Abstract： To improve welding characteristics of CO2 arc welding, sedan split case and sleeve were welded by conventional CO2 arc welding, conventional CO2 arc welding combined with vibration aging and vibration CO2 arc welding processes. The welding seam residual stress and microscopic structure at various welding conditions were also investigated. The experimental results indicated that vibration CO2 arc welding can reduce welding deformation and residual stress in the cases of proper vibration parameters, resonance frequency and higher vibration amplitude. The highest von mises stress decreases by 41.74%. Weld bond zone and transition zone of vibration CO2 arc welding is more narrower compared with the conventional CO2 arc welding. The crystalline grain in welding seam and heat affect zone (HAZ) become smaller. The microscopic structure changes from columnar grain to equiaxed grain，and the widmanstatten structure decrease even disappear increasingly.
2011, Vol. 30 
