A study on the effect to yongrak phenomenon of submerged arc welding depending on the plasma cutting surface characteristics

Abstract: This paper was to study the effect to Yongrak phenomenon of I groove submerged arc welding de-pending on the plasma cutting surface characteristics, and how to reduce the causes and characteristics Yongrak phenomenon. Shipbuilding and marine structures is designed to use the thick plates and welded by high current to obtain deep penetration. Yongrak phenomenon has been occurred frequently depending on the quality of cutting surface and it makes degrade of the welding quality and modification of the welding. As a result, it was confirmed that I Groove plasma cutting characteristics get bevel form of 2 to 4 degrees to one side direction from the vertical position with Yongrak phenomenon. This is the main reason of Yongrak phe-nomenon in butt joint welding and 4 degree reverse bevel on the upper surface of base metal by submerged arc welding brought the effect of significant reduction of Yongrak phenomenon. Keywords: Shipbuilding and Marine Structures, Plasma cutting, Yongrak phenomenon, Submerged arc welding.