Abstract
Due to high productivity of tandem cold rolling mills, it is beneficial to produce not only mild steels but stainless steels by using the process, instead of conventional reverse rolling mills with smaller diameter 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 designed and developed to contend with these conflicting requirements. In order to make oil film thickness at inlet zone of roll bite be thinner, the droplet size is reduced down to about 1μm. Also, kinematic viscosity of base oil is increased up to 320mm2/s, which makes the film stronger and prevent heat stratch, even if the film thickness is reduced. Through laboratory tests and cold rolling tests using a production mill, the superiority of this type of lubricant is clarified and good surface brightness of SUS430 can be obtained with large diameter of work rolls in high speed rolling conditions.
