Hydrogen-induced cracking and blistering in steels: A review

This paper presents a review of the current state of scientific understanding of the corrosion phenomenon known as Hydrogen-Induced Cracking (HIC). HIC is defined as cracking in low-to medium-strength steels where cracking is driven by the precipitation of gaseous hydrogen molecules within the crack, which typically occurs in sour (H₂S containing) environments. It is a complicated phenomenon, encompassing a surface reaction for hydrogen uptake, hydrogen diffusion to vulnerable microstructural sites, hydrogen gas precipitation creating an incipient crack, and crack growth driven by hydrogen gas pressure within the crack. While HIC has been studied for decades, understanding of the critical factors controlling each step of the phenomenon has been elusive. The maturation of many characterization techniques gives hope that a full mechanistic understanding may occur in the near future.