Theorical and experimental determination of the forming limit diagram for the AISI 304 stainless steel

The theoretical prediction and the experimental validation of the forming limit curve (FLC) have been made for the AISI 304 stainless steel during linear strain paths. The Marciniak–Kuczynski (M–K) method has been used in the theoretical prediction. For the calculation, the Hill’48 yield criterion has been used. For the experimental survey of the forming limit curve (FLC) we have used: non-grooved tension specimens simulating a uniaxial tension strain path; grooved tension specimens simulating a strain path ranging between uniaxial tension and plane strain and also circular specimens to reach a path representing biaxial tension. The circular specimens were submitted to the biaxial expansion through the bulge test. To determine the strain values at the necking moment we used Zurich number 5 method. Using a heterogeneity factor of 0.955 an optimal adjustment of the theoretically predicted forming limit curve was achieved with that one obtained experimentally.