Effect of Formability Process Parameters in Dynamic Strain Ageing Region ofAustenitic Stainless Steel

Abstract

The consumption of Austenitic Stainless-Steel ASS 304 has been increasing recently in the outer body of Automobileapplications. Sheet Metal Forming is one of the processes used to convert ASS 304 sheet into an end product. ASS 304 hasgood ductility with the rise in temperature up to 450oC and later dynamic strain aging (DSA) in the temperature range 450-600oC. Formability studies of ASS 304 in the DSA region and the effect of process parameters like anisotropy and strainrate are investigated in the present paper. Stretch forming Investigations have been carried out at a temperature of 500oC intwo quasi-static strain rate ranges 1x 10-4 s-1 and 1x 10-1 s-1 concerning three orientations parallel (R0), diagonal (R45) andTransverse(R90) to Rolling Direction. The experiments were carried out at both the necking and fracture regions. Deformedspecimens' major and minor strains are measured to plot Fracture Forming limit Diagrams, strain distribution, and limitingDome height. Particular attention is given to the evaluation of strain rate and orientation of the sheet concerning rollingdirection on formability.