In order to characterize the growth behavior of fatigue cracks propagationg along the weld interface, a series of fatigue crack growth tests was conducted on center notched plate specimens fabricated from SUS304/SUS304 fricion welded butt joint of 40mm in diameter. Results indicated that cracks grew faster along the interface at the inner part of the joint than those of the base material, presummably depending on the tensile residual stress introduced during thermal hysteresis following friction welding process and on structural discontinuites at weld interface. Furthermore, retardation of crack growth rate of the joint specimen due to overload application was not so distinct in comparison with that of the base material. This suggests that the weld interface has higher flow resistance than the base material.
