service wise requirement for PWHT

[Sadique Sheikh]

Hello to all of you.
Dear friends I have one query which I like to ask you
As per table 331.1.1 of ASME B31.3,it is mentioned here the
requirement of PWHT as per thickness and tensile strength for
mentioned materials.But how can I get information according to service
vise? This requirement is depend on project specification but i want
to know that, on which basis they calculate this requirement? Which
factors will consider during calculation? and how this factors affect
during service?
Regards
SADIQUE

[Panomsit Srirunpetch]

As I know, sour service may requires PWHT...

We should refer to documents from NACE...

Regards,

PAN

2009/7/4 Sadique Sheikh <sadiq...@gmail.com>

[tong tong]

You can refer to NACE 0472 and 0296

[rahul...@akersolutions.com]

Hello Sadique,

PWHT requirement can be defined in 2 categories 1) Thickness basis 2)
Actual service basis.
1 ) The Thickness basis requirement, which you have already studied
about is code dependant, and the thickness criteria for PWHT varies from
design code to code.
2) The PWHT requirement for fluid based is more primary criteria for
selection of material for the fluids.
The main intension of PWHT to control the hardness of the weld area ,
which may lead to various corrosion types.
Main fluid which requires PWHT requirement on base metal is Caustic,
AMDEA - DMEA , H2S, H2 etc.
For detail understanding you must refer to Appendix F of ASME 31.3
and NACE standards like MR-0103 & MR-0175.

reg


Rahul Pisat
Engineer - Material Engineer

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[G Padmanabhan]

Hi sadique,
Designer has to specify pwht requirements.For example CS in amine service required PWHT irrespective of thickness.Even support welding  required pwht.
It depends upon how material will react to service condition.

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With Warm regards,

G.Padmanabhan
00967771103169

[Roger Hornberger]

Gentleman,

 

If I may ask how is PWHT accomplished in this case, is it with a furnace, induction heating or with a gas torch?

 

Many thanks

 

Roger H.

 

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[Institute of Inspection Technology & NDT IITNDT]

Dear,

 

   You may can use furnace or induction but not a gas torch.

 

Sharief

[Shashank Vagal]

Not a direct gas for it will cause oxide scales and other aberrations, induction or furnace heating is expensive (we have to be conservative in this respect now) unless the job size/volume warrant it. Otherwise, simple coil heating with proper insulation has helped me unfailingly all the while. You may try it  to be pleasantly surprised. And decide wisely on TC locations. Some Shell codes say to put one on the weld and under the heating coils, which I have never understood Shashank --- On Thu, 6/8/09, Institute of Inspection Technology & NDT IITNDT <iit...@gmail.com> wrote:

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