Effect of specimen orientation to the rolling direction on uniaxial tensile forming and failure limits

Abstract

Alteration of forming and failure limits due to planar anisotropy of the sheet metal significantly affects the safe forming operation region and finally successfully manufacturing of a sheet metal formed component. This article presents the effect of planar anisotropy on uniaxial tensile properties, forming and failure limits of cold-rolled ferritic and dual-phase steels. In-situ three dimensional digital image correlation technique is used to measure the evolution of local strain components during uniaxial tensile test. For both the steels, necking limit is highest for the specimen at an orientation of 90° to rolling direction, while failure limit is highest for those specimen whose orientation is 45° to rolling direction for ferritic steel, and both 0° and 90° to rolling direction for dual-phase steel. Uniaxial tensile deformation path for ferritic steel holds lower slope than dual-phase steel as depicted in major versus minor strain plot.

Formability study of bake hardening steel and its correlation with microstructure

“…The formability of sheet metals is generally evaluated using a forming limit curve (FLC), representing maximum values of major and minor strains at localized necking of sheet for various linear strain conditions. [15][16][17] A boundary is established between different strain states that facilitate sheet forming and lead the sheets into failure. [18][19][20] Narayanasamy et al 21,22 experimentally investigated the formability of bake hardening and extra galvannealed interstitial free (IF) steel sheets.…”