Causes and methods of alleviating variations in the shading of tin plate during temper rolling

The Ispat Karmet metallurgical plant has made a study of the reasons for the formation of “ring-shaped bands” on the backup rolls of its temper-rolling mill and the associated variation in the shading of tin plate rolled on the mill. The plant examined the interactions that take place in the stands of the mill and used the findings to determine the mechanism responsible for the formation of the above-mentioned defects. A method of alleviating these problems was also developed. Improvements that were introduced have led to a fivefold increase in the amount of time that the backup rolls of stand No. 2 remain in service without the formation of the ring-shaped bands. The measures that were adopted have also signficantly reduced the intensity of the variable shading on the tin plate.