Similar and dissimilar resistance spot weldability of Q&P980 and TWIP1180 steels

The resistance spot weldability of the newly developed TWIP1180 and Q&P980 with different thicknesses was evaluated. The different sheet thicknesses, heat conductivities and melting points caused that the Q&P/TWIP spot welds showed significantly asymmetric weld nuggets, and correspondingly influenced the tensile shear properties and failure modes of the spot welds. Pullout or partial pullout failure modes were obtained for the Q&P/Q&P and Q&P/TWIP combinations under proper welding currents, while only interfacial failure mode was observed for the TWIP/TWIP combination owing to the high strength and large thickness. Furthermore, the proper welding lobe for the Q&P/TWIP combination was obtained, which was crucial for the application of TWIP1180 and Q&P980 in automobile industry.