Effect of process parameters on the mechanical performance of resistance spot welded joints of AISI 409M ferritic stainless steel

摘要

In this study, the effect of process parameters on mechanical performance of the resistance spot welded joints of AISI 409M ferritic stainless steel sheets is investigated. Mechanical performance of the spot weld is evaluated in terms of output quality characteristics, such as load carrying capacity and energy absorption capacity. Important process variables, such as current, time, electrode force and holding time were varied separately and corresponding output parameters, which decide the mechanical performance of the spot welded joint have been analysed. Weld nugget geometrical parameters such as nugget size and surface indentation have also been analysed with respect to various process variables. It has been found that peak load and energy absorption capacity are in direct relationship with welding current as well as welding time, in expulsion free welds. Surface indentation increases with increase in current and welding time. It has also been observed that increasing electrode force results in slight reduction of both tensile shear strength and energy absorption capacity. The effect of holding time on mechanical performance of the resistance spot welded joint is found to be almost insignificant. Regression-based relations are developed to correlate the mechanical performance of the spot welds with nugget size.