CONTROLLING METHOD FOR CONVECTION OF MOLTEN POOL IN BUILD-UP WELDING

摘要

PURPOSE:To prevent the generation of undercuts in weld beads and to form normal build-up beads in the stage of build-up welding using a band-like electrode by flowing earth current in the direction right under the molten pool and generating forced magnetic fields in the welding advance direction by external magnetic field generating sources. CONSTITUTION:In the stage of building-up welding of a base metal 11 with an arc 13 by using a band-like electrode 12, an earth current conducting plate 16 consisting of a nonmagnetic metal such as copper is mounted freely slidably on the rear surface of the metal 11 by means of springs 17 on a carriage 18. The earth current A during build-up welding is flowed to the direction right under a molten pool 14, and is flowed to an earth terminal through the plate 16. At the same time, U-shaped iron cores 21a, 21b are disposed in both end parts of the electrode 12, and electricity is conducted to coils 23a, 23b in such a way that the forced magnetic fields C of opposite directions are generated in the coils 23a, 23b. Uniform convection is generated in the width direction of the pool 14 by the effect of the electromagnetic forces generated by the magnetic fields C and the earth current A, by which the generation of undercuts is effectively prevented and the normal build-up beads are formed.