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PETROMAKS-Maksimal utnyttelse av petroleumsreserver

Prevention of hydrogen induced stress cracking (HISC) in subsea pipelines and production systems made from stainless steel.

Awarded: NOK 6.9 mill.

There has been an increasing trend in the use of stainless steel alloys instead of carbon steel for subsea flowlines and production systems during the last 10 years in the oil industry. Even if this normally is a more robust solution compared to the use of carbon steel insofar as internal corrosion problems are concerned, the use of stainless steels has lead to leakage, production shutdown and expensive repair work. The reported failures were associated with hydrogen entrapment resulting from welding and /or external cathodic protection, combined with a certain stress/strain level. Atomic hydrogen entering the alloy can weaken the mechanical strength of the alloy, cause cracks and destroy the integrity of equipment or a system. This first part of this p roject will look at the mechanisms for hydrogen entering a metal during cathodic protection and how this is influenced by different material and environmental parameters. This will be done through experimental work and development of mathematical models for hydrogen formation and transport in stainless steels. The other main part of the project is to develop a fundamental understanding of the hydrogen induced deformation and cracking mechanisms of relevant stainless steels. This will be done through th e establishment of a cohesive zone model based approach for modeling the local failure mechanisms and linking them to the macroscopic deformation and fracture. A total of three PhDs will be included in this project.

Funding scheme:

PETROMAKS-Maksimal utnyttelse av petroleumsreserver