A parametric study of friction stir spot welding (FSSW) using pinless tool with a scrolled shoulder ofaluminium alloy 5754 in a lap joint is presented. Experimental plan was done according to theresponse surface methodology (RSM), where tool rotation speed varied between 988 and 3511 revmin-1, plunge rate between 24.4 and 150 mm min-1 and dwell time between 1 and 3.5 s. The plungedepth was constantly 0.4 mm. During the welding an axial force and torque were monitored usingdynamometer. The welds were tensile-shear tested and the broken samples were visually examined.The weld bond line and microstructure was analysed using light optic microscope under polarisedlight. Mathematical models describing the relationship between welding parameters and spot strength,axial force and rotational moment were developed. Optimal FSSW parameters were found at whichmaximal joint strength was obtained. At these welding parameters the axial force and torque were inthe lower range among tested parameters.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 13240859FSW of 4 mm thick casting aluminium alloy AlSi12 and dissimilar welding of AlSi12 with Al 99.5 in butt joint was done. A classical tool was used with tilt angle of 2°, tool rotation speed varied from 235 to 1180 rev/min, welding speed between 71 to 450 mm/min and joint gap width from 0 to 0.5 mm. From the produced welds, samples for microstructure analysis were prepared for observation on a light microscope under the polarized light source. A Vickers micro-hardens was measured across the weld. Analysis of microstructure, hardness measurement and tensile test of FSW welds were done. A set of FSW welding parameters was determined at which acceptable welds were obtained. Dissimilar welding of AlSi12 with Al 99.5 is possible.
F.06 Development of a new product
COBISS.SI-ID: 1424223A parametric analysis of aluminium-3% magnesium alloy AA5754 lap joints made by the friction stir spot welding (FSSW) is presented. Experimental plan was done according to the response surface methodology (RSM), where the tool rotation speed varied between 988 and 3511 rpm, the plunge rate between 24.4 and 150 mm/min and the dwell time between 1 and 3.5 s. The plunge depth was held constant at 0.4 mm. The welds were tensile-shear tested and the microstructure was analysed. Mathematical models describing the relationship between welding parameters and spot strength, axial force and rotational moment were developed and the optimal FSSW parameters were established.
F.01 Acquisition of new practical knowledge, information and skills
COBISS.SI-ID: 12907547