New project for subsea materials

Connect, no.119, July - August 2002, p.6

Cracking at the interface between steel and nickel alloy weld metal

Steel to weld-deposited nickel alloy interfaces exist in a wide variety of components, either where nickel alloy claddings are employed or where there are dissimilar joints between steels and a range of corrosion resistantalloys.

Much satisfactory service has been experienced, recent failures of subsea hubs in the North Sea, employing AISI 8630 and ERNiCrMo-3/ERNiCrMo-15 combinations, have raised questions about the performance of these interfaces in thesubsea environment.

TWI is launching a new Group Sponsored Project which will address the concerns raised by the recent failures by developing a testing method to reproduce the failure mode experienced. In this way variables influencing failure can beexplored. Once the controlling factors have been identified, guidelines for the safe manufacture and use of steel to nickel alloy joints in subsea applications will be formulated.

For further details please contact either Andrew Leonard or Mike Gittos .