The industrial application of dynamic testing for the study of metallic strength and toughness properties

Abstract
The specific type of specimens were prepared from X80 pipeline steel with perpendicular sampling orientation for the dynamic testing of impact tensile at given strain rate, 10² /s and instrumented pendulum impact with the given stress intensity factor rate, 510⁵ MPa m^{1 / 2}/s in the present paper. The comparison of the yield stress and tensile strength corresponding to quasi static and dynamic loading clearly indicates that the strength of X80 steel is sensitively dependent of the strain rate change. The correlation of and F_gy obtained from instrumented impact by means of Server equation was proved to be satisfactory. Moreover tensile toughness index LST is also proposed as the plastic energy distribution throughout the cross section area under static and impact tensile loading, reveling the dependence of strength and plasticity combination of structural steel on the loading variation. In addition, dynamic crack extension resistance curve, J- , was acquired for the evaluation of toughness property, also effectively revealing the mechanism of crack initiation and growth under dynamic loading.