6Mo or Monel 400 fitting which is better for 90/10 Cu/Ni tubing

[tonylichun]

What material of tube fitting (6Mo VS Monel 400) should I use for FPSO ballast?
The tube specified is 90/10 Cu/Ni alloy 706 tubing.
The system media is hydraulic oil @ 50 Celsius.
The tubing and fitting will be sinked in seawater.

Thanks in advance.

 

[EdStainless]

I would use 400, since it is closer to the 90/10 in corrosion potential.


= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[metengr]

Agree, Monnel 400 would be a better choice over the 6Mo material.

 

[moltenmetal]

Just out of curiosity, who do you know that sells 6Mo tube fittings? I want to know, in case I ever need them, as none of the major manufacturers use this material. Monel is a shelf stock standard for most of them.

 

[tonylichun]

Swagelok supplied 6Mo fittings

 

[moltenmetal]

Guess I missed that- they do carry a handful of fittings in 254SMO which is a 6Mo alloy- that must be relatively new. But they carry nearly a full line of fittings in Monel, and have done for probably 40 years.

 

[EdStainless]

I have seen full hydraulic systems that were done in 6%Mo (AL-6XN tube and 254SMO fittings).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube