Flux-cored wire for gas shield arc welding with low fume

A metal based flux-cored wire for gas shield arc welding comprising a mild steel sheath and a flux composition filled in said mild steel sheath,

• wherein said flux composition is filled in said mild steel sheath in an amount of 10 to 30% based on the total weight of said wire;
• and
• said flux composition contains, based on the total weight of said flux, 60 to 85% of Fe powder, 0.5% or less of C, 0.5 to 3.0% of Ti, and 0.01 to 0.3%, as Cs or Rb converted value or both, of the total of one or more compounds of Cs, Rb or both, the contents of C, Cs, Rb and Ti satisfying a relation of C/(Cs+Rb)+Ti=3 or more, wherein the values of Cs, Rb or both are converted from those in compounds of Cs and Rb wherein percentage is based on the weight of the total flux.

A titania based flux-cored wire for gas shield arc welding comprising a mild steel sheath and a flux composition filled in said mild steel sheath,

• wherein said flux composition is filled in said mild steel sheath in an amount of 5 to 30% based on the total weight of said wire;
• and
• said flux composition contains, based on the total weight of said flux, 8 to 60% of TiO.sub.2, 0.01 to 1.0% of Cs compound as Cs converted value, and 0.5% or less of C, said ratio between TiO.sub.2 /compounds of Cs being in the range of from 20 to 2000.

A metal based flux-cored wire for gas shield arc welding comprising a mild steel sheath and a flux composition filled in said mild steel sheath,

• wherein said mild steel sheath is made of a mild steel containing, based on the total weight of said sheath, 0.02% or less of C, 0.01 to 0.20% of Ti, and 0.01 to 0.10% 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
• said flux composition contains, based on the total weight of said wire, 0.01 to 0.30%, as alkali metal converted value, of one or more kinds of oxides and fluorides of alkali metals other than Cs and Rb, 5 to 28% of Fe powder, 94% or more, based on the total weight of said flux, of metal powder, and 0.001 to 0.10%, as Cs or Rb converted value or both, of the total of one or more compounds of Cs, Rb or both, and further 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 content in the sheath.

A titania based flux-cored wire for gas shield arc welding comprising a mild steel sheath and a flux composition filled in said mild steel sheath,

• wherein said mild steel sheath is made of a mild steel containing, based on the total weight of said 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
• said flux composition contains, based on the total weight of said wire, 1.00 to 8.50% of TiO.sub.2, 0.01 to 1.50%, as alkali metal converted value, of oxides of alkali metals other than Cs, 0.0005 to 0.3%, as Cs converted value, of a compound of Cs, said ratio between TiO.sub.2 /compounds of Cs, as Cs converted value being in the range of from 20 to 2000, 0.06% or less of C, 0.50 to 3.60% of Mn, including the Mn amount in the sheath, and 0.10 to 1.50% of Si, including the Si amount in the sheath.