Abstract: The effects of different shielding gases CO₂, Ar and mixture gases(CO₂+Ar)on the slag detachability of type 347L flux-cored wire for stainless steels containing Nb were investigated. Slag detachability of home-made GDQA347L(3#)was compared with that of TFW-347L flux-cored wire and AT-Y347L flux-cored in the same condition. The effects of slag microstructure and macroscop on the slag detachability of three type flux-cored wires were investigated.The results showed that the best slag detachability of GDQA347L flux-cored wire was under the shielding gas of Ar, and the better slag detachability was under the shielding gas of mixture gas(CO₂+Ar), and the worst slag detachability was under the shielding gas of CO₂. Because the CO₂ gas transfer into active gas at high temperature with strong oxidizability which will make detachment difficult on the slag detachability, and it is proved that the regular of microstructure of three flux-cored wires under different shielding gases is similar. It is benefit for the slag detachability when the trunk of the strip-shaped slag microstructure is long and the area of the branch is large.