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Discussion Forums - The Hendrix Group
HomeHomeDiscussionsDiscussionsOil Refinery Co...Oil Refinery Co...HIC, SSC, SCC, HCL and HTHAHIC, SSC, SCC, HCL and HTHA
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2/17/2006 9:00 AM
 
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Mr. C.V.Srinivasan Once again thank you very much for your useful inputs. After PWHT requirements for strength welds of tubes into the tube sheet headers, to meet MR0175 and MR0103 requirements we have to control the hardness of tube sheet to tube strength weld joints in a way to have less than 22 Rockwell. Through Header boxes plugholes is not possible to measure the hardness of tube-to-tube sheet strength welds. This is the reason why we are questioning the project Receive my best regards Luis Marques
 
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2/17/2006 9:00 AM
 
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Luis Hardness : now it is lowered to Rc 20 (< 200 BHN) by NACE MR 0175. It is certainly possible to achieve hardness lower than NACE needs (< 200 BHN or < Rc 20) even with dissipation of heat . I see no problem in getting lower than < 200 BHN. with proper time and care in PWHT for your P11 and T11 material strength weld getting lower than 200 BHN. We have done with success in proper PWHT with P 5 tube-sheet and P 5 tubes strength welded and with Inconel overlay in high pressure hydrogen service than your service temp. Tube sheet was > 250 mm thick of P 5 with Inconel overlay and P 5 with hydrogen partial pressure of > 2000 PSIG and temperature around 350 - 370 deg cent. Your service pressuer and temp is far lower than those. I personally feel / think that you should get over mental reservations. Trust this is of help to you C.V.Srinivasan Nishi Engineers Pvt Ltd India Feb 18 E-mail:nishi@vsnl.com >Mr. C.V.Srinivasan > >Once again thank you very much for your useful inputs. > >After PWHT requirements for strength welds of tubes into the >tube sheet headers, to meet MR0175 and MR0103 requirements >we have to control the hardness of tube sheet to tube >strength weld joints in a way to have less than 22 Rockwell. > >Through Header boxes plugholes is not possible to measure >the hardness of tube-to-tube sheet strength welds. This is >the reason why we are questioning the project > > >Receive my best regards > >Luis Marques
 
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2/17/2006 9:00 AM
 
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(1) as per the latest NACE requirement , I believe Hardness requirement is 200BHN ( %7E 18 HRC) max. KIndly review. (2) Yes , in-situ confirmatory ( before and after PWHT) measurement of hardness at tube-to-tubesheet strength fillets are really difficult. But small pin arial type instruments are nowadys available. You can try. Also you can make simulator test piece and can test before and after PWHT alongwith Job. regards DM
 
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