Gasket Material 1

[pipeneer]

Hi to All
The answer to the following question shall be greatly appreciated:
I am trying to install a SSDS (super Duplex)2500# RTJ flanged madular DB&B valve on a Flow Line using a 6"x 2"-2500# RTJ Nipoflange in A350 LF2 material (Flow line is API 5LX52N), now, What type of Gasket is the most appropriate between these two diffrent type of flanges ?, I am contemplating gaskets of type Octagonal Ring AISI 316 R26! will this be OK with regards to Corrosion?
Thanks a lot

 

[SJones]

Subsea?

Steve Jones
Materials & Corrosion Engineer

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

 

[pipeneer]

Thanks Steve, no the line is not Subsea but it is on a platform at sea !

 

[SJones]

The ring will but the carbon steel groove might not. Is it being given an overlay?

Steve Jones
Materials & Corrosion Engineer

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

 

[pipeneer]

No, the Nipoflange is a standard 2500# RTJ and does not have any perticular weld overlay, if you mean the surface of the flange grooves has been treated. Do you mean the ring might corrode ?
Thanks.

 

[SJones]

No - I mean that the carbon steel will corrode and the seal will be degraded.

Steve Jones
Materials & Corrosion Engineer

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

 

[pipeneer]

Hi
I found out (in addition to your comments)that HARDNESS of the gasket in comparison with the 2 different type of surface material of the flanges, play a significant part when it comes to corrosion and leakage.
Thank you

 

[SJones]

Hardness plays a role in ring deformation and galling. Too hard and you risk embedding the ring into the flange material.

http://www.europeansealing.com/uplo...-FSA-Guidelines-Flange-Gaskets-009_98_ENG.pdf

Steve Jones
Materials & Corrosion Engineer

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

 

[AbyssUK]

Hi pipeneer, if your worried about corrosion, you can get specific gaskets that aid the joints resistance to corrosion.

Flexitallic make a flange rescue gasket in an RTJ form to fight corrosion.

http://www.flangerescuegasket.com/products/flange-rescue-gasket-ring-joint

Pikotech also make there VCS gaskets

http://www.pikotek.com/ViewProduct?product=300&region=1

There are a few others if you Google. Also due to the difference in metals across the flange ensure you get a full insulating kit for the whole joint (insulating bolt sleeves + washers), this will prevent galvanic corrosion.

Disclaimer:- I work for Flexitallic, but I am not a salesperson so am not promoting anything just trying to help.

AbyssUK