JPS5736001A - Method and apparatus for lubricating different roll speed rolling work - Google Patents

Abstract

PURPOSE: To eliminate the difference of rolling lubrication generated between a lower-speed side work roll and a higher-speed side work roll, and to make the brilliance of the front and back surfaces of a rolled sheet uniform, by adjusting the contact angle between the rolled sheet and the lower-speed side work roll in a different roll speed rolling mill, in order to increase the thickness of oil film therein.

CONSTITUTION: A sheet 15 to be rolled is fed in an angle θ against the pass line into the gap between a lower-speed side upper work roll 1 covered by a thin oil film and a higher-speed side lower work roll 2 covered by an oil film thicker than that of the work roll 1. This feed of the sheet 15 is carried out under a condition that a guide roll 5 is elevated up, and a lower belly roll 4 is located higher than the pass line. Hereby, the contact angle between the sheet 15 and the upper work roll 1 is reduced by θ degrees; whereas, the contact angle between the sheet 15 and the lower work roll 2 is increased by θ degrees, so that the thickness of oil film covering the upper work roll 1 is increased, and the difference of the rolling lubrication between the upper and lower work rolls 1, 2 is eliminated. As a result, the generation of heat streaks on the lower-speed roll side is prevented, the rolling friction factor is restricted to a low value, and the danger of rupture of the sheet due to an increased forward tension is avoided.

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