To obtain welded metal part excellent in the ductility at low temp. in a submerged arc welding of a controlled deoxidized steel and to enable the welding of a structural material for low temp. service by using bond flux and a wire having specific composition to each.
In the submerged arc welding, a steel plate having ≤0.015wt.% in the total content of the elements of one or more selected from Ca. Mg, Zr and Al, is welded. At this time, the bond flux for submerged arc welding, satisfying the equations I, II and III and having 8≤(SiO2)F≤16%, (Si)F≤0.5%, 0.1≤(Al)F≤1.5%, (Mg)F≤4.5% and 0.1≤(Al)F+0.25×(Mg)F≤1.5%, and the wire for submerged arc welding, satisfying the equations I, II and III and having 0.0005 ≤[C]W≤0.08%, 0.005%≤[Si]W≤0.10% and 1.5%≤[Ni]W≤3.5%, are used. Wherein, ()F shows each content in the flux and [ ]W shows each content in the wire.
OHAMA NOBUYUKI
TOBISHIMA NOBUAKI
NANBU MIKIO
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