Abstract: In the presence of ultrasonic, Fe3O4 nano-particles having an average particle size of 20 nm and modified with oleic acid, were dispersed in an emulsion, which was a selected base oil compounded with appropriate additives, such as surfactants, rust inhibitors and defoamers. The tribological properties of the newly developed cold-rolling emulsion containing nano-Fe3O4 were evaluated using MRS-10A four-ball test machine. The worn surfaces of the steel balls were investigated by optical microscope. Besides, the lubricity of this cold-rolling emulsion was evaluated on a cold-rolling tester using conventional emulsion as reference. Results indicate that Fe3O4 nano-particles as additive in cold-rolling emulsion could significantly improve the friction-reducing, anti-wear and surface quality of the friction pair. The new emulsion containing nano-Fe3O4 shows good lubricity performance during cold-rolling steel strips, the surface quality of the rolled strip is improved, and at the same time, the rolling force and energy parameters are decreased.

Key words: Steel strip, Nano-Fe3O4, Cold-rolling, Rolling lubrication