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

Abstract

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.