Microstructure, Anisotropy and Formability Evolution of an Annealed AISI 430 Stainless Steel Sheet

The effect of the microstructure on the principal strain paths (uniaxial, plane, and biaxial) in the formability processes of ferritic stainless steel AISI 430 sheets is studied. The Marciniak test (determination of the plastic strain of sheet metal with a flat tip punch) is applied to determine the forming limit curves and different strain levels in the strain paths by the digital image correlation technique. The formability is discussed in light of the microstructure, standard mechanical properties, work hardening behavior, and anisotropy measurements (R-value). Electron backscatter diffraction analysis is carried out to determine the texture of the selected strain paths. The texture evolution shows a marked gamma (// normal direction [ND]) fiber and cube ({001} ) texture component under the biaxial strain mode, whereas the alpha (// rolling direction [RD]) fiber is somewhat favored under uniaxial plane strain. The results are compared with texture simulations performed under the fully constrained Taylor model, finding reasonable agreement with the experimentally measured main components.

Automated summary

This study investigated the influence of microstructure on principal strain paths during the formability processes of ferritic stainless steel AISI 430 sheets. The Marciniak test and digital image correlation technique were used to determine forming limit curves and strain levels, with discussion on formability in relation to microstructure, mechanical properties, work hardening behavior, and anisotropy measurements. The texture evolution was examined using electron backscatter diffraction analysis, showing distinct texture components under different strain modes.