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RE: [MW:11431] SS 304L piping leaking

By Materials & Welding
Dear Mr. Ilangkumaran,
 
If you cut a sample and send to lab for failure analysis, including SEM and EDAX it would definitely provide you correct root cause for such failure.The possible causes could be:-
  1. Pitting/Crevice corrosion in and around the weld and HAZ  if the  chloride level is high. If the biocides, such as bleaching agents are used for chlorination the water chemistry would definitely be affected. 304L does get prone to attack if the chlorine content get above 50ppm and the operating /ambient temperature  is above 30-40 deg C
  2. MIC attack/under deposit corrosion attack.Austenitic stainless steels have high high immunity of such attack in oxidizing environments.But in the environments containing sulfate-reducing bacteria, such failures are likely to occur.
  3. Sometime wrong welding consumables could be the cause.However it would not be advisable to arrive at the correct conclusion till one has the failure analysis done.
Thanks.
 
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Prasad Joshi
Sent: Tuesday, June 21, 2011 8:11 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:11417] SS 304L piping leaking

Is there any rust visible on the piping? If yes, the chances are the welders have mixed up filler metals at some point of time.
 
CSCC may be possible depending upon the salinity of water if there is any vibration caused by cyclic loading. Otherwise, the CSCC is less likely for Utility water service in such a short period.
 
Regards,
 
Prasad Joshi
 
On Mon, Jun 20, 2011 at 7:36 PM, Fred Majdnia <FMajdnia@technip.com> wrote:
   Dear Kumaran,
 
For a technical root cause analysis you need to perform the testing of the water. The dissolved gases, PH, chloride ion being the most important parameters. Without the water analysis report, no one can help and all would be guess and anticipation. 
I can guess the reason but prefer to leave it to the test result.
 
Regards
 

 
-----materials-welding@googlegroups.com wrote: -----
To: materials-welding@googlegroups.com
From: Raghuram Bathula <raghurambathula@gmail.com>
Sent by: materials-welding@googlegroups.com
Date: 06/19/2011 11:55PM
Subject: Re: [MW:11397] SS 304L piping leaking


it depends on salinity (ppm) and temperature also, any chance of mixng sea water?

On Mon, Jun 20, 2011 at 11:16 AM, k.ilangkumaran ilangkumaran <k.ilangkumaran@yahoo.com> wrote:
Dear experts,
 
                Could you please anyone explain me why SS 304L piping leaking. Its service is just utility water and duration of service is not even 1 year. Also leaks were observed many locations only on weld and HAZ. What could be the causes leak?
 
Regards
Ilangkumaran
 


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