In this study, the effects of welding current and time on the tensile-peel strength and tensile-shear strength of welding joint in electrical resistance spot welding of chromided micro-alloyed steel sheets having 0.8 mm thickness and galvanized chromided micro-alloyed steel sheets having 1.0 min thickness were 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 current periods of 5, 10, 15, 20 and 25 were selected and it was adjusted by increasing 1 kA from 3.5 to 10 kA during welding process. The electrode pressure was fixed at 6 kN. The obtained welding joints were exposed to tensile-peel and tensile-shear tests and their core sizes, heights and nucleus size ratios were calculated by means of an optical microscope. The effect of nucleus size ratios on tensile-peel strength and tensile-shear strength were researched by using related diagrams and the optimum welding currents and times were advised. (c) 2004 Elsevier Ltd. All rights reserved.
