Analysis of the Welding Deformation of Resistance Spot Welding for Sheet Metal with Unequal Thickness

概要

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Coupled electrical-thermal and thermo-elastic-plastic analysis were performed to analyze the transient thermal and mechanical behaviors of resistance spot welding (RSW) process of the mild steel sheet metals with unequal thickness. The thermal histories of the whole process and temperature distributions in the sheet metals were obtained through the electrical-thermal analysis. Different from the temperature field distribution of RSW with the same thickness mild steel sheet metals, the research showed that the center of the weld nugget of RSW with unequal thickness mild steel sheets leaned to the thicker sheet. It accords with the practical RSW process of the sheet metals with unequal thickness. The residual plastic strain distributions and the deformations of the sheets after welding were obtained through the thermo-elastic-plastic analyses. Due to the asymmetry of the temperature field distribution in the sheet metals with unequal thickness, the edges of the two mild steel sheets warped to the thinner one. The warpage deformation of the two sheets with the thickness 1.0mm and 1.5mm was 5µm after RSW. Detailed studies showed that the warpage deformation of the asymmetric sheet structure was resulted from the changed residual plastic strain.