Fatigue Strength of Friction-Welded 6061 Aluminum Alloy Joints

Abstract

The Ono's rotary bending fatigue test and the cantilever rotary bending fatigue test were carried out on friction-welded 6061 aluminum alloy joints, and the relationship between the deformation heat input in the upset stage or the upset burn-off length and fatigue strength was examined. In the Ono's type test, sound joints, which fractured in the heat affected zone in the tensile test, fractured in the heat affected zone also and the fatigue limit of these joints was slightly lower than that of 6061 aluminum alloy base metal. This is because joints fractured in the softened area in both tensile test and Ono's type test using smoothed test specimens. While, in the cantilever type test, the fatigue limit of sound joints was a little more than or a little less than that of 6061 aluminum alloy base metal. It seems that a weld and a structure at the weld interface affected fatigue strength in the cantilever type test using notched test specimens. Judging from the fatigue limit obtained, sound joints could be produced when either the deformation heat input in the upset stage or the upset burn-off length exceeded a certain value.

Tensile strength and fatigue crack growth rate of chamfered and clamped A6061 friction weld joints

“…The prospect that will be opened up is the opportunity to apply this method to increase the strength of the weld joint of other metals besides aluminum. This proposed method has advantages over the conventional friction welding on aluminum, such as reported in [9,10,12,17] that produced surrounded flash at the weld joint interface that needs more time to remove the flash by machining. The proposed method can be an alternative solution to remove almost all the flash at the weld joint interface, to increase the tensile strength and to reduce the fatigue crack growth rate of the aluminum weld joint.…”

“…Therefore, research on the fatigue of friction weld joints is essential. The paper [12] reported the fatigue test using an Ono-type of rotary bending test and a cantilever rotary bending test with a notch on samples of friction weld A6061. It is found that the specimens fractured at the softened area or heat affected zone in the tensile strength and fatigue test.…”

“…It appears that the structure at the weld interface influenced fatigue strength in the cantilever type test. A sound friction weld joint could be achieved if either the deformation heat input in the upset stage or the upset burn-off length ex ceeded a certain value [12]. The paper [13] reported the effect of friction welding on the fatigue properties of dissimilar friction weld joint of AISI 2205-AISI 1020.…”

Fatigue corrosion behavior of friction‐welded stainless and carbon steel dissimilar joint

“…On the other hand, solid state welding methods proved to be successfully employed in the serial production of dissimilar joints 13,14 . Specifically, in friction welding, the two parts to be welded are put into relative motion (rotational or translational) and pressed together, the heat generated by friction triggers solid‐state recrystallization phenomena that culminate in the creation of the final connection 15,16 . For instance, this technique is widely employed to join expensive parts made of stainless steel (and exposed to aggressive environments) with less critical parts made of cheaper carbon steel 12,17,18 .…”

“…13,14 Specifically, in friction welding, the two parts to be welded are put into relative motion (rotational or translational) and pressed together, the heat generated by friction triggers solid-state recrystallization phenomena that culminate in the creation of the final connection. 15,16 For instance, this technique is widely employed to join expensive parts made of stainless steel (and exposed to aggressive environments) with less critical parts made of cheaper carbon steel. 12,17,18 Clearly, the weld joint, especially in the case of welded parts of dissimilar materials, represents a point of structural weakness.…”