SPLIT TEE 3

[abdolmaleki1975]

Hello dear friends and experts;
I have a few questions about Split Tee
First, if the material of the main pipe body (pipeline) is API.5L.X60, can A 516 GR.70 sheet be used to make the split tee body? (of course calculated with a higher thickness)
Second, for the split tee with the size of 40x16 inches, if the body of the split tee is made of API 5LX.65, is it possible to use a flange with ASTM A105 material instead of the ASTM A694 GR.F52 flange (for example, for a 16 inch outlet)?
Thirdly, if the answer to the second question mentioned above is positive, can E70S filler be used instead of E6010 penetrating electrode for the root pass for welding API 5LX.65 extruded body and 16 inch ASTM A105 branch flange (it should be noted that The received PQR is accepted)
Thank you for your guidance.

 

[GD2]

abdolmaleki1975,
Hot tapping always carries the risk of burn-through and HIC due to fast cooling of the weldment due to flowing process. HIC is more prominent when you weld high strength steels with flowing fluid inside the pipe.
You are dealing with methane gas with LEL less than 5%.

All I can tell is you must be extremely careful with the hot tapping operation, DO NOT assume anything, write and get approved a nice 'Hot Tapping Procedure', consult an Welding Engineer for the WPS/PQR to build up your confidence level.

You need to evaluate the interaction between the inside pipe wall temperature and the process fluid to avoid internal explosion due to instable thermochemical reaction, where the temperature inside may change significantly due to welding.

DO NOT take a chance!!!

GDD
Canada

 

[GD2]

I kind of agree, "you can always weld higher strength steel to a lower strength steel", but the question to Dr Frankenstein was "what have you done".

1503-44,
Here Dr. Frankenstein used a good engineering judgement with a good design practice.

GDD
Canada

 

[SJones]

If we make the blinding assumption that the OP is using B31.8, then there are nice pictorial representations of the requirements for joint designs covering dissimilar thicknesses/yield strengths.

Discussion of the execution requirements for the hot tap itself are for another thread.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.