为了研究活性焊接技术增大低功率激光焊接接头性能的可行性, 提高小功率激光焊的焊接效率和降低成本, 采用活性激光焊接法, 针对SiO2和Cr2O3活性剂的添加对车体用不锈钢焊接性能的影响进行了理论分析和试验研究, 并与无活性剂焊接试件进行了对比, 取得了焊缝成形、接头显微组织、力学性能及元素分布等方面的研究数据。结果表明, 活性剂的涂覆有效提高了试样对入射激光能量的吸收, 增大了作用于试样的激光功率密度, 进而增加了焊接熔透性。在同一参数条件下, 涂覆适宜厚度SiO2和Cr2O3活性剂试件的焊缝熔深均大于未涂覆活性剂试件。在活性剂的作用下, 接头微观组织仍主要为等轴晶与柱状晶, 但热影响区略有增大。与Cr2O3活性焊接试件及无活性剂焊接试件相比, SiO2活性激光焊接试件的晶粒更细小致密。同时, 活性剂及其涂层厚度对焊缝表面形貌和接头抗拉强度也均有一定的影响, 涂层厚度为0.045 g/cm2 的SiO2活性焊接试件的焊缝平整连续、鱼鳞纹致密均匀成型质量最好, 且接头抗拉强度也最大。此外, 由能谱分析两活性元素在接头中未显著改变焊缝的化学成分相对含量。因此, 适宜活性剂的添加有效改善了低功率激光焊接不锈钢试件的综合性能。

To study feasibility of activating welding technique in increasing strength of low-power pulsed laser weld joint and improve efficiency of low-power laser welding, but decrease cost, this paper carried out theoretical analysis and experimental study to influences of activating flux Cr2O3 and SiO2 on welding performance of stainless steel plate for vehicle body, and make compare analysis of testpiece without activating flux. It acquired research data on weld appearance, joint microstructure, mechanical properties and distribution of elements (composition segregation). Results demonstrated that activating flux could effectively increase laser energy absorption of the steel plate and laser power density, thus improve penetration. Welded testpieces with activating flux coated suitable thickness is superior to that without activating flux in term of welding depth by using same technological parameters. Due to the activating flux, although the joint microstructure is dominated by refined isometric crystals and columnar crystals, the heat affected zone (HAZ) expands to a certain extent. Meanwhile, activating flux and it`s thickness could improve weld appearance achieve higher tensile strength. It acquired the weld surfaces of testpiece with activating flux SiO2 that thinkness of 0.045g/cm2 are smooth, continuous and dense even fish-scale ripples. And it`s had the best appearance and tensile strength. Compared to the testpieces without activating flux and that energy spectral, the involvement of activating flux didn’t Significant change relative contents of chemical components of the welding joint. Therefore, adding suitable activating flux improves performances of low-power laser welding testpieces effectively.