TWI Industrial Member Report Summary 863/2007
By W M Thomas, M F Gittos, P Tubby and D G Staines
This report presents preliminary fatigue studies carried out with friction Skew-stirTM. The current study was to evaluate the performance of the Skew-stirTM variant of FSW when used for 6mm thick 5083-H111 alloy aluminium sheets in the lap weld configuration.
Lap welded joints or combined lap/butt welded joints are often unavoidable in real components. The scope for the application of lap joints in aluminium alloys is potentially large, however, the level of confidence, for the manufacture of lap joints, made by the FSW process, does not match that for butt joints. The detailed morphology of the notch at the edge of the stirred zone either side of the weld is critical to joint mechanical performance.
The objectives of this work are:
- To establish the feasibility of using the Skew-stirTM techniques to lap weld 6mm thick 5083-H111 aluminium alloy sheet.
- To compare lap welds made using the Skew-stirTM techniques with welds made using a conventional cylindrical threaded-pin type probe, and two types of 'artificial lap' specimens of similar geometry, by establishing the resultant weld structures, and weld mechanical properties.
- To determine the fatigue, tensile and 'S' bend performance of Skew-stirTM techniques for lap welds in 5083-H111 aluminium alloy.