Industrial application of Instrumented DWTT in evaluating material resistance to ductile fracture for modern pipeline steels

Abstract

Abstract. CTOA C of typical X70, X80 and X90 pipeline steels plates were evaluated by using energy based regression method upon their single specimen. Clear difference in the material resistance to ductile cracking could be distinguished by the values of CTOA C and their characteristic fracture surface. The region of stable cracking on the fracture surface could be identified from the dynamic crack extension curve, with the help of key-curve method. In the meanwhile, the crucial material based parameter required by many other CTOA C algorithm, (A * σ f ) of present X70, X80 and X90 plates were experimentally determined, also proving the validity of theoretical geometric factor A * to be 0.30-0.34, close to the commonly cited constant of 1/3.