API TR 5NCL PDF

This technical report is a review of the literature and subsequent corrosion testing performed to explore if the limits on nickel (Ni)-content in low-alloy steels (LAS) can be revised.

There exists a legacy limitation on the Ni-content in LAS for deployment in sour service due to a perception on significantly reduced resistance to sulfide stress cracking (SSC) when nickel contents above 1 wt% are present.

The outcome of the study suggests that Ni-content may not restrict SSC resistance of LAS, and the underlying microstructure obtained from processing, such as heat treatment and mechanical processing, plays a more important role instead.