Weldolet Material

[ageometry]

Situation is as follow and would appreciate some advice:

Existing pipe was originally designed for >1000F operation and material is P22. After some modification to the system, the new operating condition is reduced to 500F@450psi. Now if I need to add a branch to this system, would it be acceptable to use a CS weldolet (instead of P22) for connection?

Thanks in advance.

 

[BigInch]

If I remember correctly, I'm pretty sure you're past the temperature limit for CS with that 500F. Check the temperature limit given in B31.3

**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[ageometry]

CS are good till 700F per B31.1 I thought?

 

[rneill]

Normal carbon steel is fine at 500 F in B31.3.

 

[ageometry]

Thanks... But back to my original question. Is the dissimilar metal acceptable?

 

[rneill]

Sorry, can't help you with that one. You might want to post in the Metal and Metallurgy Engineering forum and have this thread deleted or put a cross reference in this post to redirect people from here to there.

 

[MJCronin]

You are confronted with a dissimilar materials weld....

These are acceptable under the piping codes and can be made for a weldolet....but it is bad practice if othet alternatives are possible.

I suggest that you find a P22 weldolet....they are out there.

BTW, BigInch... I believe that your recollection is in error..... B31.1/31.3 allows carbon steel piping materials to ~775F in continuous duty.

-MJC

 

[ageometry]

Hi MJC,

Thanks for the input. Would you mind explaining why it would be considered as a bad practice? Thanks.