welding dissimilar materials

[jimpiper60777]

Hello to all!

Has anyone had any experience in joining two pipes (by welding instead of flange) with dissimilar material like stainless steel to carbon steel.? HOw it is done and what are the criteria or parameters to consider?

What code in piping discusses about this?


Thank you for your enlightenment.

Jim

 

[rustbuster]

It is done quite often. Maximum interpass temperature is a key consideration. 350F. Filler metals ER309L/E309L
You need to consider the galvanic differences of the materials from a corrosion perspective.

Good luck

 

[MJCronin]

jim...

As stated above, this has been done for various materials many times in the past, however, you should understand that this type of joint is not the best design in some circumstances.

For example, in high temperature applications like Heat Recovery Steam Generators (HRSGs)these joints have been known to fail early and often.

Where there are temperature transients, this type of joint can generate "secondary stresses" due to the expansion differences between the two materials. Eventualy, these can cause fatigue failure.

In many cases, a simple flanged joint is preferred

Secondly, not all metals can be welded to any other type.

Tell us more about your particular application.....?

-MJC

 

[jimpiper60777]

Thanks a lot for your reply.


I had inspection in a nitrogen package area and I found several joints with carbon steel and stainless steel. This was put into questioned by the client however I never had a chance to review how they came up with discussion for this issue.