Hydrogen-Induced Cracking (HIC) is one of several related mechanisms whereby absorbed hydrogen atoms can compromise the integrity of components manufactured of low strength steels. A “low
strength steel” is defined as having a macrohardness of 22 HRC (249 HV) maximum. The corresponding
tensile strength is of the order of 800 MPa (116 ksi) maximum. Steels having localized areas with
microhardness in excess of 22 HRC equivalent are particularly vulnerable to the development of HIC
damage.