THE LASER-ARC HYBRID WELDING WELDMENT OF CARBON STEEL, AND THE LASER-ARC HYBRID WELDING METHOD FOR THE SAME

摘要

A hybrid welded part of carbon steel capable of minimizing welding defects and giving sufficient toughness to a welded part at the same time while performing complete penetration of a but joint in which a grooving portion of a base metal is grooved in a non-processed "I" character or "Y" character shape, during a single side laser-arc hybrid welding, and a hybrid welding method for forming the same are provided. A single side laser-arc hybrid welded part of carbon steel has an "I" type or "Y" type butt joint containing, by weight percent, 0.18% or less of C, 0.70 to 1.60% of Mn, 0.10 to 0.50% of Si, and 0.02% or less of Ti as principal constituents, 0.15% or less of Nb+V and 1.05% or less of Cu+Cr+Ni+Mo as traces of alloy elements, and the balance of Fe and unavoidable impurities, wherein a cross sectional welded part perpendicular to a welding proceeding direction satisfies a mathematical expression 1, D(%)=[{WM-(GÎT)}/(WU+WM+WB)]Î100=70, or a mathematical expression 2, theta(‹)=tan^-1{(UL/2)/PA}, 20=theta=50, among area(WU) of an upper cradle(11) projected upward to the outside from upper surfaces of two base metals(10), total welding metal area(WM) between two base metals, a lower cradle area(WB), a gap(G) between the two base metals, base metal thickness(T), penetration depth(PA) of arc welding metal, and width(UL) of an upper surface or the upper cradle of an arc welding metal(12), wherein D is a dilution ratio of a welding metal matrix, and theta is an arc welding part angle.