Flux-cored wire

Abstract

The invention provides a flux-cored wire which is excellent in high temperature and fissure resistance, welding property and machinery property of welding metals. The flux-cored wire is filled with welding flux in an outer steel skin, wherein relative to the total weight of the wire, the welding flux has a filling ratio of 10 to 25 wt.%, the content of C is 0.03 to 0.08 wt.%, the content of Si is 0.10 to 1.00 wt.%, the content of Mn is 2.4 to 3.7 wt.%, the content of Ti is 0.15 to 1.00 wt.%, the content of TiO is 2.5 to 8.0 wt.%, the content of Al is 0.20 to 0.50 wt.%, the content of Al2O3 is 0.05 to 0.50 wt.%, the content of B is 0.003 to 0.020 wt.%, and the residue is Fe and unavoidable impurities; 4*Ti plus 10*Al minus 3*Si is more than or equal to 1.0; and Ti mass is calculated according to the content of Ti and TiO2 in the wire.

Description

technical field [0001] The present invention relates to a flux-cored welding wire suitable for gas-shielded arc welding of steel plates made of mild steel and high-tensile steel. Background technique [0002] Conventionally, the following configurations have been proposed as flux-cored wires suitable for gas-shielded arc welding. For example, Patent Document 1 proposes a gas-shielded arc welding flux-cored wire containing a predetermined amount of TiO with respect to the total mass of the wire. 2 , SiO 2 , ZrO 2 , CaO, Na 2 O, K 2 O, F, C, Si, Mn, Al, Mg, P, S, B, Bi, Fe and unavoidable impurities in the balance, and Na 2 O+K 2 O, Mn / Si, and Al+Mg are predetermined amounts. [0003] Patent Document 1: JP-A-2006-289404 [0004] However, the welding wire described in Patent Document 1 does not contain Ti and also has a small Mn content. Therefore, there is a problem of high-temperature cracking in the first layer welding in single-face butt joint welding of steel plate...

AI Technical Summary

Problems solved by technology

[0004] However, the welding wire described in Patent Document 1 does not contain Ti and also has a small Mn content. Therefore, there is a problem of high-temperature cracking in the first layer of welding in single-face butt joint welding of steel plates.

In addition, since the welding wire does not contain Al 2 o 3 , so there is a problem that the bead shape of the horizontal fillet weld is poor, or the bead sags in the vertical upward welding, and the welding workability in the full posture welding is poor.

In addition, since the amount of Mn and B in the welding wire is small, there is a problem that the mechanical properties (toughness) of the weld metal are poor

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