Carbon Steel to Stainless Steel Flange connections

• Jul 20, 2010

• #2

micalbrch

Mechanical

Jan 9, 2010

955

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?

 

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• Jul 20, 2010

• Thread starter
• #3

Powerman81

Mechanical

Sep 3, 2008

15

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

 

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• Jul 21, 2010

• #4

micalbrch

Mechanical

Jan 9, 2010

955

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

 

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• Jul 21, 2010

• #5

strider6

Materials

May 4, 2007

616

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

 

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• Jul 22, 2010

• #6

OSIRIS7

Mechanical

Jan 31, 2006

83

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.

 

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• Jul 22, 2010

• Thread starter
• #7

Powerman81

Mechanical

Sep 3, 2008

15

Thank you all for the help

 

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• Jul 22, 2010

• #8

SJones

Petroleum

Apr 22, 2001

3,930

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

 

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