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Column Plates Cracking


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#1 benabed

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Posted 02 June 2018 - 08:15 AM

Dear freinds,

Attached is image taken from the inside of a crude oil stabilizer column during the turnarrond inspection. The image is showing crack in the plate of the column made of 316L stainless steel . This is the second inspection we are facing such problem and each time we are welding the cracks with out chaging the damaged elements.

We are suspecting a chloride stress corrosion cracking to be the main cause of the cracks because the stabiliser is located just down stream the dessalter . I want  your expert opinion on the problem   in order to pin point clearly the true cause. If so what are the suitable solutions to be implimented .

Regards

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#2 Bobby Strain

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Posted 02 June 2018 - 08:54 AM

Enlist the services of a metallurgist.

 

Bobby



#3 Technical Bard

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Posted 03 June 2018 - 01:45 AM

Are the tray decks under "stress"  If not, stress corrosion cracking cannot be the source.  I would suspect something like fatigue (pressure cycling inside the column) or simply deformation cracks (liquid level hitting a tray from below).  But Mr. Strain is correct.  You need a metallurgist to inspect and analyze the cracks themselves. 



#4 benabed

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Posted 03 June 2018 - 04:28 AM

Technical Bard

 

It may be not applied stress but rather residual stress from fabrication and welding.  The pressure inside the column is constant.  The reason why I am suspecting SCC is the high temperature and the presence of chloride.


Edited by Art Montemayor, 03 June 2018 - 08:51 AM.
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#5 Technical Bard

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Posted 03 June 2018 - 10:39 AM

The crack in the photo would have required a load being applied to the material to deform it.  Residual stresses wouldn't do that.






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