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Discussion Forums - The Hendrix Group
HomeHomeDiscussionsDiscussionsMaterial Select...Material Select...Temper embrittlement of HTLA Steels like P22 - Effect oTemper embrittlement of HTLA Steels like P22 - Effect o
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10/23/2007 9:00 AM
 
w.r.t. the subject issue, It has been recognised that "Sb" has the highest susceptibility towards Temper Embrittlement though it's presence in the MOC chemistry is near nil. It has been also realised that "Mo" and "W" has some beneficial scavenging effect towards the principle contributer of Temper embrittlement i.e. "P". It is also known that very trace amount of Sb is harmful w.r.t. the issue. It has been researched out that even 405 ppm of the trace elements are present, embrittled FATT ( Fracture appearance transition temperature ) reaches a minimum -45%C2°C. Now our intent is to keep FATT subzero so that above RT the MOC remains ductile and practically effect free from temper embrittlement. The question is for P22, P11 Material if by chance there exists chemical occulation of "Sb" which is being reflected by PMI or wet chemical analysis at the Receiving Inspection Stage can be be a cause of rejection w.r.t. it's embrittlement issue in-service ?
 
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10/24/2007 9:00 AM
 
Debasis Temper embrittlement of P 22 / P 11 is a long term effect and service exposure. This forum has discussed many times about this. Answering your doubt or question : In a specific P.O which has categorically specified that user would be looking for analysis of trace elements whose contribution to temper embrittlement will be considered or given importance at the receiving stage of acceptance, then as a purchaser you can reject at the receiving inspection stage (whether P or Sb or any other likely occluded elements that can cause deleterious effect on long term service performance viz., temper embrittlement, creep, fatigue etc type of deterioration). If at the time of P.O such categorical specific need and analysis is not given, then raising a theoretical doubt on performance of low alloy materials like P 22 or P 11 which had proved to be successful, for different types of industries all over the world, with good long service performance, i guess it would be difficult reason for the user to reject. Notional fear or doubt based on theoretical search results of research publications is more of academic interest to the user of P 22 or P 11. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Oct 24, 2007 E-mail: nishi@vsnl.com >w.r.t. the subject issue, It has been recognised that "Sb" >has the highest susceptibility towards Temper Embrittlement >though it's presence in the MOC chemistry is near nil. It >has been also realised that "Mo" and "W" has some beneficial >scavenging effect towards the principle contributer of >Temper embrittlement i.e. "P". > >It is also known that very trace amount of Sb is harmful >w.r.t. the issue. It has been researched out that even 405 >ppm of the trace elements are present, embrittled FATT ( >Fracture appearance transition temperature ) reaches a >minimum -45%C2°C. Now our intent is to keep FATT subzero so >that above RT the MOC remains ductile and practically effect >free from temper embrittlement. > >The question is for P22, P11 Material if by chance there >exists chemical occulation of "Sb" which is being reflected >by PMI or wet chemical analysis at the Receiving Inspection >Stage can be be a cause of rejection w.r.t. it's >embrittlement issue in-service ?
 
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