Non-Destructive Dielectric Characterization of Secondary Mill Scale on Hot-Rolled Steel

Secondary mill scale is a flaky byproduct formed on the outer surface of hot-rolled steel strip during the manufacturing process, and its composition is comprised of three iron oxides, namely hematite (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Fe_{2}O_{3}$</tex>), magnetite (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Fe_{3}O_{4}$</tex>), and wüstite (FeO). Owing to the nonuniform surface texture and thickness, cracks and fractures are presented in mill scale, resulting in the deteriroation of surface quality of hot-rolled steel, as well as adhesion of subsequent coatings on steel. Mill scale must be removed thoroughtly prior to the next stage.