Abstract: ThermoCalc software was used to simulate the oxidation process of decarburized annealing plates for oriented silicon steel, and the oxides that can be generated with different pH₂O/pH₂ were analyzed. During decarburization annealing at 800 ℃，It was found that when the range of pH₂O/pH₂ values was 0.19～23, the oxidation products were FeO and Fe₂SiO₄. Using a glow spectrometer to analyze the oxide layers of three different decarburized annealing plates with different oxygen contents, as well as the surface characteristics of the corresponding finished plates. Found out than the total oxygen content of decarburized annealed plates is different, but the oxygen content in the surface is alike, all of which are very high. As the oxygen content in the decarburized annealing plate increases, the thickness of the oxide layer increases.The oxygen content in the surface insulation film of the three finished boards is almost the same, and the forsterite film in the finished board corresponding to the decarburized annealing board with the thickest oxide layer is also the thickest, and the spinel is the deepest.

Key words: Oxidized layer, oxygen content, forsterite film