Welding time effect on mechanical properties of automotive sheets in electrical resistance spot welding

In this study, the effects of welding time on the tensile-peel strength and tensile-shear strength of welding joints in electrical resistance spot welding of chromate micro-alloyed steel sheets having 1.2 mm thicknesses were investigated. A timer and current controlled electrical resistance spot welding machine having 120 kV A capacity and a pneumatic application mechanism with a single lever was used to prepare the specimens. Welding current periods of 5-10 kA and 12 kA were selected, and it was adjusted by increasing 5 cycle from 5 cycle to 15 cycle during the welding process. The electrode pressure was fixed at 6 kN. The welding joints were exposed to tensile-peel and tensile-shear tests, and the effect of welding time on tensile-peel strength and tensile-shear strength was researched by using related period diagrams. The optimum welding times were obtained. (C) 2007 Elsevier Ltd. All rights reserved

Effect of welding current on mechanical properties of galvanized chromided steel sheets in electrical resistance spot welding

In this study, the effect of welding current on the quality of weld joint and obviously on tensile-shear and tensile-peel strengths of galvanized chromate steel sheets having 1.2 mm thickness in electrical resistance spot welding was investigated. A timer and current controlled electrical resistance spot welding machine having 120 kVA capacity and pneumatic application mechanism with a single lever was used to prepare the specimens. Welding periods were chosen as 5, 10, 12 and 15 cycles and also welding currents were increased from 4 kA up to 12 kA by rise of 1 kA. The electrode force was kept constant at 6 kN. The prepared welding specimens were exposed to tensile-shear and tensile-peel tests and the obtained results were supported by diagrams and, finally, appropriate welding parameters were advised to the users. (c) 2005 Elsevier Ltd. All rights reserved

Modeling and Analysis of the Weld Bead Geometry in Submerged Arc Welding by Using Adaptive Neurofuzzy Inference System

This study is aimed at obtaining a relationship between the values defining bead geometry and the welding parameters and also to select optimum welding parameters. For this reason, an experimental study has been realized. The welding parameters such as the arc current, arc voltage, and welding speed which have the most effect on bead geometry are considered, and the other parameters are held as constant. Four, three, and five different values for the arc current, the arc voltage, and welding speed are used, respectively. So, sixty samples made of St 52-3 material were prepared. The bead geometries of the samples are analyzed, and the thickness and penetration values of the weld bead are measured. Then, the relationship between the welding parameters is modeled by using artificial neural network (ANN) and neurofuzzy system approach. Each model is checked for its adequacy by using test data which are selected from experimental results. Then, the models developed are compared with regard to accuracy. Also, the appropriate welding parameters values can be easily selected when the models improve