The alternate bending tests were conducted on butt-welded specimens of 5083-0 aluminum alloy with thickness of 6mm having serious porosities as the weld defects. The porosity was artificially introduced into the welds by MIG welding using the excessively wet filler wire. The state of existing porosities was examined for all buttwelded specimens by radiography.
The principal results observed were as follows.
1) The fatigue fracture of butt-welded specimens with reinforcement occurred at the weld toe even though the specimens contained remarkable porosities. The presence of porosities in the weld does not affect the fatigue strength in the as-welded condition.
2) The fatigue strength of specimens containing serious porosities, but having the small reinforcement angle by machining the deposite metal near the weld toe, was slightly greater than that of the defect-free specimens. The fatigue strength in the as-welded condition is more affected by the reinforcement shape than by the porosities.
3) In the case of the butt-welded specimen with the reinforcement machined flush, considerable decrease of the fatigue strength resulted from the existence of serious porosities.