METHOD AND APPARATUS FOR FORMING A ROOT BEAD BY A SUBMERGED ARC WELDING PROCESS

摘要

ABSTRACT OF THE DISCLOSUREThis disclosure relates to a method and apparatusfor welding a root bead in a gap between two relative-ly thick plates by a submerged arc welding process. Anarc is formed by moving the welding electrode parallelto and closely adjacent the gap, and the weldingcurrent is alternated between a background currentlevel and a higher or peak current level. The peakcurrent level is high enough to heat and melt thelands at the bottom of the groove between the twoplates, and the background current level is sufficientto deposit filler metal to form the root bead withoutcracking or burning through the root bead. Afterthe root bead has been formed, the groove is filledby depositing additional filler metal.