STUDIES ON MECHANICAL PROPERTIES OF RESISTANCE SPOT WELD-BONDED STEEL

Abstract

Lap joints of 1.2 mm thick mild steel sheet was obtained by the application of adhesive, resistance spot welding and weldbonding (combination of adhesive bond and resistance spot weld). During resistance spot welding and weldbonding the welding current and time was varied. The adhesive joints and weldbonds are carried at different curing temperature and time. The joint properties were studied by shear-tensile test. Microstructures of the joints was studied under optical microscope. The nugget size of the resistance spot welded and weldbonded specimens was, also studied under optical microscope. Hardness of nugget and HAZ in the spot welded and weldbonded specimens were studied. The shear-tensile load carrying capacity of the joints are compared and co-rrelated with the welding parameters and curing schedule. The correlation of the mechanical properties of the joint with their microstructure, nugget size and hardness are discussed. It is observed that at a suitable process parameters weldbond can achieve significant higher mechanical properties than that observed in resistance spot weld