Investigation of hydrogen assisted cracking of a high strength steel using circumferentially notched tensile test

► Novel CNT testing was successfully employed for HASCC study of a high strength steel. ► Effects of both internal and external hydrogen were examined. ► Fracture toughness KIcH relates to theoretical hydrogen distribution at/around crack tip. ► KIcH for lower loading rates agree with published threshold fracture toughness data. ► Utility of CNT tests for study of HASCC in steels was established.