Abnormal fracture appearance in drop-weight tear test specimens of pipeline steel

The abnormal fracture appearance (AFA), which is frequently observed on the drop-weight tear test (DWTT) fracture surface of high performance pipeline steels, makes the DWTT technique difficult to utilize. Different DWTT specimens are tested at different temperatures. The cleavage regions of different AFA result from different phenomena during specimen fracture. All of the specimens exhibiting AFA should not be discarded as invalid specimens. Some new approaches are proposed to prevent or reduce the occurrence of AFA. The evaluation of DWTT specimens exhibiting AFA is re-examined considering the coupled effects of deformation, material behavior and fracture on the fracture appearance of high performance pipeline steel. (C) 2007 Elsevier B.V. All rights reserved.