Abstract
In order to study the effect of as-cast surface on the fatigue properties of cast aluminum alloy, 4 point bending fatigue tests were carried out in air and sprayed 3.5vol% salt water. As the results, no effect of the as-cast surface on the fatigue properties was found both in air and corrosion environment. This was mainly caused by the effect of shrinkage cavity in surface layer, which was responsible as a fatigue crack initiation site: The very thin surface layer hardly showed resistance to fatigue crack initiation. That means that the presence of the as-cast surface brought no improvement of the fatigue strength.
