Abstract: Realized is a welding wire containing flux used for a gas shielded arc welding of a direct current/positive polarity mode, with use of which a quantity of sputter generated is small, a good weldability is realized and a weld metal with an excellent toughness is obtained in all the welding positions under application of a welding current in the range of a low current to a medium current, or in a definite manner in the range of 50 to 300 A. The flux contains 0.7 to 3 wt % Al, 0.1 to 1.0 wt % Mg and 1.2 to 5 wt % BaF2, each content being a value in wt % to a total weight of the wire and the sum of a content of Al plus a content of Mg multiplied by 3 being in the range of 1.3 to 5 wt %, a filling ratio of the flux to the total weight of the wire is in the range of 5 to 30 wt %, a total Mn content in a steel sheath and the flux combined is in the range of 0.2 to 1.9 wt % and a total Si content in the steel sheath and the flux combined in the range of 0.001 to 0.9 wt %.

Abstract: Disclosed is a flux-cored wire for gas shield arc welding comprising a mild steel sheath and a flux composition filled in the mild steel sheath, wherein the mild steel sheath is made of a mild steel containing, based on the total weight of the sheath, 0.02% or less of C, 0.01 to 0.20% of Ti, and 0.01 to 0.15% of Al, the contents of Ti and C satisfying a relation of (Ti/C.gtoreq.1.0) and the contents of Al and C satisfying a relation of (Al/C.gtoreq.1.5); and the flux composition contains, based on the weight of the total wire, 0.50 to 3.60% of Mn (including the Mn amount in the sheath), and 0.10 to 1.80% of Si (including the Si amount in the sheath).

Abstract: A gas shielded arc welding method in which a non-consumable electrode and a filler wire are respectively connected to independent DC power sources and the non-consumable electrode is located in a preceding position, feeding the filler wire from behind the electrode. The non-consumable electrode is held in a forwardly tilted position to form an angle smaller than 85.degree. with a workpiece, and the non-consumable electrode and filler wire are applied with inverse electric currents to thereby control the arc direction for formation of sound joints. A welding apparatus is also disclosed which is capable of effecting arc extension control and oscillation simultaneously.

Abstract: A bare welding electrode of a diameter of at least 3.0 mm for use in a large current gas shielded arc welding process in which steel for low temperature use is welded by a welding current of at least 500 A in a shielding gas composed mainly of an inert gas such as Ar, He or the like. In one aspect the electrode comprises up to 0.12% C, up to 0.8% Si, up to 3.0% Mn up to 0.25% Ti, at least one member selected from the group consisting of up to 4.0% Ni, up to 0.8% Cr and up to 1.0% Mo and the carbon equivalent (Ceq), of said electrode being up to 0.60% which is represented by the formulaCeq = C + 1/6Mn + 1/24Si + 1/40Ni + 1/5Cr + 1/4 Mowherein each element denotes the content, % by weight of the element. In the second aspect the bare welding electrode comprises up to 0.12% C, up to 0.8% Si, up to 3.0% Mn, up to 0.19% Ti, 0.0005 to 0.015% B, at least one member selected from the group consisting of up to 4.0% Ni, up to 0.8% Cr and up to 1.0% Mo and which a carbon equivalent of up to 0.

Abstract: A method of manufacturing a thick, high-strength steel pipe for low temperature service comprising the steps of forming into tubular shape a steel plate having a thickness of over 12 mm and a specific composition, of which the C.sub.eq value is adjusted to less than 0.50, when the Mn content is less than 1.0 % whereas the C.sub.eq value is adjusted to less than 0.45 when the Mn content is over 1.0 % and less than 2.0 %, and nextly of welding said tube form at high speeds and high efficiency by the process of single electrode or multiple electrode large-current gas-shielded arc welding with one pass per electrode on each side of the seam at a specific condition, each electrode preferably consisting of a solid wire essentially containing less than 0.3 % Ti with or without the addition of less than 0.