高温超低碳IF钢在轧制过程中的氧化实验研究

Pin point spots defects appear easily on the surface of Interstitial-free steel during the manufacturing process and badly influence the surface quality. This paper exploited thermal-gravity experiments to investigate the experimental research on the oxidation mechanism of IF steel in air. Results showed that the oxidation degree of IF steel increases with reacting temperature with exponential relationship; and oxidation of IF steel is more sensitive to temperature. In experiments, weight gains per unit area of IF steel were 24.46, 108, 220 and 355 mg/cm²at furnace temperature 868, 977, 1 087 and 1 200 ℃, steel temperature 868.4, 976.9, 1 087.4, 1 199.5 ℃. By analyzing the morphology and composition of the oxide layer at four different temperatures, it was found that the oxide layer exhibites a jagged inner and outer surface at a temperature of 868.4 ℃, the interface is rough, and there is no void inside the oxide layer. When the steel temperature is 976.9 ℃, pores appear inside the oxide layer, and the oxide layer is tightly bonded to the steel matrix. When the steel temperature is 1 087.4 ℃, the inner and outer surfaces of the oxide layer are flat, and no pores appear inside the oxide layer, but the surface of the steel substrate shows obvious oxidation. The inner and outer surfaces of the oxide layer formed at a steel temperature of 1 199.5 ℃ are flat, the oxide layer is dense, and no pores appear inside. The composition of the oxide layer is mainly FeO, and Fe₂O₃and Fe₃O₄are little.