Anisotropic damage behavior in high-strength line pipe steels

Abstract : High-strength steel line pipes have different mechanical properties (plasticity, ductility and toughness) in each direction. This anisotropy is developed by a thermo-mechanical control process (TMCP) in a heavy plate mill and a cold forming process in a pipe mill. In this study, experimental work was carried out using both as received and pre-strained (up to 6% along the T direction) steel plates for X100-grade pipes, in order to analyze anisotropic toughness. Compact tests were conducted in the longitudinal (L) and transverse (T) directions. Further, a new damage model based on the GTN model was proposed, in order to represent anisotropic damage behavior in high-strength line pipe steels.