2023 年 64 巻 2 号 p. 485-491
The tool pin profile damage during successive passes in friction stir welding (FSW) of dissimilar aluminium alloys AA6061-T6 and AA7075-T651 is recorded during the present investigation. A right-hand threaded with three intermittent flat faces tool pin at 900 rpm tool rotation and 98 mm/min of weld speed without and with the application of secondary heating (using butane gas torch) is used for joint fabrication. Two separate tools are used to obtain weld length of total 1 metre each without and with secondary heating. Tool profile damage is progressively monitored using scanning electron microscopy along with measuring tensile strength of the joints obtained. The leading edge of the threaded profile (at the end of flat face) distorts with mechanical damage and chipping while the incident material is being plasticized and pressurized by flat region. Secondary heating helps in eased material flow by material softening leading to load reduction and thereby tool wear. The tools experienced slight bending, tearing near shoulder. For both the tools certain amount of wear is being noticed however joint strength is retained without significant adverse effect even after completion of welding for a meter of total weld length.
