Application of Narrow Gap Welding Process with High Speed Rotating Arc to Box Column Joints of Heavy Thick Plates

Recently, heavy thick plates of high strength steel have been applied to the columns of high-rise buildings in Japan. The maximum thickness of the plates reaches 100 mm and the application of SA440 steel, having yield strength of 590 N/mm 2 , has now become common. In addition, unprecedent high welding performance, such as higher than 70 J CV at 0°C for the welded metal, is now required to fabricate these plates. The authors have developed a new welding system to combine the narrow gap welding process with high speed rotating arc (Patented by JFE Engineering) and the submerged arc welding to keep the required quality for the corner welding of plates with the thickness more than 70 mm. The paper introduces the outline of the new system.