Optimization of GMA welding process under vibration of high strength steel

The WQ960 high strength steel was welded by GMAW welding under mechanical vibration. The welding current, vibration frequency and amplitude were changed to achieve welding with vibration during the welding process. In order to determine the optimal vibration welding process parameters of high strength steel, the orthogonal test method was used. The microstructure, tensile and impact properties of the welded joint at different parameters were analyzed to determine the optimal parameters. The relationship between vibration parameters and welding parameters and microstructure and properties of welded joints were researched, the action mechanism was also discussed. The results showthat the optimal properties of welded joints are obtained at welding current I=220 A, frequency f=50 Hz, and vibration amplitude A=0.5 mm, whicharetensile strength R_m=875 MPa, the impact energy A_Kv==70 J. The vibrations can refine grains, reduce eutectoid ferrite precipitation, increase the number of needle ferrite, thereby the mechanical properties of welded joints can be improved.