本项目提出一种采用活性元素氧改变耦合电弧/熔池界面行为的方法，可以明显抑制大电流高速TIG焊的咬边和驼峰缺陷，同时增加熔深并保证焊接接头力学性能，有望成为一种新型的高效低成本焊接方法。为此，将对以下问题展开深入研究：建立活性元素氧在耦合电弧/熔池界面的传输模型，研究氧从电弧气氛到熔池的传输行为，实现对氧传输过程的定量描述；建立耦合电弧-熔池一体化数学模型，结合实验研究，研究氧作用下的耦合电弧/熔池界面行为和交互作用机理；在此基础上，探讨高速焊熔池流动驱动机制与咬边和驼峰焊道抑制机理，建立工艺参数与焊缝成形、接头组织和力学性能之间的相关关系，揭示氧与耦合电弧联合作用下高速焊焊缝成形与改善机理。本项目的研究对于深入认识电弧/熔池界面行为和抑制焊接缺陷，推动高效优质低成本焊接制造的发展和应用具有重要意义。

In present project, coupled arc is employed together with oxygen introduced as activating element to control the interface of arc plasma and weld pool. As a result, undercut and humping defects generated in high current TIG welding with high speed can be eliminated significantly. In addition, an increased weld penetration is obtained with good mechanical property and thus can become a high efficient welding process with low cost. For all this, following critical issues is going to be studied further: a model is to be developed of oxygen transfer across the interface of coupled arc and weld pool and the oxygen transfer from the arc plasma to the weld pool is to be researched, so that the oxygen transfer can be formulated quantitatively; on the basis of experiment, an integrated mathematical model of coupled arc and weld pool is established to investigate the interface behavior and interaction mechanisms of the coupled arc and weld pool; following this, mechanisms of weld pool flow driven and suppression of undercut and humping to be examined as well as the relationship of process parameter, weld formation, welding joint and mechanical property is to be established, the mechanisms of weld bead formation and regulation of high speed welding with combination of oxygen and coupled arc is clarified accordingly. This study of the project are of great significances in understanding interaction and interface of arc and weld pool to restrain welding defect and thus promote the development and application of high efficiency welding manufacturing with high quality and low cost.