Hydrogen induced cracking processes in structural microalloyed steels. Characterization and modelling

Microalloyed steels are of great importance in the petroleum industry where they are used in structural and tubular components in pipelines and platform supports. The high toughness they provide and their mechanical resistance to stress corrosion cracking (SCC) processes make these steels extremely useful in the above mentioned fields. Most local environmental conditions present in these types of structures make the high resistance to cracking of these steels unsuitable for characterization using conventional methods based on Linear Elastic Fracture Mechanics. Once an experimental and analytical methodology based on Elastic-Plastic Fracture Mechanics has been developed [1,2] and shown to be suitable for the characterization of cracking processes in environmental conditions, it has been applied to characterize hydrogen induced cracking (HIC) in two different structural microalloyed steels, offering a quantitative characterization of the cracking behaviour which can be correlated with the fracture micromechanisms that generate the fracture path.