Hi Mr. Ravinder,
Please see Table PG-20, of ASME Sec-1, 2010 edition. If the forming strain is > 20% then bends shall be normalized and tempered, if the strain is between 5-20%, bends shall be heat treated as per the notes in the table ( which is stress relieving or Normalized + Tempered depending on the strain level during forming).
If you have access to API TR 938-B- Use of 9Cr-1Mo-V steel in oil refining operations the recommendations of this technical report is as follows:-
6.2 Cold Bending:-Cold bending is typically performed after post weld heat treatment because 9Cr-1Mo-V steels in the as welded condition are very hard. The degree of cold working is usually limited to 17 % maximum (wall thickness reduction), if steels are applied at creep range temperatures. Most users would require that cold worked 9Cr-1Mo-V steels be normalized and tempered if the steels are applied in the creep range and the degree of cold working exceeds 17 %. Cold deformation requires heat treatment by most codes for deformation greater than 5 %.
Thanks.
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Ravinder Sharma
Sent: Friday, August 12, 2011 4:05 AM
To: 'Ravinder Sharma'; materials-welding@googlegroups.com
Subject: [MW:12202] Normalising of T91 Bends
Can anybody tell me the condition where it is mandatory to do normalizing on
T91 bends.
regards
Ravinder
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