MATERIALS SELECTION

[NasserAlNaimi]

Deer guys the issue in brine area we have titanium piping with joint with GRP piping flange joints with hot deep galvanized bolts..... is this allowed to be used in this corrosive area like the brine piping . With also GRP piping support are made from CS with galvanized coating that brine can splash on .the contractor is replying that Galvanized CS can resist rust and it won’t corrode as replied and no issue with it !!! also The bolts is in direct contacts with flange as dissimilar material joints . pleas advice !!!

 

[cloa]

I doubt the galvanised steel just by itself will last long in oxygenated brine- galvanised steel is only good for atmospheric with low salt. If its in direct contact with Titanium it will be destroyed very quickly and might given certain conditions cause hydrogen embrittlement of the Titanium. Specify the full conditions of the situation including temperature, composition of brine especially oxygenisers, approximate geometry- if the English part is too much there is a forum (Translation Assistance for Engineers) to translate between English and your native language.

 

[SJones]

What is the normal corrosion protection coating applied to pipe supports in existing facilities within the plant? If the brine is supposed to be on the inside of the pipe, how will it be splashing on the pipe supports on a continuous basis? Just to clear the situation: is there a titanium-GRP flange couple that is bolted with HDG coated fasteners? If yes, then that is not a good idea, particularly in a moist environment. The fasteners should ideally be super duplex stainless steel.

Steve Jones
Materials & Corrosion Engineer

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

All answers are personal opinions only and are in no way connected with any employer.