The article shows the possibilities of the groove welding process in carbon dioxide under the impulse arc power supply. The method makes it possible to reduce the extent of splashing, enables the control of the transfer of electrode metal and weld formation, improvement of the technology of narrow-gap welding, the possibility of carrying and welding in all spatial position is, improvement of the quality of welded joints, and a decrease in the probability of the defect formation. In the application of powerful pulses of welding current the process of solidification of the welded joint is affected resulting in the refining of the structure of deposited metal.