Ar-N₂ガスシールド溶接における銅溶接金属の機械的性質および焼鈍組織に及ぼす窒素ならびにチタンの影響

抄録

Oxygen-free copper plates were welded with copper and copper-titanium alloy electrode wires using argon-nitrogen gas mixture shielding. The effects of the nitrogen percent (N₂%) in the shielding gas and the titanium content (Ti%) of the electrode wire on mechanical properties and annealed structures of the weld metal were examined. The Vickers hardness increases with Ti% of the electrode wire. The yield stress and the tensile strength of the weld metal increase with Ti% of the electrode wire, while the elongation and the reduction of area show maximum at about 0.5%Ti in the wire. Those tensile properties of the weld metal are independent of N₂% in the shielding gas. β' precipitates are observed in some of the weld metals annealed at 573-1173 K for 3.6 ks. The precipitation is the most remarkable after annealing at 700-800 K, and the amount of the precipitates increases with increase of Ti% in the wire and with decrease of N2% in the shielding gas. The Vickers hardness increases with the amount of the precipitates.