| Summary: | In this research, the effect of spot welding parameters on weld quality was investigated. The main affecting welding parameters such as weld current, weld time, electrode force and holding time were determined as the basis for quality evaluation. The selected quality features were classified into mechanical properties and failure behavior, which were required for application with highly dynamic loading. The peak load as one of the important mechanical properties, as well as the two distinct failure modes which were cross-nugget and complete button pull, were observed using tensile-shear stress. To obtain detailed shear stress testing results and to determine the significance of parameters, a servo-hydraulic testing machine was run at a constant cross-head speed of 2mm/min followed by statistical analysis methods, which were Taguchi's L16 orthogonal array and Analysis of Variance (ANOVA). Furthermore, the failure mode was to be observed based on the fracture surface used as reference for acceptance or rejection of the weld joint. Based on the results, the weld current was the significant factor affecting shear stress and the complete button pull was mostly found, which leads to the satisfactory condition of the joint. Cross-nugget and full button pull-out were the dominant failures observed in the lap-shear test. The cross-nugget failure leads to a low shear load, while complete button pull-out displays maximum shear load. © Universiti Malaysia Pahang, Malaysia.
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