STUDIES ON WELDBONDING OF STAINLESS. STEEL

Abstract

Lap joints of 1.0 mm thick austenitic stainless steel sheet were prepared by adhesive bonding, resistance spot welding and wel.dbonding (combination of adhesive bonding and resistance spot welding) processes. Before joining, faying surfaces were polished with 400 grade emery paper. The adhesive layer thickness of adhesive joint was varied by rolling the green joint under different load on a Teflon - Roller set up. The adhesive layer thickness was optimized with respect to joint strength of adhesive bonded joint studied by shear - tensile test. During resistance spot welding and weldbonding the welding current and time were varied. The adhesive bonds and weldbonds were cured at the temperature of 120°C for 60 minutes. The joint properties were studied by shear - tensile test. Microstructure of the joint were 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 fatigue properties of the weldbonded specimens were studied. The ultimate shear-tensile load carrying capacity of resistance spot weld and weldbonded joints are compared and correlated with welding parameters. The correlation of the mechanical properties of the joint with their microstructure, nugget size and hardness were discussed. It is observed that at a suitable process parameters weldbond can achieve significantly higher mechanical properties than that observed in resistance spot weld, especially under a situation of dynamic loading