating component, esters of a higher fatty acid having a viscosity at 40 ° C of 80 cSt to 400 cSt and a polyhydric alcohol. The ester used may be one kind or a mixture of two or more kinds, and the viscosity at 40 ° C. is 80 cSt.
It should not be less than 400 cSt. 80 cSt viscosity
When it is below, it is difficult to prevent seizure in high-speed rolling of the stainless steel sheet, and when the viscosity is 400 cSt or more, the degreasing property of the rolled steel sheet in the washing line is significantly reduced.

The corresponding esters include polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, trimethylolpropane, and sorbitan, and fatty acids such as lauric acid, myristic acid, and palmitin. Esters with acids, stearic acid, oleic acid, linoleic acid, erucic acid, ricinoleic acid, hydroxystearic acid and the like are illustrated. Particularly preferred lubricating components are esters of hindered alcohols such as trimethylolpropane and pentaerythritol having no hydrogen atom at the carbon atom adjacent to the carbon having an OH group, and higher fatty acids. These esters are generally called hindered esters, but these esters not only have excellent heat resistance, but also have a small increase in the viscosity of the oil film even at high extreme pressures, and do not cause oil film breakdown. , Metal contact between the roll / strip can be avoided. As a result, the seizure of stainless steel can be prevented and the oil film can be made thin, so that a finished product having good surface gloss can be obtained.
The higher fatty acids suitable for esterification with hindered alcohols may be any of the fatty acids as described above, but use ricinoleic acid or hardened ricinoleic acid for part or all of the fatty acid, and replace a part or all of the remaining hydroxyl groups of ricinoleic acid. Further fatty acid, for example, monocarboxylic acid such as acetic acid, octylic acid, lauric acid, stearic acid, ricinoleic acid, oleic acid, fumaric acid, phthalic acid, maleic acid, and further esterified with dicarboxylic acid such as adipic acid to reduce the molecular weight. It may be enlarged. Alternatively, dimer acid may be used as a part of the fatty acid to increase the molecular weight.

[0007] The lubricating component used in the present invention contains at least an ester of a polyhydric alcohol and a higher fatty acid.
The ester may be one or a mixture of two or more esters having a particle size of from 80 cSt to 4 at 40 ° C.
It should be 00 cSt, more preferably 200 to 300 cSt, and should comprise 20 to 99.5% by weight, more preferably 60 to 99.5% by weight of the total rolling oil.

The lubricating component in the rolling oil of the present invention may further contain other lubricating components such as esters with monohydric alcohol higher fatty acids, mineral oils and synthetic oils.

In the present invention, the emulsion used as a coolant has an average particle size of 3 μm or less.
Standard deviation (σ) 1 μm or less, volume fraction within 3σ is 90%
It is desirable that this is the case. If the average particle size exceeds 3 μm, good surface gloss cannot be obtained. Also, average particle size 3μm
If the volume fraction is less than 90% when σ is 1 μm or more and / or within 3σ, good surface gloss cannot be obtained.

As described above, in order to adjust the particle size, it is important to select an emulsifier. Examples of the essential emulsifier include nonionic surfactants such as polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, and polyoxyalkylene alkylamine. The content of the emulsifier is 0.5 to 15% by weight, more preferably 2 to 15% by weight of the total amount of the rolling oil.
-10% by weight. If the emulsifier content is 15% or more, the lubricating properties and oil film strength are reduced, and as a result, damage to the roll and seizure are likely to occur. If the content is 0.5% or less, it is difficult to obtain the above-mentioned particle size distribution. Furthermore, when a nonionic surfactant is not used, it is difficult to maintain a constant particle size distribution over a long period of time. Hereinafter, the present invention will be described with reference to examples.

[0011]

EXAMPLES Four types of rolling oils were prepared according to the recipe shown in Table 1.

[Table 1]

The rolling oil is diluted with water at 50 ° C., and the rotation speed is set to 100 using a homomixer (M type: manufactured by Tokushu Kika Kogyo).
The mixture was stirred at 00 rpm for 10 minutes to form an emulsion. Table 1 also shows the average particle size, standard deviation, and volume distribution ratio of the volume distribution of this emulsion determined using a Coulter counter (TA-II: manufactured by Coulter Electronics Co., Ltd.).
Shown in When using a coulter counter, Example 1 used a 30 μm aperture tube, Example 2 used a 50 μm aperture tube, and Examples 3 and 4 used a 100 μm aperture tube.

In the formulation, trimethylol cypropane triester is mixed with 14.4 parts by weight of trimethylolpropane and 85.6 parts by weight of tall oil-decomposed fatty acid, and reacted at 260 ° C. for 8 hours in a nitrogen stream to obtain an acid value. 10 esters were obtained. The viscosity of the obtained ester at 40 ° C. is 100 c.
St. Pentaerythritol mixed fatty acid ester is composed of 25 parts by weight of pentaerythritol,
2.5 parts by weight and 12.5 parts by weight of dimer acid were mixed and synthesized in the same manner as above. The acid value was 9, and the viscosity at 40 ° C was 674.1 cSt. A commercial product was used as trimethylolpropane trioleate. The viscosity at 40 ° C. was 49.4 cSt. As a tallow fatty acid methyl ester, a commercially available product was used, and the viscosity at 40 ° C. was 4.8 cst.

Four-ball friction test The rolling oils shown in Table 1 were subjected to a four-ball friction test under the following conditions. Sample: neat Measurement temperature: 50 ° C. Number of revolutions: 500 rpm Ball: φ1 / 2 inch SUS440 ° C. Load speed: 120 kg / min The results are shown in Table 2.

[0015]

[Table 2]

High-speed rolling test A rolling oil having a formulation shown in Table 1 was diluted in water to obtain a 5% by weight emulsion (temperature: 60 ° C.), which was placed in a 2-stage high-speed test rolling mill at a rate of 6 l / min. SUS430 was cold-rolled under the conditions shown in Table 3 while being supplied using a pump.

[0017]

[Table 3]

Table 4 shows the gloss of the plate surface and the presence or absence of gloss.

[Table 4]

As is clear from Tables 2 and 4, it can be seen that the rolling oil of the present invention has excellent heat resistance and can provide a high surface gloss material.

Actual test using a tandem mill.
And bath preparation ³ of the tank, shown while supplying the rolling oil emulsion 25000 l / min tandem mill work rolls, hot rolling, annealing, pickling, a SUS430 subjected to coil grinder formulation in Table 5 rolling Cold-rolled under the conditions. The results are also shown in Table 5.

[0021]

[Table 5]

As a result, it was confirmed that the rolling oil of the present invention was excellent in heat resistance and obtained a high surface glossy material even in an actual machine.

[0023]

According to the rolling method of the present invention, a stainless steel sheet having a good surface gloss can be cold-rolled under high-speed and high-pressure without causing seizure.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 105: 38 145: 36 145: 38 149: 04 125: 14) C10N 30:00 40:24 (72) Inventor: Seiichi Murata 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Keiji Takatsu 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Ikuo Mori Yao, Osaka 2-3-1 Shibukawa-cho, Japan City Quaker Chemical Co., Ltd. (72) Inventor Hiroshi Hayashi 2-3-1 Shibukawa-cho, Yao City, Osaka Japan Quaker Chemical Co., Ltd. (56) References Special JP-A-4-118101 (JP, A) JP-A-3-172392 (JP, A) JP-A-2-175798 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1 / 22-1/36 B21B 3/02 B21B 45/02 C10M 173/00

Claims (1)

(57) [Claims] 1. A viscosity at 40 ° C. of 80 cSt to 400.
A rolling oil containing 20 to 99.5% by weight of an ester of a polyhydric alcohol and higher fatty acid as cSt and 0.5% by weight or more of a nonionic surfactant is used.
It is diluted with water at a concentration of weight%, and the average particle size of the volume distribution is 3μ.
A cold rolling method for stainless steel in which an emulsion having a volume fraction of 90% or more of particles having a standard deviation of 1 μm or less and a standard deviation not more than 3 times the standard deviation from the average particle diameter is supplied as a coolant.