4 replies to this topic

[Paktongkoi]

Hi All,
I wonder what will happen if we put gasket with stainless steel outer ring (some people call it centering ring) in between two carbon steel flanges?
Some time we are short of the right type of gasket.
Can we just put whatever we have?

[ankur2061]

Hi All,
I wonder what will happen if we put gasket with stainless steel outer ring (some people call it centering ring) in between two carbon steel flanges?
Some time we are short of the right type of gasket.
Can we just put whatever we have?

Paktongkoi,

No big deal. SS316 centering rings are used for carbon steel flanges commonly. Any gasketing material that provides integrity of the flange joint, has no compatibility issues with the process fluid, is safe to use (no asbestos content) and costs reasonably should be acceptable. Of course, SS costs more compared to other common gasketing materials and you need to evaluate your costs of using SS against the other materials.

Hope this helps.

Regards,
Ankur.
Ankur.

[Paktongkoi]

Dear Ankur,
Since we put carbon steel and stainless steel mating, will there be galvanic corrosion happen?

[ankur2061]

Dear Ankur,
Since we put carbon steel and stainless steel mating, will there be galvanic corrosion happen?

Paktongkoi,

Galvanic corrosion can only occur if the two dissimilar metals are in contact with a medium which acts as an electrolyte and allows migration of ions from the anodic metal to the cathodic metal through the electrolytic medium. Sea water, sandy and salty soil as well as salt and moisture laden air can act as strong electrolytes.

Normally pipes are under positive pressure and if the fluid in the pipe does not act as an electrolyte, then you have nothing to worry.

Regards,
Ankur.

[Qalander (Chem)]

Dear Ankur,
Since we put carbon steel and stainless steel mating, will there be galvanic corrosion happen?

Paktongkoi,

Galvanic corrosion can only occur if the two dissimilar metals are in contact with a medium which acts as an electrolyte and allows migration of ions from the anodic metal to the cathodic metal through the electrolytic medium. Sea water, sandy and salty soil as well as salt and moisture laden air can act as strong electrolytes.

Normally pipes are under positive pressure and if the fluid in the pipe does not act as an electrolyte, then you have nothing to worry.

Regards,
Ankur.

Just to slightly add to whatever very correctly/accurately guided by our ankur.
Please be careful in Grease's selection as well as application to such surface vicinity where galvanic corrosion possibilities are strong;since most of the greases are conducting indeed!
Hope this helps.