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Re: [MW:23338] Pre-heat & pre heat maintenance

By Materials & Welding
The purpose of pre-heating is to slow down the cooling rate. so for thickness >25mm you must follow resistance coil method for pre heating to ensure that the full material volume surrounding the joint is heated.

regards,
LALU


On Mon, Aug 24, 2015 at 9:14 AM, Rejoy Thomas <rejoythomas90@gmail.com> wrote:
Dear Sir,
             Is it OK to preheat the pipe using cooper heating method for high thickness (say >25mm) carbon steel/ alloy steel pipes, like SA335 P22? Root and hot pass will be performed by GTAW & subsequent passes by SAW or FCAW. Is there any restriction in using this type of heating in power piping, where the heating equipment is stationary and the pipe is rotating which might affect the uniform heating?


Regards

Rejoy Thomas
Piping/Welding QC & Expeditor
STF SpA

On 20 August 2015 at 14:43, pgoswami <pgoswami@quickclic.net> wrote:
ASME B-31.1, specifies that uniform ,preheat, post heating(when specified by design specifications) and PWHT (when specified by design code), needs to be done for power piping. Performing the above with resistance coils(local PWHT) are common practice for in situ fabricated piping.
 
Please look at AWS-D-10.10-2009, for  detailed guidance.
 
Thanks.
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Engineering Specialist
Hamilton, Ontario, Canada
 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of george.dilintas@gr.bureauveritas.com
Sent: Thursday, August 20, 2015 4:02 AM
To: pradip kumar Sil
Subject: Re: [MW:23317] Pre-heat & pre heat maintenance

The preheat method is not specified in the ASME Code. It is a matter of sound engineering practice

Sent from my BlackBerry 10 smartphone.
From: pradip kumar Sil
Sent: Πέμπτη, 20 Αυγούστου 2015 - 10:29
To: materials-welding
Subject: [MW:23316] Pre-heat & pre heat maintenance

 Dear All,
Is there any code requirement for  ASTM A335 Gr P-22 material before welding & pre heat maintenance by resistance coil ( For uniform pre-heating  pre heat maintenance ) for power piping
Regards
Pradip

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