Novel water-based nanolubricant with superior tribological performance in hot steel rolling

Abstract

Novel water-based nanolubricants using TiO2 nanoparticles (NPs) were synthesised by adding sodium dodecyl benzene sulfonate (SDBS) and glycerol, which exhibited excellent dispersion stability and wettability. The tribological performance of the synthesised nanolubricants was investigated using an Rtec ball-on-disk tribometer, and their application in hot steel rolling was evaluated on a 2-high Hille 100 experimental rolling mill, in comparison to those without SDBS. The water-based nanolubricant containing 4 wt% TiO2 and 0.4 wt% SDBS demonstrated superior tribological performance by decreasing coefficient of friction and ball wear up to 70.5% and 84.3%, respectively, compared to those of pure water. In addition to the lubrication effect, the suspensions also had significant effect on polishing of the work roll surface. The resultant surface improvement thus enabled the decrease in rolling force up to 8.3% under a workpiece reduction of 30% at a rolling temperature of 850 °C. The lubrication mechanisms were primarily ascribed to the formation of lubricating film and ball-bearing effect of the TiO2 NPs.

Eco-Friendly Water-Based Nanolubricants for Industrial-Scale Hot Steel Rolling

“…By comparing the different compositions in various lubricants, it can be thus concluded that the addition of glycerol and SDBS is conducive to the improvement of wettability, which becomes particularly remarkable when there is an increase in TiO 2 concentration. These findings have been well explained and consistent with those in our previous study [30], although the particle size of nano-TiO 2 used in this study is relatively larger. It needs to be emphasised that the lubricant with better wettability on work roll surfaces is more likely to accommodate effective amounts of TiO 2 NPs and other additives which can be transferred to the contact zone between the work roll and the workpiece.…”

“…Glycerol is a colorless, odorless and viscous liquid that aids in enhancing the viscosity and wettability of nanolubricants [28]. SDBS is an organic dispersant with a linear structure (LAS) and hydrophilic group, which helps improve the wettability, dispersion stability and also the viscosity of the nanolubricants [30]. Snailcool is a novel aqueous additive that not only boosts the extreme pressure property of the nanolubricants but also compensates the degradation of lubrication performance due to the use of relatively coarse TiO 2 NPs.…”

“…This is to further reduce the integrated cost of applying the water-based nanolubricants on an industrial scale. The formulation of as-synthesised nanolubricants in this study is based on the optimal TiO 2 concentrations obtained previously [27,30], and their chemical compositions are listed in Table 2. For comparison purpose, pure water, a commonly used coolant of industrial-scale work rolls, was selected as a benchmark.…”

“…In our previous studies, the physicochemical and tribological properties of water-based nanolubricants containing P25 TiO 2 NPs were systematically investigated in terms of different loads, steel surfaces and temperatures [24][25][26]. The formulas of as-prepared water-based nanolubricants have been optimised, and therefore they exhibited largely enhanced lubrication performance in hot steel rolling [27][28][29][30]. However, all the fundamental research on water-based nanolubricants is only confined to the laboratory scale.…”

A Comprehensive Review of Water-Based Nanolubricants

“…Over the past decade, water-based nanolubricants have been emerging as promising eco-friendly lubricants by dispersing nanoadditives into water [12][13][14][15][16][17][18][19][20][21][22][23], which integrates superb cooling capacity of water with excellent lubricity contributed by the nanoadditives. The use of water-based nanolubricants not only provides protection against friction and wear between the tool and the workpiece, but also improves overall quality of the product, demonstrating a great potential in engineering applications, such as metal forming [24][25][26][27][28][29]. Despite an increasing number of experimental studies on various nanomaterials as nanoadditives in water, several aspects including dispersion stability, tribological behaviour, and lubrication mechanism have not yet been fully understood.…”