Abstract: The aim of developing the automatic welding machine for welding nozzle sinto vessels is to replace the heavy labour of manual welding by low physical,high efficient and good quality mechanization.The welding head can rotate to weld circular seams continuously.It is positioned and electrically driven together with a suspending frame on support wheels.The torch possesses four degrees of freedom in motion:vertical,radial,revolving and angular swinging.Sc801 cmicrocomputer is applied to control the welding process,technological parameters and the torch motion with great flexibility and accuracy.Argon-rich shielded pulsed current spray metal transfer ensures a very stable welding processwith cxcellent quality and without spatter.