Determination of the Forming Limit Diagram of an Ultra‐Thin Ferritic Stainless Steel Sheet

Abstract

The forming limit diagram (FLD) of a 98 mu m-thick ferritic stainless steel sheet sample was determined using a modified Marciniak test and the conventional Nakazima test (ASTM E2218-2). Wrinkling and undesired fracture were not observed in the modified Marciniak test. However, for some strain paths, wrinkling of the sheet specimens and undesired fracture at the upper die radius and the draw bead locations occurred in the Nakazima test. In spite of the problems observed with the Nakazima test, similar FLDs were obtained with the two methods.