ADVANCES IN TEST METHODS FOR FRACTURE TOUGHNESS BASED ON CTOD/CTOA FOR PIPELINE STEELS

The high-level pipeline steel is characterized by high toughness, with a wide range of plastic yielding zone around the crack tip, the existing test methods are difficult to meet the requirements for determination of its fracture toughness by using low constraint specimens. This paper reviews two kinds of fracture parameters based on CTOD and CTOA, which can characterize the deformation state of the crack tip. The present research status and the development trend of these test methods are summarized. A variety of factors influencing the testing accuracy of the fracture toughness for the pipeline steels are analyzed, and suggestions are made to improve the experimental design for measuring the fracture toughness of pipeline steels.