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Re: [MW:23920] Bulge P-91 Pipe after PWHT

By Materials & Welding

Why longer soaking for 12.7mm thick. The Hardness is very less on the bulged area, may be over heating?

On 24-Nov-2015 9:27 pm, "pradip kumar Sil" <pradipsil@gmail.com> wrote:
Dear Mr. Rems,
Bulge happened just outside PWHT heat band.Pipe thickness is 12.70mm & did soaking 2 hrs. I already attached Time temp. chart. Header has eight nos of pipe but during PWHT only two pipes are bulge.
Thanks & Regards,
Pradip  

On Tue, Nov 24, 2015 at 4:22 PM, Rems Okonkwo <rems.okonkwo@gmail.com> wrote:

Hello Pradip,

I believe the bulging did not occur on the weld zone but rather on the pipe and I believe that this area where part of the PWHT heat band.

There are two possible thing that will lead to this bulge.

1. The pipe collapsing on its weight during the PWHT as a result of softening effect.

2. The PWHT soaking temperature might be greater than the material heat treatment during the forming process which will also lead to softening and both 1&2 combining effect can lead to this bulge.

You will have to find a way to support the collapsing weight of the vertical pipe and also check if you have exceeded during the PWHT the tempering temperature during the pipe forming.

Rems Okonkwo

IWE Nigeria

On 24 Nov 2015 10:37, "pradip kumar Sil" <pradipsil@gmail.com> wrote:
It is closed

On Tue, Nov 24, 2015 at 2:15 PM, shanmuganathan .subbiah <shanmuganathan.subbiah@gmail.com> wrote:
Dear 

Both end closed or not during PWHT?


On Tue, Nov 24, 2015 at 12:26 PM, pradip kumar Sil <pradipsil@gmail.com> wrote:
Dear Expert,
In P91 Material ( HRSG header Joint ) after pwht one joint is bulge.We did  Preheating ,Welding , Post Heating,& PWHT in proper way.
Can anybody explain why this bulge occurs & remedy.
During fit-up inspection & weld visual inspection all round the joint is perfect but after PWHT pipe is bulge 140 mm away from the   weld ment
Pic Attached
Regards,
Pradip

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Regards

SHANMUGANATHAN SUBBIAH
AIB- Vincotte International & Partners LLC

PO.Box-420, PC -116

MAF, Sultanate of Oman

Tel: +968 24565771

Fax: +968 24565772

Mob: +968 92096714

Web:www.vincotte.com

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