PURPOSE: To control the forward slip ratio in a proper range and to prevent the accuracy of a strip thickness from deteriorating by obtaining the concentration of lubricant making the target forward slip ratio from a predicting formula of friction coefficient and setting the concentration of the lubricant on the inlet side of cold tandem mills.
CONSTITUTION: When the strip is rolled in cold tandem mills, the forward slip ratios are obtained from roll speeds at each roll stand 2, 3 and the sheet speeds on the outlet side of each stand, in a rolling time. Friction coefficient predicting formulas are created respectively from an obtained forward slip ratio when the forward slip ratio is in a positive area or in a negative area. The concentration of the lubricant making the target forward slip ratio is obtained from these friction coefficient predicting formulas and the concentration of lubricant on the inlet side of the cold tandem mills is set. The concentration is controlled by a computing element 10 and a pump pressure controller 11 to control the concentration. Consequently, the forward slip ratio can be controlled is a proper range, rolling can be performed by the same roll and a defective shape of a plate can be prevented from being generated.
KITAMURA KUNIO
YARITA YUKIO
KURODA SHIGERU
MIZUSHIMA SHIGETO
