Occurrence and Prevention of Defects in Depplty Penetrated Sudmerged-Arc Weld Bead

Abstract

The correlation between occurrence of weld defects and welding parameters in high-current sub-mnerged-arc welding was studied over the range of 500 to 2000 amp, 25 to 50 volt and 25 to 250 cm/min, and a deep penetration multi-electrode submerged-arc welding process was developed. Main results obtained were as follows;
(1) Solidification cracks, undercutting and overlapping were apt to occur in the weld bead made by the buried arc at high-current and low-voltage.
(2) To prevent such cracks and undercutting it was effective to improve the solidification mode of weld metal by using a multi-electrode submerged-arc system suitably spacing the electrodes.
(3) To prevent such overlapping it was necessary to select adequate groove geometry.
(4) The multi-electrode submerged-arc welding process, which was characterized by the buried leading arc and the trailing arc operating as hot-top was able to provide a sound weld bead with deep penetration.