Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11029891 | Journal of Materials Processing Technology | 2019 | 24 Pages |
Abstract
Three 6061-T6 aluminum sheets with a thickness of 1âmm for each were subjected to the flat friction stir spot welding technique, which contains two steps of welding process. In step 1, a specially designed back plate with a pre-drilled dent was used in order to form a protuberance on the bottom side of the joint. In step 2, the keyhole and the protuberance were removed by using a probe-less rotating tool and a smooth back plate. The optimized welding condition for the three sheet spot welding was 700âkg/550ârpm/2âs in step 1 and 1000âkg/600ârpm/2âs in step 2. Two sheet/sheet interfaces were formed in the bowl-like stir zone. The stir zone showed a grain size varied from 4.2 to 8.6âμm, much smaller than the 17.6âμm of the base metal. Three different tensile test modes were used to evaluate the failure behavior of the joints. The interface between the top and middle sheet showed a longer bonding length of 11.5âmm and a higher fracture load of about 6438âN. While the interface between the middle and the bottom sheet showed a bonding length of 5.2âmm and a fracture load of about 4450âN. The step 2 joints showed plug-type failure mode during the shear tensile tests.
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Authors
Yufeng Sun, Hidetoshi Fujii, Shijie Zhu, Shaokang Guan,