Microstructural analysis of AISI 304 bars welded with high speed pulsed discharges

In a way similar to the resistance welding the high speed pulsed welding exploits the power of elevated discharging current through an electrical circuit, which contains the two parts to be welded. During welding edges profile interact with the process parameters to determine both the weld microstructure and mechanical strength. In this paper, the welding profiles at the opposite surfaces was machined so to have linear contacts instead of a classic single protrusion contact. The effect of this multilinears contact geometry was a weld that was in the midway between the capacitor discharge welding (CDW) and the projection welding (PW). Pulsed welding experiments were performed using AISI 304 cylindrical bars in butt configuration. The welded microstructures were studied using an optical microscope and image analysis software. The Vickers microhardness tests were performed to a better characterization of the welding microstructures.