FUSION WELDING METHOD Russian patent published in 2007 - IPC B23K26/20 B23K9/00 B23K15/00 

FIELD: machine engineering, namely processes and equipment for fusion welding, possibly of different-structure parts, for example providing fluid-tightness of active zones of nuclear reactors at usual condition and from remote places.

SUBSTANCE: method comprises steps of supplying energy to welding zone by pulses; performing welding by several passes while controlling energy density in heating spot of heat source during process of forming seam; selecting relation of pulse energy density in heating spot to pulse duration at first pass in range ( 5 - 350) x 10² J/(mm² s); selecting less values of said relation for lowered thickness of welded edges and selecting larger value of said relation for increased thickness of welded edges in given range. At each next pass relation of energy density of pulse in heating spot to pulse duration is set equal to or less than value of said relation in first pass.

EFFECT: possibility for improving quality and operational reliability of welded joints of different structures due to lowered size of pores and of oxide inclusions and due to their partial removal.