Corrosion resistant subsea and splashzone fasteners
Status: Project
Date Announced: May, 2026
Fastener materials for offshore applications often require a combination of excellent corrosion resistance in seawater, high mechanical strength, and resistance to hydrogen embrittlement. This is particularly critical for fasteners deployed in the splash zone, where connections are exposed to repeated wetting and drying cycles, as well as to cathodic protection when fully immersed. While precipitation-hardened nickel alloys with high pitting corrosion resistance and mechanical strength have traditionally been used in such applications, concerns have been raised over their long-term integrity due to their potential susceptibility to hydrogen embrittlement, especially where pre- load and in-service stresses induce high strain at threads and grooves.
There is therefore scope to assess the suitability of a wide range of alloys beyond those traditionally used subsea and in the splash zone, to determine whether they perform better under these challenging environmental conditions. This assessment will be crucial to the materials selection process and forms the core focus of this proposed JIP.
Solution
The solution to the problem lies in a systematic engineering approach to the evaluation of the materials under the specific loading and environmental conditions relevant to offshore bolted connections. Work packages will therefore be designed to provide a better understanding of the integrity of the fasteners in terms of applied load, evolution of strain, corrosion resistance, and threshold hydrogen embrittlement performance.
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