Need help with a choice of bolting material 2

[valvesarefun]

Hello All,

I am faced with the issue of joining 2 large peices of nickel plated steel together in a sub sea environment, and I need help with an appropriate choice of bolting material. My first thought was Duplex SS, but I am not sure where duplex actually falls in the galvanic series in relation to Nickel.

I am thinking 300 series is not a good option because of the temperature ranges supplied to me by the end user, perhaps Alloy 825 would be an option?

Any input or suggestions for other economical alloy choices would be appreciated.

Best Regards,

-VRF

 

[CoryPad]

SAE J2280 SHIP SYSTEMS AND EQUIPMENT—FASTENERS—SELECTION AND IDENTIFICATION REQUIREMENTS recommends the following materials for joining nickel to nickel members that are submerged:

NiCu Alloy 400, NiCuAl, Alloy 625+, Alloy 725, Titanium

Those would work regarding corrosion, but maybe not for other factors like thermal expansion. For joining steel to steel members that are submerged, the following fastener materials are recommended:

MP35N, Titanium, NiCu alloy 400, NiCuAl, CRES 660/A286, coated C & alloy steel


The NiCuAl alloy looks like a good choice. It is identified in the USA Federal Government document QQ-N-286 NICKEL-COPPER-ALUMINUM ALLOY, WROUGHT (UNS N05500).

 

[valvesarefun]

Thanks Corypad. Monel K500 seems reasonable enough!

Best Regards,

VRF

 

[EdStainless]

Make sure that you use fasteners in a medium strength condition. Don't use cold formed. direct aged. This material may be susceptible to cracking.

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