PURPOSE: To fix the nitrogen in weld metal owing to the nitrogen in the air remained in a dry type chamber and eliminate its harm without requiring any shielding gas by beforehand containing the specified weight % of titanium in the bare electrode steel wire used for welding.
CONSTITUTION: In the captioned welding within the chamber suspended from an assisting ship on the sea, titanium is beforehand contained in the bare electrode steel wire used and welding is done without using any shielding gas by He gas. In this case, the amount of penetration of the nitrogen in the air remained in the chamber into the weld metal is fixed by the foregoing titanium. Tutanium is contained in the bare electrode steel wire so that free nitrogen becomes 0.01wt% or less. For example, without shielding gas, the N-content in the weld metal becomes 0.05wt% and in order to make 0.01wt% of good metal, the Ti amount at which the balance 0.04wt% of N is made TiN, that is, 0.14wt% of Ti becomes necessary.
TAYAMADA KUWATAROU
OZAKI HIRONORI
