Pipe support material

[Sachinkathe]

Hi
I a want to know that can we use same pipe shu material (Shu i.e. inverted T welded to pipe directly) for hot insulated carbon stell pipe and stainless stell pipe? Any criteria behind it?

Sachin

 

[SWMechanical]

For carbon steel line, you can use carbon steel for shoes. But for SS pipe, if you use carbon steel for shoes, it will have bimetal welds on the pipe. We usually try to avoid bimetal welds on piping. So for the pipe shoe, you can use clamped ones (the clamps will be SS).

 

[C2it]

You could get serious problems with stainless pipe and carbon steel shoe. Don't do it. If you need a welded carbon steel shoe, use a stainless wrap plate welded to the pipe, and weld the carbon steel shoe to it.

 

[europipe]

Unless it's an anchor or stop, I should use clamped shoes.
CS shoe on ss pipe with a ptfe or neoprene layer in it.

Greetings

 

[DSB123]

Don't just weld inverted tee's to a pipe to act as supports without investigating the stress levels around the attachment.

 

[Sachinkathe]

Thanks a lot, ok it is concluded that cs shoes can't be directly welded to SS pipe but is it because of metallurgical reasons (chemical comp. of mats.) or differential thermal expansion coefficients or difficulty in welding process?

Sachin

 

[JohnBreen]

.......also the SS material has a different coefficient of expansion than does the CS material - so if there is a significant temperature involved the local stresses at the (mismatched material) welds will be high. Welded-on supports that are not completely insulated act as "heat-sinks" too and this will exacerbate the local stress problem. Please see PFI ES-26 regarding welding appurtenances to pipe.

John.