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Discussion Forums - The Hendrix Group
HomeHomeDiscussionsDiscussionsMaterial Select...Material Select...Material SelectionMaterial Selection
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9/11/2007 9:00 AM
 
Dear wifi, As U hv mentioned that the reason for ur group decision to change over from CS to SS pipe in cooling water circuit to heavy >corresion and deposits found inside the pipes. But at the same time u hv mentioned that ur cooling water is in principle chloride free. As such ur first job is to analyse the root cause behind the "deposit" by a prudent deposit analysis and to determine the ions, radicals . ph therein which are contributing for the corrosion and if possible the rate of corrosion. Still I am not in favour of changing CS to SS right at the moment without having a detail investigation. Let some Engineering be done before you take any costly decision. regards and pl. shere your outcome.
 
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9/11/2007 9:00 AM
 
Dear DMI, Thank you for your reply. The decission to change the CS to SS was originally recommended by the furnace manfacturer when they have found corrosion deposits in the system. I agree with you that investigation to find the root cause should take place. However, the furnace was under the resposibility of the furnace supplier at the time. The situation deterriated recently and I have no choice other than to change the pipes to SS due to the criticality of the furnaces. My findings on the other hand was that the reason for the corression was because the system was subjected to be open circuit during the PMs, air (Oxygen) have contributed to the phenomenna. Although the system is supposed to be a closed circuit system, it was prudent that Operation do leave the system open. The furnace supplier have never came to this conclusion but they encouraged us to go a head changing the pipes to SS. Going back to the original question, given the parameters to select the SS SCH. 10 at the pressure 3 to 4 bars for the pipe size 4" and 5" for a close system cooling system, can any body give another etailed calculations confirming my selection? Thanks again for your support and constructive contribuation. Regards, Jassim
 
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9/11/2007 9:00 AM
 
Dear wifi, you r defining SS pipe size = 4" and 5" NPS . you know operating Pr = 3 - 4 Bars you know operating fluid as CW and itsTemp. Pl. refer ASME Sec. II Pt.D for corresponding stress calculation at T and find practical hoop stress as per ASME SEc. VIII Div.1 and chk whether hopp is lower than the allowable stress.regards but still ask the manufacturer to give a long term gurantee on any failure + overall cost of faliure.
 
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9/12/2007 9:00 AM
 
Dear DMI, Thanks a million for your recommendation. However, would you kindly send me the link to reach to the recommended ASME site please. I will definately post you with latest... Best regards,
 
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9/12/2007 9:00 AM
 
Dear wifi, ASME Sections are not available in site free. You have to purchase it hardcopy or purchase CD-ROm or get loan from any nearby small/large engineering/manufacturing compnay . Pl. take help of your management. regards
 
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