High strength solder joint having excellent impact hardness at very low temperature, and a corresponding flux cored arc welding wire

摘要

Provided are a high strength welding joint having excellent impact toughness at very low temperature, and a flux-cored arc welding wire therefor. The present invention relates to: a high strength welding joint having excellent toughness at very low temperature obtained by welding a cryogenic high-strength high-Mn steel, comprising 0.1-0.61 wt% of C, 0.23-1.0 wt% of Si, 14-35 wt% of Mn, 6 wt% or less of Cr, 1.45-3.5 wt% of Mo, 0.02 wt% or less of S, 0.02 wt% or less of P, 0.001-0.01 wt% of B, 0.001-0.2 wt% of Ti, 0.001-0.3 wt% of N, and the balance of Fe and other inevitable impurities; and a flux-cored arc welding wire comprising 0.15-0.8 wt% of C, 0.2-1.2 wt% of Si, 15-34 wt% of Mn, 6 wt% or less of Cr, 1.5-4 wt% of Mo, 0.02 wt% or less of S, 0.02 wt% or less of P, 0.01 wt% or less of B, 0.1-0.5 wt% of Ti, 0.001-0.3 wt% of N, 4-15 wt% of TiO 2, 0.01-9 wt% of at least one of Si0 2 , ZrO 2 and Al 2 O 3 , 0.5-1.7 wt% of at least one of alkali elements such as K, Na, and Li, 0.2-1.5 wt% of at least one of F and Ca, and the balance of Fe and other inevitable impurities.