Research On Laser-Arc Hybrid Welding Technology Of High Strength Steels

In this paper, on the basis of summarizing hybrid welding technique, the hybrid welding test is carried out by CO2 laser and MAG welding machine, and the welding temperature field of hybrid welding is simulated by using ANSYS software.The effects of laser power, arc voltage, arc current and shielding gas on bead profile and droplet transfer are studied. The results indicate that laser power has greater effect on welding penetration. The welding penetration increases with laser power increasing when the other parameters are fixed. Arc has greater effect on welding width. The welding width increases with arc current increasing. Arc current has little effect on the welding penetration, but the welding penetration decreaces when arc current is too large. Because the plasma and droplet shield laser. Droplet transfer turns from short circuiting to rotating transfer when arc current is 180A. When the gas flow rate is increased(from 15L/min to 35L/min), the hybrid welding process is changed from stability to instability. The welding penetration first increases, then decreases. The plasma height, frequency of droplet transfer and separation velocity of droplet decrease while the droplet diameter increases significantly.The double ellipsoid heat source model is used to summarize temperature field of hybrid welding for finite element analysis. The results indicate that the range of isotherm of hybrid welding is less than MAG welding and larger than laser welding. The results of temperature field show that welding seam is narrow and deep in depth, which means hybrid welding keeps laser welding superior ability to penetrate. The double ellipsoid heat source model is suited to summarize temperature field and the shape of metallic bath.