Resistance Spot Welds of 3041 Austenitic Stainless Steel, Part 2:Signals Measurement, Dynamic Resistance, Electrically Generated Forging Force, Metallurgy and Hardness Distribution Analysis

Abstract

Part 1 of this research introduces the spot welds growth on 304L stainless steel; primarily supported by information such as the chemical property, specimen size, calculated-static resistance, welding lobe, welding schedule, simulation, tensile shear load, indentation, failure mode, and also the elongation during tensile test. In part 2, the analysis is furthered to understand the dynamic resistances, force profiles, electrically generated forging forces, macro and micro structural orientation and also the hardness distribution. Heat development during the welding process is proportionally influenced by the dynamic resistances and therefore several detailed analytical approaches have been included to understand the process variables certainly. Literally the dynamic resistances are proportionally related for the welding current and welding time changes but reversely behaved for the electrode force changes within the welding lobe limits. These resistive changes became the ischolar_main cause of weld growth pertaining to heat variations. So the computations have been carried out from the perspective of welding current against the terminal voltage. On the other end, the force profiles are relatively measured to observe the electrode force variation with respect to the welding current changes. With the changes of process variables, the corresponding weld growth is analysed in terms of dynamic resistances in this experiment. Eventually the micro structural changes show the enrichment of coarsened grains but transformed in phases as results; which lead to slight increment of hardness at the welded areas as Rockwell hardness proves these increments as well.