Qualitative study and a novel solution to nozzle clogging problem in roll gap lubrication used in hot rolling

Abstract

Nozzle clogging in roll gap lubrication (RGL) is a pain area for hot strip steel rolling. Nozzle clogging severely affects lubrication affecting rolled surface quality causing prominent hot rolling defects like banding and peel-off phenomenon in work roll. Uneven coefficient of friction leads to variable or poor lubrication, which raises the chances of cobble and tail chewing in coils, lowers roll force reductions ultimately increasing the power consumption of the mill. The present work focuses on a holistic approach where causes leading to nozzle clogging have been identified and eliminated in a stepwise manner. Gas chromatography has been employed for the first time to get an understanding about the specific carbon chains contributing towards pulp generation. Optimising the distance between mixer and spray header and using indigenously modified spray header improves the lubrication during hot rolling. roll force reduction upto 15%-16% could be achieved.