Determining Forming Limit Diagrams Using Sub-Sized Specimen Geometry and Comparing FLD Evaluation Methods

Sheet metal forming boundaries are established using the limit diagram (FLD). The Nakajima and Marciniak tests, which based on stretching a material punch, most commonly used methods for determining FLD or fracture (FFLD). results usually evaluated by calculating local strain, strain rates, specimen thickness reduction strain. When amount of experimental is insufficient, miniaturization testing specimens may be solution. However, interchangeability standard miniaturized has not been proven yet. In this study, tests were performed sub-sized made manganese–boron steel 22MnB5, in automotive industry. Afterwards, four FLD/FFLD evaluation applied compared. yielded higher values, was explained varied ratio thickness/punch diameter different bending conditions. highest compliance recorded FFLD.