Y. Ohue

Fatigue fracture characteristics of friction welded butt joints with corrosion pits

Summary Studies on the fatigue behaviour of friction welded butt joints between similar carbon steels in ordinary atmospheric environments have revealed that the fatigue strength of the joint is higher than that of the base metal, but the joint shows the larger scatter in fatigue life. On the other hand, the results of corrosion fatigue tests on the joint carried out in artificial seawater indicated that: (1) the corrosion fatigue strength of the joint was almost the same as that of the base metal in the long life region; (2) the scatter in corrosion fatigue life in the joint became smaller with an increase in fatigue life than that of the base metal specimen; and (3) the above mentioned characteristics were governed by corrosion pits preferentially generated near the weld interface. The main aim of this study is to clarify the cause of the fatigue strength reduction by corrosion pits. For this purpose the joint and base metal specimens were immersed in artificial seawater in a stress free condition to ge...

ON CORROSION FATIGUE OF FRICTION WELDED BUTT JOINT

ABSTRACT The present paper describes the characteristics of the fatigue strength and the fatigue life distribution of S25C/S25C friction welded butt joint in artificial seawater. It is revealed that the corrosion fatigue strength of the joint shows a trend to take the lower value than that of the base metal in long life region, presumably depending on high sensitivity of the material near the weld interface to aggressive environment. And furthermore, statistical evaluation of corrosion fatigue lives indicates that, in the case of the joint, the lower is the stress level the smaller is the scatter of fatigue lives in contrast to the case of the base metal. Such fatigue behaviors composed of two phases seem to be affected by the corrosion pits generated near the weld interface.