Comparative investigation of deep drawing formability in austenitic (AISI 321) and in ferritic (DIN 1.4509) stainless steel sheets

One of the most challenging activities of the today's industry is to balance productivity and quality of the production. Across the years there was an evolution on the technologies of production, of raw materials fabrication and on the qualification of the working force. In some circuits, however, there still remain gaps on the knowledge of various stages of the production chain, which need to be solved in order to the improve product quality. One of these gaps is the knowledge of the basic properties of raw material that is being used on the stamping production. The present work discusses and compares formability, as evaluated by the forming limit curve, of two different stainless steel 2mm sheets: an austenitic class (AISI 321) and a ferritic class (DIN 1.4509). The main mechanical properties and a differentiation between the grades on the deep drawing ability are presented by the results of some well known tests, such as the Tensile, Erichsen, Swift and Nakazima. The differences in formability between the two materials are discussed in terms of physical metallurgical reasoning, microstructure, and texture evolution, and allows to understand the characteristics and limitations of formability, concerning deep drawing of these steel grades.