窄间隙脉冲激光辅助缆式焊丝GMAW电弧物理行为及接头性能影响机制研究

Twisted multi wire arc welding is a kind of high efficiency, energy saving, high quality welding method. Unique arc rotating and coupling effect both with vortex flow of molten pool can increase the liquidity of metal. However, coarse grains will appear in the heat affected zone in the condition of large parameters welding, which will result in a decline in joint performance. Based on the above background, a innovative hybrid pulsed laser-twisted wire arc welding method is proposed to applied in narrow gap welding in this project. By make use of the arc voltage-drop effect of laser to reduce the heat input and the cyclical impact of laser to change the crystallite size and orientation to acquire high quality welding seam. The combination of numerical approaches and the experimental tests will makes it possible to get the influence law of process parameters on welding specification, establish the correlation between arc welding procedure parameters, coupling behavior, molten pool and weld form through the study of the arc coupling mechanism, droplet transfer and molten pool fluid behavior, and optimize hybrid pulsed laser-twisted multi wire arc welding process. This project can promote the systematical understanding of hybrid pulsed laser-twisted multi wire arc welding and lay a foundation both in theory and technique for high-efficient, high quality narrow gap welding.

缆式GMAW是一种高效、优质、低耗的焊接方法，独特的电弧旋转耦合行为可改善焊缝侧壁熔透性，解决窄间隙侧壁熔合不良的问题。然而这种焊接方法在大线能量焊接时，接头热影响区组织会出现晶粒粗大现象，导致接头性能下降。本项目针对上述问题，提出在缆式GMAW中加入脉冲激光用于窄间隙焊接，在改善窄间隙侧壁熔透性的同时，利用激光的周期性冲击作用破坏粗大晶粒，适当减小系统热输入，细化晶粒，提高焊缝质量。拟采用数值模拟和试验检测相结合的方法，分析大侧壁拘束条件下电弧形态、熔滴过渡形式、匙孔行为及熔池的动态特征，并根据流体动力学与热力学构建接头热、力及流体流动的数值分析模型，对热源系统在时空尺度上的能量耦合行为进行定量研究，阐明热源耦合机制及熔池流体流动行为规律，确立“焊接规范参数-电弧耦合行为-小孔和熔池形态-焊缝成形”之间的相关性，为厚板窄间隙高效、优质的焊接提供理论和技术基础。

缆式焊丝电弧焊是一种高效、优质、低耗的焊接方法，独特的电弧旋转耦合行为可改善焊缝侧壁熔透性，解决窄间隙侧壁熔合不良的问题。然而这种焊接方法在大线能量焊接时，接头热影响区组织会出现晶粒粗大现象，导致接头性能下降。本项目针对上述问题，提出在缆式焊丝电弧焊中加入脉冲激光用于窄间隙焊接，利用激光降低电弧电压的特性，减小系统热输入，同时激光的周期性冲击作用还可以破坏粗大晶粒，细化组织，提高焊缝质量。拟采用数值模拟和试验检测相结合的方法，分析大侧壁拘束条件下电弧形态、熔滴过渡形式、匙孔行为及熔池的动态特征，并根据流体动力学与热力学构建接头热、力及流体流动的数值分析模型，对热源系统在时空尺度上的能量耦合行为进行定量研究，阐明热源耦合机制及熔池流体流动行为规律，确立“焊接规范参数-电弧耦合行为-小孔和熔池形态-焊缝成形”之间的相关性，为厚板高效、优质的焊接提供理论和技术基础。

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