Material Compatibility Issues Subsea Flanges & Fittings
Material Compatibility Issues Subsea Flanges & Fittings
(OP)
Could anyone provide any guidance on any material compatibility issues with specifying A453 Grd660 fasteners for use in a marine environment on Inconel Alloy fittings? I have checked the coefficients of expansion and there isn't a major difference so I wouldn't of thought this would/could lead to excessive bolt stresses or flange connection integrity issues.





RE: Material Compatibility Issues Subsea Flanges & Fittings
NiCu Alloy 400/405
NiCuAl QQ-N-286
Alloy 625+
Alloy 725
Titanium
RE: Material Compatibility Issues Subsea Flanges & Fittings
RE: Material Compatibility Issues Subsea Flanges & Fittings
RE: Material Compatibility Issues Subsea Flanges & Fittings
I assumed that CP was not being used based on the materials you mentioned, which was obviously a bad assumption on my part. As long as the full length of the fastener will be exposed to CP, then ASTM A 453 Grade 660 is acceptable in contact with Ni-based alloys. In addition to ISO 10463, heere is an article that discusses the topic of fasteners for seawater use, galvanic coupling, etc.
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RE: Material Compatibility Issues Subsea Flanges & Fittings
The SAE document I referred to shows Grade 660 as compatible with nickel alloys in wet environments, but not compatible for submerged conditions.