Advances in the optimization of thin strip cast austenitic 304 stainless steel

This study is about the latest advances in the optimization of the microstructure and properties of thin strip cast austenitic stainless steel (AISI 304, 1.4301). Concerning the processing steps the relevance of different thin strip casting parameters, in-line forming operations, and heat treatments for optimizing microstructure and properties have been studied. The microstructures obtained from the different processing strategies were analysed with respect to phase and grain structures including the grain boundary character distributions via EBSD microtexture measurements, the evolution of deformation-induced martensite, the relationship between delta ferrite and martensite formation in austenite, and the texture evolution during in-line deformation. It is observed that different process parameters lead to markedly different microstructures and profound differences in strip homogeneity. It is demonstrated that the properties of strip cast and in-line hot rolled austenitic stainless steels are competitive to those obtained by conventional continuous casting and hot rolling. This means that the thin strip casting technique is not only competitive to conventional routes with respect to the properties of the material but also represents the most environmentally friendly, flexible, energy-saving, and modern industrial technique to produce stainless steel strips.