Tribological Behaviors and Lubrication Mechanism of Water-based MoO3 Nanofluid during Cold Rolling Process

Abstract

The MoO3 nanofluid was prepared by mixing deionized water with MoO3 nanoparticles and some other organic additives. The tribological behaviors of prepared MoO3 nanofluid in various nanoparticle concentrations were tested by four-ball tribotester. The results obtained therein revealed that the dispersion of the nano-MoO3 in water was conducive to the reduction of friction coefficients and wear volume, and the increase in the load-bearing capacity, especially the optimal concentration of additive was 0.4 wt.%. To investigate the lubrication mechanism of water-based MoO3 nanofluid under steel cold rolling condition, cold rolling lubrication performance of 0.4 wt.% MoO3 in water-based fluid was evaluated using a four-high rolling mill. The rolling outputs such as rolling force, rolling power and reduction were used as measurands for determining the process efficiency. Erosion corrosion was found to happen during steel cold rolling process, MoO3 was transformed to MoO2 and iron was oxidized to iron hydroxide. A lubricating film composed of MoO3, MoO2 and Fe(OH)3 was considered to form on strip surfaces due to chemisorption and deposition of MoO3.