Volume 49, No. 02, Month MARCH, Year 2022, Pages 155 - 167

Investigation of shear strength and metallurgy on semi-solid metal 356 aluminium alloy with lap joint by friction stir spot welding

Chaiyoot Meengam, Suppachai Chainarong, Siva Sitthipong

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The SSM 356 aluminum alloy formed by GISS technique, which was developed to be used in the production of automobile parts and necessary for FSSW process, is found to be good adhesion of the lap joint. The results of all experiments were very satisfying. For rotation speed at 380 rpm, the plug depth of 1.5 mm and the welding time of 60 sec, the maximum shear strength was 174.2 MPa, whose Joint efficiency was 92.12 percent compared with the base metal. The values of hardness in SZ ranged lower than those in other regions, while the hardness values in the advancing side of thermo-mechanically affected zone (AS-TMAZ) were higher than those in other regions. The evaluation of the microstructure in SZ shows that external force and heat cause the material to become plastic deformation resulting in the new precipitations from β-Mg2si phase to β՛՛-Mg2si homogenous phase whose particle size is smaller around 2-7 µm. The analyzed experimental design was a general mixed-level design which had a test coefficient of R2 of 0.96 at confidence level of 95.00%.


Friction stir spot welding, SSM 356 aluminium alloy, Shear strength, Joint efficiency, Globular structures


Published by : Faculty of Engineering, Khon Kaen University
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