Investigation of joinability of TRIP and micro alloyed steels in electric resistance spot welding

The aim of this study is to both determination optimum mechanic properties provider welding parameters and investigation of electric resistance spot welding of micro alloyed and TRIP steels. With the aim of obtain electric resistance spot welding joints were used having 120 kVA capacity and electric current controlled a pneumatic application mechanism welding machine. As welding time preferred, 5, 10, 15, 20, 25 and 30 cycle (1 cycle =0,02 s) furthermore welding currents were increased approximately by rise of 500 A from 9000 A to 16500 A. The electrode force was described constant as 6 kN. The obtained welding joints were implemented tensile- share, tensile- peel and cross tensile tests. Optic microscope was used and described macro dimension nugget geometry. Moreover analyzed microstructure, EDS and SEM images and measured micro – hardness. As a conclusion, was described effects of tensile- share, tensile- peel and cross tensile strengths of Welding currents , welding time and welding nugget geometry. Relied on the optimum welding time and welding current was obtained weld lobe diagram.