Studies on the underwater CO₂ arc welding method with a curtain nozzle

Fillet welding of mild steel

Abstract

In case of the butt joint, previous report indicated that good welds were obtained by using the water curtain type CO₂ arc welding method.
This paper presents the results of experimental investigation of the horizontal fillet welding used by th, said method, and following conclusions were reached.
1) The water curtain type CO₂ arc welding method was also effectively available for underwater horizontal fillet joint.
2) Good welds without blowholes and cracks were obtained by selection of optimum welding conditions.
3) Welding speed used with flux cored wire faster about twice than that of used with solid wire. 4) From the results of studies on effect of O₂ mixing in Ar and CO₂ shileding gas, the hardness of welds decreased with the increace of oxygen content in case of solid wire.
5) The joint with root gap up to 2-3 mm did not affect the welding result.