Junichi Kinugawa

Preliminary Experiment on Improvement of Underwater Wet Plasma Welds Using Filler Metal

The possibility of improving the ductility and notch toughness of underwater wet plasma welds was investigated by controlling the chemical composition of them using filler metals.The welding environment was selected in fresh water under the pressurized condition of 10 kgf/cm2 [gauge].Results of this experiment are summarized as follows.(1) Two kinds of filler metals, one of them had the basic composition of 0.013 wt% carbon, 0.081 wt% silicon, 1.05 wt% manganese and iron as the balance-base filler metal-and the other was added 0.59 wt% titanium to the above-mentioned base filler metal, were shown the possibility of improving the ductility of single pass double Vee butt joint.(2) Addition of niobium alone or molybdenum with boron to the base filler metal had less contribution to the improvement of weld metal ductility.(3) It is necessary to reconsider the chemical composition of filler metal for filled pass in multi-pass welding, because the dilution of the deposited metal with the base metal in filled pass differs from that of the root pass.