High strength welding joint having excellent impact toughness at very low temperature, and flux-cored arc welding wire therefor

Abstract

A high strength welding joint having excellent toughness at 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 balance of Fe and 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 TiO2, 0.01-9 wt % of at least one of SiO2, ZrO2 and Al2O3, 0.5-1.7 wt % of at least one of alkali elements including K, Na, and Li, 0.2-1.5 wt % of at least one of F and Ca, and balance of Fe and inevitable impurities.

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