Susceptibility to SOHIC for Linepipe and Pressure Vessel Steels – Review of Current Knowledge

Abstract

Abstract Stress orientated Hydrogen Induced cracking (SOHIC) is a manifestation of sulfide stress cracking (SSC) in C-Mn steels by a mechanism involving the linking of planar cracks normal to the primary propagation direction of the crack. It has been known for many years, and the solution has been considered to be the use of hydrogen induced cracking (HIC) resistant steels. Work by the Materials Properties Council has, however indicated that HIC resistant steels may be more susceptible to SOHIC. This raises questions about both the most appropriate steels, and test methods for evaluating them Published literature has been surveyed, and information pertaining to the mechanisms of SOHIC, with particular reference to the effects of material, fabrication, and service conditions on the risk of cracking, has been extracted. A critical review of this information, along with published information on test methods and results, and information on industrial experience including service failures due to SOHIC, has allowed conclusions to be drawn and recommendations to be made on materials selection, fabrication and testing for resistance to SOHIC.