WELDING DEVICE FOR INSIDE SURFACE OF STEEL PIPE

摘要

PURPOSE:To make welding by a 3-electrode system possible in the stage of subjecting the inside surface of a small diameter steel pipe to submerged arc welding by a 3-electrode tandem method by so improving the flux supply system that the flux is supplied from the outside of the steel pipe. CONSTITUTION:In the stage of subjecting the inside surface of a steel pipe of <=500mm. inside diameter to submerged are welding, a flux supply device consisting of a flux storage hopper 8, a flux dispensing means 10 and a guide hopper 11 for flux for the purpose of making a 3-electrode system possible is provided on the outside part of the steel pipe. A welding head 2 provided with three pieces of welding electrodes is mounted to the leading end of a boom 1, and a flux supply pipe 3 provided with a screw conveyor is inserted therein. Flux is supplied at a constant rate to the flux supply port 7 of the head 2 through the pipe 3 from the flux supply device on the outside of the steel pipe.