By employing CaF2-SiO2 and CaF2-SiO2-MnO system fluxes, the roles of SiO2 and MnO in decarburization behaviors during submerged arc welding of EH36 shipbuilding steel have been quantified and evaluated. All possible reactions associated with C transfer and interfaces at which these reactions occur are systematically discussed. It is concluded that the addition of SiO2 and MnO exerts synergistic effects on the extent of decarburization due to increased partial pressures of O2 and SiO gases in the plasma, improved O level in the weld pool, and higher activities of the oxides, such as SiO2, MnO, and FeO, at the slag–metal interface. The investigation over the macrographic detached slag surfaces shows that the possibility of bubble nucleation is highly influenced by flux formula. The effect of heat input on decarburization is discussed, and the optimal flux compositions expected in the present study are analyzed.

中文翻译：

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阐明 SiO2 和 MnO 对埋弧焊脱碳的作用：EH36 造船钢的热力学研究

通过使用 CaF2-SiO2 和 CaF2-SiO2-MnO 系统焊剂，对 EH36 造船钢埋弧焊过程中 SiO2 和 MnO 在脱碳行为中的作用进行了量化和评估。系统讨论了与 C 转移相关的所有可能反应和这些反应发生的界面。得出的结论是，由于等离子体中 O2 和 SiO 气体的分压增加，焊池中 O 水平的提高以及氧化物（如 SiO2）的活性更高，因此添加 SiO2 和 MnO 对脱碳程度产生协同作用、MnO 和 FeO，在渣-金属界面。对宏观分离渣表面的研究表明，气泡成核的可能性受熔剂公式的影响很大。讨论了热量输入对脱碳的影响，