PURPOSE: To obtain beautiful weld beads having no defects on both front and rear surfaces in the stage of subjecting low melting metallic materials to high- energy density welding by subjecting said materials to penetration welding at the energy density at which a backing strip made of copper or copper alloy does not melt.
CONSTITUTION: The low melting metallic materials consisting of an Al alloy, Mg alloy, etc. are used as materials to be welded and are subjected to the penetration welding of high-energy density by using the backing strip made of the copper or copper alloy. The welding conditions under which the backing strip does not melt are set in this stage from the relation between the value ab obtd. by dividing the distance D0 from the center of the focusing coil 2 of an energy beam 1 to the surface of the work 3 by the distance DF from the center of the coil 2 to the beam focus 4 and the beam current. The good weld beads having no defects on both the front and rear surfaces are thus obtd.
NUMATA ATSUSHI
MORIBE MASANORI
