Analysis of Deformed Oxide Layers Grown on Steel

The deformation of the oxide layer grown in ultra low carbon steel was studied by means of electron backscattered diffraction analyses. Samples of the steel were reheated for shorts periods of time at 1050 °C in a chamber designed to obtain thin scale layers before deforming them by plane strain compression at temperatures ranging from 650 to 1050 °C. Microstructural analyses showed that the oxide layer was made almost exclusively of wustite that is ductile when deformed above 900 °C. It is found that wustite develops texture components of the cube and rotated cube type while growing; these components rotate towards 〈201〉 {100} components once a certain degree of deformation is achieved. Undeformed ferrite close to the oxide layer shows weak 〈201〉 {100} components that rotate into weak rotated cube components when the substrate is deformed in the austenite range and to strong 〈554〉 {225} components when deformed in ferrite. Rolling trials carried out in an experimental mill showed similar trends.