Fatigue Behavior of Tube-to-Tubesheet Expanded Joints

In order to study the fatigue behavior of expanded tube-to-tubesheet joints for steam generators and tubular heat exchangers under cyclical loading, both static and fatigue tests were performed. As a result of the sticking interface which is formed between the tube and tubesheet hole, it is shown that: 1) the expanded joint of tube-tubesheet interface is not sensitive to cyclic loads, 2) the fatigue strength of the expanded joint is higher than that of the tube materials, and 3) cyclic loads have no obvious effect on the static pull-out strength.