Anit-Corrosion Coating on 2205 Duplex Flowline Spools?

[DarrenHeal]

Guys

Working on a project which involves SUBSEA structures with duplex stainless steel (probably API 5LC LC65-2205) cooling loops within them.
Inlet temperature is about 100 Celsius, although some "headroom" might be advisable. Need to spec. amn anti-corrosion coating for the loops (which will be 150 to 200 metres long welded-up 5-inch nominal diameter pipe coils).
Client suggested gold plating them!!!
I was thinking thermal-sprayed aluminium with an organic sealer applied over the completed spool (including welds) in one fell swoop.
Any suggestions / tips / comments?
Specified coating must meet DNV-RP-F112 HISC-prevention criteria.
Many thanks
Darren

 

[SJones]

Best not to double post - see the reply under 'offshore structures'

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[davefitz]

Gold plating? Must be a gov't job.

Crevice corrosion is oone weak point of 2205 in some applications, so flake glass lining and /or coating with organic sealer ( gasket joint compound) is often used in above ground applications.

weld metal protection is likely related to the practice of "overmatching" the weld meaterial- may vary according to the weld metal selected.