渣金间辅助外电场提高焊接工艺稳定性分析

为探索焊接过程实现高稳定性工艺的潜在途径,最大限度地减少重要钢结构制造中焊缝咬边及成形缺陷带来的焊后返修工作,提出并试验了一种利用埋弧焊渣金间随焊施加辅助外电场对渣金电导载流进行导流,进而提高焊接工艺稳定性的方法,并应用焊接电信号分析仪对弧压信号进行了采集统计分析.结果表明,以钨电极作阴极利用电场在渣金熔体内部形成稳定的电导载流,可使熔渣电导性能得以改善,并引导电子进入电弧阴极中心以增强电弧的集聚程度.同时外电场作用也使渣金内部的带电粒子形成有序运动并在界面结合成低表面能的活性氧化物,又可改善液态熔渣在焊缝金属表面的润湿铺展性能.实施辅助电场引入的这些有益作用使焊缝形状、表面光洁度、尤其是焊缝边缘平直均匀性得到较好地改观,焊接过程工艺稳定性得以进一步提高.

Analysis of improving stability of welding technology by applying auxiliary electric field between slag and metal

To improve the stability of welding technology and reduce the post-weld repair due to defects like surface imperfections in key steel structure,a new method by applying auxiliary electric field between the slag and metal during submerged arc welding to guide electric current was developed. The electric signal instrument was used to collect arc voltages for statistics and analysis. The results show that the electric conductivity of molten slag can be improved with tungsten electrode as the cathode,and the electrons are guided into the arc centre to contract the welding arc. Meanwhile,positive and negative ions in the molten slag and weld pool metal migrated to the interface and combined into active oxides with low surface energy. Thus the wetting and spreading performance of molten slag on the surface of weld pool metal are improved. With the beneficial effect brought by the auxiliary electric field,the weld surface is smooth,the appearance of weld and especially the consistency of weld width are improved. Also,the welding process is more stable.