Investigation into hydrogen-induced blister cracking and mechanical failure in pipeline steels

Abstract

This work aims to investigate the role of hydrogen-induced blisters on tensile and fatigue damage of pipeline steels (X65 and X80). The electrochemical method of hydrogen charging is employed to simulate hydrogen-induced blister formation. Similar hydrogen charging conditions resulted in different sizes, shapes, and numbers of blisters in both types of steels. DIC analysis coupled with in-situ tensile testing confirmed the blisters as potential stress concentration sites. Synergistic action of hydrogen and stress concentration around these blister-type notches intensified the overall mechanical damage of material under the hydrogen atmosphere. The size and relative position of blisters are significant factors to degrade the mechanical performance of investigated pipeline steels.