The formation and performance of oxide scale on a low-alloy steel were investigated during hot rolling at 850 and 950 °C under various lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing various concentrations of nano-TiO2 from 1.0 to 8.0 wt%. The results showed that the addition of nano-TiO2 particles in the lubricant significantly reduced the thickness of oxide scale and surface oxide roughness. The reduction reached the maximum when the concentration of TiO2 was 4.0 wt%. Detailed oxide phase characterisation and oxide component fraction determination revealed that hot rolling destroyed the conventional multi-layer oxide scale and promoted magnetite and haematite formation because of easy access of oxygen from the deformed structure. The effect of TiO2 was explained by the decrease in the rolling force, which led to a higher fraction of dense retaining wustite and therefore reduced the extent of further oxidation. Increasing temperature did not change the trend of lubrication effect but raised the rate of steel oxidation in general.

中文翻译：

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含TiO2水基纳米润滑剂对钢热轧氧化行为的影响

在各种润滑条件下，包括基准（干燥条件和水）和含有不同浓度纳米 TiO2 的水性纳米润滑剂，在 850 和 950 °C 的各种润滑条件下，研究了低合金钢上氧化皮的形成和性能。 1.0 至 8.0 重量％。结果表明，纳米TiO2颗粒在润滑剂中的加入显着降低了氧化皮厚度和表面氧化粗糙度。当 TiO2 的浓度为 4.0 wt% 时，减少量达到最大。详细的氧化物相表征和氧化物组分分数测定表明，热轧破坏了传统的多层氧化皮，并促进了磁铁矿和赤铁矿的形成，因为变形结构中的氧气很容易进入。TiO2 的作用是通过轧制力的降低来解释的，这导致更高的致密保留方铁体比例，因此降低了进一步氧化的程度。温度升高并没有改变润滑效果的趋势，但总体上提高了钢的氧化速率。