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Pipe crack after welding

Pipe crack after welding

Pipe crack after welding

Good day everyone,
May I ask about our pipe that after welding it cracks.
-pipe is a106 GRB.
-Size 2inches schedule 20
-distance between two welds is 150 MM
-pre heating is 10 degree celcius
-no pwht

What could be the possible reason for this?
This is the first time i saw like this.
Our past experiences in middle east,
welding 2 inches even in closer distance apart
the pipe did not crack.

Please see the attached photo.
Thanks every one.

RE: Pipe crack after welding

Cracking in carbon steel base material weldments can be caused by several factors; poor cleanliness resulting in hydrogen pick-up, poor weld rod control, poor welding technique and last, poor fit-up or alignment.

A photograph you mentioned was not attached to your post so without any further information you can sort out each of the possibilities I mentioned.

RE: Pipe crack after welding

Thank you for your comment Sir,
due to slow connection i was not able to attached the file.
the photo is now available, please re access my thread. thanks

RE: Pipe crack after welding

Sorry but no photograph or file was attached in my view. Is the crack transverse to the circumferential but weld or parallel with it?

RE: Pipe crack after welding

The crack is actually not on weld but on pipe horizontal formation (or going to the length of pipe) almost 2 inches in length. the crack is in the middle between two welded joints.
the length between two joints is approx 15mm.

Thanks in advance

RE: Pipe crack after welding

Please upload a photo, it did not end up on the site for users to download. So its a longitudinal crack?

RE: Pipe crack after welding

Where is the crack relative to the termination of the weld? Was the weld made in the 5G position from 6:00 to 12:00?

RE: Pipe crack after welding

Sounds to me like you overstressed the pipe material from welding sequence for the butt welds or poor alignment of the pup piece.

RE: Pipe crack after welding

Only 10 degree C preheat?

RE: Pipe crack after welding

Are you sure that is Sch 20 ?
Lot of weld on that Olet for very thin pipe.

RE: Pipe crack after welding

Based on review of the photograph, you had a section of pipe containing a fabrication flaw.

RE: Pipe crack after welding

I concur with metengr - such defects do not arise in healthy pipe during normal fabrication processes.
Recommend you scrap all pipe from the same lot.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Pipe crack after welding

Your "preheat" requirement is dead wrong. You should NEVER plan on welding that cold. Get it up to at least room temperature (20-25 degree C)

RE: Pipe crack after welding

Concur with metengr. Pipe has a linear flaw of some sort. I would suggest cutting it out and determine the nature of the flaw. In any event it needs to be cut out and replaced. And that is a rather large amount of welding on the o'let.

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