DEVELOPMENT OF AN O W EMULSION WITH HIGH- VISCOSITY AND FINE DROPLET SIZE IN COLD-ROLLING OF STAINLESS-STEELS/

Due to high productivity of tandem cold rolling mills, it is beneficia l to produce not only mild steels but stainless steels by using the pr ocess, instead of conventional reverse rolling mills with smaller diam eter of work rolls. Requirements to lubricant in order to realize the process are conflicting which one side oil film thickness is required to be reduced to provide brightness of products, beside too thin film causes seizure and heat stratch. In this study, an O/W emulsion is des igned and developed to contend with these conflicting requirements. In order to make oil film thickness at inlet zone of roll bite be thinne r, the droplet size is reduced down to about 1 mu m. Also, kinematic v iscosity of base oil is increased up to 320mm(2)/s, which makes the fi lm stronger and prevent heat stratch, even ii the film thickness is re duced. Through laboratory tests and cold rolling tests using a product ion mill, the superiority of this type of lubricant is clarified and g ood surface brightness of SUS430 can be obtained with large diameter o f work rolls in high speed rolling conditions.