保护气体对接头形貌及熔滴过渡的影响与模拟

为了研究保护气体流量对复合焊接接头形貌及熔滴过渡的影响，采用5mm厚的高强钢板材进行了激光电弧复合焊接试验的理论分析和实验验证，获得了不同气流量下的焊缝形貌以及焊接过程中电弧和熔滴图像。结果表明，随着保护气体流量的增大，焊接熔深先增大后减小；当保护气体流量在25L/min，焊接熔深达到最大；且焊缝的铺展性较好，飞溅较少；保护气体流量通过影响熔滴过渡的形式，对熔滴过渡频率产生影响；随着气流量的增大，熔滴过渡频率减小，且在25L/min时，熔滴过渡频率较稳定；采用FLUENT软件对气流量进行数值模拟，气流量越大，保护气体流速越大，在工件表面的作用面积减小。该研究结果为实际工程应用中选择保护气体流量制备高质量的焊缝奠定了基础。

Influence and simulation of protective gas on joint morphology and droplet transition

In order to study effect of protective gas flow on morphology and droplet transition of hybrid welding joint, theoretical analysis and experimental verification of laser arc hybrid welding test were carried out by using 5mm thick high strength steel sheet. The morphology of welding seam under different gas flow, arc and droplet image during the welding process were obtained. The results show that the welding depth first increases and then decreases with the increase of shelding gas flow. The welding depth reaches the maximum with shelding gas flow of 25L/min. The welding seams have good spreading and less splash. Shelding gas flow affects droplet transition frequency by affecting droplet transition form. Droplet transition frequency reduces with the increase of shelding gas flow. Droplet transition frequency is stable with shelding gas flow of 25L/min. FLUENT software was used to simulate gas flow. The larger the gas flow, the greater the shelding gas flow rate, the smaller the action area on the workpiece surface. The results lay the foundation for the preparation of high quality welding seam with shelding gas flow in practical engineering.