| 摘要 |
PROBLEM TO BE SOLVED: To execute high speed rolling of a steel sheet required for high gloss even when a new liquid is supplied to adjust concentration and a liquid level by using a uniform solution prepared through previous addition of a prescribed amount of water to a stock solution of a rolling mill lubricant as the rolling mill lubricant of an oil-in-water type emulsion. SOLUTION: Water of 1-10 vol.% is previously added to the stock solution of a rolling mill lubricant used as an oil-in-water type emulsion to get a uniform solution, then the solution is used as the emulsion of concentration-in-water of 1-10 vol.% and thus cold rolling of a steel sheet is executed at a high speed of >= 400 mpm. Above all, by making the amount of the upper limit of water added to the stock solution of a rolling mill lubricant equal or less than the amount of blending of the emulsion in the stock solution of the rolling mill lubricant, the required time for the particle size of the emulsion to become a stationary state is shortened. Further, when the making-up supply is made after solubilization by previous addition of water to the stock solution of the roling mill lubricant, the average particle size of the oil in the water of emulsion is made into a fine particle size of <=3μm.
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