Application of nanoclay lubricants for lowering wear of tools for steel meshing - A case study

The tools that are employed for industrial woven steel wire mesh processing suffer significant wear, particularly those employed for bending the steel wire at the beginning of the process due to the high forces that are required. Lubricants are employed for the purpose of reducing friction between the tool and the steel wire in these types of processes, hence reducing tool wear. Nanoparticle additives have been investigated for improving the tribological performance of lubricants; due to their small size they may fill surface valleys reducing surface roughness, act as nanobearing limiting metal-metal contact, amongst others. Particularly, nanoclay nanoparticles, such as montmorillonite (MMT), have been proposed as nanoadditives for tribological applications due to being naturally occurring, environmentally friendly, and low-cost. In our work, MMT clay nanoparticles were dispersed by homogenization and ultrasonication in a water-based synthetic lubricant with varying concentrations (0.01, 0.05, and 0.10 wt.%). The wear preventive tribological properties of the prepared nanolubricants were characterized experimentally with a T-02 four-ball tribostester according to ASTM D4172. The wear scar diameters of the three lower steel balls of the four-ball tribopair were measured with an Alicona EdgeMaster optical measurement system. In our laboratory experiments wear scar diameter was reduced by 19% with a MMT clay nanoparticle concentration of only 0.01 wt.%. Higher concentrations (0.05 and 0.10 wt.%) resulted in lower improvements due to nanoparticle agglomeration in the lubricant. Finally, MMT clay nanolubricants were employed for the wire-bending process in a steel-meshing equipment with the nanoparticle concentration where the best tribological performance was found (0.01 wt.%). Tools were monitored for 120 h; tool wear was recorded by measuring the change in the wire-bending tool dimensions compared to the change obtained when the unfilled base lubricant was employed. For the first inch of the tool, where the highest force for bending the wire is required, tool wear in was lowered from 0.014 in to 0.006 in, representing an improvement of 57%. In average, the improvement on wear resistance for the tool was found to be 30%. The results found for this study demonstrate that MMT clay nanoparticle additives are able to improve wear resistance and extend tool life, resulting in considerable savings.