INFLUENCE OF THE STRAIN RATE ON THE MECHANICAL AND TECHNOLOGICAL PROPERTIES OF STEEL SHEETS

摘要

The paper analyses the influence of strain rate on the behaviour of un-alloyed steels with R_e (yield strength) in the range of 210 ... 550 MPa in the deformation process. It analyses the results of the influence of strain rate ranging from 10~(-3) to 2,5-10~2 s~(-1) on the yield strength, the ultimate tensile strength (R_m), the elongation (A) and the reduction of area (Z). Achieved results of strain rate in relationship on values of Erichsen number /_E are also given. By increasing of strain rate ranging from 10~(-3) to 2,5-10~2s~(-1) the ratio R_e/R_m is increased, whereas it was observed more intensively for steels with the lower value of R_e. By increasing of strain rate up to 1 s~(-1) are /_E values of tested steels increased, whereas the ratio R_e/R_m was equal 0,82. After exceeding of this strain rate was the ratio R_e/R_m increased and /_E value is remarkable decreased.