Influence of SiO2 Activating Flux on the Performance of Low Power Laser Welding of Stainless Steel
L-F. Mei, D-B. Yan, J-H. Qin, D. Xie and X-H. Ge
Theoretical analysis and experimental verification are conducted to determine the effects of SiO2 activating flux on the welding performance of stainless steel to verify that activating flux increases the penetration of laser welding, improves the efficiency of low power laser welding, and reduces the production cost. Data are acquired on the variation in weld penetration, joint forming characteristics, mechanical properties, microstructure, and distribution of elements of the activating-laser welding specimens. The results indicate that a coating of activating flux can effectively improve the specimen’s absorption of the incident laser, increase the laser energy acting on the specimen, and consequently increase the penetration. Additionally, an activating flux with the appropriate coating thickness can improve the quality of weld formation, increase weld depth, refine the grain structure of the weld zone, reduce the width of the heat-affected zone (HAZ), and improve the mechanical properties the joints. No evident diffusion or segregation of active elements is observed in the weld joint. The effect of the activating flux does not change the relative contents and distribution of chemical components of the weld. Therefore, an activating flux with the appropriate coating thickness on the specimen surface effectively improves the overall performance of stainless-steel specimens welded by low power laser.
Keywords: Nd:YAG laser, SUS304 stainless steel, SiO2 activating flux, laser , weld penetration, performance