The paper deals with the determination of dynamic mechanical properties of steel sheets by the miniature testing technique. Several materials were investigated, namely S235, S355 and 1.4301. The newly developed micro-tensile test (M-TT) allows local mechanical properties measurement which can be successfully used for example for weld heterogeneity determination. Furthermore, due to small size samples (tensile sample gauge section dimension of 0,5x1,5x3mm), much higher strain rates can be attained using relatively slow loading velocities in comparison to standard dynamic tests resulting in high results consistency thanks to significant reduction of the oscillations which are typical for common high strain rate tests. The results obtained from M-TT and standard tensile tests were compared
Sheet metal forming boundaries are established using the forming limit diagram (FLD). The Nakajima and Marciniak tests, which are based on stretching a material using a punch, are the most commonly used methods for determining the FLD or fracture forming limit diagram (FFLD). The results are usually evaluated by calculating local strain, strain rates, specimen thickness reduction or fracture strain. When the amount of experimental material is insufficient, miniaturization of the testing specimens may be a solution. However, the interchangeability of the results for standard and miniaturized specimens has not been proven yet. In this study, the Nakajima tests were performed using standard and sub-sized specimens made of manganese–boron steel 22MnB5, commonly used in the automotive industry. Afterwards, four FLD/FFLD evaluation methods were applied and compared. The miniaturized specimens yielded higher strain values, which was explained by the varied ratio of material thickness/punch diameter and different bending conditions. The highest compliance of the results was recorded for the standard and miniaturized FFLD.