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[MW:12209] RE: 12202- Normalizing of T91 Bends

By Materials & Welding

Thanks Mr. P. Goswami for useful information provided. One more thing I want to clarify.

 Can we consider the strain percentage as the percentage of reduction of wall thickness during cold bending ? if not how can we measure that on return bend (180 degree) of 38 OD tube on 48 bending radius.

 

regards

Ravinder

 

From: pgoswami [mailto:pgoswami@quickclic.net]
Sent: Saturday, August 13, 2011 6:09 AM
To: materials-welding@googlegroups.com
Cc: ravinder@isgec.com
Subject: MW: 12202- Normalizing of T91 Bends

 

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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