Search Results

Friction stir welding (FSW) is a new welding process developed at The Welding Institute in Cambridge, U.K. This process uses a non-consumable rotating third body to generate frictional heat and create forging to facilitate continuous solid-state joints. In this paper, the current state of the art of FSW is discussed. A preliminary description of the process is provided, followed by the results of some relatively simple thermal modeling. The modeling results are used to provide a description of temperature distributions in FSW, as well as illustrate the effects of variations in process conditions. Representative microstructures of FSW on an Al 6061 alloy are then presented. Properties of these friction stir welds are then discussed and compared to those of both the base metal and to comparable GTAW welds. Some discussion is then given to the effects of section thickness on FSW. Examples are given of friction stir welds on aluminum alloys ranging from 2 to 30 mm in thickness.

Welding residual stress is one of the primary factors responsible for cracking at the access hole interface between the flange and web plate of welded heavy W-shapes. During multi-pass welding, cracks can be found in either the flange plate or the web plate, depending upon welding sequence, joint details and access hole size. In this study, an integrated numerical and experimental investigation was conducted to evaluate the effects of welding parameters and joint geometry on the magnitude and distribution of residual stresses in thick-section butt joints. The results provide guidelines for improved design for welding of heavy W-shapes.