Experimental study on evolution of oxidation behavior on high-temperature continuous casting slab surface

The oxidation kinetics, oxide layers composition and thicknesses of X70 steel, Y55 steel and 304 stainless steel are investigated. The results show that the oxidation rate of X70 steel increases rapidly at 1000 °C, while that of Y55 steel and 304 stainless steel increases rapidly at 1100 °C. The oxidation kinetic coefficients of X70 steel, Y55 steel and 304 stainless steel are exp (10.7), exp (11.58) and exp (30.15), respectively, and the apparent activation energy of oxide layer are 196879.7 J/mol, 207608.1 J/mol and 469284.3 J/mol, respectively. The cross-sectional morphology and element distribution of oxide layer are obtained. With the oxidation time increases from 30min to 80 min at 1100 °C, the oxide layer thickness of X70 steel and Y55 steel increases by 1242.33 μm and 965.59 μm respectively when the weight of steels increases by 1 mg/mm2, and the oxide layer of Y55 steel is denser than that of X70 steel. A variable temperature oxidation mathematical model of the slab surface is established to predict the oxide layer thickness of slab surface.