알루미늄합금 용접부의 피도강도특성에 관한 연구

Abstract

In this study, GMA welding was carried out by varying ratio of mixture gas in order to prove and verify the relationship of mixture ratio and effectiveness of shield gas of Al5083-O which is aluminum alloy used frequently for low temperature containers. Tensile test and fatigue test were carried out at the various temperature ranges from high to extremely lower temperature.

The summarized results from the experiment are as follows ;

1) Fatigue limit of the material Al5083-O at room temperature was appeared approximately 80.3MPa and fatigue limit of weld rigions were appeared increased higher order of Heat Affected Zone, fusion line and weld metal. 2) Mechanical properties of GMA weld according to mixture ratio of protection gas were appeared the best results the best with the ratio of Ar33%+He67%. 3) Fatigue life of weld metal was decreaced with increase of Helium in protection gas mixture ratio, while fusion line and heat Affected Zone were increased. 4) Initial fatigue crack propagation of weld metal was appeared lower rate in low Helium ratio(0∼33%), fusion line and H.A.Z were appeared lower rate in High(50∼67%) Helium ratio. 5) The fatigue life increased at lower temperatures, particularly at -196℃, However different gas ratio and welding zone had little effect upon the fatigue life.