“…Nanoparticles, such as molybdenum disulfide (MoS 2 ) [ 3 , 4 ], silicon dioxide (SiO 2 ) [ 3 , 5 ], titanium dioxide (TiO 2 ) [ 6 , 7 , 8 ] and aluminum oxide (Al 2 O 3 ) [ 8 ], can create the appropriate conditions for machining process [ 9 ]. Recent studies have confirmed that nanoparticles have potential applications in the steel rolling process [ 10 , 11 ], machine cutting process [ 12 , 13 , 14 ], micro-drilling process [ 15 ], etc. Previous studies reported that nano-TiO 2 has good friction-reducing, anti-wear, and cooling properties, so it can reduce the coefficient of friction and rolling force during the hot rolling process [ 16 , 17 ].…”