Identification of flow instabilities in the processing maps of AISI 304 stainless steel

Among the various existing instability theories, a simple instability condition based on the Ziegler's continuum principles as applied to large plastic flow, is found to be more appropriate for delineating the regions of unstable metal flow during hot deformation. It can be used to any flow stress versus strain rate curve. This criterion has been validated using the flow stress data of AISI 304 stainless steel with microstructural observations.