Re: [MW:10442] RE: 10277] RE: 10276] corrosion stainless steel

Dear All,

 

We too had a similar problem and we did some excercise to know the actual cause.

Please find the Attachment which detail the Activity.

 

Dear Goswami Sir, All our Fabrication activity was near to Sea. Can you please provide more light on this subject. Its a very useful tip.

 

Regards

VPV- Doha

 

_____________________________________________________________________________

On Sun, Mar 13, 2011 at 7:16 AM, pgoswami <pgoswami@quickclic.net> wrote:

Hello Ali,

 

The issue does not look to be due to wrong use of mechanical tool alone. Wrong mechanical tool will cause pick of  localized iron/ impurities and would cause pitting, discoloration.

 

Can you send a few pictures, showing corrosion as welded/before pickling, corrosion after pickling.

 

Is the fabrication location close to sea, what's the relative humidity or salinity in the fabrication areas??

 

Thanks.

 

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Pablo J Acelajado
Sent: Friday, March 11, 2011 2:45 AM
To: materials-welding@googlegroups.com
Subject: [MW:10277] RE: 10276] corrosion stainless steel

March 11, 2011

 

Hi!

 

You are correct about the wrong use of mechanical tools made of carbon steel as possible cause.

 

Stainless steel 316L is supposed to have already very low carbon content and will lessen the occurrence of chromium depletion during welding which causes the formation of chromium carbide precipitation.

 

You possibly need to check the chemical analysis of the 316L before and after welding at the point of localized corrosion to determine the cause.

 

PJA

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Ali Asghari
Sent: Friday, March 11, 2011 8:58 AM
To: materials-welding@googlegroups.com
Subject: [MW:10276] corrosion stainless steel

 

Dear All

In fabrication of stainless steel piping  ( material made by 316L and filler metal is 316L) in HAZ& cap of weld joint the severe locallized corrosion occured.

I guest that the cuase of it is wrong use of mechanical tools made by Carbon Steel, but locallized corrosion occured again in cap of weld& close HAZ after pickling.

now how can i find what is the cause of  corrosion. or is it intergranular corrosion with considering limitations& availibity  that existed in fabrication site?

Regards

 

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