RE: [MW:14185] RE: 14178] Fwd: Time span for RT after PWHT

Samshuddin,

AWS D1.1 requires NDT to be perform on some material minimum of 48hrs after welding and not after PWHT. The reason for nthis request is because, some material grades are susceptible to under bead or delay cracking. There was no code requirement for time frame of NDT after PWHT except that RT should be perform when the test coupon is at ambient temp for practical purposes.

You should also understand that after PWHT, all entrapped hydrogen must have escaped and hardness values are generally reduced, natural essence of PWHT. Entrapped H2 and high hardness value are the major causes of delay cracking and these are reduced to bearable minimal after PWHT. You do not need to wait for 72 hrs to perform your NDT after PWHT except if your client spec requires that.

Regards,

Rems Okonkwo
Welding Engineer
Nigerdock Nig PLC.

Sent from my Nokia phone
-----Original Message-----
From: Obidike, Boniface (GE Oil & Gas)
Sent: 04/05/2012, 14:08
To: materials-welding@googlegroups.com
Subject: [MW:14184] RE: 14178] Fwd: Time span for RT after PWHT

Samshuddin,

This depends on the type/grade of material you are working with. Some
material require RT as soon as the weld cools, some material 24hrs after
welding, some 48hrs, while some 72hrs after welding. It all depends on
your material.
Note: some material demand NDE before and after PWHT

"Quality is the Bone, Be the Dog Always"

Boniface Obidike
QA/QC Engineer
Speciality Connectors & Pipes
Drilling and Production Systems
GE Oil & Gas Business
Mail: Boniface.Obidike@ge.com
Office: +234(1)4629400
Mobile: +2348163479738
Home: +2348039409934

-----Original Message-----
From: materials-welding@googlegroups.com
[mailto:materials-welding@googlegroups.com] On Behalf Of samshuddin k
Sent: Thursday, May 03, 2012 4:03 PM
To: materials-welding
Subject: [MW:14178] Fwd: Time span for RT after PWHT

Dear Sir

Good Evening

Generally after 72hrs of welding, we will do RT.
But in our repair marine project, we dont get sufficient time to follow
this.

Is it acceptable by Code (ASME /AWS) to do RT immediately after PWHT
Please guide me with Code reference.

regards
Samshudddin.K
NKOM Qatar

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