Optimization and nanoreinforcements of lubricant concentration for steel sheet forming process

In metal-mechanic industry, lubricants are applied to improve products’ quality and tools useful life, while reducing friction and wear, also removing the generated heat during the material processing. Tribological evaluations are performed varying the water content of two widely used lubricants in automotive metal-forming operations. Evaluations are first performed to determine the optimal lubricant dilutions, followed by reinforcement of 2D-nanostructures of hexagonal Boron Nitride (h-BN). Tribological characterization under extreme pressures (EP) are performed with a four-ball tribometer according to the Institute for Sustainable Technologies –National Research Institute (ITeE-PIB) Polish method under scuffing conditions. The optimized concentrations are determined for Ecodraw and Montgomery lubricants, representing a 28% and 3% improvement in pressure loss limit at 1:8 and 1:6 concentrations, respectively. Block-on-ring tribotest is used to determine the coefficient of friction (COF) of the optimized lubricant dilutions and h-BN nanolubricants, which represent ~10% improvement. These results could be attributed to diverse factors such as a layering mechanism of the 2D nanostructures, soft van der Waals forces between 2D h-BN layers, and the deposition of h-BN on the worn surface, decreasing the shearing stress and COF. Finally, thermal conductivity evaluations showed an enhancement by 30% and 15% with addition of h-BN, demonstrating the potential of 2D nanostructures for improving the efficiency on antiwear and thermal transport.