Consequences of Welding on Fitting & Flange Body.

[Vimal Kumar]

Dear All,

Need your suggestions on both the cases as given in these photos.

My contractor has done these, his stand is that if welding of theses are to be avoided, then there will be problems during installation & will result in leakage during Hydrotest.

Request you all to provide your suggestions to avoid these in future.

Regards,

Vimal Kumar.

[Sundaram Elumalai]

Hi,

They need to fabricate proper steel support without welding on the
Fittings. The SUPPORT can be arrested during the shipment.

But it looks, lack of material, knowledge etc. It may give problem, if
the welded materials are not compatible with Fittings.

With Kind Regards,

Malai

Dear All,

Regards,

Vimal Kumar.

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[T. Mahendran]

The welding direct to  piping and flanges are not at all accepted. The heating effect will create improper seating of flanges  or weakness of piping structure.   The alternate way using sufficient  clamps or keeping  extra material prior to direct welding  can be reduced some adverse effect at later stage. With regards     T.Mahendran, Tabouk - KSA, Ph: 059 3423 767. --- On Thu, 2/9/12, Vimal Kumar <jvku...@gmail.com> wrote:

From: Vimal Kumar <jvku...@gmail.com> Subject: [MW:13639] Consequences of Welding on Fitting & Flange Body.

[Narayanan, Jyothidas [Heston]]

Dear Vimal,

 

So you want suggestions to avoid these type of incidents in future, means you are leaving this particular incident.

If you have such Contractors, you can never avoid these type of incidents.

 

Regards,

Jyothidas.

 

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Vimal Kumar

Sent: Thursday, February 09, 2012 10:06 AM
To: material...@googlegroups.com

Subject: [MW:13639] Consequences of Welding on Fitting & Flange Body.

 

Dear All,

--

[vijayan]

Hi

 

This is the common practice! everywhere. Only ensure that there is no welding done on the flange face. Temporary supports shall be from the similar material type from the weldability point of view. Tack welding if any shall removed properly and the surface shall be free from defects.  

BR

M.Vijayan

 

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Vimal Kumar
Sent: Thursday, February 09, 2012 10:06 AM
To: material...@googlegroups.com
Subject: [MW:13639] Consequences of Welding on Fitting & Flange Body.

 

Dear All,

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[manpreet]

Hi Vimal,

I see it as a serious Flaw in your and Contractor's working style, while designing
piping/pipeline, Stress calculations are carried out to determine where and how many supports
are required, from the pictures provided, it appears that designing phase is bypassed.

Anyway since you wanted to know about Design of supports, please find as described below:-

*For Pipeline:- ASME B31.4 clause 404.9.1, if pipeline is operated above 20% of SMYS (specified
metal yield strength) then support must be attached to full encircle reinforcement (ATTACH NOT
Welded)

*For Pipeline:- ASME B31.8 clause 834.5, if hoop stress is greater than 50% then support must
be welded to full encirclement reinforcement (Welded to 2 180deg RF PAD)

*For Piping:- ASME B31.3 allows to weld support with RF PAD.

*For Pipeline:- AS2885 states that if pipeline is operated above 50% of SMYS, a support and
clamp shall completely encircle the pipe, when it is necessary to provide positive attachment,
the pipe may be welded only to encircling member,support shall be encircling member not
directly to pipe.

To conclude, Support welding to pipeline/piping is prohibited, greater %of Yield strength is
reserved exclusively for hoop stress utilization, so no introduction of additional stresses by
rigid welded to the pipe restraint is welcome.

Another factor to consider is that for pipelines, a non-metallic PTFE pad are provided in
between of encircling member and pipeline,it is placed to avoid corrosion of pipeline with
direct contact.

Regards
Manpreet Singh




On Fri, 10 Feb 2012 15:47:25 +0530 wrote

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