Effect of Heating Atmosphere on Structure of Oxide Scale on the Surface of Q345B Steel

Taking Q345B steel produced by a steel mill as the research object, the microstructure evolution of the oxide scale of the surface of Q345B steel in the furnace under three types of heating atmospheres were analyzed by scanning electron microscope (SEM), energy spectrometer (EDS) and X ray diffraction (XRD), and the influence of heating atmosphere on the structure of oxide scale of Q345B steel was studied. The results show that the furnace sheet iron is composed of three types of oxides FeO, Fe₃O₄ and Fe₂O₃ under three types of atmospheres. Compared with the matrix interface, the micro cracks and cracks occurs in the oxide scale interface. In the three types of heating atmospheres, the FeO layer of oxide scale corresponding to the heating atmosphere 3 is relatively thick, which is conducive to the oxide scale shedding during the subsequent descaling, thus it is an ideal heating atmosphere.