Fracture responses of microstructures of electron beam-welded D6AC

In this study, D6AC steel was produced from flow forming (wall thickness reduction: 67%) and then it was subjected to electron beam welding and tempering treated. We characterized the specimens in terms of their microstructures and nanotribological properties. After tempering treatment at 315 °C, the yield strength increased from 381 to 1334 MPa and the percentage elongation increased remarkably from 0.5 to 7.8%. We performed these mechanical studies for the samples subjected to each set of experimental conditions, and determined the tribological characteristics from the heat-affected zone and the fusion zone. Lower degrees of adhesion reflected the presence of interlinks and rearrangements of indenter tip at lateral force that have been responsible for fluctuations in the coefficients of friction.

► D6AC steel was produced from flow forming (reduction: 67%). ► We investigated tempering effects of EB-welded D6AC. ► Tempering treatment induced the YS and UTS. ► The percentage elongation increased remarkably from 0.5 to 7.8%. ► Heavily misfit dislocations at RT and few dislocation multiplication at tempered.