激光填丝焊是一种具有广泛应用领域的焊接工艺。针对现有旁送丝填焊工艺存在的不足,提出了光束中空、正向同轴送丝创新方案。利用所研制的光内同轴送丝焊接装置进行了焊接试验。结果表明,同轴送丝焊接具有光丝耦合姿态固定、热源对称、能量分布合理等突出优势。焊缝表面光滑平整,截面形状对称。焊缝质量各向同性,适用于一维和多维焊接。对变动激光功率、扫描速度和送丝速度进行了工艺试验,获得了一组优化的工艺参数。焊缝的扫描电镜(SEM)分析和拉伸试验表明,激光光内同轴送丝所获得的焊道组织致密、均匀,无气孔、夹渣等缺陷,是理想的激热激冷组织;焊缝与基材结合牢固,结合区无明显缺陷。

Laser welding with filler wire is a widely used welding technology. In view of the disadvantages of the welding technology with side wire feeding,a new method of coaxial wire-feeding is put forward based on an annular laser beam. The welding experiments have been done with the self-design internal coaxial wire feeding welding equipment. The results show that the coaxial wire feeding welding technology has prominent advantages on many aspects,such as stability of coupling between beam and wire,symmetry of heat resource,and optimization of energy distribution. The welding seam surfaces are smooth and flat and their cross sections are symmetrical. The property of isotropic quality is suitable for one-dimensional and multi-dimensional welding. Through altering of laser power,scanning speed,and wire feeding speed,a set of optimal process parameters have been obtained. The results of scanning electron microscope (SEM) analysis and tensile test show that the welding seam produced by this new method has excellent microstructure which is very dense without pores and impurities. Moreover,the metallurgical bonding between welding seam and substrate is very strong and has no obvious flaws.