Investigating of the tensile mechanical properties of structural steels at high strain rates

St37 and St52 structural steel plates were tested in uniaxial tension at room temperature over various strain rates ranging from 0.001/s to 0.1/s. The yield stress, flow stress and fracture behavior of steels were analyzed. It was found that the strain rate has a strong effect on the tensile mechanical properties of St37 steel, while St52 has a less sensitive strain rate and that the yield strength of both steels exhibits a higher strain sensitivity rate than the other mechanical properties. An increase in the loading rate from 0.001/s to 0.1/s led to a %30 increase in the lower yield strength of St37 steel and an increase of %6 for St52. The equations were derived to express the yield stress behavior with the strain rate. The ductile dimple fracture was observed in static and dynamic conditions; however, increasing the strain rate resulted in a pronounced cleavage-type fracture in both steels. The St37 fracture strain decreased considerably by increasing the strain rate.