Clamped CS shoe for SS Pipe--Corrosion issue
Clamped CS shoe for SS Pipe--Corrosion issue
(OP)
thread378-337956: Support of SS pipe
Dear All,
I am in a situation wherein there is a 2" SS Drain piping to be supported by CS bolted clamped shoe.
There are no insulators like liners etc. to avoid the contact in between the 2 different metals CS with SS.
Kindly advice on this at the earliest about how this is done or the above situation is acceptable?
What are the various ways to avoid the SS to CS contact in above situation?
Dear All,
I am in a situation wherein there is a 2" SS Drain piping to be supported by CS bolted clamped shoe.
There are no insulators like liners etc. to avoid the contact in between the 2 different metals CS with SS.
Kindly advice on this at the earliest about how this is done or the above situation is acceptable?
What are the various ways to avoid the SS to CS contact in above situation?
Thanks & Regards,
Abhijit





RE: Clamped CS shoe for SS Pipe--Corrosion issue
Sometimes its possible to do all the right things and still get bad results
RE: Clamped CS shoe for SS Pipe--Corrosion issue
In practice, SS/CS galvanic joints don't tend to be much of a problem except again in services where the CS is already of marginal corrosion resistance.
We've used galvanized steel pipe shoes in contact with stainless steel pipe for at least the two decades I've been with my present company, and have never heard from a client that there's been a problem. In milder external corrosion situations, we've also used painted carbon steel shoes in contact with stainless steel pipe, again without problems in two decades. The coatings are NOT good enough in that case to eliminate galvanic coupling between the pipe and the shoe/structure.
Galvanized parts should not be used in contact with pipe above 200 C (400 F), since the galvanizing is of little if any benefit at these temperatures- and well above these temperatures, the risk of liquid metal embrittlement is at least a theoretical possibility.
RE: Clamped CS shoe for SS Pipe--Corrosion issue
If you are not near salt water and these are exposed to rain they should be fine.
Isolating them is safest.
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P.E. Metallurgy, Plymouth Tube
RE: Clamped CS shoe for SS Pipe--Corrosion issue
However, pls note provision for the same is not there in my support standard. If want to deviate, I need to get approved from Client as it is additional material/scope.
Moltenmetal,
It looks like you are of the opinion that I should overlook this problem & move forward. The support standard itself is not talking about it.
But I still feel that I should have a word with Client however, I wanted to make the grounding before I take it up to Client.
EdStainless,
Yes it is coastal environment then I need to isolate.
Pls share ways of isolating per your experience?
Thanks & Regards,
Abhijit
RE: Clamped CS shoe for SS Pipe--Corrosion issue
They need to have drain holes in them also.
I am sure that there are other things that will work.
Just make sure that there are no chlorides and that it cannot absorb moisture.
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P.E. Metallurgy, Plymouth Tube