According to an aspect of the present invention, there is provided a flux-cored wire including a steel sheath and a flux that fills the steel sheath. The flux contains fluorides of which a total value a of F-equivalent values is 0.21% or more, oxides of which the total value of amounts ranges from 0.30% to less than 3.50%, and carbonates of which a total value of amounts ranges from 0% to 3.50%. An amount of CaO ranges from 0% to less than 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A X-value is 5.0% or less. The amount of CaF.sub.2 is less than 0.50%. The amount of Ti oxides ranges from 0.10% to less than 2.50%. A ratio of to ranges from 0.10 to 4.00. A total value of amounts of MgCO.sub.3, Na.sub.2CO.sub.3, and LiCO.sub.3 ranges from 0% to 3.00%. Other chemical composition is within a predetermined range. Ceq ranges from 0.45% to 1.20%.

The present invention relates to steel pipe excellent in toughness of the weld metal part at a low temperature obtained by submerged arc welding in the longitudinal direction from both the inside and outside surfaces having strengths of the X60 to X70 class. The steel pipe of the present invention is a pipe having weld zones welded in a longitudinal direction at an inside surface and outside surface, wherein the tensile strength of the base metal is 480 to 620 MPa, the weld metal has a predetermined composition of constituents, when % X expresses a content of an element X in the weld metal, Pcm defined by Pcm=% C+% Si/30+(% Mn+% Cu+% Cr)/20+% Ni/60+% Mo/15+% V/10+5% B is 0.2% or less, Ceq defined by Ceq=% C+% Mn/6+(% Cr+% Mo+% V)/5+(% Ni+% Cu)/15 is 0.35 to 0.45%, defined by =(1.5(% O0.89% Al)+3.4% N% Ti)1000 is 20 to 40, and % Al/% O is 0.3 to 0.8.

A weld wire of the present invention comprises a steel sheath encapsulating a fluxed core having a combination of fluxing compounds and alloying elements. The fluxing compounds comprise up to 2% Wt of fluoride compounds and up to 49% Wt of oxide compounds. The alloying elements comprise Mn, Ni, Co, Ti and up to about 0.98% Wt of C. The amount of Co is sufficient to produce a ferrite-bainite weld metal morphology of a resulting weld. A yield strength of the resulting weld was measured from about 95 ksi to about 111 ksi.

A submerged arc welding wire is provided that has a composition including, by mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Cr: 6.0 to 15.0%, and N: 0.120% or less, the balance being Fe and incidental impurities. Where necessary, the wire may contain one or two selected from Ni and Mo, may further contain one, or two or more selected from V, Ti, and Nb, and may additionally contain one, or two or more selected from Cu, Al, Ca, and REM.

A metal cored wire for submerged arc welding, the wire comprising a steel sheath with a core comprising powders of: carbon in a range of about 0.3 wt. % to about 1.2 wt. %; silicon in a range of about 0.1 wt. % to about 3.0 wt. %; manganese in a range of about 9.0 wt. % to about 30 wt. %; chromium in an amount less than about 8 wt. %; nickel in an amount less than about 6 wt. %; molybdenum in an amount less than about 6 wt. %; tungsten in an amount less than about 5 wt. %; copper in an amount less than about 4 wt. %; niobium in an amount less than about 2 wt. %; vanadium in an amount less than about 2 wt. %; titanium in an amount less than about 2 wt. %; nitrogen in an amount less than about 0.4 wt. %; boron in an amount less than about 1 wt. %; at least one of: (i) sulfur in an amount less than about 0.3 wt. %; (ii) phosphorous in an amount less than about 0.03 wt. %; or a combination thereof; and the balance with iron.

A TIG welding filler metal is provided that has a composition including, by mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Cr: 6.0 to 15.0%, and N: 0.120% or less, the balance being Fe and incidental impurities. Where necessary, the filler metal may contain one or two selected from Ni and Mo, may further contain one, or two or more selected from V, Ti, and Nb, and may additionally contain one, or two or more selected from Cu, Al, Ca, and REM. This configuration reduces the occurrence of welding cracks during TIG welding, that is, realizes excellent hot crack resistance, and allows for easy production of a weld joint having high strength and excellent cryogenic impact toughness.

A method for producing a part includes providing a first and a second precoated sheet (1,2), butt welding the first and second precoated sheets (1) to obtain a blank (15), and heating the blank (15) to a heat treatment temperature at least 10 C. lower than the full austenitization temperature of the weld joint (22) and at least 15 C. higher than a minimum temperature T.sub.min: $T_{\min }\left(C.\right)=\mathrm{AC}3\left(\mathrm{WJ}\right)-\frac{{}_{\mathrm{IC}}^{\max }}{100}\left(\mathrm{Ac}3\left(\mathrm{WJ}\right)-673-40\mathrm{Al}\right).$ where Ac3(WJ) is the full austenitization temperature of the weld joint (22) ${}_{\mathrm{IC}}^{\max }=(1-\frac{\left(1+\right)(}{}$

A submerged arc welded joint in a high-Mn content steel material that can be formed with reduced occurrence of hot cracking during the welding process and has high strength and excellent cryogenic impact toughness. In the welded joint, the high-Mn content steel material has a chemical composition including, by mass %, C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 18.0 to 30.0%, P: 0.030% or less, S: 0.0070% or less, Al: 0.010 to 0.070%, Cr: 2.5 to 7.0%, N: 0.0050 to 0.0500%, and O: 0.0050% or less, the balance being Fe and incidental impurities, and a weld metal has a chemical composition including C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.100% or less, Cr: 6.0 to 14.0%, and N: 0.100% or less, the balance being Fe and incidental impurities.

The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. The tubular welding wire is configured to form a weld deposit on a structural steel workpiece, wherein the weld deposit includes less than approximately 2.5% manganese by weight.

The present invention relates to a welded structural member having excellent corrosion resistance and crack resistance, and a method for manufacturing same.