Welding Procedure for Stub to Delivery Pipe
Welding Procedure for Stub to Delivery Pipe
(OP)
Hello there,
How are you all?
We need to install a thermowell into a large diameter pipe.
It looks like we will be welding a stub to the outside of the delivery pipe (8000 kPa).
What is the correct procedure to follow to ensure that the stub can handle the pressure?
I am planning on doing the following:
1. Grind paint off delivery pipe at required location.
2. Ensure that there is a 45 degree chamfer on the stub.
3. Place the stub onto the pipe, ensuring that there is a 1-2mm gap for weld penetration.
4. Tack weld stub into place.
5. Initial filler run.
6. Intermediate filler run.
7. Final full run.
8. NDT Testing of weld.
9. Drilling of hole through delivery pipe.
Are there any recommendations you suggest?
Regards,
Laurence
How are you all?
We need to install a thermowell into a large diameter pipe.
It looks like we will be welding a stub to the outside of the delivery pipe (8000 kPa).
What is the correct procedure to follow to ensure that the stub can handle the pressure?
I am planning on doing the following:
1. Grind paint off delivery pipe at required location.
2. Ensure that there is a 45 degree chamfer on the stub.
3. Place the stub onto the pipe, ensuring that there is a 1-2mm gap for weld penetration.
4. Tack weld stub into place.
5. Initial filler run.
6. Intermediate filler run.
7. Final full run.
8. NDT Testing of weld.
9. Drilling of hole through delivery pipe.
Are there any recommendations you suggest?
Regards,
Laurence





RE: Welding Procedure for Stub to Delivery Pipe
"What is the correct procedure to follow to ensure that the stub can handle the pressure?"
I think that is why people spend years in university - they are called "engineers" - they decide whether your stub can handle the pressure - not an internet forum.
As for the rest, have you heard of a WPS - that is what you require for the rest of your welding operations.
Regards,
DD
RE: Welding Procedure for Stub to Delivery Pipe
Correct procedure is to follow the design code, presumably b 31.3. This is normally accomplished by welding on a weldolet, either set on or set in which you buy specifying the main pipe od and your stub od and pressure rating. This will provide a fully certified connection providing you have a weld procedure qualified for this work.
Anything else is simply not acceptable.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way