高圧Ar-CO_2混合ガス雰囲気下でアーク溶接した鋼溶接金属の機械的性質

概要

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Mild steel sheets with V-groove were welded in pressurized Ar-CO_2 gas mixture atmospheres up to 2.0 MPa, using a 1.6 mm diameter solid wire. The effect of ambient gas pressure and gas composition on the mechanical properties of weld metals were studied. The Vickers hardness and tensile properties of weld metals were varied with the ambient gas composition but did not depend on the ambient gas pressure. The Charpy V notch toughness of weld metal was changed markedly with CO_2 partial pressure in the atmosphere, and showed a maximum at 0.1〜0.2 MPa CO_2 partial pressure which resulted in about 0.03% oxygen content of weld metal having a fine ferrite microstructure. This suggests that toughness is strongly influenced by the oxygen content of weld metal. Mechanical properties of pressurized steel weld metal can be controlled by CO_2% in the welding atmosphere, because the oxygen content of weld metal is determined by CO_2 partial pressure.
社団法人溶接学会の論文
1991-05-05