A small number of duplex and superduplex stainless steel components have failed in subsea service due to hydrogen induced stress cracking (HISC). The significance of these failures has led to research to define critical loading conditions for HISC, to allow confident design of components in future. Data relating to the Foinaven superduplex hub failures were published at OTC in 1999 and NACE Corrosion conference in 2001 and data from TWI Group Sponsored Projects were published at OMAE in 2004. DNV RP F112 has been based on these and other data, to provide a conservative approach to design. There are a number of gaps in the published literature and in the data available when DNV RP F112 was prepared, related to differences between small scale specimens tested at typical seabed temperature and actual components in operation, ie the operating temperature and pressure, and data from full-scale tests on pipe material with fine austenite spacing and hence good resistance to HISC. The paper presents new data on these issues and indicates where technology gaps remain.

This content is only available via PDF.
You do not currently have access to this content.