| The mechanism of oxide formation in a weld line of high-frequency induction welding was studied through the microstructural observation and the oxide characterization. A decarburized weld line was produced by the reaction between wustite, which was formed in a heating stage, and carbon in steels. At welding temperature, 1400℃, however, wustite melted down and dissolved oxygen to the decarburized zone to form complex oxides, SiO₂-MnO-FeO-Al₂O₃. Therefore, the formation of a weld line is basically consisted with two processes: the simultaneous oxidation and decarburization process in a heating stage. and the oxygen dissolution and internal oxidation process in a welding stage. The composition of complex oxides, especially the content of MnO and SiO₂, showed a good relationship with the manganese-to-silicon ratio of steels. |
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