活性激光电弧复合焊接法研究

Research on Activating Laser Arc Hybrid Welding

为了进一步提高激光电弧复合焊接的熔深,提出活性激光电弧复合焊接法。在氧气的保护下,用小功率光纤激光在待焊焊件表面进行预熔处理,使表面熔化生成一层氧化层,然后用激光电弧复合焊接覆盖氧化层,达到增加熔深的目的。结果表明,激光预熔后进行激光电弧复合焊接,电弧明显收缩,熔深增加1.5倍左右,表面成形良好。激光预熔后,焊缝含氧量增加,熔池表面张力温度系数由负变正,使得复合焊接熔深增加。研究工艺参数对焊缝熔深和熔宽的影响,随着激光预熔功率的增加,熔深增加熔宽减小;随着电流的增加,熔深熔宽都增加,但激光预熔后的焊道增加更快。随着复合焊接速度的增加,熔深和熔宽都减小。随着复合焊接中激光功率的增加,熔深增加,对熔宽的影响较小。利用活性激光电弧复合焊接法,可以得到较为细小的焊缝组织,提高焊接接头的抗拉强度,能达到母材抗拉强度的95%,且面弯和背弯180°后未出现裂纹,表明接头具有良好的韧性。

In order to improve the penetration of laser arc hybrid welding, activating laser arc hybrid welding is proposed. The surface of weld is melted by the tiny laser power protected by oxygen; as a result, there is a layer of oxide on the surface. Then laser arc hybrid welding is used to cover the weld, which can increase the penetration. Results show that the penetration of laser arc hybrid welding is increased about twice. The formation of the weld surface is elegant. The content of oxygen will be increased when surface of weld is melted by laser. The temperature dependence of surface tension gradient can be changed from a negative value to a positive value by oxygen which can increase the penetration. The influence of welding parameters on the welding melts depth and the width is studied. Increasing the preheated power of laser conditioning can increase penetration and reduce the width. Increasing arc current can increase the width and depth of molten weld. The increase of welding speed can reduce the width and depth of molten weld.The increase laser power of hybrid welding can increase the weld penetration and have little influence on the width. Tiny microstructures of weld metal can be produced by activating laser arc hybrid welding, which can improve the tensile strength. The tensile strength of activating laser arc hybrid weld joint can reach 95% of base metal. No crack or defects are noticed on the surfaces during bending experiment, this observation confirms that the toughness of the weld joint is good.