Design Aspects of An Advanced Emulsion Application System in a Cold Rolling Mill for Reduction in Iron Pick-Up Defect on Strip Surface

摘要

During cold deformation process in a cold rolling mill, lots of free iron-fines are generated at the roll-strip interface due to friction. Emulsion residues are also generated at the roll bite from the oil-in-water emulsion used for lubrication. These loose iron fines and emulsion residues are carried over the rolled strip and generate iron pickup defect on the strip surface during subsequent dry temper rolling process. The design of an efficient system for lubrication at the roll-bite and washing of the rolls is very critical and is highly influenced by mill design and operating conditions. This paper discusses a novel approach in designing such a system installed at Tandem Cold Mill-1 (TCM-1) of Bokaro Steel Plant (BSL). The earlier emulsion application system was inadequate to take care of the effective lubrication at roll-bite as well as the thermal condition of rolls, which resulted in a higher iron fines generation due to lowering viscosity of lubricant at the roll-bite caused by higher temperature.