Analysis of TiO 2 nano-additive water-based lubricants in hot rolling of microalloyed steel

Performance Evaluation and Lubrication Mechanism of Water-Based Nanolubricants Containing Nano-TiO2 in Hot Steel Rolling

“…Although water displays slightly higher thermal conductivity than water-based nanolubricants, it still leads to a lower cooling rate due to its poorer wettability when adhering onto the roll surface before rolling. In this case, the cooling rate of nanolubricants is higher than that of water, let alone that of dry condition, and it increases gradually with the increase of nano-TiO2 concentration based on the variation trend of wettability reported in our previous study [22]. Thus, the ferrite grains obtained during hot rolling are supposed to be more readily refined with the application of nanolubricants, compared to those of dry condition and water.…”

“…The formation of oxide scale during hot rolling process involves temperature, oxygen, and water, and the possible reasons to generate different thickness under different lubrication conditions have been investigated in our previous study [22]. …”

“…With a growing number of concerns about energy crisis and environmental pollution in modern society, "Green Manufacturing" or "Environmentally Conscious Manufacturing" and its sustainable development are becoming increasingly more important in the field of engineering applications [1]. Hot steel rolling, one of the most important manufacturing processes, has drawn considerable attention due to its huge energy consumption and pollutant emission.…”

“…In this regard, a type of environment-friendly lubricant with excellent lubricating performance is urgently needed to substitute conventional oil-containing lubricants. In recent years, the research trend on water-based lubricants added with nanoparticles (NPs) is continuously ascending due to their excellent tribological properties and promising potential in hot steel rolling, even though the relevant reports are still scarce [8,[16][17][18][19][20][21][22][23]. For instance, Bao et al [8] carried out hot steel rolling tests at temperatures of 750-950 • C using water-based lubricants containing SiO 2 NPs, and found that the use of as-prepared lubricants with the addition of 0.5 wt% nano-SiO 2 resulted in improved surface morphology, reduced oxide scale thickness, and refined grain size, compared to that of the base lubricant.…”

“…In our previous study [22], the lubricating performance of water-based nanolubricants containing nano-TiO 2 applied in hot steel rolling has been analysed in terms of rolling force, surface roughness and oxide scale thickness of rolled steel with proposed lubrication mechanism. However, lubrication effect on surface microstructure and hardness and corresponding mechanism have not been examined until now.…”