Fatigue Behavior of Mechanically Peened HY-80 Weldments Subjected to Axial Loading

An evaluation of the axial fatigue behavior of mechanically peened transverse tee-weldments and transverse butt-welded joints in HY-80 steel is presented. The data show that mechanical peening along the toe of the weld results in an improvement In the fatigue resistance of both types of weldment relative to the behavior of similar joints tested in the as-welded condition. The process of fatigue crack initiation and propagation was examined for several of the mechanically peened weldments. In the majority of members cracks nucleated at the toe of the weld in the trough formed by the peening operation. Nucleation normally occurred within the first 20 percent of the cyclic lifetime of a specimen, and was followed by a long period of slow, erratic crack propagation, eventually culminating in a short final stage of rapid extension to failure.Bureau of Ships, U.S. Navy.Contract NObs 92240Project Serial No. SR-007-01-01, Task 85