INVESTIGATION ON PROPERTIES OF STRUCTURAL STEELS DEFORMED AT DYNAMIC CONDITIONS

摘要

Results of dynamic tensile tests performed for three grades of carbon structural steel are presented in the paper. The selected steels are typically used for making elements of the road sign support structures. The tests were performed on a flywheel machine that allowed to achieve strain rates corresponding to those obtained during vehicle collisions against fixed objects. Although expected positive stress sensitivity to strain rate was confirmed for all steels, two carbon steels exhibited significantly lower UTS values in tests performed at the highest strain rate (ca. to 1400 s~(-1)) due to their limited formability in such conditions. Fractographic analysis revealed ductile and mixed ductile - brittle character of fractures.