Carbon Steel to Stainless Steel Flange connections

[Powerman81]

Is it possible to connect a stainless steel flange to carbon steel flange (24" piping) with river water as the flowing fluid? what type of problem would the flange connection experience? do I need insulating kit? any help would be appreciated

 

[micalbrch]

You can expect contact corrosion between stainless steel and steel especially if water is involved. So, any insulation between the flange contact surfaces is recommended. Can't you coat the steel flanges?

 

[Powerman81]

Its desired to install insulating flange gasket kit. But how would the corrosion affect the stainless steel surface?

 

[micalbrch]

Not much as the steel part will mainly corrode. It is the ignoble metal.

 

[strider6]

you'll have galvanic corrosion on the carbon steel part, both on the internal and external surfaces. You can use an isolating flange kit or better an isolating pipe spool.

here you can find information on isolating kit:

http://www.farwestcorrosion.com/ccp/flange/pikotek04-insulating.htm

http://www.corrosionist.com/Galvanic_Corrosion.htm

S

Corrosion & Rust Prevention Control

 

[OSIRIS7]

Remember to use an insulating gasket as well. It needs to be a thicker gasket, because the water can act as an electrolyte, creating a bridge between the two flanges, giving the opportunity for corrosion.
Thus a bolting and gasket insulation kit is recommended.

 

[Powerman81]

Thank you all for the help

 

[SJones]

Remember: if you do use a coating, coat the stainless steel only!!

Study NACE SP0286 for isolation guidance.

Steve Jones
Materials & Corrosion Engineer

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