Hydrogen in HY-130 Weld Metal

Abstract : This report summarizes progress in producing welding electrodes containing known amounts of misch metal for reducing hydrogen embrittlement in HY-130 steel welds. Two methods of filler metal fabrication were evaluated during the period covered. In one method an effort was made to produce wire with a misch metal core by extruding, rolling, and wire drawing a composite billet. This effort was not successful because of cracking during rolling the extruded billet. Based on this experience alternate methods, procedures for making the desired wire without rolling were outlined. A specifically fabricated cored electrode wire containing rare earth silicides rather than misch metal was evaluated in welding tests. Several difficulties were noted. These are most importantly related to the silicon content of the resultant welds and their mechanical properties. Production of useful welds was hampered by weld cracking when rare earth contents over 0.05 percent were used. Addition techniques are, at least partially responsible for the inability to make welds with higher concentrations of rare earths. Mechanical test results indicated losses in weld ductility which may not be tolerable. The cause of this may be the silicon or the rare earths or both. Continuing work involves production of electrode wires containing only misch metal in order to isolate their effect on weld metal properties.